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Available online
, doi: 10.7541/2018.119
Abstract:
It has been discovered that low-head dam could impact local habitat conditions, and alter fish assemblages in streams. However, how fish assemblages respond to the size and function of low-head dams is still not clear. Based on the data collected from 15 impounding segments upstream and 15 plunging areas downstream of low-head dams in the Wannan Mountains at July and November 2016, respectively, we examined how habitat factors and fish assemblages varied seasonally, and the differences in their response to dam size and function. Furtherly, after classifying the collected samples into two types (indigenous species and native-invasive species), we determined whether the indigenous fishes and native-invasive fishes were different in their responses to dam disturbance. A total of 24 fish species representing four orders and ten families were collected, including 11 indigenous species and 13 native-invasive species. Although fish assemblages in the plunging areas did not vary seasonally, the assemblages in the impounding areas was significantly different between July and November, where fishes were more abundant in November than in July. Only the assemblage structure of native-invasive fishes in the plunging areas was influenced by dam size. However, both native fish assemblages in the impounding areas and native-invasive fish assemblages in the plunging areas showed difference in their response to the between-dam-function, suggesting that dam function was more important in impacting fish assemblages than dam size. Compared to those associated with the impounding dams, the irrigating dams had less Zacco platypus but more Cobitis sinensis and Ctenogobius spp. in the impounding areas, and more Rhodeus ocellatus and Misgurnus anguillicaudatus in the plunging areas. In addition, the response of the whole fish assemblages (including both indigenous and native-invasive species) to dam disturbance was similar to the indigenous fish assemblages, instead of the native-invasive fish assemblages. Our results suggest that, in this study area, dam function was more important in influencing local fish assemblages than dam size. Due to their potential differences in response to dam disturbance for the indigenous species and native-invasive species, it is necessary for us to distinguish these two types of species when we assess how anthropogenic activities affect fish diversity in streams.
It has been discovered that low-head dam could impact local habitat conditions, and alter fish assemblages in streams. However, how fish assemblages respond to the size and function of low-head dams is still not clear. Based on the data collected from 15 impounding segments upstream and 15 plunging areas downstream of low-head dams in the Wannan Mountains at July and November 2016, respectively, we examined how habitat factors and fish assemblages varied seasonally, and the differences in their response to dam size and function. Furtherly, after classifying the collected samples into two types (indigenous species and native-invasive species), we determined whether the indigenous fishes and native-invasive fishes were different in their responses to dam disturbance. A total of 24 fish species representing four orders and ten families were collected, including 11 indigenous species and 13 native-invasive species. Although fish assemblages in the plunging areas did not vary seasonally, the assemblages in the impounding areas was significantly different between July and November, where fishes were more abundant in November than in July. Only the assemblage structure of native-invasive fishes in the plunging areas was influenced by dam size. However, both native fish assemblages in the impounding areas and native-invasive fish assemblages in the plunging areas showed difference in their response to the between-dam-function, suggesting that dam function was more important in impacting fish assemblages than dam size. Compared to those associated with the impounding dams, the irrigating dams had less Zacco platypus but more Cobitis sinensis and Ctenogobius spp. in the impounding areas, and more Rhodeus ocellatus and Misgurnus anguillicaudatus in the plunging areas. In addition, the response of the whole fish assemblages (including both indigenous and native-invasive species) to dam disturbance was similar to the indigenous fish assemblages, instead of the native-invasive fish assemblages. Our results suggest that, in this study area, dam function was more important in influencing local fish assemblages than dam size. Due to their potential differences in response to dam disturbance for the indigenous species and native-invasive species, it is necessary for us to distinguish these two types of species when we assess how anthropogenic activities affect fish diversity in streams.
,
Available online
, doi: 10.7541/2018.111
Abstract:
β2-microglobulin plays an important role in the immune system of fish as an essential subunit of MHC class I molecules. We identified 30 SNPs in the β2m gene by directly sequencing method from the parents (P0) of Oreochromis niloticus. The results showed that 1 SNP located in 5′UTR, 17 SNPs located in the exon region (16 synonymous mutations, a synonymous mutation site), 9 SNPs located in the intron region, and 4 SNPs located in the 3′UTR. Snapshot method was used to genotype 102 resistant individuals and 102 susceptible individuals of F1 generation. The genetic parameters such as He, Ho, Ne and PIC of SNPs of β2m gene in Nile tilapia were analyzed with Popgen 32 and PIC-CALC software. The results indicated that 7 SNPs in the susceptible group were moderate polymorphism (0.25<PIC<0.5), and 25 SNPs in the resistant group were moderate polymorphism (0.25<PIC<0.5). In order to reveal its correlation with streptococcal resistant or susceptible traits, the genotype and allele frequencies of 30 SNPs in both resistant and susceptible groups of F1 generation were analyzed by SPSS 23.0 software. These results indicated that 24 SNPs were significantly associated with the streptococcal resistant or susceptible trait (P<0.05). The results of linkage disequilibrium analysis showed that 30 SNPs formed 4 haplotype blocks and 14 haplotypes. 4 haplotypes were significantly associated with streptococcal susceptible trait, and 4 haplotypes were significantly associated with streptococcal resistance trait (P<0.05). Haplotype block 2 and block 3 were two htSNPs inβ2m gene, which contain 4 SNPs and 13 SNPs, respectively, and highly link with each other (r2> 0.9). In this study, the SNPs and haplotypes associated with streptococcal resistant or susceptible traits can be applied to the breeding of streptococcicosis-resistant Nile tilapia as potential markers.
β2-microglobulin plays an important role in the immune system of fish as an essential subunit of MHC class I molecules. We identified 30 SNPs in the β2m gene by directly sequencing method from the parents (P0) of Oreochromis niloticus. The results showed that 1 SNP located in 5′UTR, 17 SNPs located in the exon region (16 synonymous mutations, a synonymous mutation site), 9 SNPs located in the intron region, and 4 SNPs located in the 3′UTR. Snapshot method was used to genotype 102 resistant individuals and 102 susceptible individuals of F1 generation. The genetic parameters such as He, Ho, Ne and PIC of SNPs of β2m gene in Nile tilapia were analyzed with Popgen 32 and PIC-CALC software. The results indicated that 7 SNPs in the susceptible group were moderate polymorphism (0.25<PIC<0.5), and 25 SNPs in the resistant group were moderate polymorphism (0.25<PIC<0.5). In order to reveal its correlation with streptococcal resistant or susceptible traits, the genotype and allele frequencies of 30 SNPs in both resistant and susceptible groups of F1 generation were analyzed by SPSS 23.0 software. These results indicated that 24 SNPs were significantly associated with the streptococcal resistant or susceptible trait (P<0.05). The results of linkage disequilibrium analysis showed that 30 SNPs formed 4 haplotype blocks and 14 haplotypes. 4 haplotypes were significantly associated with streptococcal susceptible trait, and 4 haplotypes were significantly associated with streptococcal resistance trait (P<0.05). Haplotype block 2 and block 3 were two htSNPs inβ2m gene, which contain 4 SNPs and 13 SNPs, respectively, and highly link with each other (r2> 0.9). In this study, the SNPs and haplotypes associated with streptococcal resistant or susceptible traits can be applied to the breeding of streptococcicosis-resistant Nile tilapia as potential markers.
,
Available online
, doi: 10.7541/2018.117
Abstract:
Myxobolus haichengensis Chen, 1958 forms numerous small plasmodia on the gill filaments of wild cyprinid Abbottina rivularis Basilewaky. The species described originally was lacking important characters, which made the accurate identification difficult. Here, we supplemented its characteristics with morphological and molecular data. Plasmodia of M. haichengensis are oval. Mature spores are ellipsoidal-shaped in frontal view and fusiform-shaped in lateral view, measuring (10.8±0.7) μm (10.1—11.5 μm) long, (8.1±0.5) μm (7.5—9.0 μm) wide, and (5.7±0.4) μm (5.2—9.0 μm) thick; two unequal polar capsule are pyriform with tapering anterior, large polar capsule averaging (4.7±0.5) μm (4.8—6.7 μm) long and (2.5±0.2) μm (3.2—4.3 μm) wide; small polar capsule averaging (4.4±0.2) μm (4.1—4.8 μm) long and (2.2±0.1) μm (2.0—2.5 μm) wide; polar filaments coil with four to five turns. The nuclear 18S rDNA sequence was obtained and deposited in GenBank (KY965936), and sequences alignment analyses revealed that M. haichengensis was most similar with the actinosporean Hexactinomyxon type 2 (AY162272, 97%) released from the freshwater tublificid oligochaete Limnodrilus hoffmeisteri.
Myxobolus haichengensis Chen, 1958 forms numerous small plasmodia on the gill filaments of wild cyprinid Abbottina rivularis Basilewaky. The species described originally was lacking important characters, which made the accurate identification difficult. Here, we supplemented its characteristics with morphological and molecular data. Plasmodia of M. haichengensis are oval. Mature spores are ellipsoidal-shaped in frontal view and fusiform-shaped in lateral view, measuring (10.8±0.7) μm (10.1—11.5 μm) long, (8.1±0.5) μm (7.5—9.0 μm) wide, and (5.7±0.4) μm (5.2—9.0 μm) thick; two unequal polar capsule are pyriform with tapering anterior, large polar capsule averaging (4.7±0.5) μm (4.8—6.7 μm) long and (2.5±0.2) μm (3.2—4.3 μm) wide; small polar capsule averaging (4.4±0.2) μm (4.1—4.8 μm) long and (2.2±0.1) μm (2.0—2.5 μm) wide; polar filaments coil with four to five turns. The nuclear 18S rDNA sequence was obtained and deposited in GenBank (KY965936), and sequences alignment analyses revealed that M. haichengensis was most similar with the actinosporean Hexactinomyxon type 2 (AY162272, 97%) released from the freshwater tublificid oligochaete Limnodrilus hoffmeisteri.
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Available online
, doi: 10.7541/2018.110
Abstract:
GPR54 is the cognate receptor of Kisspeptin, which plays a significant role in fish reproduction regulation by acting on the Gonadotropin-Releasing Hormone (GnRH). In order to study the regulation of GnRH by Kisspeptin/GPR54 system in the Dabry’s sturgeon (Acipenser dabryanus), the full-length cDNAs of two gpr54 genes were cloned, which were designated as dsgpr54-1 and dsgpr54-2, encoding 379 and 368 amino acids, respectively. Multiple amino acid sequences alignment and evolutionary tree analysis indicated that Gpr54 of Dabry's sturgeon shared higher sequence identities and closer evolutionary distances with its counterparts in tetrapods. By quantitative real-time PCR, it showed that dsgpr54-1 were transcribed in both gonad (testis and ovary) and brain (hypothalamus, pituitary, mesencephalon and telencephalon) with the highest transcription level in the hypothalamus. Conversely, dsgpr54-2 was only found in the brain, with high expression levels in the pituitary, mesencephalon and hypothalamus. In order to investigate whether gpr54 could regulate the expression of gnrh in the hypothalamus by combined to its ligand Kisspeptin, decapeptides of both Kiss-1 and Kiss-2 (10 nmol/L and 1000 nmol/L) of Dabry's sturgeon were synthesized and injected to the peritoneal cavities of 9 month juveniles. It showed by quantitative real-time PCR that both the two doses of Kiss-1 and Kiss-2 injection induced the increase of gpr54 expression, and 10 nmol/L Kiss-2 injection increased the transcription of dsgpr54-2 significantly (P<0.05). Besides, both two doses of Kiss-1 injection reduced thegnrh expression. However, 10 nmol/L Kiss-2 injection caused the increase of the gnrh1 expression and the decrease of gnrh2 expression, while in the 1000 nmol/L Kiss-2 injection group, gnrh1 expression decreased with no changes of the gnrh2 transcription. The above results revealed that both the two gpr54 genes could bind to its ligands kiss-1 and kiss-2, but with receptor-ligand selection discrepancy. Kiss-1 and Kiss-2 regulate the gnrh expression differently by activating their receptor GPR54 in the hypothalamus of Dabry’s sturgeon.
GPR54 is the cognate receptor of Kisspeptin, which plays a significant role in fish reproduction regulation by acting on the Gonadotropin-Releasing Hormone (GnRH). In order to study the regulation of GnRH by Kisspeptin/GPR54 system in the Dabry’s sturgeon (Acipenser dabryanus), the full-length cDNAs of two gpr54 genes were cloned, which were designated as dsgpr54-1 and dsgpr54-2, encoding 379 and 368 amino acids, respectively. Multiple amino acid sequences alignment and evolutionary tree analysis indicated that Gpr54 of Dabry's sturgeon shared higher sequence identities and closer evolutionary distances with its counterparts in tetrapods. By quantitative real-time PCR, it showed that dsgpr54-1 were transcribed in both gonad (testis and ovary) and brain (hypothalamus, pituitary, mesencephalon and telencephalon) with the highest transcription level in the hypothalamus. Conversely, dsgpr54-2 was only found in the brain, with high expression levels in the pituitary, mesencephalon and hypothalamus. In order to investigate whether gpr54 could regulate the expression of gnrh in the hypothalamus by combined to its ligand Kisspeptin, decapeptides of both Kiss-1 and Kiss-2 (10 nmol/L and 1000 nmol/L) of Dabry's sturgeon were synthesized and injected to the peritoneal cavities of 9 month juveniles. It showed by quantitative real-time PCR that both the two doses of Kiss-1 and Kiss-2 injection induced the increase of gpr54 expression, and 10 nmol/L Kiss-2 injection increased the transcription of dsgpr54-2 significantly (P<0.05). Besides, both two doses of Kiss-1 injection reduced thegnrh expression. However, 10 nmol/L Kiss-2 injection caused the increase of the gnrh1 expression and the decrease of gnrh2 expression, while in the 1000 nmol/L Kiss-2 injection group, gnrh1 expression decreased with no changes of the gnrh2 transcription. The above results revealed that both the two gpr54 genes could bind to its ligands kiss-1 and kiss-2, but with receptor-ligand selection discrepancy. Kiss-1 and Kiss-2 regulate the gnrh expression differently by activating their receptor GPR54 in the hypothalamus of Dabry’s sturgeon.
,
Available online
, doi: 10.7541/2018.116
Abstract:
The enteric microsporidiosis of hatchery-bred juvenile grouper, Epinephelus spp., is the most important in the mariculture area off coast of South China Sea in recent years, however, the taxonomy of the causative agent remains unknown. In this study, histopathological, ultrastructural and molecular evidences were provided to identify the aetiological agent, designated herein as Enterospora epinepheli sp. n.. The intranuclear development of the present species was consistent with Enterospora canceri, the type species of Enterospora genus. The early stages of uninucleate meronts were observed within the infected nuclei, separating from the host nucleus by a simple electron dense membrane. Later, the uninucleate meronts transformed into multinucleate plasmodia (merogonial plasmodia). At this stage, the infected nuclei were hypertrophic, or even ruptured by the multinucleate plasmodia. Sporogonial plasmodia were characterized by the appearance of multiple, small, spherical, membrane-bound vesciles. Then, multiple copies of these membrane-bound vesciles developed into the precursors of the polar filament and anchoring disk of mature spore which surrounded the diplokaryotic nuclei. With the development, sporoblasts separated from the plasmodia by successive division and direct development to mature spores. Mature spores were oval, in direct contact with host nucleus. Spores measured 1.56±0.31 (1.07—1.96) μm in length and 1.08±0.98 (0.93—1.28) μm in width. The spore walls were trilaminar, including an electron dense exospore coat [15.51±0.95 nm (9.87—26.18 nm) thick], surrounding a thick electron lucent endospore [(81.13±2.71) nm (57.16—110.81 nm) thick] and the plasma membrane. The polar filaments were isofilar, coiled with 5—6 turns in two rows. Histopathological analysis clearly revealed that the spores located in the nucleus of goblet cell of the intestinal epithelial and a large amount of spores appeared in the intestinal contents with the shedding necrotic infected enterocytes. Molecular analysis indicated that genetic distances ofEnterospora epinepheli sp. n. form the species of Enterocytozoondiae ranged from 0.162 to 0.225 which was generally out of intraspecies variation. Phylogenetic analysis revealed that the species of Enterocytozoondiae could separate into Clade Ⅰand Clade Ⅱ, and Enterospora epinepheli sp. n. was an independent lineage, clustering with Enterospora hepatopenaei, E. nucleophilia, E. canceri and Enterocyozoon bieneusi within the Clade Ⅱ.
The enteric microsporidiosis of hatchery-bred juvenile grouper, Epinephelus spp., is the most important in the mariculture area off coast of South China Sea in recent years, however, the taxonomy of the causative agent remains unknown. In this study, histopathological, ultrastructural and molecular evidences were provided to identify the aetiological agent, designated herein as Enterospora epinepheli sp. n.. The intranuclear development of the present species was consistent with Enterospora canceri, the type species of Enterospora genus. The early stages of uninucleate meronts were observed within the infected nuclei, separating from the host nucleus by a simple electron dense membrane. Later, the uninucleate meronts transformed into multinucleate plasmodia (merogonial plasmodia). At this stage, the infected nuclei were hypertrophic, or even ruptured by the multinucleate plasmodia. Sporogonial plasmodia were characterized by the appearance of multiple, small, spherical, membrane-bound vesciles. Then, multiple copies of these membrane-bound vesciles developed into the precursors of the polar filament and anchoring disk of mature spore which surrounded the diplokaryotic nuclei. With the development, sporoblasts separated from the plasmodia by successive division and direct development to mature spores. Mature spores were oval, in direct contact with host nucleus. Spores measured 1.56±0.31 (1.07—1.96) μm in length and 1.08±0.98 (0.93—1.28) μm in width. The spore walls were trilaminar, including an electron dense exospore coat [15.51±0.95 nm (9.87—26.18 nm) thick], surrounding a thick electron lucent endospore [(81.13±2.71) nm (57.16—110.81 nm) thick] and the plasma membrane. The polar filaments were isofilar, coiled with 5—6 turns in two rows. Histopathological analysis clearly revealed that the spores located in the nucleus of goblet cell of the intestinal epithelial and a large amount of spores appeared in the intestinal contents with the shedding necrotic infected enterocytes. Molecular analysis indicated that genetic distances ofEnterospora epinepheli sp. n. form the species of Enterocytozoondiae ranged from 0.162 to 0.225 which was generally out of intraspecies variation. Phylogenetic analysis revealed that the species of Enterocytozoondiae could separate into Clade Ⅰand Clade Ⅱ, and Enterospora epinepheli sp. n. was an independent lineage, clustering with Enterospora hepatopenaei, E. nucleophilia, E. canceri and Enterocyozoon bieneusi within the Clade Ⅱ.
,
Available online
, doi: 10.7541/2018.127
Abstract:
This study investigated the effects of Cd2+ on the biomass, chlorophyll a content, phycoerythrin content and ATP content, the maximum quantum yield of PSII (Fv/Fm), the effective photochemical yield of PSII (YII), the relative electron transfer rate (ETR) and non-photochemical fluorescence of quenching (NPQ) of the Porphyridium purpureum. The results showed that the growth rate of P. purpureum decreased significantly by the stress of Cd2+ in a dosage-dependent pattern. The content of chlorophyll a, phycoerythrin and ATP decreased significantly by Cd2+ stress with a dose-dependent way. The chlorophyll fluorescence parameters (Fv/Fm, YII and ETR) under Cd2+ stress were significantly lower than those of the control groups and decreased rapidly with increased Cd2+ concentration. NPQ value increased significantly at low Cd2+ (<200 μmol/L) and decreased significantly at high Cd2+ (>500 μmol/L). Therefore, the gorwth and phtochemical activities ofPorphyridium purpureum would be significantly affected by the concentration of the Cd2+ above 5 μmol/L and the accumulation of Cd2+ would have an impact on the ecological balance of the Porphyridium purpureum in aquatic environment.
This study investigated the effects of Cd2+ on the biomass, chlorophyll a content, phycoerythrin content and ATP content, the maximum quantum yield of PSII (Fv/Fm), the effective photochemical yield of PSII (YII), the relative electron transfer rate (ETR) and non-photochemical fluorescence of quenching (NPQ) of the Porphyridium purpureum. The results showed that the growth rate of P. purpureum decreased significantly by the stress of Cd2+ in a dosage-dependent pattern. The content of chlorophyll a, phycoerythrin and ATP decreased significantly by Cd2+ stress with a dose-dependent way. The chlorophyll fluorescence parameters (Fv/Fm, YII and ETR) under Cd2+ stress were significantly lower than those of the control groups and decreased rapidly with increased Cd2+ concentration. NPQ value increased significantly at low Cd2+ (<200 μmol/L) and decreased significantly at high Cd2+ (>500 μmol/L). Therefore, the gorwth and phtochemical activities ofPorphyridium purpureum would be significantly affected by the concentration of the Cd2+ above 5 μmol/L and the accumulation of Cd2+ would have an impact on the ecological balance of the Porphyridium purpureum in aquatic environment.
,
Available online
, doi: 10.7541/2018.107
Abstract:
One of the serious problems in aqua-cultural yellow catfish is that the background of female parents is confused. It is particularly important to establish all-female families for the all-male and hybrid yellow catfish production, in which sex-reversal of XX female to XX male is a key step. Development of sex chromosome-linked markers provides a technical support for the identification of XX males in yellow catfish. In this study, different concentrations of 17α-methyltestosterone (MT) and aromatase inhibitor letrozole (LZ) were used for 54 days to treat yellow catfish (7 to 60 days post fertilization). The survival rate, body length, and body weight of each group were measured at 61 days after fertilization (61 days post fertilization). Gonadal structure was observed and histologically analyzed in XX individuals that were identified by sex-linked markers. As a result, MT and LZ treatments had no significant effects on the survival rate when compared with the control group. In addition, the XX gonad treated by MT showed seminal vesicles and could not be reversed into functional testis. However, appropriate dose of LZ could induce the sex-reversal of XX female to normal XX male, and the induction effect was enhanced with the increase of dose as well. The XX male could normally mate with XX female and YY female, which demonstrated appropriate reproductive ability. The present study proposed a reliable method to create XX male using the aromatase inhibitor LZ, which lays the foundation for the breed improvement of all-male yellow catfish and cultivation of new varieties of yellow catfish.
One of the serious problems in aqua-cultural yellow catfish is that the background of female parents is confused. It is particularly important to establish all-female families for the all-male and hybrid yellow catfish production, in which sex-reversal of XX female to XX male is a key step. Development of sex chromosome-linked markers provides a technical support for the identification of XX males in yellow catfish. In this study, different concentrations of 17α-methyltestosterone (MT) and aromatase inhibitor letrozole (LZ) were used for 54 days to treat yellow catfish (7 to 60 days post fertilization). The survival rate, body length, and body weight of each group were measured at 61 days after fertilization (61 days post fertilization). Gonadal structure was observed and histologically analyzed in XX individuals that were identified by sex-linked markers. As a result, MT and LZ treatments had no significant effects on the survival rate when compared with the control group. In addition, the XX gonad treated by MT showed seminal vesicles and could not be reversed into functional testis. However, appropriate dose of LZ could induce the sex-reversal of XX female to normal XX male, and the induction effect was enhanced with the increase of dose as well. The XX male could normally mate with XX female and YY female, which demonstrated appropriate reproductive ability. The present study proposed a reliable method to create XX male using the aromatase inhibitor LZ, which lays the foundation for the breed improvement of all-male yellow catfish and cultivation of new varieties of yellow catfish.
,
Available online
, doi: 10.7541/2018.128
Abstract:
In this research, the effects of different concentrations of melatonin (MLT) on the growth, accumulation of astaxanthin, reactive oxygen species (ROS), signal molecules, and the expression of DXS were studied in Haematococcus pluvialis LUGU under abiotic stress conditions (e.g., high light, nitrogen starvation, etc.). The results showed that the astaxanthin content was efficiently enhanced in alga cells treated with 10 μmol/L of MLT, the maximum astaxanthin content achieved was 31.32 mg/g, being 2.36 times higher than that of the control. In addition, MLT inhibited intracellular ROS levels and up-regulated the content of signaling molecules (nitric oxide and salicylic acid). Additionally, the relative expression level of DXS gene was increased by 11.3-fold higher than that of control. These results demonstrated that the massive accumulation of astaxanthin in Haematococcus pluvialis is associated with the regulation of intracellular ROS, signaling molecules, and gene expression by exogenous MLT under abiotic stress conditions.
In this research, the effects of different concentrations of melatonin (MLT) on the growth, accumulation of astaxanthin, reactive oxygen species (ROS), signal molecules, and the expression of DXS were studied in Haematococcus pluvialis LUGU under abiotic stress conditions (e.g., high light, nitrogen starvation, etc.). The results showed that the astaxanthin content was efficiently enhanced in alga cells treated with 10 μmol/L of MLT, the maximum astaxanthin content achieved was 31.32 mg/g, being 2.36 times higher than that of the control. In addition, MLT inhibited intracellular ROS levels and up-regulated the content of signaling molecules (nitric oxide and salicylic acid). Additionally, the relative expression level of DXS gene was increased by 11.3-fold higher than that of control. These results demonstrated that the massive accumulation of astaxanthin in Haematococcus pluvialis is associated with the regulation of intracellular ROS, signaling molecules, and gene expression by exogenous MLT under abiotic stress conditions.
,
Available online
, doi: 10.7541/2018.122
Abstract:
A 42-day feeding trial was conducted to investigate the effects of α-ketoglutarate (α-KG) on gill Na+/K+-ATPase activity and blood biochemical parameters of grass carp, Ctenopharyngodon idellus, exposure to ammonia. A total of 270 individuals [initial body weight: (24.79±0.11) g] were randomly assigned to 9 tanks, and these tanks were divided into three groups (Ⅰ: treated with 1.51 mg/L of aerated water and basal diet; Ⅱ: treated with 18.37 mg/L of ammonia solution and basal diet; Ⅲ: treated with 18.37 mg/L of ammonia solution and 0.75% α-KG added diet), with three replicates per each group (n=30). Experimental fish were sampled on 1st, 14th, 28th, and 42 days, respectively. The results showed that: (1) diet α-KG could effectively alleviate a significant increase in the content of plasma ammonia on the 1st day, the activity of plasma aspartate transaminase on 14th day and plasma alkaline phosphatase on 28th day, which were caused as being exposure to ammonia; diet α-KG could effectively alleviate a significant decrease in the activity of gill Na+/K+-ATPase on 28th day, plasma alanine aminotransferase on 28th and 42th days, and the content of plasma urea on 28th day because of being exposure to ammonia. Diet α-KG could significantly increase plasma globulin content on 28th day exposure to ammonia. In conclusion, dietary α-KG could alleviate the increase of plasma ammonia content exposure to ammonia, and maintain the stabilization in the activity of gill Na+/K+-ATPase, plasma alanine transaminase (ALT), plasma aspartate aminotransferase (AST), plasma alkaline phosphatase (ALP), and the content of GLB, as well as urea in grass carp exposure to ammonia.
A 42-day feeding trial was conducted to investigate the effects of α-ketoglutarate (α-KG) on gill Na+/K+-ATPase activity and blood biochemical parameters of grass carp, Ctenopharyngodon idellus, exposure to ammonia. A total of 270 individuals [initial body weight: (24.79±0.11) g] were randomly assigned to 9 tanks, and these tanks were divided into three groups (Ⅰ: treated with 1.51 mg/L of aerated water and basal diet; Ⅱ: treated with 18.37 mg/L of ammonia solution and basal diet; Ⅲ: treated with 18.37 mg/L of ammonia solution and 0.75% α-KG added diet), with three replicates per each group (n=30). Experimental fish were sampled on 1st, 14th, 28th, and 42 days, respectively. The results showed that: (1) diet α-KG could effectively alleviate a significant increase in the content of plasma ammonia on the 1st day, the activity of plasma aspartate transaminase on 14th day and plasma alkaline phosphatase on 28th day, which were caused as being exposure to ammonia; diet α-KG could effectively alleviate a significant decrease in the activity of gill Na+/K+-ATPase on 28th day, plasma alanine aminotransferase on 28th and 42th days, and the content of plasma urea on 28th day because of being exposure to ammonia. Diet α-KG could significantly increase plasma globulin content on 28th day exposure to ammonia. In conclusion, dietary α-KG could alleviate the increase of plasma ammonia content exposure to ammonia, and maintain the stabilization in the activity of gill Na+/K+-ATPase, plasma alanine transaminase (ALT), plasma aspartate aminotransferase (AST), plasma alkaline phosphatase (ALP), and the content of GLB, as well as urea in grass carp exposure to ammonia.
,
Available online
, doi: 10.7541/2018.131
Abstract:
The ecological risk of a Microcystis bloom was evaluated on the basis of the ecotoxicological risk assessment method. The effects of Microcystis bloom on benthic fauna, zooplankton, fish, and submerged macrophytes were assessed by using acute and chronic exposures experiments and the findings reported by previous studies. The algal cell densities were calculated by using toxicity percentile rank (TPR) method, and aquatic ecological risk assessment for Microcystis bloom was performed by using risk quotient approach. The criteria required for acute and chronic ecological risk assessment of Microcystis bloom were defined based on the algal cell density, algal bloom coverage in lake, as well as duration of algae blooms. The acute ecological risk was classified as low-, moderate-, and high- levels. A Microcystis bloom with cell density less than 3.4×106 cells/L was defined as low risk-level, with cell density at the range of 3.4×106—3.4×107 cells/L was denoted as moderate-risk level, and with cell density higher than 3.4×107 cells/L was defined as high-risk level. Similarly, chronic ecological risk of Microcystis bloom was also classified as low-, moderate-, and high-levels of risk. The Microcystis bloom with cell density less than 1.1×106 cells/L was classified as low risk, cell density between 1.1×106—1.1×107 cells/L was classified as moderate risk, and the cell density greater than 1.1×107 cells/L was classified as high risk. In practical applications, cell density, algal bloom coverage, and duration of algal blooms are essential factors to formulate a robust ecological risk assessment strategy for Microcystis bloom in Erhai Lake. In presence of moderate-risk level, early warning of Microcystis bloom should be alarmed, and improvement of water quality or implementation of biological control should be carried out. Under the high risk level, emergent removal or control of algal bloom should be undertaken as well.
The ecological risk of a Microcystis bloom was evaluated on the basis of the ecotoxicological risk assessment method. The effects of Microcystis bloom on benthic fauna, zooplankton, fish, and submerged macrophytes were assessed by using acute and chronic exposures experiments and the findings reported by previous studies. The algal cell densities were calculated by using toxicity percentile rank (TPR) method, and aquatic ecological risk assessment for Microcystis bloom was performed by using risk quotient approach. The criteria required for acute and chronic ecological risk assessment of Microcystis bloom were defined based on the algal cell density, algal bloom coverage in lake, as well as duration of algae blooms. The acute ecological risk was classified as low-, moderate-, and high- levels. A Microcystis bloom with cell density less than 3.4×106 cells/L was defined as low risk-level, with cell density at the range of 3.4×106—3.4×107 cells/L was denoted as moderate-risk level, and with cell density higher than 3.4×107 cells/L was defined as high-risk level. Similarly, chronic ecological risk of Microcystis bloom was also classified as low-, moderate-, and high-levels of risk. The Microcystis bloom with cell density less than 1.1×106 cells/L was classified as low risk, cell density between 1.1×106—1.1×107 cells/L was classified as moderate risk, and the cell density greater than 1.1×107 cells/L was classified as high risk. In practical applications, cell density, algal bloom coverage, and duration of algal blooms are essential factors to formulate a robust ecological risk assessment strategy for Microcystis bloom in Erhai Lake. In presence of moderate-risk level, early warning of Microcystis bloom should be alarmed, and improvement of water quality or implementation of biological control should be carried out. Under the high risk level, emergent removal or control of algal bloom should be undertaken as well.
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Available online
, doi: 10.7541/2018.123
Abstract:
In order to explore a proper bait of larva and adult fish Gobiocypris rarus, we randomly divided hatchetfish, 35 day after hatching, into five groups: Group A was fed with Artemia nauplii; Group B was fed with A. nauplii for 6 days, and was fed with commercial micro pellet diet for 1 day per week; Group C was fed with A. nauplii for half a week, and was fed with artificial diet for another half a week; Group D group was fed with A. nauplii for 1 day per week, and was fed with artificial diet for 6 days per week; Group E was fed the artificial diet. Each group was fed with a feeding satiation strategy. Each 2 weeks, growth and survival indicators were counted until 21st week (147th day). Reproductive capacity and offspring abnormal rate were calculated after spawning. The gonads obtained in 17th week (119th day) were used for histological studies. The results showed that: (1) In group E group, survival and specific growth rates were significantly lower than other groups (P < 0.05); (2) reproductive capacity of group B was significantly higher than other groups ( P < 0.05); (3) different feeding strategies had no significant effect on testis maturity, while had influence on ovarian maturation. The results of this study suggest that addition of A. nauplii contains superior results than single feeding with commercial micro pellet diet, which was more conducive to the growth and reproduction of G. rarus. We suggested that optimal feeding ratio for A. nauplii and commercial micro pellet diet is 6:1, that would be more appropriate for larvae and juvenile G. rarus in the process of standardized cultivation.
In order to explore a proper bait of larva and adult fish Gobiocypris rarus, we randomly divided hatchetfish, 35 day after hatching, into five groups: Group A was fed with Artemia nauplii; Group B was fed with A. nauplii for 6 days, and was fed with commercial micro pellet diet for 1 day per week; Group C was fed with A. nauplii for half a week, and was fed with artificial diet for another half a week; Group D group was fed with A. nauplii for 1 day per week, and was fed with artificial diet for 6 days per week; Group E was fed the artificial diet. Each group was fed with a feeding satiation strategy. Each 2 weeks, growth and survival indicators were counted until 21st week (147th day). Reproductive capacity and offspring abnormal rate were calculated after spawning. The gonads obtained in 17th week (119th day) were used for histological studies. The results showed that: (1) In group E group, survival and specific growth rates were significantly lower than other groups (P < 0.05); (2) reproductive capacity of group B was significantly higher than other groups ( P < 0.05); (3) different feeding strategies had no significant effect on testis maturity, while had influence on ovarian maturation. The results of this study suggest that addition of A. nauplii contains superior results than single feeding with commercial micro pellet diet, which was more conducive to the growth and reproduction of G. rarus. We suggested that optimal feeding ratio for A. nauplii and commercial micro pellet diet is 6:1, that would be more appropriate for larvae and juvenile G. rarus in the process of standardized cultivation.
,
Available online
, doi: 10.7541/2018.115
Abstract:
In 2017, to further confirm the speculation and epidemiological traits of carp edema virus (CEV), 26 carp farms in 5 provinces of north China, where " acute rot gills disease of carp”, were occurred, surveyed, and sampled. CEV and koi herpes virus (KHV) were detected using quantitative polymerase chain reaction (qPCR) and nested PCR techniques. In addition, 97 carp farms in 9 provinces of China were randomly surveyed for CEV and PCR products for sequencing and analyzing viral DNA of CEV. The results showed that 20 farms were CEV-positive samples, 1 farm was KHV-positive sample, and 1 farm was infected by Sporozoa among 26 farms in north China. Besides, 50 farms were CEV-positive samples among 97 randomly surveyed farms, and infected strains belonged to genogroup II (GII). CEV was detected in different study regions, temperature of water, size of fish, and species of carp with high rate of infection, and there were no significant differences between them. In summary, CEV infection was found to be the major cause of " acute gill-rot disease of carp” in several provinces, and showed high-rate of positive detection in carp farms in north of China. In addition, CEV infection affected various species of common carps including koi carp with different sizes at the temperature range of 12—27℃.
In 2017, to further confirm the speculation and epidemiological traits of carp edema virus (CEV), 26 carp farms in 5 provinces of north China, where " acute rot gills disease of carp”, were occurred, surveyed, and sampled. CEV and koi herpes virus (KHV) were detected using quantitative polymerase chain reaction (qPCR) and nested PCR techniques. In addition, 97 carp farms in 9 provinces of China were randomly surveyed for CEV and PCR products for sequencing and analyzing viral DNA of CEV. The results showed that 20 farms were CEV-positive samples, 1 farm was KHV-positive sample, and 1 farm was infected by Sporozoa among 26 farms in north China. Besides, 50 farms were CEV-positive samples among 97 randomly surveyed farms, and infected strains belonged to genogroup II (GII). CEV was detected in different study regions, temperature of water, size of fish, and species of carp with high rate of infection, and there were no significant differences between them. In summary, CEV infection was found to be the major cause of " acute gill-rot disease of carp” in several provinces, and showed high-rate of positive detection in carp farms in north of China. In addition, CEV infection affected various species of common carps including koi carp with different sizes at the temperature range of 12—27℃.
,
Available online
, doi: 10.7541/2018.124
Abstract:
Coreius guichenoti (Sauvage & Dabry de Thiersant, 1874) is an endemic and commercially important fish in the upper Yangtze River, and its spawning grounds are mainly distributed in the main stem of the middle and lower reaches of the Jinsha River (which belong to the upper streams of the upper Yangtze River) and its tributary, the Yalong River. However, due to dam cascade in the Jinsha River and Yalong River, the spawning and feeding habitats of C. guichenoti have changed dramatically, leading to a significant decline in the population of endemic fish over last decade. To protect the fish resource ofC. guichenoti, many protective plans, including captive breeding, have been designed and implemented. It is very important to study their reproductive biology to provide basic information for captive breeding. Thus, based on the parent fish of C. guichenoti collected at the Jiaopingdu spawning ground from 2013 to 2014, and at the Jinanqiao-Qiaojia river located in the middle and lower reaches of the Jinsha River from 2006 to 2014, the reproductive biology of C. guichenoti was studied. The results showed that the minimum total length, weight, and age of mature females were 330 mm, 441 g and 4 years, respectively, while those for the mature males were 352 mm, 396.6 g and 3 years, respectively. The age and total length at which 50% of the individuals reached sexual maturity were 4.32 years and 406 mm for females, and 4.44 years and 412 mm for males, respectively. The sex ratio between male and female in the Jiaopingdu spawning ground was 1.37﹕1, which was not significantly different from 1﹕1, and the age structure of sexually mature individuals were 4—7 years in female and 3—7 years in male. The mean gonadosomatic index (GSI) displayed the highest value of 10.55% for female and 3.45% for male in 6-year-old for both genders. The average egg diameter ofC. guichenoti was 0.16 cm, and the egg diameter distribution displayed two groups of ooctes within the same ovary. The absolute fecundity of mature female varied from 4055 to 137900 eggs with an average of 22817 eggs, while the relative fecundity ranged from 5 to 73 eggs per gram with an average of 20 eggs per gram. Moreover, the absolute fecundities for the 75.68% individuals were between 10000 eggs and 30000 eggs, while the relative fecundities for the 70.27% individuals were between 15 and 20 eggs per gram. The absolute and relative fecundities of mature female increased with the total length and body weight, and the relationships between the total length and body weight and the absolute fecundity or relative fecundity could be represented by an exponential function (absolute fecundity) or quadratic function (relative fecundity). The research results can provide important basic data support for the protection of C. guichenoti fish resources in the Yangtze River Basin.
Coreius guichenoti (Sauvage & Dabry de Thiersant, 1874) is an endemic and commercially important fish in the upper Yangtze River, and its spawning grounds are mainly distributed in the main stem of the middle and lower reaches of the Jinsha River (which belong to the upper streams of the upper Yangtze River) and its tributary, the Yalong River. However, due to dam cascade in the Jinsha River and Yalong River, the spawning and feeding habitats of C. guichenoti have changed dramatically, leading to a significant decline in the population of endemic fish over last decade. To protect the fish resource ofC. guichenoti, many protective plans, including captive breeding, have been designed and implemented. It is very important to study their reproductive biology to provide basic information for captive breeding. Thus, based on the parent fish of C. guichenoti collected at the Jiaopingdu spawning ground from 2013 to 2014, and at the Jinanqiao-Qiaojia river located in the middle and lower reaches of the Jinsha River from 2006 to 2014, the reproductive biology of C. guichenoti was studied. The results showed that the minimum total length, weight, and age of mature females were 330 mm, 441 g and 4 years, respectively, while those for the mature males were 352 mm, 396.6 g and 3 years, respectively. The age and total length at which 50% of the individuals reached sexual maturity were 4.32 years and 406 mm for females, and 4.44 years and 412 mm for males, respectively. The sex ratio between male and female in the Jiaopingdu spawning ground was 1.37﹕1, which was not significantly different from 1﹕1, and the age structure of sexually mature individuals were 4—7 years in female and 3—7 years in male. The mean gonadosomatic index (GSI) displayed the highest value of 10.55% for female and 3.45% for male in 6-year-old for both genders. The average egg diameter ofC. guichenoti was 0.16 cm, and the egg diameter distribution displayed two groups of ooctes within the same ovary. The absolute fecundity of mature female varied from 4055 to 137900 eggs with an average of 22817 eggs, while the relative fecundity ranged from 5 to 73 eggs per gram with an average of 20 eggs per gram. Moreover, the absolute fecundities for the 75.68% individuals were between 10000 eggs and 30000 eggs, while the relative fecundities for the 70.27% individuals were between 15 and 20 eggs per gram. The absolute and relative fecundities of mature female increased with the total length and body weight, and the relationships between the total length and body weight and the absolute fecundity or relative fecundity could be represented by an exponential function (absolute fecundity) or quadratic function (relative fecundity). The research results can provide important basic data support for the protection of C. guichenoti fish resources in the Yangtze River Basin.
,
Available online
, doi: 10.7541/2018.129
Abstract:
Purifying wastewater with biological methods is highly important in the field of ecological recirculating aquaculture. To study the effects of temperature on the absorption of nitrogen and phosphorus and photosynthetic performance of macroalgae in sea water, four species including Ulva fasciata, Ulva intestinalis, Gracilaria lemaneaformis and Pyropia haitanensis were cultured under four temperature conditions (15, 20, 25 and 30℃). The results showed that: (1) most N and P had been absorbed by the four macroalgae species, and the absorbing ability from high to low is Ulva intestinalis>Ulva fasciata>Pyropia haitanensis>Gracilaria lemaneaformis; (2) extremely high and low temperature will limit the absorbing of N and P, growth, relative electron transfer rate, and chlorophyll fluorescence in four macroalgae species; (3) U. fasciata and U. intestinalis were the best choices due to their high absorption rates of N and P and the tolerance of a wide temperature range; (4) nitrogen and phosphorus could be completely absorbed within 48h by the four macroalgae species. To promote algal growth, improve the removal efficiency of nutrients, as well as prevent secondary pollution caused by nutrition limited negative growth of macroalgae, it’s better to replace the wastewater within 24—48h, or apply the circulation mode in the process of wastewater treatment.
Purifying wastewater with biological methods is highly important in the field of ecological recirculating aquaculture. To study the effects of temperature on the absorption of nitrogen and phosphorus and photosynthetic performance of macroalgae in sea water, four species including Ulva fasciata, Ulva intestinalis, Gracilaria lemaneaformis and Pyropia haitanensis were cultured under four temperature conditions (15, 20, 25 and 30℃). The results showed that: (1) most N and P had been absorbed by the four macroalgae species, and the absorbing ability from high to low is Ulva intestinalis>Ulva fasciata>Pyropia haitanensis>Gracilaria lemaneaformis; (2) extremely high and low temperature will limit the absorbing of N and P, growth, relative electron transfer rate, and chlorophyll fluorescence in four macroalgae species; (3) U. fasciata and U. intestinalis were the best choices due to their high absorption rates of N and P and the tolerance of a wide temperature range; (4) nitrogen and phosphorus could be completely absorbed within 48h by the four macroalgae species. To promote algal growth, improve the removal efficiency of nutrients, as well as prevent secondary pollution caused by nutrition limited negative growth of macroalgae, it’s better to replace the wastewater within 24—48h, or apply the circulation mode in the process of wastewater treatment.
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Available online
, doi: 10.7541/2018.126
Abstract:
Tintinnids are the best known group of marine ciliates and recognized as indicator species of different water masses due to their hard loricae. In the present study, a number of tintinnid species were identified based on samples obtained at six representative sites located in the Bay of Amoy from May 2015 to March 2016. Samples were collected from surface water, concentrated using 20 μm mesh, fixed by ethanol (>80% final concentration), and then stored at dark and cool conditions for further analysis. Tintinnids were isolated under a stereomicroscope and the morphological characteristics of lorica were examined under compound light microscope and documented using a charge-coupled device (CCD) camera. Totally, 27 species were identified includingTintinnopsis (20 species), Favella (1 species), Stenosemella (1 species), Codonellopsis (2 species), and Leprotintinnus (3 species), respectively. Besides, Tintinnopsis ventricosoides species (Meunier, 1910) was believed as the first record in China. Based on their lorica features, all species were here detailed.
Tintinnids are the best known group of marine ciliates and recognized as indicator species of different water masses due to their hard loricae. In the present study, a number of tintinnid species were identified based on samples obtained at six representative sites located in the Bay of Amoy from May 2015 to March 2016. Samples were collected from surface water, concentrated using 20 μm mesh, fixed by ethanol (>80% final concentration), and then stored at dark and cool conditions for further analysis. Tintinnids were isolated under a stereomicroscope and the morphological characteristics of lorica were examined under compound light microscope and documented using a charge-coupled device (CCD) camera. Totally, 27 species were identified includingTintinnopsis (20 species), Favella (1 species), Stenosemella (1 species), Codonellopsis (2 species), and Leprotintinnus (3 species), respectively. Besides, Tintinnopsis ventricosoides species (Meunier, 1910) was believed as the first record in China. Based on their lorica features, all species were here detailed.
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Available online
, doi: 10.7541/2018.114
Abstract:
The epidemiological investigation, symptom observation, pathogenic detection, and the pathology detection were used to examine the cause of the disease of Sciaenop socellatus of cultured pond in Zhuhai, Guangdong Province from June to October. These results showed that the disease had obvious infectious. The anatomy examination revealed the anemia of the gill filament, swollen spleen and kidney with hemorrhagic spots, and no observed large number of parasites by microscopy. Meanwhile, no pathogenic bacteria were isolated from the liver, spleen, kidney and intestine of the diseased fish. A large number of swelling cells were observed in pathological sections of liver, spleen and kidney of diseased fish. The 570 bp fragment was amplified by PCR using the specific primers of OIE. MCP sequence alignment showed that the amplification of the gene sequence had 99.2% of homology with gene sequence of RSIV. The comprehensive results showed that the cause of the disease of the Sciaenop socellatus is infected by the iridovirus of Megalocytivirus genus.
The epidemiological investigation, symptom observation, pathogenic detection, and the pathology detection were used to examine the cause of the disease of Sciaenop socellatus of cultured pond in Zhuhai, Guangdong Province from June to October. These results showed that the disease had obvious infectious. The anatomy examination revealed the anemia of the gill filament, swollen spleen and kidney with hemorrhagic spots, and no observed large number of parasites by microscopy. Meanwhile, no pathogenic bacteria were isolated from the liver, spleen, kidney and intestine of the diseased fish. A large number of swelling cells were observed in pathological sections of liver, spleen and kidney of diseased fish. The 570 bp fragment was amplified by PCR using the specific primers of OIE. MCP sequence alignment showed that the amplification of the gene sequence had 99.2% of homology with gene sequence of RSIV. The comprehensive results showed that the cause of the disease of the Sciaenop socellatus is infected by the iridovirus of Megalocytivirus genus.
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Available online
, doi: 10.7541/2018.125
Abstract:
This study investigated cell ultrastructure of Rhopilema esculentum during embryogesis and metamorphosis into a polyp using scanning and transmission electron microscopy combined with protargol staining method. Our study showed that (1) Cell cleavage was almost equal from fertilized egg to gastrula. All divided cells were similar in morphology, and cell junctions were observed among adjacent cells; (2) Vacuoles in cell were firstly observed at ectoderm of early planula, and became bigger as developing to 4-tentacle polyp, while the vacuoles of entoderm were firstly found at 4-tentacle polyp stage. The suspected apoptotic body were observed at scyphostoma and polyp stages; (3) Immature cnidocytes were firstly observed in ectodermal area closed to mesoglea ectoderm at early planula stage, moved to outside, located at outermost layer, and matured at polyp stage; (4) Cilium was observed at early planula stage, gradually degraded, and completely disappeared at polyp stage; (5) Lots of yolk bodies with dark stain were observed at all developmental stages, and the phagocytosis of ectodermal cell of planula was firstly observed. These phenomena suggest that planulae of R. esculentum were both planktotrophic and lecithotrophic, which would provide the scientific basis for illuminating the developmental pattern of embryonic and metamorphosis of cnidarians.
This study investigated cell ultrastructure of Rhopilema esculentum during embryogesis and metamorphosis into a polyp using scanning and transmission electron microscopy combined with protargol staining method. Our study showed that (1) Cell cleavage was almost equal from fertilized egg to gastrula. All divided cells were similar in morphology, and cell junctions were observed among adjacent cells; (2) Vacuoles in cell were firstly observed at ectoderm of early planula, and became bigger as developing to 4-tentacle polyp, while the vacuoles of entoderm were firstly found at 4-tentacle polyp stage. The suspected apoptotic body were observed at scyphostoma and polyp stages; (3) Immature cnidocytes were firstly observed in ectodermal area closed to mesoglea ectoderm at early planula stage, moved to outside, located at outermost layer, and matured at polyp stage; (4) Cilium was observed at early planula stage, gradually degraded, and completely disappeared at polyp stage; (5) Lots of yolk bodies with dark stain were observed at all developmental stages, and the phagocytosis of ectodermal cell of planula was firstly observed. These phenomena suggest that planulae of R. esculentum were both planktotrophic and lecithotrophic, which would provide the scientific basis for illuminating the developmental pattern of embryonic and metamorphosis of cnidarians.
,
Available online
, doi: 10.7541/2018.130
Abstract:
In order to investigate the diversity of Pseudo-nitzschia species in China’s coast and their ability in producing neurotoxin domoic acid (DA), a total of fifteen monoclonal Pseudo-nitzschia strains were isolated and established. Using a liquid chromatography tandem-mass spectrometry (LC-MS/MS) technique, DA was accordingly detected from ten monoclonal strains. Based on the morphology observed by using a light microscope (LM), a transmission electron microscope (TEM), as well as molecular analysis inferred from an internal transcribed spacer region, these fifteen strains were precisely identified which belonged to three different species involving, P. cuspidata (Hasle) Hasle, P. pseudodelicatissima (Hasle) Hasle, and P. fraudulenta(Cleve) Hasle. In addition, three out of eleven established P. cuspidata strains were nontoxic, while other eight cases were toxic with the DA abundance rate of 0.4—5.5 fg/cell. Also, one P. pseudodelicatissima strain was nontoxic, while DA production rate of 1 fg/cell was detected in another strain. Besides, no DA was tested in the two P. fraudulenta strains. Several strains were selected and their DA productions were induced by the available Artemia salina. As a result, it was shown that the ability of DA production decreased in P. cuspidate (MC4049) and P. pseudodelicatissima (MC3015) strains, from 2 and 1 to 0.2 and 0.4 fg/cell, respectively. However, the ability of DA production in P. fraudulenta(MC4074) strain swiftly increased, from an undetected level to 17.5 fg/cell. The results achieved in this study enrich the diversity of toxic Pseudo-nitzschiaspecies in China’s coast, and may establish strong research basis for conducting further studies.
In order to investigate the diversity of Pseudo-nitzschia species in China’s coast and their ability in producing neurotoxin domoic acid (DA), a total of fifteen monoclonal Pseudo-nitzschia strains were isolated and established. Using a liquid chromatography tandem-mass spectrometry (LC-MS/MS) technique, DA was accordingly detected from ten monoclonal strains. Based on the morphology observed by using a light microscope (LM), a transmission electron microscope (TEM), as well as molecular analysis inferred from an internal transcribed spacer region, these fifteen strains were precisely identified which belonged to three different species involving, P. cuspidata (Hasle) Hasle, P. pseudodelicatissima (Hasle) Hasle, and P. fraudulenta(Cleve) Hasle. In addition, three out of eleven established P. cuspidata strains were nontoxic, while other eight cases were toxic with the DA abundance rate of 0.4—5.5 fg/cell. Also, one P. pseudodelicatissima strain was nontoxic, while DA production rate of 1 fg/cell was detected in another strain. Besides, no DA was tested in the two P. fraudulenta strains. Several strains were selected and their DA productions were induced by the available Artemia salina. As a result, it was shown that the ability of DA production decreased in P. cuspidate (MC4049) and P. pseudodelicatissima (MC3015) strains, from 2 and 1 to 0.2 and 0.4 fg/cell, respectively. However, the ability of DA production in P. fraudulenta(MC4074) strain swiftly increased, from an undetected level to 17.5 fg/cell. The results achieved in this study enrich the diversity of toxic Pseudo-nitzschiaspecies in China’s coast, and may establish strong research basis for conducting further studies.
,
Available online
, doi: 10.7541/2018.112
Abstract:
This study attempted to theoretically support and comprehensively perceive genetic diversity and reproduction of Corbicula fluminea from the Laodao River in Liuyang city was investigated. Partial sequences of the cytochrome oxidase c subunit 1 (COⅠ) of mitochondrial genes were utilized to evaluate the genetic diversity, and reproductive characteristics were observed by gonadal histology and sperm morphology using light microscopy. Among examined 40 individuals, only 4 haplotypes and 17 variable sites were detected in the partial sequences of the COⅠ, with an average haplotype diversity, nucleotide diversity, and number of variable sites equal to 0.664±0.042, 0.014±0.006, and 8.595, respectively. Hermaphrodite was a predominant reproduction in the population studied, and the hybrid hermaphrodite-sex ratio was 6﹕3﹕1. Furthermore, there were two types of reproductive follicles in hermaphroditic individuals, including sperm and egg cells in the same and in different follicular cells. The observation of sperm morphology revealed that biflagellate spermatozoa were discovered in both hermaphrodite (n=23) and male (n=8) cases. The results also showed that Corbicula fluminea samples from the Laodao River of Liuyang city contained a relatively low genetic diversity, but with multiple reproduction modes, and the predominant mode was androgenesis. This study attempted to present significant biological reproduction information required for Corbicula fluminea protection in China.
This study attempted to theoretically support and comprehensively perceive genetic diversity and reproduction of Corbicula fluminea from the Laodao River in Liuyang city was investigated. Partial sequences of the cytochrome oxidase c subunit 1 (COⅠ) of mitochondrial genes were utilized to evaluate the genetic diversity, and reproductive characteristics were observed by gonadal histology and sperm morphology using light microscopy. Among examined 40 individuals, only 4 haplotypes and 17 variable sites were detected in the partial sequences of the COⅠ, with an average haplotype diversity, nucleotide diversity, and number of variable sites equal to 0.664±0.042, 0.014±0.006, and 8.595, respectively. Hermaphrodite was a predominant reproduction in the population studied, and the hybrid hermaphrodite-sex ratio was 6﹕3﹕1. Furthermore, there were two types of reproductive follicles in hermaphroditic individuals, including sperm and egg cells in the same and in different follicular cells. The observation of sperm morphology revealed that biflagellate spermatozoa were discovered in both hermaphrodite (n=23) and male (n=8) cases. The results also showed that Corbicula fluminea samples from the Laodao River of Liuyang city contained a relatively low genetic diversity, but with multiple reproduction modes, and the predominant mode was androgenesis. This study attempted to present significant biological reproduction information required for Corbicula fluminea protection in China.
,
Available online
, doi: 10.7541/2018.113
Abstract:
The fermented soybean meal (FSM) was used as a replacement of fish meal (FM) in a practical diet with 45% protein and 10% lipid, to investigate its effects on the growth, intestinal histology, and the structure of intestinal dominant bacteria in juvenile large yellow croaker. FM was replaced by 0, 15%, 30%, 45%, 60% and 75% of FSM (FSM0, FSM15, FSM30, FSM45, FSM60 and FSM75), respectively. The fish of 10.49 ± 0.03 g was hand-fed daily to satiation twice for 56 days. Results showed that survival was not significantly affected with all the diets (P>0.05), but in groups FSM60 and FSM75, theSR had a downward trend. In comparison with FM0, the weight gain rate (WGR) and specific growth rate (SGR) in FSM60 and FSM75 groups decreased significantly (P<0.05), while the feed conversion rate (FCR) increased significantly (P<0.05). Feed intake (FI) increased significantly in FSM60 and FSM75 groups (P<0.05), compared with that in FSM0, FSM15, FSM30 and FSM45 groups. The observed intestinal histology results showed that Mucosa thickness, Mucosafold height, Laminapropria width and Gobletcell quantity were not significantly affected in all the diets (P>0.05). Sequencing results of intestinal contents from Illumina-MiSeq high-throughput sequencing technology showed that the index of Chao1, Shannon, Simpson and Good coverage in FSM0 (TC the control), FSM45 (TB the best group in growth) and FSM75 (TW the worst group in growth) were not significantly affected (P>0.05).Firmicutes group totally dominated the bacterial communities in juvenile large yellow croaker. Paenibacillus genus was the most dominant bacteria in microbial ecosystem. Bacterial composition had certain effect on the growth of large yellow croaker: compared with TW group, the species richness of Paenibacillus and Alkaliphilus increased significantly in TB group and TC group (P<0.05). However, compared with TW group, the species richness ofEnhydrobacter in TB and Paracoccus in TC decreased significantly (P<0.05). These results suggested that the optimal dietary protein level was about 45% without negtive effects on the growth, intestinal histology, and the structure of intestinal dominant bacteria in juvenile large yellow croaker.
The fermented soybean meal (FSM) was used as a replacement of fish meal (FM) in a practical diet with 45% protein and 10% lipid, to investigate its effects on the growth, intestinal histology, and the structure of intestinal dominant bacteria in juvenile large yellow croaker. FM was replaced by 0, 15%, 30%, 45%, 60% and 75% of FSM (FSM0, FSM15, FSM30, FSM45, FSM60 and FSM75), respectively. The fish of 10.49 ± 0.03 g was hand-fed daily to satiation twice for 56 days. Results showed that survival was not significantly affected with all the diets (P>0.05), but in groups FSM60 and FSM75, theSR had a downward trend. In comparison with FM0, the weight gain rate (WGR) and specific growth rate (SGR) in FSM60 and FSM75 groups decreased significantly (P<0.05), while the feed conversion rate (FCR) increased significantly (P<0.05). Feed intake (FI) increased significantly in FSM60 and FSM75 groups (P<0.05), compared with that in FSM0, FSM15, FSM30 and FSM45 groups. The observed intestinal histology results showed that Mucosa thickness, Mucosafold height, Laminapropria width and Gobletcell quantity were not significantly affected in all the diets (P>0.05). Sequencing results of intestinal contents from Illumina-MiSeq high-throughput sequencing technology showed that the index of Chao1, Shannon, Simpson and Good coverage in FSM0 (TC the control), FSM45 (TB the best group in growth) and FSM75 (TW the worst group in growth) were not significantly affected (P>0.05).Firmicutes group totally dominated the bacterial communities in juvenile large yellow croaker. Paenibacillus genus was the most dominant bacteria in microbial ecosystem. Bacterial composition had certain effect on the growth of large yellow croaker: compared with TW group, the species richness of Paenibacillus and Alkaliphilus increased significantly in TB group and TC group (P<0.05). However, compared with TW group, the species richness ofEnhydrobacter in TB and Paracoccus in TC decreased significantly (P<0.05). These results suggested that the optimal dietary protein level was about 45% without negtive effects on the growth, intestinal histology, and the structure of intestinal dominant bacteria in juvenile large yellow croaker.
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, doi: 10.7541/2018.109
Abstract:
The present study aimed to examine the genetic diversity and genetic structure of the successive selective breeding populations of Cyprinus carpio rubrofuscus from F1 to F4 generations by using 16 microsatellite markers. The results showed that 99 alleles were detected among 16 polymorphic microsatellite loci. The number of alleles detected on each locus varied from 3 to 10, and the average number of alleles was 6.1875. From F1 to F4 generations, the average number of alleles for 16 microsatellite markers decreased from 5.6875 to 4.6755, the average of heterozygosity ranged from 0.7943 to 0.7135, and the average of polymorphism information content (PIC) reduced from 0.6577 to 0.5834, respectively. The genetic distance between F1 and its descendant generations (F2-F4) increased from 0.1486 to 0.2181, while the genetic identity decreased from 0.8619 to 0.8041. The values of genetic differentiation index (Fst) between the adjacent generations decreased (0.062 between F1-F2; 0.058 between F2-F3; and 0.051 between F3-F4), whereas the values of genetic identity increased. Pairwise values of Fst ranged from 0.05 to 0.15, reflecting that the selective breeding populations contained moderate genetic differentiation among four generations and the genetic structure has been varied from one generation to the next one through selective breeding. This study suggested that the selective breeding was an efficient approach, and there was a decrease in genetic heterozygosity and genetic diversity, while high genetic diversity and genetic potential were maintained in the selective breeding populations, indicating that there is a great potential for future selections of Cyprinus carpio rubrofuscus through selective breeding. Our study provides precious information for genetically breeding in Cyprinus carpio rubrofuscus as well.
The present study aimed to examine the genetic diversity and genetic structure of the successive selective breeding populations of Cyprinus carpio rubrofuscus from F1 to F4 generations by using 16 microsatellite markers. The results showed that 99 alleles were detected among 16 polymorphic microsatellite loci. The number of alleles detected on each locus varied from 3 to 10, and the average number of alleles was 6.1875. From F1 to F4 generations, the average number of alleles for 16 microsatellite markers decreased from 5.6875 to 4.6755, the average of heterozygosity ranged from 0.7943 to 0.7135, and the average of polymorphism information content (PIC) reduced from 0.6577 to 0.5834, respectively. The genetic distance between F1 and its descendant generations (F2-F4) increased from 0.1486 to 0.2181, while the genetic identity decreased from 0.8619 to 0.8041. The values of genetic differentiation index (Fst) between the adjacent generations decreased (0.062 between F1-F2; 0.058 between F2-F3; and 0.051 between F3-F4), whereas the values of genetic identity increased. Pairwise values of Fst ranged from 0.05 to 0.15, reflecting that the selective breeding populations contained moderate genetic differentiation among four generations and the genetic structure has been varied from one generation to the next one through selective breeding. This study suggested that the selective breeding was an efficient approach, and there was a decrease in genetic heterozygosity and genetic diversity, while high genetic diversity and genetic potential were maintained in the selective breeding populations, indicating that there is a great potential for future selections of Cyprinus carpio rubrofuscus through selective breeding. Our study provides precious information for genetically breeding in Cyprinus carpio rubrofuscus as well.
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, doi: 10.7541/2018.108
Abstract:
In the present study, the effects of isoleucine on the mammalian target of rapamycin signaling (mTOR) pathway and nitrogen metabolism were investigated through Intraventricular (ICV) administration in Chinese perch (Siniperca chuatsi). In one hand, the ammonia excretion significantly increased, and mRNA levels of nitrogen metabolism genes involving glutamate dehydrogenase (GDH), glutamic oxaloacetic transaminase (GOT), and adenosine monophosphate deaminase (AMPD) remarkably increased after ICV injection of isoleucine as well (P<0.05). On the other hand, the results showed that blood glucose levels markedly decreased at 0.5h post-injection. The expression of liver ribosomal protein S6 was also notably enhanced, demonstrating that mTOR signaling pathway was activated. The results also indicated that isoleucine could activate the mTOR signaling pathway, mediate amino acid metabolism, and enhance ammonia-N excretion via nitrogen metabolism genes in Chinese perch.
In the present study, the effects of isoleucine on the mammalian target of rapamycin signaling (mTOR) pathway and nitrogen metabolism were investigated through Intraventricular (ICV) administration in Chinese perch (Siniperca chuatsi). In one hand, the ammonia excretion significantly increased, and mRNA levels of nitrogen metabolism genes involving glutamate dehydrogenase (GDH), glutamic oxaloacetic transaminase (GOT), and adenosine monophosphate deaminase (AMPD) remarkably increased after ICV injection of isoleucine as well (P<0.05). On the other hand, the results showed that blood glucose levels markedly decreased at 0.5h post-injection. The expression of liver ribosomal protein S6 was also notably enhanced, demonstrating that mTOR signaling pathway was activated. The results also indicated that isoleucine could activate the mTOR signaling pathway, mediate amino acid metabolism, and enhance ammonia-N excretion via nitrogen metabolism genes in Chinese perch.
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In this study, the method of irradiation breeding was applied to wetland plants in order to improve its cold resistance. Herein, 25, 45, 60 and 80 Gy doses of gamma ray were used to irradiate Canna indica Linn (CIL) seeds, and the dose rate was 6 Gy/min. After CIL seeds were grown up, they were exposed to a low temperature stage, and their cold hardiness was accordingly evaluated. The results showed that the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in irradiated CIL seeds were higher than that of the control group. Malondialdehyde (MDA) in control group accumulated in large quantities under low temperature, which was higher than that of the irradiation treatment group. Besides, at low temperature, the content of proline, the total soluble sugar, and protein of irradiated seedlings were totally higher than that of the control group. The score of cold resistance in irradiated group was also higher than that of the control group, and the 45 Gy dose of gamma ray group showed the highest score. Moreover, CIL with the strongest cold resistance was planted in the constructed wetland to evaluate its purification effect in winter, and evaluation indexes were total phosphorus (TP), total nitrogen (TN), and chemical oxygen demand (COD). Results revealed that the removal rate of TP in the group of CIL in constructed wetland by using 45 Gy dose of gamma ray was significantly higher than that of the control group (P<0.05). It can be concluded that irradiation treatment can effectively improve the cold resistance ofCIL and enhance the effect of artificial wetland purification in winter.
In this study, the method of irradiation breeding was applied to wetland plants in order to improve its cold resistance. Herein, 25, 45, 60 and 80 Gy doses of gamma ray were used to irradiate Canna indica Linn (CIL) seeds, and the dose rate was 6 Gy/min. After CIL seeds were grown up, they were exposed to a low temperature stage, and their cold hardiness was accordingly evaluated. The results showed that the activity of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in irradiated CIL seeds were higher than that of the control group. Malondialdehyde (MDA) in control group accumulated in large quantities under low temperature, which was higher than that of the irradiation treatment group. Besides, at low temperature, the content of proline, the total soluble sugar, and protein of irradiated seedlings were totally higher than that of the control group. The score of cold resistance in irradiated group was also higher than that of the control group, and the 45 Gy dose of gamma ray group showed the highest score. Moreover, CIL with the strongest cold resistance was planted in the constructed wetland to evaluate its purification effect in winter, and evaluation indexes were total phosphorus (TP), total nitrogen (TN), and chemical oxygen demand (COD). Results revealed that the removal rate of TP in the group of CIL in constructed wetland by using 45 Gy dose of gamma ray was significantly higher than that of the control group (P<0.05). It can be concluded that irradiation treatment can effectively improve the cold resistance ofCIL and enhance the effect of artificial wetland purification in winter.
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In order to provide basic information for protecting and rational utilizing resources of the Yangtze Estuary, feeding types, trophic level, energy flow, and food web, 43 aquatic animals were studied by using stomach content analysis. The species were classified into four groups according to their feeding habit: plankton feeding, benthic feeding, nekton feeding, and mixed feeding (benthic and nekton feeding). Among the samples collected in this study, the plankton predators were dominant accountings for 39.53%, and the nekton predators had the minimum dominancy, accounting for 11.63%. The results of trophic level showed that according to the dietary habits, these aquatic animals can be also divided into 3 different groups, which herbivorous consumers were dominant, and accounted for 76.75%, while intermediate carnivorous fish had the minimum dominancy, accounting for 4.65%. Through the overfishing and environmental degradation, the trophic levels of the 12 common fish in the Yangtze Estuar were generally lower than those of the 1990s, the average trophic level dropped from 3.80 to 2.87. According to each consumer’s stomach content, this study determined the benthic algae and phytoplankton, and organic detritus, including particulate organic matter (POM), as the main producers of the Yangtze Estuar aquatic food web, and drew their own energy flow. Eventually, based on the nutritional relationship among different aquatic animals, this study proposed a simplified model for the Yangtze Estuar aquatic animals’ food web.
In order to provide basic information for protecting and rational utilizing resources of the Yangtze Estuary, feeding types, trophic level, energy flow, and food web, 43 aquatic animals were studied by using stomach content analysis. The species were classified into four groups according to their feeding habit: plankton feeding, benthic feeding, nekton feeding, and mixed feeding (benthic and nekton feeding). Among the samples collected in this study, the plankton predators were dominant accountings for 39.53%, and the nekton predators had the minimum dominancy, accounting for 11.63%. The results of trophic level showed that according to the dietary habits, these aquatic animals can be also divided into 3 different groups, which herbivorous consumers were dominant, and accounted for 76.75%, while intermediate carnivorous fish had the minimum dominancy, accounting for 4.65%. Through the overfishing and environmental degradation, the trophic levels of the 12 common fish in the Yangtze Estuar were generally lower than those of the 1990s, the average trophic level dropped from 3.80 to 2.87. According to each consumer’s stomach content, this study determined the benthic algae and phytoplankton, and organic detritus, including particulate organic matter (POM), as the main producers of the Yangtze Estuar aquatic food web, and drew their own energy flow. Eventually, based on the nutritional relationship among different aquatic animals, this study proposed a simplified model for the Yangtze Estuar aquatic animals’ food web.
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To investigate the effects of exhaustive chasing training on parameters of respiratory and circulatory system and excess post-exercise oxygen consumption (EPOC) in juvenile qingbo (Spinibarbus sinensis) and rock carp (Procypris rabaudi), sixty samples of S. sinensis (28.36±0.08) g and sixty samples of P. rabaudi (19.53±0.13) g were randomly divided (equally 30 fish in each group) into control group and training group, respectively. Then, these fish in the training group were analyzed under exhaustive chasing training once per day for 3 weeks at 25℃ to measure the heart index, gill index, hematological parameters, and EPOC. The results showed that there were no significant differences in the heart index, gill index, hemoglobin content, and number of red cells between the control group and training group of S. sinensis and Procypris rabaudi(P<0.05). The gill index in the control group ofP. rabaudi was significantly lower than that in the control group of S. sinensis(P>0.05), whereas the heart index, hemoglobin content, and number of red cells in the control group ofP. rabaudi were not significantly different than that in the control group of S. sinensis(P<0.05). No significant differences were found in pre-exercise metabolic rate, peak post-exercise metabolic rate, factorial metabolic scope, and recovery rate between the control group and training group (P>0.05), whereas duration of EPOC in the training group was significantly higher than that in the control group ofS. sinensis (P<0.05). The pre-exercise metabolic rate in the control group was significantly lower than that in the training group (P<0.05), whereas peak post-exercise metabolic rate and factorial metabolic scope, duration of EPOC, and recovery rate in the control group were not significantly different than that in the training group ofP. rabaudi(P>0.05). The pre-exercise metabolic rate, peak post-exercise metabolic rate, EPOC magnitude, and recovery rate in the control group ofP. rabaudi were significantly lower than that in the control group of S. sinensis(P<0.05), whereas factorial metabolic scope and duration of EPOC in the control group ofP. rabaudi were not significantly different than that in the control group of S. sinensis(P>0.05). Our results suggested that (1) exhaustive chasing training had no significant effects on the parameters of respiratory and circulatory system ofS. sinensisandP. rabaudi(P>0.05); (2) exhaustive chasing training significantly increased anaerobic capacity ofS. sinensis(P<0.05); and (3) the pre-exercise metabolic rate and peak post-exercise metabolic rate ofS. sinensis were significantly higher than those of P. rabaudi(P<0.05), which may be related to active habits ofS. sinensis.
To investigate the effects of exhaustive chasing training on parameters of respiratory and circulatory system and excess post-exercise oxygen consumption (EPOC) in juvenile qingbo (Spinibarbus sinensis) and rock carp (Procypris rabaudi), sixty samples of S. sinensis (28.36±0.08) g and sixty samples of P. rabaudi (19.53±0.13) g were randomly divided (equally 30 fish in each group) into control group and training group, respectively. Then, these fish in the training group were analyzed under exhaustive chasing training once per day for 3 weeks at 25℃ to measure the heart index, gill index, hematological parameters, and EPOC. The results showed that there were no significant differences in the heart index, gill index, hemoglobin content, and number of red cells between the control group and training group of S. sinensis and Procypris rabaudi(P<0.05). The gill index in the control group ofP. rabaudi was significantly lower than that in the control group of S. sinensis(P>0.05), whereas the heart index, hemoglobin content, and number of red cells in the control group ofP. rabaudi were not significantly different than that in the control group of S. sinensis(P<0.05). No significant differences were found in pre-exercise metabolic rate, peak post-exercise metabolic rate, factorial metabolic scope, and recovery rate between the control group and training group (P>0.05), whereas duration of EPOC in the training group was significantly higher than that in the control group ofS. sinensis (P<0.05). The pre-exercise metabolic rate in the control group was significantly lower than that in the training group (P<0.05), whereas peak post-exercise metabolic rate and factorial metabolic scope, duration of EPOC, and recovery rate in the control group were not significantly different than that in the training group ofP. rabaudi(P>0.05). The pre-exercise metabolic rate, peak post-exercise metabolic rate, EPOC magnitude, and recovery rate in the control group ofP. rabaudi were significantly lower than that in the control group of S. sinensis(P<0.05), whereas factorial metabolic scope and duration of EPOC in the control group ofP. rabaudi were not significantly different than that in the control group of S. sinensis(P>0.05). Our results suggested that (1) exhaustive chasing training had no significant effects on the parameters of respiratory and circulatory system ofS. sinensisandP. rabaudi(P>0.05); (2) exhaustive chasing training significantly increased anaerobic capacity ofS. sinensis(P<0.05); and (3) the pre-exercise metabolic rate and peak post-exercise metabolic rate ofS. sinensis were significantly higher than those of P. rabaudi(P<0.05), which may be related to active habits ofS. sinensis.
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In order to provide biological information for research on sex-determination mechanism in Pelodiscus sinensis, we here first attempted to clone and analyze the partial-length of Foxl2 cDNA. In addition, to address the differential expression of Foxl2 at genetic and physiological levels, both male and female sexes of Pelodiscus sinensis were treated with 10 mg/kg E2 and 17α-methyltestosterone (MT), respectively; Foxl2 mRNA expression was quantitatively examined in the gonads after injection treatment at 6, 12, 24, and 48h, as well as 7 and 14d, respectively. Foxl2 (GenBank Accession No.KP734210) was achieved, belonging to Forkhead family of transcription factors that is involved in ovarian development and functional maintenance, as well as a 903 bp of open reading frame (ORF) encoding 300 amino acids. Multiple sequence alignment showed that Foxl2 contained typical FH-domain, and the most similar ortholog was Trachemys scripta, reaching up to 99%. Stability analysis of phylogenetic trees showed that Pelodiscus sinensis Foxl2 was clustered with reptile Foxl2 as a sub-branch, and was closely associated with Foxl2 from Chrysemys picta bellii. Results of quantitative reverse transcription PCR (RT-qPCR) indicated that, compared to the control group, E2 significantly up-regulated Foxl2 mRNA repression in ovary after 24h (P<0.001), which in testis was significantly increased after 7 and 14d (P<0.001). MT treatment strongly and equally up-regulated expression levels ofFoxl2 mRNA in ovary and testis at 24h (P<0.001). These results suggested that E2 and MT could up-regulate Foxl2 expression. Moreover, the sex differences in E2 promoting Foxl2 expression is more significant than MT. It can be concluded that the present research contributes to better understanding of the functional role of Foxl2 and provide basic data for further study on how exogenous hormone mediates Foxl2 in Pelodiscus sinensis.
In order to provide biological information for research on sex-determination mechanism in Pelodiscus sinensis, we here first attempted to clone and analyze the partial-length of Foxl2 cDNA. In addition, to address the differential expression of Foxl2 at genetic and physiological levels, both male and female sexes of Pelodiscus sinensis were treated with 10 mg/kg E2 and 17α-methyltestosterone (MT), respectively; Foxl2 mRNA expression was quantitatively examined in the gonads after injection treatment at 6, 12, 24, and 48h, as well as 7 and 14d, respectively. Foxl2 (GenBank Accession No.KP734210) was achieved, belonging to Forkhead family of transcription factors that is involved in ovarian development and functional maintenance, as well as a 903 bp of open reading frame (ORF) encoding 300 amino acids. Multiple sequence alignment showed that Foxl2 contained typical FH-domain, and the most similar ortholog was Trachemys scripta, reaching up to 99%. Stability analysis of phylogenetic trees showed that Pelodiscus sinensis Foxl2 was clustered with reptile Foxl2 as a sub-branch, and was closely associated with Foxl2 from Chrysemys picta bellii. Results of quantitative reverse transcription PCR (RT-qPCR) indicated that, compared to the control group, E2 significantly up-regulated Foxl2 mRNA repression in ovary after 24h (P<0.001), which in testis was significantly increased after 7 and 14d (P<0.001). MT treatment strongly and equally up-regulated expression levels ofFoxl2 mRNA in ovary and testis at 24h (P<0.001). These results suggested that E2 and MT could up-regulate Foxl2 expression. Moreover, the sex differences in E2 promoting Foxl2 expression is more significant than MT. It can be concluded that the present research contributes to better understanding of the functional role of Foxl2 and provide basic data for further study on how exogenous hormone mediates Foxl2 in Pelodiscus sinensis.
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There is limited information available on effects of aquaculture on lake ecosystems. Community structure and biodiversity of phytoplankton were investigated from July to September, 2015 in 23 lakes in the middle reach of the Yangtze River Basin, which include four groups: reservoir group (A), aquaculture ban group (B), low stocking aquaculture group (C) and high stocking aquaculture group (D). The analysis showed that dominant genera of the four groups were different. Group A was dominated by Pseudanabaena (Y=0.642) and Planktolyngbya (Y=0.064). Group B was dominated by Merismopedia (Y=0.428), Planktolyngbya (Y=0.118), Pseudanabaena (Y=0.133), and Scenedesmus (Y=0.066). Group C was dominated by Pseudanabaena (Y=0.395), Merismopedia (Y=0.097), and Planktolyngbya (Y=0.122). Group D was dominated by Merismopedia (Y=0.308), Microcystis (Y=0.118), and Pseudanabaena (Y=0.077). The phytoplankton abundance in group A was significantly lower than those in other lake groups (P<0.05). There was no significant difference in Shannon-Wiener index, Margalef index and Pielou index of phytoplankton among the four lake groups. The study indicated that fish culture could affect the abundance and dominant genera of phytoplankton, which may provide some implications for lake ecosystem management.
There is limited information available on effects of aquaculture on lake ecosystems. Community structure and biodiversity of phytoplankton were investigated from July to September, 2015 in 23 lakes in the middle reach of the Yangtze River Basin, which include four groups: reservoir group (A), aquaculture ban group (B), low stocking aquaculture group (C) and high stocking aquaculture group (D). The analysis showed that dominant genera of the four groups were different. Group A was dominated by Pseudanabaena (Y=0.642) and Planktolyngbya (Y=0.064). Group B was dominated by Merismopedia (Y=0.428), Planktolyngbya (Y=0.118), Pseudanabaena (Y=0.133), and Scenedesmus (Y=0.066). Group C was dominated by Pseudanabaena (Y=0.395), Merismopedia (Y=0.097), and Planktolyngbya (Y=0.122). Group D was dominated by Merismopedia (Y=0.308), Microcystis (Y=0.118), and Pseudanabaena (Y=0.077). The phytoplankton abundance in group A was significantly lower than those in other lake groups (P<0.05). There was no significant difference in Shannon-Wiener index, Margalef index and Pielou index of phytoplankton among the four lake groups. The study indicated that fish culture could affect the abundance and dominant genera of phytoplankton, which may provide some implications for lake ecosystem management.
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The histology of gonadal development in Ptychobarbus dipogon was studied by using conventional paraffin sections and HE staining, in order to obtain information on its reproductive systems useful for its artificial breeding. The results showed that the development of oocytes can be divided into five phases, and ovarian development can be divided into six stages. In stage V ovaries, ovum worship was found to occur, indicated by the 1.38:1 ratio of small ova to large ova. Phase 3 oocytes were characterized by appearance of yolk granules and follicles; phase 4 oocytes by rapid increase of yolk granules, and the movement of the nucleus toward the animal poles; phase 5 by the fusion of yolk granules, and the separation of oocytes from follicular membranes to float in the ovarian cavity. Male P. dipogen had lobular testes, and their germ cells can be categorized into spermatogonia, spermatocytes; spermatids; and spermatozoa. Their testes also developed in six stages. The species followed a batch-synchronous spawning pattern.
The histology of gonadal development in Ptychobarbus dipogon was studied by using conventional paraffin sections and HE staining, in order to obtain information on its reproductive systems useful for its artificial breeding. The results showed that the development of oocytes can be divided into five phases, and ovarian development can be divided into six stages. In stage V ovaries, ovum worship was found to occur, indicated by the 1.38:1 ratio of small ova to large ova. Phase 3 oocytes were characterized by appearance of yolk granules and follicles; phase 4 oocytes by rapid increase of yolk granules, and the movement of the nucleus toward the animal poles; phase 5 by the fusion of yolk granules, and the separation of oocytes from follicular membranes to float in the ovarian cavity. Male P. dipogen had lobular testes, and their germ cells can be categorized into spermatogonia, spermatocytes; spermatids; and spermatozoa. Their testes also developed in six stages. The species followed a batch-synchronous spawning pattern.
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Knowledge of the vulnerability of different species and size groups to various types of fishing methods is vital to the development of optimal harvesting strategies and rational exploitation of fish resources. In this study, the selectivity of four types of fishing methods (weir nets, gill nets, electrofishing, and cormorants) used simultaneously in a typical multi-species shallow lake (Lake Niushan, China) within the Yangtze River basin, was compared for catch composition, efficiency, and size selection. Species selectivity was evaluated with the index of relative importance (IRI). Potential fishing effects on the trophic structure of fish community were analyzed by calculating the mean trophic level (MTL) of the catches and the weight ratio between prey and predator fishes. Results indicated the use of weir nets and electrofishing should be reduced or eliminated, because they were relatively unselective and caught many species, including juvenile individuals. Fishing efforts of cormorants should be restricted due to their high fishing efficiency, especially on piscivorous fishes. Gill nets with appropriate mesh size are likely to be a more sustainable fishing method since they were more selective in capturing larger individuals and could balance the prey-predator relationship. We suggest shifting from single-species approaches toward multi-species management, and taking trophic interactions into account to better manage fishery resources.
Knowledge of the vulnerability of different species and size groups to various types of fishing methods is vital to the development of optimal harvesting strategies and rational exploitation of fish resources. In this study, the selectivity of four types of fishing methods (weir nets, gill nets, electrofishing, and cormorants) used simultaneously in a typical multi-species shallow lake (Lake Niushan, China) within the Yangtze River basin, was compared for catch composition, efficiency, and size selection. Species selectivity was evaluated with the index of relative importance (IRI). Potential fishing effects on the trophic structure of fish community were analyzed by calculating the mean trophic level (MTL) of the catches and the weight ratio between prey and predator fishes. Results indicated the use of weir nets and electrofishing should be reduced or eliminated, because they were relatively unselective and caught many species, including juvenile individuals. Fishing efforts of cormorants should be restricted due to their high fishing efficiency, especially on piscivorous fishes. Gill nets with appropriate mesh size are likely to be a more sustainable fishing method since they were more selective in capturing larger individuals and could balance the prey-predator relationship. We suggest shifting from single-species approaches toward multi-species management, and taking trophic interactions into account to better manage fishery resources.
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The yellow perch, Perca flavescens, is an economically significant freshwater fish species in the Midwest of the United States. TypeⅠ markers are useful for comparative mapping and other genetic analyses, but limited quantities in yellow perch. In the present study, EST containing microsatellite sequences were identified and characterized for yellow perch by data mining from updated public EST databases. Out of 21,968 EST sequences of yellow perch, about 14.4% of ESTs contain repeat motifs of various types and length. CA repeat was the most abundant dinucleotides. Out of the 62 EST-SSRs for which PCR primers were designed, 15 loci showed polymorphic in a yellow perch population with the alleles per locus ranging from 4 to 19 (average 9). The observed (HO) and expected (HE) heterozygosity of these EST-SSRs were 0.103—0.929 and 0.116—0.934, respectively. Four EST-SSR loci significantly deviated from the Hardy-Weinberg equilibrium (HWE) expectation, and the remaining 11 loci were in HWE. These new EST-SSR markers should provide sufficient polymorphism for population genetic studies and genomic mapping of yellow perch.
The yellow perch, Perca flavescens, is an economically significant freshwater fish species in the Midwest of the United States. TypeⅠ markers are useful for comparative mapping and other genetic analyses, but limited quantities in yellow perch. In the present study, EST containing microsatellite sequences were identified and characterized for yellow perch by data mining from updated public EST databases. Out of 21,968 EST sequences of yellow perch, about 14.4% of ESTs contain repeat motifs of various types and length. CA repeat was the most abundant dinucleotides. Out of the 62 EST-SSRs for which PCR primers were designed, 15 loci showed polymorphic in a yellow perch population with the alleles per locus ranging from 4 to 19 (average 9). The observed (HO) and expected (HE) heterozygosity of these EST-SSRs were 0.103—0.929 and 0.116—0.934, respectively. Four EST-SSR loci significantly deviated from the Hardy-Weinberg equilibrium (HWE) expectation, and the remaining 11 loci were in HWE. These new EST-SSR markers should provide sufficient polymorphism for population genetic studies and genomic mapping of yellow perch.
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To assess possible bias of different fishing methods is essential to appropriate fisheries management. In the current study, fish assemblage structure of a shallow Yangtze River lake was assessed by combining one international standard sampling gear (multi-mesh gillnet), and one traditional Chinese gear (the dense-mesh weir). Using Lake Biandantang as a case study, a total of 27 fish species were collected from the two gears combined, including 2 new species that had not been recorded previously in this lake. Results suggested that fish assemblages had changed greatly compared to a previous study conducted in the 1990s. Specifically, differences were found in species composition, abundance, biomass, and length distributions collected from the two gears. Difference in total length (TL) distributions of fishes caught was the most conspicuous change. Fishes collected from the weir ranged from 40—70 mm TL, whereas fishes collected from gillnets ranged from 90—140 mm TL. Multivariate ordinations based on relative abundance and biomass data also indicated fish assemblage structural differences between the two gears. The comparative results showed that the multi-mesh gillnet was effective at assessing fish assemblages in shallow lakes, such as those found along the middle and lower reaches of the Yangtze River. Additionally, assessments using only one gear could have some limitations with respect to interpreting fish assemblage changes over time.
To assess possible bias of different fishing methods is essential to appropriate fisheries management. In the current study, fish assemblage structure of a shallow Yangtze River lake was assessed by combining one international standard sampling gear (multi-mesh gillnet), and one traditional Chinese gear (the dense-mesh weir). Using Lake Biandantang as a case study, a total of 27 fish species were collected from the two gears combined, including 2 new species that had not been recorded previously in this lake. Results suggested that fish assemblages had changed greatly compared to a previous study conducted in the 1990s. Specifically, differences were found in species composition, abundance, biomass, and length distributions collected from the two gears. Difference in total length (TL) distributions of fishes caught was the most conspicuous change. Fishes collected from the weir ranged from 40—70 mm TL, whereas fishes collected from gillnets ranged from 90—140 mm TL. Multivariate ordinations based on relative abundance and biomass data also indicated fish assemblage structural differences between the two gears. The comparative results showed that the multi-mesh gillnet was effective at assessing fish assemblages in shallow lakes, such as those found along the middle and lower reaches of the Yangtze River. Additionally, assessments using only one gear could have some limitations with respect to interpreting fish assemblage changes over time.
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Asian carp are expanding their range throughout the Mississippi River; however, abundance is thought to be highest in reaches within close proximity to the Illinois River. In the Mississippi River, Lock and Dam 19 (L&D 19) at Keokuk, Iowa is the primary barrier to slow the expansion upstream. As Asian carp abundance increases below L&D 19, it is important to investigate potential means of control (i.e., reduction through harvest and barriers) that will prevent complete invasion of the Mississippi River above L&D 19. Silver Carp and Bighead Carp were collected below L&D 19, a subsample were implanted with ultrasonic transmitters to evaluate passage through the lock chamber and the remainder were used to determine population dynamics at the leading edge of invasion. Although the dam portion of the structure poses a complete barrier to upstream expansion, we documented lock chamber passage demonstrating the lock chamber has the capability to provide passage upstream. Based on the results of the population assessment, in order to induce recruitment overfishing at this leading edge of invasion, Asian carp will need to be intensively harvested at 300 mm and larger. The combination of commercial fishing efforts and research investigating ways to prevent passage upstream must be employed.
Asian carp are expanding their range throughout the Mississippi River; however, abundance is thought to be highest in reaches within close proximity to the Illinois River. In the Mississippi River, Lock and Dam 19 (L&D 19) at Keokuk, Iowa is the primary barrier to slow the expansion upstream. As Asian carp abundance increases below L&D 19, it is important to investigate potential means of control (i.e., reduction through harvest and barriers) that will prevent complete invasion of the Mississippi River above L&D 19. Silver Carp and Bighead Carp were collected below L&D 19, a subsample were implanted with ultrasonic transmitters to evaluate passage through the lock chamber and the remainder were used to determine population dynamics at the leading edge of invasion. Although the dam portion of the structure poses a complete barrier to upstream expansion, we documented lock chamber passage demonstrating the lock chamber has the capability to provide passage upstream. Based on the results of the population assessment, in order to induce recruitment overfishing at this leading edge of invasion, Asian carp will need to be intensively harvested at 300 mm and larger. The combination of commercial fishing efforts and research investigating ways to prevent passage upstream must be employed.
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Our study examined spatial distribution differences of rotifer resting eggs (RRE) in lakes of the Poyang Lake Wetland Area during dry season, January 2015. Field sampling was conducted in both Nanshen Lake and Baisha Lake. We found that densities of RRE in different habitats were significantly different (P<0.05), and their distribution had an obvious gradient. The highest mean density was in the marshland vegetation area of Nanshen Lake, where it was (3.34±1.28) ind./cm3. The density of resting eggs in the Zizania latifolia area was up to 5.45 ind./cm3. The density of RRE was different spatially, with the greatest in the vegetation area, then in the muddy area, and then the lowest in the water area. ANOVAs results showed that water depth, vegetation, and sediment had significant effects on RRE (P=0.001, 0.007, <0.001, respectively). The trend of resting egg densities in different aquatic habitats was: emergent aquatic plant > marshland vegetation > floating-leaf plants > submerged plants. The distribution of RRE in areas of different water depths was inconsistent. The density of RRE was higher in the hard than soft sediment.
Our study examined spatial distribution differences of rotifer resting eggs (RRE) in lakes of the Poyang Lake Wetland Area during dry season, January 2015. Field sampling was conducted in both Nanshen Lake and Baisha Lake. We found that densities of RRE in different habitats were significantly different (P<0.05), and their distribution had an obvious gradient. The highest mean density was in the marshland vegetation area of Nanshen Lake, where it was (3.34±1.28) ind./cm3. The density of resting eggs in the Zizania latifolia area was up to 5.45 ind./cm3. The density of RRE was different spatially, with the greatest in the vegetation area, then in the muddy area, and then the lowest in the water area. ANOVAs results showed that water depth, vegetation, and sediment had significant effects on RRE (P=0.001, 0.007, <0.001, respectively). The trend of resting egg densities in different aquatic habitats was: emergent aquatic plant > marshland vegetation > floating-leaf plants > submerged plants. The distribution of RRE in areas of different water depths was inconsistent. The density of RRE was higher in the hard than soft sediment.
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Sexual dimorphism refers to the morphological differentiation between males and females in the same population, such as sizes, morphological features, and colors. Cold water fish Glyptosternum maculatum, is an endemic teleost species of notable economic importance and with high potential for controlled rearing of the species in Tibet Autonomous Region. In this study, morphological measurements and related analysis were conducted on sexually mature G. maculatum to investigate their morphological differences in Tibet Autonomous Region. Results indicated the sexually mature populations indeed display really displayed significant sexual dimorphism: males exhibited significantly greater body length, weight, and males also exhibited in addition to greater tail length while females exhibited significantly greater eye diameter, body depth, trunk length, and lengths of dorsal, pectoral, pelvic, anal, and caudal fins at a given body length. Principal components analysis on 16 morphological parameters showed that the differences were largely due to features of the body shape (including lengths of body parts and fins) and the head, and differences in the above features differences contributed 76.7%. The t-statistic test on the allometry index b in the total length-weight function showed that during the breeding season, the total lengths and weights of G. maculatum females developed proportionally, while the male specimens were allometrical.
Sexual dimorphism refers to the morphological differentiation between males and females in the same population, such as sizes, morphological features, and colors. Cold water fish Glyptosternum maculatum, is an endemic teleost species of notable economic importance and with high potential for controlled rearing of the species in Tibet Autonomous Region. In this study, morphological measurements and related analysis were conducted on sexually mature G. maculatum to investigate their morphological differences in Tibet Autonomous Region. Results indicated the sexually mature populations indeed display really displayed significant sexual dimorphism: males exhibited significantly greater body length, weight, and males also exhibited in addition to greater tail length while females exhibited significantly greater eye diameter, body depth, trunk length, and lengths of dorsal, pectoral, pelvic, anal, and caudal fins at a given body length. Principal components analysis on 16 morphological parameters showed that the differences were largely due to features of the body shape (including lengths of body parts and fins) and the head, and differences in the above features differences contributed 76.7%. The t-statistic test on the allometry index b in the total length-weight function showed that during the breeding season, the total lengths and weights of G. maculatum females developed proportionally, while the male specimens were allometrical.
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Silver carp Hypophthalmichthys molitrix were introduced into the U.S. to control water quality in aquaculture ponds. From this point of origin, silver carp escaped into nearby rivers through multiple flood events. Because of their documented negative effects on native biota, silver carp have been labeled as problematic. Therefore, evaluating the biology and ecology of these non-indigenous species is critical. Multiple parameters are needed to evaluate silver carp populations (length, weight, age, and sex). Furthermore, developing methods for rapidly acquiring these data are needed. In relation to sex determination, sexual dimorphism was observed where males exhibit distinct pectoral fin ray features. Specifically, males have pronounced ridges or a " rough patch” on the dorsal surface of pectoral fins. Therefore, to test if this was an applicable way of determining silver carp gender; silver carp were collected from Midwestern U.S. rivers (N=2,015) in the fall of 2011 (N=870), spring of 2012 (N=645), winter of 2013-2014 (N=202) and summer 2015 (N=323) via electrofishing. For each silver carp collected, presence (e.g., rough patch) or absence (e.g., smooth) of pronounced ridges on the top side of the pectoral fins was recorded, and an incision was made in the body cavity to identify gender. Based on the results of our evaluation, gender was correctly identified over 99% of the time (2,006 out of 2,015) based on the pectoral fin dimorphism. In the samples taken in the winter of 2013—2014 and summer of 2015, accuracy for silver carp shorter than 300 mm and longer than 800mm was 53.7% (19 out of 41) while accuracy for silver carp between 300 mm and 800mm total length was 98.9% (289 out of 292). This study provides a rapid assessment approach for evaluating silver carp gender.
Silver carp Hypophthalmichthys molitrix were introduced into the U.S. to control water quality in aquaculture ponds. From this point of origin, silver carp escaped into nearby rivers through multiple flood events. Because of their documented negative effects on native biota, silver carp have been labeled as problematic. Therefore, evaluating the biology and ecology of these non-indigenous species is critical. Multiple parameters are needed to evaluate silver carp populations (length, weight, age, and sex). Furthermore, developing methods for rapidly acquiring these data are needed. In relation to sex determination, sexual dimorphism was observed where males exhibit distinct pectoral fin ray features. Specifically, males have pronounced ridges or a " rough patch” on the dorsal surface of pectoral fins. Therefore, to test if this was an applicable way of determining silver carp gender; silver carp were collected from Midwestern U.S. rivers (N=2,015) in the fall of 2011 (N=870), spring of 2012 (N=645), winter of 2013-2014 (N=202) and summer 2015 (N=323) via electrofishing. For each silver carp collected, presence (e.g., rough patch) or absence (e.g., smooth) of pronounced ridges on the top side of the pectoral fins was recorded, and an incision was made in the body cavity to identify gender. Based on the results of our evaluation, gender was correctly identified over 99% of the time (2,006 out of 2,015) based on the pectoral fin dimorphism. In the samples taken in the winter of 2013—2014 and summer of 2015, accuracy for silver carp shorter than 300 mm and longer than 800mm was 53.7% (19 out of 41) while accuracy for silver carp between 300 mm and 800mm total length was 98.9% (289 out of 292). This study provides a rapid assessment approach for evaluating silver carp gender.
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A tag-release-recapture study was conducted to evaluate effects of size at release on survival, growth and yield of hatchery-reared mandarin fish Siniperca chautsi fingerlings stocked in a shallow Yangtze lake. In May and June 2012, a total of 2,400 juvenile mandarin fish were graded into three size groups, identified with coded wire tags and tail fin, and released into Xiaosai Lake. Mandarin fish were collected after the lake drained in December 2012. Overall, a total of 973 mandarin fish individuals were captured, with an average survival rate of 40.5%. Survival rate of large sized group (63%) is more than three times higher than that of small sized group (19.5%) and 1.5 times higher than that of middle sized group (39.1%). The mean final length and weight of mandarin fish increased with the increase of release size and showed significant difference among groups. Yield was significantly affected by release size, which was the highest in large sized group and the lowest in small sized group. The net income of stocked mandarin fish increased with the increase of fish size at release. Our results indicated that mandarin fish size at release can have a major impact on success of hatchery releases, and it is suggested that the optimum release size of mandarin fish should not be less than 50 mm in Xiaosai Lake.
A tag-release-recapture study was conducted to evaluate effects of size at release on survival, growth and yield of hatchery-reared mandarin fish Siniperca chautsi fingerlings stocked in a shallow Yangtze lake. In May and June 2012, a total of 2,400 juvenile mandarin fish were graded into three size groups, identified with coded wire tags and tail fin, and released into Xiaosai Lake. Mandarin fish were collected after the lake drained in December 2012. Overall, a total of 973 mandarin fish individuals were captured, with an average survival rate of 40.5%. Survival rate of large sized group (63%) is more than three times higher than that of small sized group (19.5%) and 1.5 times higher than that of middle sized group (39.1%). The mean final length and weight of mandarin fish increased with the increase of release size and showed significant difference among groups. Yield was significantly affected by release size, which was the highest in large sized group and the lowest in small sized group. The net income of stocked mandarin fish increased with the increase of fish size at release. Our results indicated that mandarin fish size at release can have a major impact on success of hatchery releases, and it is suggested that the optimum release size of mandarin fish should not be less than 50 mm in Xiaosai Lake.
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We analysed spatial pattern in the fish assemblage structure along a longitudinal gradient of the Upper Yangtze River and the Three Gorges Reservoir. We tested the hypothesis that shifts from lotic to lentic environment affect the richness and structure of the fish assemblage. Samplings were carried out from 2005 to 2012 in four zones: 1) Hejiang reach, river upstream from the reservoir; 2) Mudong reach, upper part of the reservoir; 3) Wanzhou reach, middle part of the reservoir, and 4) Zigui reach, lower part of the reservoir. A total of 368706 fish representing 132 native species of 17 families were collected during the study period with Cyprinidae as the dominant group. The results showed that the native species richness decreased while the non-native species increased from river (Hejiang reach) to reservoir (Zigui reach). Patterns in fish assemblage ordination evaluated by correspondence analysis reflected a clear division of the riverine and reservoir zones. Uppermost sampling stations were characterized by species characteristic of flowing waters, whereas in the lowland most lentic species were captured. Further, 22 species, three functional groups (rheophilic, equilibrium, insectivorous) were identified for the upper reach and 16 species, three functional groups (herbivorous, planktivorous, stagnophilic) for the lowland reach by indicator species analysis (P<0.05). Therefore, it is evident that impoundment of the Three Gorges Reservoir is the major driving factor to structuring the fish assemblage structure along the longitudinal gradient from river to the reservoir. Different fisheries management actions should be made to conserve or rehabilitate native fish assemblages and control invasive non-native species.
We analysed spatial pattern in the fish assemblage structure along a longitudinal gradient of the Upper Yangtze River and the Three Gorges Reservoir. We tested the hypothesis that shifts from lotic to lentic environment affect the richness and structure of the fish assemblage. Samplings were carried out from 2005 to 2012 in four zones: 1) Hejiang reach, river upstream from the reservoir; 2) Mudong reach, upper part of the reservoir; 3) Wanzhou reach, middle part of the reservoir, and 4) Zigui reach, lower part of the reservoir. A total of 368706 fish representing 132 native species of 17 families were collected during the study period with Cyprinidae as the dominant group. The results showed that the native species richness decreased while the non-native species increased from river (Hejiang reach) to reservoir (Zigui reach). Patterns in fish assemblage ordination evaluated by correspondence analysis reflected a clear division of the riverine and reservoir zones. Uppermost sampling stations were characterized by species characteristic of flowing waters, whereas in the lowland most lentic species were captured. Further, 22 species, three functional groups (rheophilic, equilibrium, insectivorous) were identified for the upper reach and 16 species, three functional groups (herbivorous, planktivorous, stagnophilic) for the lowland reach by indicator species analysis (P<0.05). Therefore, it is evident that impoundment of the Three Gorges Reservoir is the major driving factor to structuring the fish assemblage structure along the longitudinal gradient from river to the reservoir. Different fisheries management actions should be made to conserve or rehabilitate native fish assemblages and control invasive non-native species.
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The establishment of a highly efficient planktivore, Silver Carp (Hypophthalmichthys molitrix), in the Mississippi River Basin has been documented as having negative impacts on native planktivore populations. Silver Carp have the potential, to alter the trophic food web through negative interactions with native planktivores in large river systems. Due to increasing Silver Carp ranges, interactions between Silver Carp and other native planktivores is likely to increase. One abundant native planktivore that is often found in similar habitats as Silver Carp is Gizzard Shad (Dorosoma cepedianum). Potential competition for resources exists because of overlapping habitat use and forage. Given the similarities between these two planktivores, we sought to evaluate daily growth rates and determine hatch dates of age-0 Silver Carp and Gizzard Shad in the Middle Mississippi River. Silver Carp and Gizzard Shad were collected from the Middle Mississippi River using an electrified surface trawl from June through September with sizes ranging from 21—65 mm total length for Gizzard Shad and 24—85 mm total length for Silver Carp. A sample of age-0 fish (n=697) was collected at the end of the growing season including 292 Gizzard Shad and 405 Silver Carp. Size structure (total length in mm) of Silver Carp (49.05±0.41; X ̅ ± SE) was significantly greater (T=-16.43, df=695, P<0.001) than Gizzard Shad (38.95 ± 0.45). Hatch dates were similar between Silver Carp (July 26th to August 18th) and Gizzard Shad (July 28th to August 19th). Growth of Silver Carp (2.24 mm per day) was significantly greater (P<0.001, T=-11.1, df=82) than Gizzard Shad (1.72 mm per day). Mortality was similar between Silver Carp (28.1%) and Gizzard Shad (25.1%) at this early life stage. The faster growth rates in Silver Carp result in Silver Carp entering the winter season larger in size with likely an increased capacity to consume plankton and decreased predation ultimately leading to higher recruitment. Knowing that there exists an overlap between Silver Carp and Gizzard Shad diets and habitat could alone call cause for concern. Adding that spawning occurs at a similar time and Silver Carp have the ability to outgrow Gizzard Shad early in life leads to major concerns about food web balance. Knowing that invasive planktivores have already shown to alter food webs in aquatic systems in North America, extra caution should be taken.
The establishment of a highly efficient planktivore, Silver Carp (Hypophthalmichthys molitrix), in the Mississippi River Basin has been documented as having negative impacts on native planktivore populations. Silver Carp have the potential, to alter the trophic food web through negative interactions with native planktivores in large river systems. Due to increasing Silver Carp ranges, interactions between Silver Carp and other native planktivores is likely to increase. One abundant native planktivore that is often found in similar habitats as Silver Carp is Gizzard Shad (Dorosoma cepedianum). Potential competition for resources exists because of overlapping habitat use and forage. Given the similarities between these two planktivores, we sought to evaluate daily growth rates and determine hatch dates of age-0 Silver Carp and Gizzard Shad in the Middle Mississippi River. Silver Carp and Gizzard Shad were collected from the Middle Mississippi River using an electrified surface trawl from June through September with sizes ranging from 21—65 mm total length for Gizzard Shad and 24—85 mm total length for Silver Carp. A sample of age-0 fish (n=697) was collected at the end of the growing season including 292 Gizzard Shad and 405 Silver Carp. Size structure (total length in mm) of Silver Carp (49.05±0.41; X ̅ ± SE) was significantly greater (T=-16.43, df=695, P<0.001) than Gizzard Shad (38.95 ± 0.45). Hatch dates were similar between Silver Carp (July 26th to August 18th) and Gizzard Shad (July 28th to August 19th). Growth of Silver Carp (2.24 mm per day) was significantly greater (P<0.001, T=-11.1, df=82) than Gizzard Shad (1.72 mm per day). Mortality was similar between Silver Carp (28.1%) and Gizzard Shad (25.1%) at this early life stage. The faster growth rates in Silver Carp result in Silver Carp entering the winter season larger in size with likely an increased capacity to consume plankton and decreased predation ultimately leading to higher recruitment. Knowing that there exists an overlap between Silver Carp and Gizzard Shad diets and habitat could alone call cause for concern. Adding that spawning occurs at a similar time and Silver Carp have the ability to outgrow Gizzard Shad early in life leads to major concerns about food web balance. Knowing that invasive planktivores have already shown to alter food webs in aquatic systems in North America, extra caution should be taken.
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A comprehensive investigation on macrophyte community in Hongze Lake was conducted seasonally from May 2010 to February 2011. Overall, twelve species representing eight families of macrophytes were identified in Hongze Lake, including nine species of submerged plants, two species of floating-leaved plants, and one species of emerging plant. In general, Potamogeton malaianus, P. maackianu, P. pectinatus and P. crispus were the four dominant species throughout the whole year, the highest biomass of macrophytes was presented in autumn, followed by summer and winter, while spring had the lowest biomass of macrophytes. Based on field data, we used kriging interpolation in ArcGis to map the spatiotemporal distribution of the entire macrophyte community as well as each of the four dominant species. From the GIS maps we observed that the northern area of the lake, namely the Chengzihu region, had the highest biomass of macrophytes potentially as a result of better water quality and greater transparency. Potential factors that affected the community structure, biomass, and distribution patterns of macrophytes considerably were then discussed. The results of this study illuminate the need for more information on the role and importance of aquatic macrophytes in shallow lake ecosystems. Conservation of macrophytes should be taken to maintain the lake ecosystem health.
A comprehensive investigation on macrophyte community in Hongze Lake was conducted seasonally from May 2010 to February 2011. Overall, twelve species representing eight families of macrophytes were identified in Hongze Lake, including nine species of submerged plants, two species of floating-leaved plants, and one species of emerging plant. In general, Potamogeton malaianus, P. maackianu, P. pectinatus and P. crispus were the four dominant species throughout the whole year, the highest biomass of macrophytes was presented in autumn, followed by summer and winter, while spring had the lowest biomass of macrophytes. Based on field data, we used kriging interpolation in ArcGis to map the spatiotemporal distribution of the entire macrophyte community as well as each of the four dominant species. From the GIS maps we observed that the northern area of the lake, namely the Chengzihu region, had the highest biomass of macrophytes potentially as a result of better water quality and greater transparency. Potential factors that affected the community structure, biomass, and distribution patterns of macrophytes considerably were then discussed. The results of this study illuminate the need for more information on the role and importance of aquatic macrophytes in shallow lake ecosystems. Conservation of macrophytes should be taken to maintain the lake ecosystem health.
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Schizothorax macropogon and Ptychobarbus dipogon are important economic fishes in the Yarlung Zangbo River. Both are Schizothoracinaes containing a variety of essential fatty acids with high nutritional values. As food products, the textural characteristics of their meat determine important factors like taste or methods of treatment. To explore the preservation and utilization of fish resources in the Tibet Autonomous Region, China, the texture profile analysis (TPA) method was used to analyze 12 textural parameters. Fish were captured from the Yarlung Zangbo River in Shigatse and Nyingchi City. Principal component analysis showed that the texture of P. dipogon captured from the Nyingchi segment was different from the same species captured in the Shigatse segment, and different from S. macropogon captured from both segments. Factorial analysis indicated that the textural characteristics of Schizothoracinae fishes in Tibet Autonomous Region can be summarized as hardness indices, overcome attraction indices and contractility indices, of which the accumulated variance contribution rate of the first four principal component factors was 81.472%. The three categories of the four principal component axes could be the main deciding parameters of the textural characteristics of Schizothoracinae fishes in Tibet Autonomous Region. This provides scientific data for subsequent development and utilization of Schizothoracinae fishes from the Yarlung Zangbo River in different geographical areas.
Schizothorax macropogon and Ptychobarbus dipogon are important economic fishes in the Yarlung Zangbo River. Both are Schizothoracinaes containing a variety of essential fatty acids with high nutritional values. As food products, the textural characteristics of their meat determine important factors like taste or methods of treatment. To explore the preservation and utilization of fish resources in the Tibet Autonomous Region, China, the texture profile analysis (TPA) method was used to analyze 12 textural parameters. Fish were captured from the Yarlung Zangbo River in Shigatse and Nyingchi City. Principal component analysis showed that the texture of P. dipogon captured from the Nyingchi segment was different from the same species captured in the Shigatse segment, and different from S. macropogon captured from both segments. Factorial analysis indicated that the textural characteristics of Schizothoracinae fishes in Tibet Autonomous Region can be summarized as hardness indices, overcome attraction indices and contractility indices, of which the accumulated variance contribution rate of the first four principal component factors was 81.472%. The three categories of the four principal component axes could be the main deciding parameters of the textural characteristics of Schizothoracinae fishes in Tibet Autonomous Region. This provides scientific data for subsequent development and utilization of Schizothoracinae fishes from the Yarlung Zangbo River in different geographical areas.
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To investigate the influence of artificial substrates (AS) on the growth performance of fish in pond poly-culture systems, a feeding experiment was conducted in six individual earthen ponds, which were divided into two groups. The ponds with AS in the water were labeled as the " AS group” and that without the use of AS were labeled as the " control group” (three ponds per group). A total of 3867 common carp [Cyprinus carpio, (310±11) g], being artificial-feeds feeding fish, and 370 bighead carp (Aristichthys nobilis) and silver carp [Hypophthalmichthys molitrix, (810±15) g], being plankton filter feeding fish, were divided into six groups and cultured in the ponds respectively. The common carp in each pond were fed with commercial particle feeds three times a day and the feeding period was 62 days. Water quality, concentration of plankton and the bacterial community presenting in the water and sediment were monitored during the experiment. At the end of the experiment, all fish were harvested and the growth of the fish and feed efficiency ratio were determined. Results showed that the weight gain rate and feed efficiency ratio of common carp in AS group was significantly higher than that of the control group. Final body weights of bighead carp and silver carp in the AS group were significantly lower than that of the controls. Water transparency and diversity indices of the bacterial community in the AS group were significantly higher than that of the control (P<0.05) and the concentration of plankton in the AS group was lower than that of the control. Results showed that the application of AS in poly-culture ponds was beneficial for the growth of common carp, being artificial-feeds feeding fish, while it was not beneficial for the growth of bighead carp and silver carp, being plankton filter feeding fish.
To investigate the influence of artificial substrates (AS) on the growth performance of fish in pond poly-culture systems, a feeding experiment was conducted in six individual earthen ponds, which were divided into two groups. The ponds with AS in the water were labeled as the " AS group” and that without the use of AS were labeled as the " control group” (three ponds per group). A total of 3867 common carp [Cyprinus carpio, (310±11) g], being artificial-feeds feeding fish, and 370 bighead carp (Aristichthys nobilis) and silver carp [Hypophthalmichthys molitrix, (810±15) g], being plankton filter feeding fish, were divided into six groups and cultured in the ponds respectively. The common carp in each pond were fed with commercial particle feeds three times a day and the feeding period was 62 days. Water quality, concentration of plankton and the bacterial community presenting in the water and sediment were monitored during the experiment. At the end of the experiment, all fish were harvested and the growth of the fish and feed efficiency ratio were determined. Results showed that the weight gain rate and feed efficiency ratio of common carp in AS group was significantly higher than that of the control group. Final body weights of bighead carp and silver carp in the AS group were significantly lower than that of the controls. Water transparency and diversity indices of the bacterial community in the AS group were significantly higher than that of the control (P<0.05) and the concentration of plankton in the AS group was lower than that of the control. Results showed that the application of AS in poly-culture ponds was beneficial for the growth of common carp, being artificial-feeds feeding fish, while it was not beneficial for the growth of bighead carp and silver carp, being plankton filter feeding fish.
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Many efforts have been devoted to developing, constructing and refining fishways or fish passage facilities to facilitate the target fish species to pass barriers in fluvial systems. Once dominated by an engineering-focused approach, fishways science nowadays involves a wide range of disciplines from fish behaviour to socioeconomics, and to complex modeling of passage prioritization options in river networks. Designing efficient fishways, with minimal passage delay and post-passage impacts, requires adaptive management and continued innovations. After the completion of fishways construction, corresponding management systems usually need to be improved as well. In the current study, we first reviewed international fishways adaptive management systems (e.g., aspects of development, construction, and management) from 1991 to 2017 reporting on " fishway”, " fish passage”, " fish” and " dam”. The functions of fishways gradually transferred from conservation of economic stocks to overall biodiversity conservation, from facilitating upwards to both upwards and downwards passages, from developing a single project to considering the entire river basin, from fish passing function to habitats restorations as well, and from pure engineering construction to considering adaptive management. Finally, we discussed adaptive management systems and management prospects of fishways for China.
Many efforts have been devoted to developing, constructing and refining fishways or fish passage facilities to facilitate the target fish species to pass barriers in fluvial systems. Once dominated by an engineering-focused approach, fishways science nowadays involves a wide range of disciplines from fish behaviour to socioeconomics, and to complex modeling of passage prioritization options in river networks. Designing efficient fishways, with minimal passage delay and post-passage impacts, requires adaptive management and continued innovations. After the completion of fishways construction, corresponding management systems usually need to be improved as well. In the current study, we first reviewed international fishways adaptive management systems (e.g., aspects of development, construction, and management) from 1991 to 2017 reporting on " fishway”, " fish passage”, " fish” and " dam”. The functions of fishways gradually transferred from conservation of economic stocks to overall biodiversity conservation, from facilitating upwards to both upwards and downwards passages, from developing a single project to considering the entire river basin, from fish passing function to habitats restorations as well, and from pure engineering construction to considering adaptive management. Finally, we discussed adaptive management systems and management prospects of fishways for China.
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Abstract:
This study examined anesthetic behaviors of Schizothorax o’connori Llord in two size ranges as induced by MS-222, to acquire useful information on anesthesia of said highland fish species in out-of-water activities (surgery, labeling, measurement, etc.). Test results indicated that for both large (25.0±1.5) cm and small-sized (14.8±2.3) cm specimens, respiration rates showed no significant change in anesthetic stages I to III, and only begun to significantly decline after entering stage IV. The effective concentrations of MS-222 were 150—180 mg/L and 150 mg/L for two sizes, respectively. The 150—180 mg/L caused large specimens to enter anesthetic stage IV within 5min, and recovered within 5min; the 150 mg/L caused small specimens to enter stage IV within 5min, and recovered within 7min; both doses ensured a 100% survival rate after immersion for 20min. For large specimens anesthetized at 180 mg/L for 5min and exposed to air for 0—15min, there was no significant difference in recovery times (P>0.05); for small specimens anesthetized at 150 mg/L for 5min and exposed to air for 0—15min, there were significant differences in recovery (P<0.05).
This study examined anesthetic behaviors of Schizothorax o’connori Llord in two size ranges as induced by MS-222, to acquire useful information on anesthesia of said highland fish species in out-of-water activities (surgery, labeling, measurement, etc.). Test results indicated that for both large (25.0±1.5) cm and small-sized (14.8±2.3) cm specimens, respiration rates showed no significant change in anesthetic stages I to III, and only begun to significantly decline after entering stage IV. The effective concentrations of MS-222 were 150—180 mg/L and 150 mg/L for two sizes, respectively. The 150—180 mg/L caused large specimens to enter anesthetic stage IV within 5min, and recovered within 5min; the 150 mg/L caused small specimens to enter stage IV within 5min, and recovered within 7min; both doses ensured a 100% survival rate after immersion for 20min. For large specimens anesthetized at 180 mg/L for 5min and exposed to air for 0—15min, there was no significant difference in recovery times (P>0.05); for small specimens anesthetized at 150 mg/L for 5min and exposed to air for 0—15min, there were significant differences in recovery (P<0.05).
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Available online
Abstract:
The lower Mississippi River (LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that includes recreational and commercial fisheries. Due to river training and diversion structures constructed during the past 80 years, the historic characteristics of the LMR have been drastically altered and have likely influenced fishes and fisheries in the system. One common restoration measure used throughout the LMR has been to " notch” wing-dike structures that close secondary (side) river channels. Dike notching allows year-round flows through secondary channels, which enhances habitat diversity and promotes biological productivity at the ecosystem scale. Although notching is presumed good for LMR fishes and other biota, few studies have examined its effects on fish assemblages. In this study, fish assemblages were sampled at seven LMR secondary channels spanning from river kilometer (rkm) 628 (Louisiana-Mississippi, U.S.A.) upstream to rkm 1504 (Missouri-Kentucky, U.S.A.). Four secondary channels were termed " permanent” (i.e., with notched dikes) while three secondary channels were termed " temporary” (i.e., without notched dikes). Fishes were sampled by boat-mounted electrofishing conducted during falling and low stages from 1995—1997. Fish assemblages differed between permanent and temporary secondary channels, and varied somewhat between falling and low stages. Gizzard shad (Dorosoma cepedianum), threadfin shad (D. petenense), and white bass (Morone chrysops) demonstrated consistent preferences for low-current conditions associated with temporary secondary channels. Conversely, blue catfish (Ictalurus furcatus), flathead catfish (Pylodictis olivaris), and freshwater drum (Aplodinotus grunniens) were more associated with permanent secondary channels. Future restoration strategies in the LMR should consider dike notching and resultant maintenance of permanent secondary channels in selected river reaches. However, temporary secondary channels also contain unique fish species, and also appear to be important sites of riverine primary production. Restoration strategies should consider a balance of both secondary channel types, which should support the greatest biodiversity for the LMR ecosystem.
The lower Mississippi River (LMR) has been heavily modified for multiple human purposes such as navigation, flood control, and bank stabilization. However, the LMR simultaneously supports a diverse fish fauna that includes recreational and commercial fisheries. Due to river training and diversion structures constructed during the past 80 years, the historic characteristics of the LMR have been drastically altered and have likely influenced fishes and fisheries in the system. One common restoration measure used throughout the LMR has been to " notch” wing-dike structures that close secondary (side) river channels. Dike notching allows year-round flows through secondary channels, which enhances habitat diversity and promotes biological productivity at the ecosystem scale. Although notching is presumed good for LMR fishes and other biota, few studies have examined its effects on fish assemblages. In this study, fish assemblages were sampled at seven LMR secondary channels spanning from river kilometer (rkm) 628 (Louisiana-Mississippi, U.S.A.) upstream to rkm 1504 (Missouri-Kentucky, U.S.A.). Four secondary channels were termed " permanent” (i.e., with notched dikes) while three secondary channels were termed " temporary” (i.e., without notched dikes). Fishes were sampled by boat-mounted electrofishing conducted during falling and low stages from 1995—1997. Fish assemblages differed between permanent and temporary secondary channels, and varied somewhat between falling and low stages. Gizzard shad (Dorosoma cepedianum), threadfin shad (D. petenense), and white bass (Morone chrysops) demonstrated consistent preferences for low-current conditions associated with temporary secondary channels. Conversely, blue catfish (Ictalurus furcatus), flathead catfish (Pylodictis olivaris), and freshwater drum (Aplodinotus grunniens) were more associated with permanent secondary channels. Future restoration strategies in the LMR should consider dike notching and resultant maintenance of permanent secondary channels in selected river reaches. However, temporary secondary channels also contain unique fish species, and also appear to be important sites of riverine primary production. Restoration strategies should consider a balance of both secondary channel types, which should support the greatest biodiversity for the LMR ecosystem.
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Available online
Abstract:
This study is based on monthly sampling (from April 2013 to April 2015) of 18 fish species representing three families. Samples were obtained using benthic fyke-nets, block nets, and multi-mesh gillnets in Lake Kuilei, a shallow lake of the Yangtze River basin, China (N 31º24', E 120º51'). Using ordinary least-squares linear regression, length-weight relationships of these fish species were estimated, with equations for 3 species reported for the first time. The maximum total length records of the 15 species exceeded those reported in FishBase. This paper provides new LWR equations for these species to be included in FishBase.
This study is based on monthly sampling (from April 2013 to April 2015) of 18 fish species representing three families. Samples were obtained using benthic fyke-nets, block nets, and multi-mesh gillnets in Lake Kuilei, a shallow lake of the Yangtze River basin, China (N 31º24', E 120º51'). Using ordinary least-squares linear regression, length-weight relationships of these fish species were estimated, with equations for 3 species reported for the first time. The maximum total length records of the 15 species exceeded those reported in FishBase. This paper provides new LWR equations for these species to be included in FishBase.
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2018, 42(4): 663-672
doi: 10.7541/2018.082
Abstract:
This study was conducted to explore the effects of berberine on the mRNA expression of G protein coupled receptors 43 (GPR43) and the lipid metabolism performance of blunt snout bream fed with high-fat diet. GPR43 in blunt snout bream was cloned and sequenced with a RACE assays. The effects of berberine on GPR43 mRNA expression in tissues were also investigated. The obtained full-length nucleotide sequence covers 2026 bp, which has an open reading frame of 981 bp, and translates a total of 326 amino acids. Moreover, GPR43 mRNAs were detected in different tissues of blunt snout bream. In blunt snout bream, the expression of GPR43 in intestine, hepatopancreas, gill and white muscle were the highest. 320 fish (80.00±0.90) g were randomly divided into four trial groups (each has four replicates) and fed with 4 diets (normal diet, normal diet with 50 mg/kg berberine, high-fat diet, and high-fat diet with 50 mg/kg berberine, among which normal diet has 5% lipid and high-fat diet has 10% lipid), respectively. The expression of GPR43 mRNA in the high-fat diet group decreased compared with control group, while it significantly increased (P<0.05) after adding in berberine. Compared with the control group, the contents of free fatty acids (FFA), triglycerides (TG), cholesterol (CHO), and mRNA expressions of Cytokinins protein kinase (p38), and Peroxidase value-added factor (PPARγ) all increased (P<0.05) in the high-fat group, but a dramatic decrease (P<0.05) happened after adding in berberine. The same result was found on the composition of Polyunsaturated fatty acids (PUFA) in hepatopancreas and muscle tissues. A completely inverse variation was presented on the mRNA expressions of Carnitine palm acyltransferaseⅠ (CPTⅠ), Peroxidase value-added factor (PPARα&β) and AMP dependent protein kinase (AMPK), as well as on the compositions of Saturated fatty acids (SFA) and Monounsaturated fatty acids (MUFA) in both tissues. Nevertheless, the difference between berberine supplemental normal diet group and control group was out of regular pattern. So further work is still needed to explore the role of berberine in normal circumstances. Overall, the results showed the supplement of berberine could slow down lipid deposition in hepatopancreas, and restore lipid homeostasis which has been damaged by continuous high-fat diet feeding.
This study was conducted to explore the effects of berberine on the mRNA expression of G protein coupled receptors 43 (GPR43) and the lipid metabolism performance of blunt snout bream fed with high-fat diet. GPR43 in blunt snout bream was cloned and sequenced with a RACE assays. The effects of berberine on GPR43 mRNA expression in tissues were also investigated. The obtained full-length nucleotide sequence covers 2026 bp, which has an open reading frame of 981 bp, and translates a total of 326 amino acids. Moreover, GPR43 mRNAs were detected in different tissues of blunt snout bream. In blunt snout bream, the expression of GPR43 in intestine, hepatopancreas, gill and white muscle were the highest. 320 fish (80.00±0.90) g were randomly divided into four trial groups (each has four replicates) and fed with 4 diets (normal diet, normal diet with 50 mg/kg berberine, high-fat diet, and high-fat diet with 50 mg/kg berberine, among which normal diet has 5% lipid and high-fat diet has 10% lipid), respectively. The expression of GPR43 mRNA in the high-fat diet group decreased compared with control group, while it significantly increased (P<0.05) after adding in berberine. Compared with the control group, the contents of free fatty acids (FFA), triglycerides (TG), cholesterol (CHO), and mRNA expressions of Cytokinins protein kinase (p38), and Peroxidase value-added factor (PPARγ) all increased (P<0.05) in the high-fat group, but a dramatic decrease (P<0.05) happened after adding in berberine. The same result was found on the composition of Polyunsaturated fatty acids (PUFA) in hepatopancreas and muscle tissues. A completely inverse variation was presented on the mRNA expressions of Carnitine palm acyltransferaseⅠ (CPTⅠ), Peroxidase value-added factor (PPARα&β) and AMP dependent protein kinase (AMPK), as well as on the compositions of Saturated fatty acids (SFA) and Monounsaturated fatty acids (MUFA) in both tissues. Nevertheless, the difference between berberine supplemental normal diet group and control group was out of regular pattern. So further work is still needed to explore the role of berberine in normal circumstances. Overall, the results showed the supplement of berberine could slow down lipid deposition in hepatopancreas, and restore lipid homeostasis which has been damaged by continuous high-fat diet feeding.
2018, 42(4): 673-680
doi: 10.7541/2018.083
Abstract:
LBH (limb-bud and heart) is a novel high-conserved transcription cofactor in vertebrates involved in embryonic development and pathogenesis of some human disease. We screened the lbh-b gene that was abundantly expressed in the pituitary of gibel carp, and cloned the lbh-b (Cglbh-b) cDNA sequence of lbh gene family from gibel carp cDNA library by RACE-PCR. The full-length of Cglbh-b cDNA was 1526 bp with a 549 bp long open reading frame (ORF) coding a 182 amino acid protein. Bioinformatics analysis showed that CgLbh-b protein shared high homology (>68%) with other vertebrate LBH and is one of intrinsic disordered proteins.Cglbh-b was abundantly expressed in pituitary, telencephalon, ovary and eye of adult gibel carp. The expression of Cglbh-b in female pituitaries was 4.66 times higher than that in male pituitaries, and Cglbh-b in pituitary was up-regulated during the process of oocyte maturation. During the early embryonic development, maternal mRNA of Cglbh-b was detected in embryos from 4-cells stage to gastrula stage, and its transcripts were synthesized at bud stage. The results of whole mount in situ hybridization showed that Cglbh-b was distributed on the brain and eyes of embryos from 2 days post fertilization (dpf) to 3dpf. These results suggest that Cglbh-b may play important roles in brain and retina development, and reproductive regulation in oocyte maturation of gibel carp.
LBH (limb-bud and heart) is a novel high-conserved transcription cofactor in vertebrates involved in embryonic development and pathogenesis of some human disease. We screened the lbh-b gene that was abundantly expressed in the pituitary of gibel carp, and cloned the lbh-b (Cglbh-b) cDNA sequence of lbh gene family from gibel carp cDNA library by RACE-PCR. The full-length of Cglbh-b cDNA was 1526 bp with a 549 bp long open reading frame (ORF) coding a 182 amino acid protein. Bioinformatics analysis showed that CgLbh-b protein shared high homology (>68%) with other vertebrate LBH and is one of intrinsic disordered proteins.Cglbh-b was abundantly expressed in pituitary, telencephalon, ovary and eye of adult gibel carp. The expression of Cglbh-b in female pituitaries was 4.66 times higher than that in male pituitaries, and Cglbh-b in pituitary was up-regulated during the process of oocyte maturation. During the early embryonic development, maternal mRNA of Cglbh-b was detected in embryos from 4-cells stage to gastrula stage, and its transcripts were synthesized at bud stage. The results of whole mount in situ hybridization showed that Cglbh-b was distributed on the brain and eyes of embryos from 2 days post fertilization (dpf) to 3dpf. These results suggest that Cglbh-b may play important roles in brain and retina development, and reproductive regulation in oocyte maturation of gibel carp.
2018, 42(4): 681-689
doi: 10.7541/2018.084
Abstract:
In this study, microsatellite markers were used to assess the genetic structure and genetic diversity of the second generation of Tegillarca granosa. In addition, the correlation of these markers with growth-related traits was assessed to explore their potential use for marker-assisted breeding. Genome-wide identification and structural analysis herein led to detect 59 alleles through 18 pairs of primers. Among these, the average values of alleles (Na) in the families of F19, F21, and F22 were 2.500, 2.722, and 2.722, respectively. The average observed heterozygosity (Ho) was 0.446, 0.510, and 0.628; the average expected heterozygosity (He) was 0.394, 0.433, and 0.464, respectively. In addition, the corresponding values of polymorphism information content (PIC) were 0.346, 0.379, and 0.403, respectively. Correlation analyses of these polymorphic markers and growth traits revealed significant association of three loci with shell height, shell length, shell width, and total weight. Specifically, genotype BB of Teg-30 in F19 was remarkably associated with shell height and total weight, while genotype BB of Teg-03 and genotype BC of Teg-20 in F21 showed a significant correlation with the shell height, shell length, shell width, and total weight. As a result, the growth-related markers, identified in the present study, may provide precious genetic information and novel insights for molecular marker-assisted breeding of T. granosa.
In this study, microsatellite markers were used to assess the genetic structure and genetic diversity of the second generation of Tegillarca granosa. In addition, the correlation of these markers with growth-related traits was assessed to explore their potential use for marker-assisted breeding. Genome-wide identification and structural analysis herein led to detect 59 alleles through 18 pairs of primers. Among these, the average values of alleles (Na) in the families of F19, F21, and F22 were 2.500, 2.722, and 2.722, respectively. The average observed heterozygosity (Ho) was 0.446, 0.510, and 0.628; the average expected heterozygosity (He) was 0.394, 0.433, and 0.464, respectively. In addition, the corresponding values of polymorphism information content (PIC) were 0.346, 0.379, and 0.403, respectively. Correlation analyses of these polymorphic markers and growth traits revealed significant association of three loci with shell height, shell length, shell width, and total weight. Specifically, genotype BB of Teg-30 in F19 was remarkably associated with shell height and total weight, while genotype BB of Teg-03 and genotype BC of Teg-20 in F21 showed a significant correlation with the shell height, shell length, shell width, and total weight. As a result, the growth-related markers, identified in the present study, may provide precious genetic information and novel insights for molecular marker-assisted breeding of T. granosa.
2018, 42(4): 690-697
doi: 10.7541/2018.085
Abstract:
Myeloid differentiation factor 88 (MYD88) is a key adapter protein in Toll-like receptor (TLR) signaling, which plays significant role on the innate and adaptive immunity. In this study, a myd88 gene from lamprey (Lampetra japonica) was obtained. The ORF of myd88 was 852 bp in length, encoding a polypeptide of 283 amino acids. The theoretical molecular weight of lamprey Myd88 was 32.432 kD with a theoretical isoelectric point of 6.25. Lamprey Myd88 was predicted to have no signal peptide. Multiple protein sequence alignment revealed highly conserved death domain in N-terminal, and Box1, Box2, and Box3 in the C-terminal TIR domain, which indicated that lamprey Myd88 was homologous with the MYD88 in other species. Quantitative real-time PCR analysis showed lamprey myd88 gene was extensively expressed in all detected tissues. The highest expression level was observed in gill, which was followed by marrow and kidney. Under in vivo stimulation by lipopolysaccharide (LPS), the expression of myd88 significantly increased in leukocytes, followed by gill, which implicated its role in the defense of L. Japonica against bacteria. Furthermore, increasing expressions of downstream proteins in Myd88-dependent TLR signaling pathway, including Irak1, Traf6, Ikkβ, and Nfkb, were detected in the tested tissues stimulated with LPS. These results suggested that a conserved Myd88-dependent TLR signaling pathway was found in the lamprey, which play a fundamental role on the exploration of the origin and evolution of the signaling pathway in immune response in future.
Myeloid differentiation factor 88 (MYD88) is a key adapter protein in Toll-like receptor (TLR) signaling, which plays significant role on the innate and adaptive immunity. In this study, a myd88 gene from lamprey (Lampetra japonica) was obtained. The ORF of myd88 was 852 bp in length, encoding a polypeptide of 283 amino acids. The theoretical molecular weight of lamprey Myd88 was 32.432 kD with a theoretical isoelectric point of 6.25. Lamprey Myd88 was predicted to have no signal peptide. Multiple protein sequence alignment revealed highly conserved death domain in N-terminal, and Box1, Box2, and Box3 in the C-terminal TIR domain, which indicated that lamprey Myd88 was homologous with the MYD88 in other species. Quantitative real-time PCR analysis showed lamprey myd88 gene was extensively expressed in all detected tissues. The highest expression level was observed in gill, which was followed by marrow and kidney. Under in vivo stimulation by lipopolysaccharide (LPS), the expression of myd88 significantly increased in leukocytes, followed by gill, which implicated its role in the defense of L. Japonica against bacteria. Furthermore, increasing expressions of downstream proteins in Myd88-dependent TLR signaling pathway, including Irak1, Traf6, Ikkβ, and Nfkb, were detected in the tested tissues stimulated with LPS. These results suggested that a conserved Myd88-dependent TLR signaling pathway was found in the lamprey, which play a fundamental role on the exploration of the origin and evolution of the signaling pathway in immune response in future.
2018, 42(4): 698-708
doi: 10.7541/2018.086
Abstract:
Swimming crab (Portunus trituberculatus) is an important mariculture crab, and the light color of the pond-reared crabs may be related to low level of dietary astaxanthin. This study was designed to investigate the effects of dietary astaxanthin on ovarian development, coloration, antioxidant capacity, immune performance and biochemical composition of female P. trituberculatus. Haematococcus pluvialis powder was used as natural astaxanthin source to formulate four experimental diets with different astaxanthin levels (0, 26.60, 41.62, and 81.37 mg/kg, defined as Diet 1#—4#). The four experimental diets were fed to female P. trituberculatus for 45 days during the ovarian development; therefore, there were four treatments in this study. The results showed as follows: (1) Dietary astaxanthin had no significant effects on gonadosomatic index (GSI) and hepatosomatic index (HSI). (2) Total carotenoids content, redness (a*) and yellowness (b*) values of hepatopancreas, ovaries and carapace increased significantly with increasing dietary astaxanthin, while the lightness (L*) values of these tissues showed a decreasing trend (P<0.05). (3) For antioxidant indices, the activities of super oxide dismutase (SOD) and peroxidase (POD) in treatments (Diet 2#—4#) with supplementation of astaxanthin were significantly lower than those in Diet 1# treatment without supplementation of astaxanthin. The activities of total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) in hemolymph as well as the SOD, T-AOC in hepatopancreas increased significantly with elevated dietary astaxanthin, while a decreasing trend was found for the malondialdehyde (MDA) content in the hemolymph and hepatopancreas. (4) For the immune indices, Diet 4# treatment had the highest activity of acid phosphatase (ACP) in hemolymph and hepatopancreas, while Diet 1# treatment had the significantly higher hemolymph hemocyanin (Hc) content than other treatments (P<0.05). (5) As for the biochemical composition, the increasing trend was found on the contents of total lipids and total carbohydrate in the muscle and hepatopancreas as well as ovarian lipids with increasing dietary astaxanthin, while Diet 2# treatment had the highest total carbohydrate content in the ovaries among the four treatments (P<0.05). In conclusion, dietary supplementation of astaxanthin had no significant effect on ovarian development ofP. trituberculatus, but could improve the coloration, antioxidant capacity and the contents of total lipids and total carbohydrate in edible tissues. These results suggest the appropriate level of astaxanthin in fattening diet was approximately 50 mg/kg for adult female P. trituberculatus.
Swimming crab (Portunus trituberculatus) is an important mariculture crab, and the light color of the pond-reared crabs may be related to low level of dietary astaxanthin. This study was designed to investigate the effects of dietary astaxanthin on ovarian development, coloration, antioxidant capacity, immune performance and biochemical composition of female P. trituberculatus. Haematococcus pluvialis powder was used as natural astaxanthin source to formulate four experimental diets with different astaxanthin levels (0, 26.60, 41.62, and 81.37 mg/kg, defined as Diet 1#—4#). The four experimental diets were fed to female P. trituberculatus for 45 days during the ovarian development; therefore, there were four treatments in this study. The results showed as follows: (1) Dietary astaxanthin had no significant effects on gonadosomatic index (GSI) and hepatosomatic index (HSI). (2) Total carotenoids content, redness (a*) and yellowness (b*) values of hepatopancreas, ovaries and carapace increased significantly with increasing dietary astaxanthin, while the lightness (L*) values of these tissues showed a decreasing trend (P<0.05). (3) For antioxidant indices, the activities of super oxide dismutase (SOD) and peroxidase (POD) in treatments (Diet 2#—4#) with supplementation of astaxanthin were significantly lower than those in Diet 1# treatment without supplementation of astaxanthin. The activities of total antioxidant capacity (T-AOC) and glutathione peroxidase (GSH-Px) in hemolymph as well as the SOD, T-AOC in hepatopancreas increased significantly with elevated dietary astaxanthin, while a decreasing trend was found for the malondialdehyde (MDA) content in the hemolymph and hepatopancreas. (4) For the immune indices, Diet 4# treatment had the highest activity of acid phosphatase (ACP) in hemolymph and hepatopancreas, while Diet 1# treatment had the significantly higher hemolymph hemocyanin (Hc) content than other treatments (P<0.05). (5) As for the biochemical composition, the increasing trend was found on the contents of total lipids and total carbohydrate in the muscle and hepatopancreas as well as ovarian lipids with increasing dietary astaxanthin, while Diet 2# treatment had the highest total carbohydrate content in the ovaries among the four treatments (P<0.05). In conclusion, dietary supplementation of astaxanthin had no significant effect on ovarian development ofP. trituberculatus, but could improve the coloration, antioxidant capacity and the contents of total lipids and total carbohydrate in edible tissues. These results suggest the appropriate level of astaxanthin in fattening diet was approximately 50 mg/kg for adult female P. trituberculatus.
2018, 42(4): 709-718
doi: 10.7541/2018.087
Abstract:
To evaluate the effects of different dietary protein levels on the growth performance, non-specific immunity and protein metabolism enzymes of Rhynchocypris lagowskii Dybowski, diets with 24.98%, 30.02%, 34.99%, 40.01% and 44.98% protein formulated with fish meal, soybean meal, rapeseed meal and cottonseed meal were fed to Rhynchocypris lagowskii Dybowski (6.98±0.01) g for 8 weeks in this study. After the feeding trial, a national standard method was used for determining muscle nutrients, and kits were used to measure serum alkaline acid enzyme (AKP), acid phosphatase (ACP), superoxide dismutase (SOD) and lysozyme (LZM) activity. The results showed that, with the increase in protein levels, final mean body weight, weight gain rate and specific growth rate firstly increased with increasing protein levels, and then decreased. When the protein levels were 34.99% and 40.01%, the final mean body weight, weight gain rate and specific growth rate were significantly higher than that in the groups with 24.98% level (P<0.05). With increasing protein levels in diets, feed and protein efficiencies ofRhynchocypris lagowskii Dybowski firstly increased, and then decreased. Feed and protein efficiencies in 40.01% groups were significantly higher than those in 24.98% groups (P<0.05), but there was no significant difference among groups with 30.02%, 34.99%, and 40.01% protein levels (P>0.05). According to the polynomial regression analysis, the specific growth rate ofRhynchocypris lagowskii Dybowski was the highest when protein level was at 35.89%, and the feed efficiency was the highest when the protein level was at 36.11%. The content of crude protein in muscles increased first, and then decreased with increasing protein levels in diets. Among them, the crude protein content in muscles of 40.01% group was significantly higher than that in the other four groups (P<0.05). However, the crude fat content in muscles decreased first, and then increased with increasing protein levels. The crude fat content in 40.01% group is significantly lower than that in the 24.98%, 30.02%, and 34.99% groups (P<0.05), but the 44.98% group showed no significant difference from other groups (P>0.05). The activities of alkaline phosphatase (AKP), acid phosphatase (ACP), superoxide dismutase (SOD) and lysozyme (LZM) in hepatopancreas increased first, and then decreased with increasing protein levels. The activities of AKP, ACP, SOD, and LZM in the 40.01% group were significantly higher than those in the other four groups (P<0.05). The RNA and RNA/DNA ratios in muscles increased firstly, and then decreased with increasing protein levels. Among them, the RNA content and RNA/DNA in 40.01% group were significantly higher than those in the other four groups (P<0.05). According to the polynomial regression analysis, the RNA content in white muscle was highest when the protein level was 36.10%, and the RNA/DNA ratio was highest in white muscle when the protein level was 35.91%. Therefore, in the formulated diets, the most suitable protein level is 34.99% to 40.01%.
To evaluate the effects of different dietary protein levels on the growth performance, non-specific immunity and protein metabolism enzymes of Rhynchocypris lagowskii Dybowski, diets with 24.98%, 30.02%, 34.99%, 40.01% and 44.98% protein formulated with fish meal, soybean meal, rapeseed meal and cottonseed meal were fed to Rhynchocypris lagowskii Dybowski (6.98±0.01) g for 8 weeks in this study. After the feeding trial, a national standard method was used for determining muscle nutrients, and kits were used to measure serum alkaline acid enzyme (AKP), acid phosphatase (ACP), superoxide dismutase (SOD) and lysozyme (LZM) activity. The results showed that, with the increase in protein levels, final mean body weight, weight gain rate and specific growth rate firstly increased with increasing protein levels, and then decreased. When the protein levels were 34.99% and 40.01%, the final mean body weight, weight gain rate and specific growth rate were significantly higher than that in the groups with 24.98% level (P<0.05). With increasing protein levels in diets, feed and protein efficiencies ofRhynchocypris lagowskii Dybowski firstly increased, and then decreased. Feed and protein efficiencies in 40.01% groups were significantly higher than those in 24.98% groups (P<0.05), but there was no significant difference among groups with 30.02%, 34.99%, and 40.01% protein levels (P>0.05). According to the polynomial regression analysis, the specific growth rate ofRhynchocypris lagowskii Dybowski was the highest when protein level was at 35.89%, and the feed efficiency was the highest when the protein level was at 36.11%. The content of crude protein in muscles increased first, and then decreased with increasing protein levels in diets. Among them, the crude protein content in muscles of 40.01% group was significantly higher than that in the other four groups (P<0.05). However, the crude fat content in muscles decreased first, and then increased with increasing protein levels. The crude fat content in 40.01% group is significantly lower than that in the 24.98%, 30.02%, and 34.99% groups (P<0.05), but the 44.98% group showed no significant difference from other groups (P>0.05). The activities of alkaline phosphatase (AKP), acid phosphatase (ACP), superoxide dismutase (SOD) and lysozyme (LZM) in hepatopancreas increased first, and then decreased with increasing protein levels. The activities of AKP, ACP, SOD, and LZM in the 40.01% group were significantly higher than those in the other four groups (P<0.05). The RNA and RNA/DNA ratios in muscles increased firstly, and then decreased with increasing protein levels. Among them, the RNA content and RNA/DNA in 40.01% group were significantly higher than those in the other four groups (P<0.05). According to the polynomial regression analysis, the RNA content in white muscle was highest when the protein level was 36.10%, and the RNA/DNA ratio was highest in white muscle when the protein level was 35.91%. Therefore, in the formulated diets, the most suitable protein level is 34.99% to 40.01%.
2018, 42(4): 719-727
doi: 10.7541/2018.088
Abstract:
An experiment was conducted to investigate the effects of replacing fish meal (FM) and soybean meal (SBM) by fermented soybean meal (FSBM) on growth performance, serum biochemical indices, and immune genes in giant river prawn, Macrobrachium rosenbergii, and to find a suitable proportion of FSBM to replace FM in diets. Five isonitrogenous and isoenergetic diets were formulated for giant river prawn, among which a basal diet (T0) containing 30% FM and 18% SBM was treated as the control group, and the FM and SBM (2﹕1) in the basal diets replaced by 2% (T2), 5% (T5), 8% (T8) and 15% (T15) of FSBM respectively were treated as experimental diets. Giant river prawns with initial average body weight of (0.17±0.02) g were cultured for 64 days in indoor net cages at a cement tank. Results showed that with increasing FSBM supplemental level, the growth rate and specific growth rate increased firstly and then decreased, and the highest value was found in group T8. Serum superoxide dismutase activity and malondialdehyde content firstly increased and then decreased. MDA of all experimental groups was higher than that of the control group. Serum aspartate transaminase, alanine aminotransferase activity and total protein content had decreasing trend followed by an increasing trend, and the values in all experimental groups were lower than the control group. Gills Toll receptor mRNA and NF-κB mRNA expression levels and hepatopancreas heat shock protein mRNA relative expression levels in group T15 were the highest among all groups. All these results indicated that the replacement of FM and SBM with FSBM would affect growth, antioxidant ability and immunity, and the optimum amount of FSBM was 8% in the diets in this experiment.
An experiment was conducted to investigate the effects of replacing fish meal (FM) and soybean meal (SBM) by fermented soybean meal (FSBM) on growth performance, serum biochemical indices, and immune genes in giant river prawn, Macrobrachium rosenbergii, and to find a suitable proportion of FSBM to replace FM in diets. Five isonitrogenous and isoenergetic diets were formulated for giant river prawn, among which a basal diet (T0) containing 30% FM and 18% SBM was treated as the control group, and the FM and SBM (2﹕1) in the basal diets replaced by 2% (T2), 5% (T5), 8% (T8) and 15% (T15) of FSBM respectively were treated as experimental diets. Giant river prawns with initial average body weight of (0.17±0.02) g were cultured for 64 days in indoor net cages at a cement tank. Results showed that with increasing FSBM supplemental level, the growth rate and specific growth rate increased firstly and then decreased, and the highest value was found in group T8. Serum superoxide dismutase activity and malondialdehyde content firstly increased and then decreased. MDA of all experimental groups was higher than that of the control group. Serum aspartate transaminase, alanine aminotransferase activity and total protein content had decreasing trend followed by an increasing trend, and the values in all experimental groups were lower than the control group. Gills Toll receptor mRNA and NF-κB mRNA expression levels and hepatopancreas heat shock protein mRNA relative expression levels in group T15 were the highest among all groups. All these results indicated that the replacement of FM and SBM with FSBM would affect growth, antioxidant ability and immunity, and the optimum amount of FSBM was 8% in the diets in this experiment.
2018, 42(4): 728-735
doi: 10.7541/2018.089
Abstract:
To assess the effects of dietary supplementation with glutathione (GSH) on tissue GSH levels, immunity, and antioxidant capacity of juvenile yellow catfish (Pelteobagrus fulvidraco), a total of 800 yellow catfish with a mean body weight of (1.32±0.01) g were considered and randomly divided into 5 groups with 4 replicates per each group and 40 fish per each replicate as well. During 56d, the fish were fed by a basal diet and four test diets, which supplemented with 100, 300, 500, and 700 mg/kg of reduced GSH, respectively. The results indicated that, except for 100 mg/kg group, supplementation with GSH significantly increased the GSH content in liver and serum of yellow catfish (P<0.05). When GSH level was 300 mg/kg or higher, GSH content in liver and serum was in a stable state. With the increase of glutathione level, the immunity and antioxidant indices were initially increased, and then decreased. The lysozyme and alkaline phosphatase activities in 300 and 500 mg/kg groups, immunoglobulin M (IgM) and complement component 4 (C4) contents in 300 mg/kg group, and acid phosphatase activity in 500 mg/kg group markedly increased, compared with the control group (P<0.05). There were no significant differences (P>0.05) in complement component 3 (C3) and nitric oxide contents among all groups. Compared with the control and 700 mg/kg groups, the liver superoxide dismutase, catalase and glutathione peroxidase activities, total antioxidant capacity and the serum superoxide dismutase, as well as glutathione peroxidase activities in 300 mg/kg group were significantly higher (P<0.05), while the serum malondialdehyde content in that group was considerably lower (P<0.05). Under ammonia-nitrogen stress for 96h, compared with the control group, the liver and serum superoxide dismutase, catalase, and glutathione peroxidase activities in 300 mg/kg group were significantly greater (P<0.05), however, the serum malondialdehyde content in the mentioned group was significantly lower (P<0.05). In conclusion, dietary supplementation with GSH could enhance the tissue GSH level, immunity and antioxidant capacity of juvenile yellow catfish, and the effective range of this enhancement was 300 to 500 mg/kg as well.
To assess the effects of dietary supplementation with glutathione (GSH) on tissue GSH levels, immunity, and antioxidant capacity of juvenile yellow catfish (Pelteobagrus fulvidraco), a total of 800 yellow catfish with a mean body weight of (1.32±0.01) g were considered and randomly divided into 5 groups with 4 replicates per each group and 40 fish per each replicate as well. During 56d, the fish were fed by a basal diet and four test diets, which supplemented with 100, 300, 500, and 700 mg/kg of reduced GSH, respectively. The results indicated that, except for 100 mg/kg group, supplementation with GSH significantly increased the GSH content in liver and serum of yellow catfish (P<0.05). When GSH level was 300 mg/kg or higher, GSH content in liver and serum was in a stable state. With the increase of glutathione level, the immunity and antioxidant indices were initially increased, and then decreased. The lysozyme and alkaline phosphatase activities in 300 and 500 mg/kg groups, immunoglobulin M (IgM) and complement component 4 (C4) contents in 300 mg/kg group, and acid phosphatase activity in 500 mg/kg group markedly increased, compared with the control group (P<0.05). There were no significant differences (P>0.05) in complement component 3 (C3) and nitric oxide contents among all groups. Compared with the control and 700 mg/kg groups, the liver superoxide dismutase, catalase and glutathione peroxidase activities, total antioxidant capacity and the serum superoxide dismutase, as well as glutathione peroxidase activities in 300 mg/kg group were significantly higher (P<0.05), while the serum malondialdehyde content in that group was considerably lower (P<0.05). Under ammonia-nitrogen stress for 96h, compared with the control group, the liver and serum superoxide dismutase, catalase, and glutathione peroxidase activities in 300 mg/kg group were significantly greater (P<0.05), however, the serum malondialdehyde content in the mentioned group was significantly lower (P<0.05). In conclusion, dietary supplementation with GSH could enhance the tissue GSH level, immunity and antioxidant capacity of juvenile yellow catfish, and the effective range of this enhancement was 300 to 500 mg/kg as well.
2018, 42(4): 736-743
doi: 10.7541/2018.090
Abstract:
The study was conducted to evaluate the effects of dietary protein levels on evolution, body composition, liver biochemical indices, as well as digestive enzymes activities of juvenile Chinese crucian carp. Six isolipidic and isoenergetic diets were formulated containing 30.18%, 33.13%, 36.16%, 39.34%, 42.32%, and 45.46%, respectively. A total of 540 juvenile Chinese crucian carp with the average initial weight of (3.10 ± 0.01) g were randomly distributed into six groups with three replicates per group, containing 30 juvenile Chinese crucian carp per replicate, which were fed for eight weeks. The results indicated that with the increase of dietary protein level, the weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER), the whole body protein content (WBPC), the hepatic glutamic-pyruvic transaminase (GPT), and intestinal trypsin (TPS) activities of fish in 36.16% group were significantly higher than those in other groups (P<0.05). The hepatic total cholesterol (HTC) and triglyceride (TG) content of fish in 30.18% group were remarkably higher than those in other groups except for 33.13% group. Based on the quadratic regression analysis of theSGR, PER, and dietary protein levels, it was revealed that the rate of optimal dietary protein for Chinese crucian carp ranges from 35.29% to 37.07% under the experimental condition.
The study was conducted to evaluate the effects of dietary protein levels on evolution, body composition, liver biochemical indices, as well as digestive enzymes activities of juvenile Chinese crucian carp. Six isolipidic and isoenergetic diets were formulated containing 30.18%, 33.13%, 36.16%, 39.34%, 42.32%, and 45.46%, respectively. A total of 540 juvenile Chinese crucian carp with the average initial weight of (3.10 ± 0.01) g were randomly distributed into six groups with three replicates per group, containing 30 juvenile Chinese crucian carp per replicate, which were fed for eight weeks. The results indicated that with the increase of dietary protein level, the weight gain rate (WGR), specific growth rate (SGR), feed efficiency (FE), protein efficiency ratio (PER), the whole body protein content (WBPC), the hepatic glutamic-pyruvic transaminase (GPT), and intestinal trypsin (TPS) activities of fish in 36.16% group were significantly higher than those in other groups (P<0.05). The hepatic total cholesterol (HTC) and triglyceride (TG) content of fish in 30.18% group were remarkably higher than those in other groups except for 33.13% group. Based on the quadratic regression analysis of theSGR, PER, and dietary protein levels, it was revealed that the rate of optimal dietary protein for Chinese crucian carp ranges from 35.29% to 37.07% under the experimental condition.
2018, 42(4): 744-750
doi: 10.7541/2018.091
Abstract:
Starvation is a special period when fish cannot effectively obtain food, resulting to some problems (i.e., lack of energy required). DHA (Docosahexaenoic acid), being highly unsaturated fatty acids retained in body during starvation, is postulated to contain special energy regulation effect on the starving fish body. To explore the effect of DHA fortification on body weight loss and lipid metabolism of starved common carp (Cyprinus carpio L.) in two dietary lipid levels, a feeding trail, which followed with starvation, was conducted. Firstly, 3% DHA product was added to 6% and 12% lipid levels diets to formulate four different kinds of diet respectively, (i.e., basic diet, basic-DHA diet, high lipid diet, and high lipid-DHA diet). A total of 360 common carp (14.81±0.13) g/tail were randomly divided into four groups (triplicate per each group), fed with four diets and reared in a recycling water rearing tanks, respectively. After 74 days of feeding, some fish per each tank were sampled and eventually 6 fish per each tank were left to endure 36 days of starvation. Then, all staved fish were sampled and weight of fish and the relative indexes were determined. Result showed that the body weight loss ratio of fish in DHA groups was significantly higher than that of the non-DHA groups in the same lipid level. Besides, the hepatocyte diameter and lipid content in muscle and intestine of starved fish in DHA groups were remarkably lower than that of the non-DHA groups (P<0.05). The lipid content in hepatosomatic and serum biochemical index of fish showed that there is no significant difference. The achieved result demonstrated that DHA fortification dietary groups had significantly lower body weight, hepatocyte diameter, as well as lipid content of muscle and intestine in starved common carp, which may reflect that DHA fortification had no great advantages in fostering common carp endure starvation.
Starvation is a special period when fish cannot effectively obtain food, resulting to some problems (i.e., lack of energy required). DHA (Docosahexaenoic acid), being highly unsaturated fatty acids retained in body during starvation, is postulated to contain special energy regulation effect on the starving fish body. To explore the effect of DHA fortification on body weight loss and lipid metabolism of starved common carp (Cyprinus carpio L.) in two dietary lipid levels, a feeding trail, which followed with starvation, was conducted. Firstly, 3% DHA product was added to 6% and 12% lipid levels diets to formulate four different kinds of diet respectively, (i.e., basic diet, basic-DHA diet, high lipid diet, and high lipid-DHA diet). A total of 360 common carp (14.81±0.13) g/tail were randomly divided into four groups (triplicate per each group), fed with four diets and reared in a recycling water rearing tanks, respectively. After 74 days of feeding, some fish per each tank were sampled and eventually 6 fish per each tank were left to endure 36 days of starvation. Then, all staved fish were sampled and weight of fish and the relative indexes were determined. Result showed that the body weight loss ratio of fish in DHA groups was significantly higher than that of the non-DHA groups in the same lipid level. Besides, the hepatocyte diameter and lipid content in muscle and intestine of starved fish in DHA groups were remarkably lower than that of the non-DHA groups (P<0.05). The lipid content in hepatosomatic and serum biochemical index of fish showed that there is no significant difference. The achieved result demonstrated that DHA fortification dietary groups had significantly lower body weight, hepatocyte diameter, as well as lipid content of muscle and intestine in starved common carp, which may reflect that DHA fortification had no great advantages in fostering common carp endure starvation.
2018, 42(4): 751-761
doi: 10.7541/2018.092
Abstract:
According to previous studies on fish angling, a correlation has been established between vulnerability to angling and metabolic traits in fish. However, it still remains unknown that whether other phenotypes (i.e., swimming performance and personality) of fish are related to the vulnerability to angling. To examine the phenotypic basis, ecological consequences and fasting responses to angling in Cyprinids fish, juvenile gibel carp (Carassius auratus gibelio) was used as experimental model in this study. This study first measured the phenotypic traits (i.e. energy metabolism, swimming performance and personality) of the experimental fish, and then the fish were angled in the buckets (named as control group) under laboratory condition. After all measurements of phenotypes and angling having been completed, all fish were fasted for 7 days and angled again at the end of fasting period (named as fasting group), following by a 14-day period of continuous feeding (named as refeeding group). There were four parallel angling samples (n=40 individuals per sample) in each angling test, which was ceased when the 20th individual was successfully angled. The angled 20 individuals were considered as angling group (i.e. higher vulnerability to angling), and the other 20 individuals were considered as un-angling group (i.e. lower vulnerability to angling). The factorial aerobic scope of the angling group was smaller than that of the un-angling group. The results showed that no differences in morphology (body weight, body length and condition factor), energy metabolism (standard metabolic rate, SMR; maximum metabolic rate, MMR; and aerobic scope, AS), swimming performance (maximum accelerated swimming capacity, Ucat; and gait transition speed, Ugt), and personality (exploration, activity and boldness) between the angling group and the un-angling group. The fish had a higher percent latency in the exploration test than that in the boldness test, which led to shorter time spent in moving and lower frequency in passing through door in the exploration test than those in the boldness test. SMR was not related to Ucat and Ugt (P>0.05), whereas MMR and AS were positively correlated with bothUcat and Ugt (P<0.05). The energy metabolic parameters were related to some personality parameters. Fasting increased the total angling time, average individual angling time and coefficient variance of the individual angling time in juvenile gibel carp. The specific growth rate (SGR) of body mass was higher in the un-angling group than that in the angling group during the fasting period, but no difference in SGR was found between the un-angling group and the angling group during the refeeding period. With the exception of MMR and AS, SMR was negatively related to SGR during both the fasting period and the refeeding period (P<0.05), suggesting that higher SMR individuals decreased their body mass faster during fasting, and grew slower during refeeding. Our study suggested that the juvenile gibel carp may not have the phenotypic basis, and would decrease their vulnerability to angling due to fasting. There was difference in the ecological consequences between two phenotypes of vulnerability to angling, but this difference disappeared after the 14-day period of refeeding, indicating that the vulnerability to angling of the juvenile gibel carp is context-dependent to some extent.
According to previous studies on fish angling, a correlation has been established between vulnerability to angling and metabolic traits in fish. However, it still remains unknown that whether other phenotypes (i.e., swimming performance and personality) of fish are related to the vulnerability to angling. To examine the phenotypic basis, ecological consequences and fasting responses to angling in Cyprinids fish, juvenile gibel carp (Carassius auratus gibelio) was used as experimental model in this study. This study first measured the phenotypic traits (i.e. energy metabolism, swimming performance and personality) of the experimental fish, and then the fish were angled in the buckets (named as control group) under laboratory condition. After all measurements of phenotypes and angling having been completed, all fish were fasted for 7 days and angled again at the end of fasting period (named as fasting group), following by a 14-day period of continuous feeding (named as refeeding group). There were four parallel angling samples (n=40 individuals per sample) in each angling test, which was ceased when the 20th individual was successfully angled. The angled 20 individuals were considered as angling group (i.e. higher vulnerability to angling), and the other 20 individuals were considered as un-angling group (i.e. lower vulnerability to angling). The factorial aerobic scope of the angling group was smaller than that of the un-angling group. The results showed that no differences in morphology (body weight, body length and condition factor), energy metabolism (standard metabolic rate, SMR; maximum metabolic rate, MMR; and aerobic scope, AS), swimming performance (maximum accelerated swimming capacity, Ucat; and gait transition speed, Ugt), and personality (exploration, activity and boldness) between the angling group and the un-angling group. The fish had a higher percent latency in the exploration test than that in the boldness test, which led to shorter time spent in moving and lower frequency in passing through door in the exploration test than those in the boldness test. SMR was not related to Ucat and Ugt (P>0.05), whereas MMR and AS were positively correlated with bothUcat and Ugt (P<0.05). The energy metabolic parameters were related to some personality parameters. Fasting increased the total angling time, average individual angling time and coefficient variance of the individual angling time in juvenile gibel carp. The specific growth rate (SGR) of body mass was higher in the un-angling group than that in the angling group during the fasting period, but no difference in SGR was found between the un-angling group and the angling group during the refeeding period. With the exception of MMR and AS, SMR was negatively related to SGR during both the fasting period and the refeeding period (P<0.05), suggesting that higher SMR individuals decreased their body mass faster during fasting, and grew slower during refeeding. Our study suggested that the juvenile gibel carp may not have the phenotypic basis, and would decrease their vulnerability to angling due to fasting. There was difference in the ecological consequences between two phenotypes of vulnerability to angling, but this difference disappeared after the 14-day period of refeeding, indicating that the vulnerability to angling of the juvenile gibel carp is context-dependent to some extent.
2018, 42(4): 762-769
doi: 10.7541/2018.093
Abstract:
Age structure and growth characteristics of Culter alburnus provide a theoretical basis for the artificial reproduction, sexual maturity age, survival rate to optimize the structure of fish stocks, the scientific use of its germplasm resources and to provide reference resource utilization and conservation of the species. To study the relationship between age structure and growth characteristics, a total of 452 Culter alburnus individuals were collected in the Dianshan Lake from May 2016 to July 2017. The results showed that the body length of Culter alburnus ranged from 15.32 to 77.91 cm, and that body weight ranged from 43 to 5567 g. There were no significant differences in body length and body weight between female and male (P>0.05). The relationship between body weight and body length was described by the linear equation:W=0.00002L2.9211 (R2=0.9143, n=452), which is consistent with uniform growth characteristics. The growth pattern of Culter alburnus was described by the von Bertalanffy equation as Lt=99.65[1–e–0.1357(t+0.6287)], Wt=11874.27[1–e–0.1357(t+0.6287)]2.9211, selection of scale identification age, measurement scale radius. The age of the fish ranged from one to six years with dominated ones with three year-old (55.71%), which revealed a growth trend of youth and miniaturization. The inflection point of the growth curve occurred at 7.2711 years with a body length of 65.54 cm and weight of 3471.79 g.
Age structure and growth characteristics of Culter alburnus provide a theoretical basis for the artificial reproduction, sexual maturity age, survival rate to optimize the structure of fish stocks, the scientific use of its germplasm resources and to provide reference resource utilization and conservation of the species. To study the relationship between age structure and growth characteristics, a total of 452 Culter alburnus individuals were collected in the Dianshan Lake from May 2016 to July 2017. The results showed that the body length of Culter alburnus ranged from 15.32 to 77.91 cm, and that body weight ranged from 43 to 5567 g. There were no significant differences in body length and body weight between female and male (P>0.05). The relationship between body weight and body length was described by the linear equation:W=0.00002L2.9211 (R2=0.9143, n=452), which is consistent with uniform growth characteristics. The growth pattern of Culter alburnus was described by the von Bertalanffy equation as Lt=99.65[1–e–0.1357(t+0.6287)], Wt=11874.27[1–e–0.1357(t+0.6287)]2.9211, selection of scale identification age, measurement scale radius. The age of the fish ranged from one to six years with dominated ones with three year-old (55.71%), which revealed a growth trend of youth and miniaturization. The inflection point of the growth curve occurred at 7.2711 years with a body length of 65.54 cm and weight of 3471.79 g.
2018, 42(4): 770-778
doi: 10.7541/2018.094
Abstract:
Ink turtle is one stain of P. sinensis in south Anhui province, which is very popular in local market. In this study, the differences of basic nutrient compositions, including amino acid and fatty acid contents in the muscles, and collagen contents in the calipash of four strains of P.sinensis were compared, which are ink turtle, wild turtle, Huai River turtle, and T. japonicus. The results showed as follows: (1) the moisture contents in the muscles of four strains were 80.40%, 79.48%, 81.57% and 79.25%, respectively. The moisture contents in ink turtles and Huai River turtles were significantly higher than those in the wild turtle and T. japonicas (P<0.05). The crude protein contents in the four strains were 17.82%, 17.60%, 15.93% and 16.40%, respectively. The crude protein content in ink turtle was the highest, which was significantly higher than that in the Huai River turtle andT. japonicus (P<0.05). The crude fat contents were 0.42%, 1.43%, 0.65% and 1.06%, respectively. The crude fat content in ink turtles was significantly lower than that in other strains (P<0.05), while the ash showed no significant difference among each other (P>0.05). (2) The ink turtle had the highest contents of TAA and DAA in muscles. (3) The UFA in the four strains ofP. sinensis was 65.19%, 56.44%, 59.20% and 54.73%, respectively, which was significantly higher in the ink turtle than in other strains (P<0.05). The content of MUFA in ink turtle was significantly lower than in wild turtle, while the content of PUFA in ink turtle was significantly higher than in other strains (P<0.05). The contents of SFA in the four strains ofP. sinensis were 35.20%, 41.85%, 39.41% and 39.98%, respectively, which was significantly lower in ink turtle than that in other strains (P<0.05). (4) The contents of DHA and EPA in ink turtle were significantly higher than those in the Huai River turtle andT. japonicus , which had no significant difference with those in wild turtle. AA in muscles of ink turtle was significantly higher than that in other stains (P<0.05). (5) There was no obvious difference in the collagen content at calipash among the four strains ofP. sinensis (P>0.05). Therefore, the ink turtle is an indigenous strain with high nutritive value and delicious flavor.
Ink turtle is one stain of P. sinensis in south Anhui province, which is very popular in local market. In this study, the differences of basic nutrient compositions, including amino acid and fatty acid contents in the muscles, and collagen contents in the calipash of four strains of P.sinensis were compared, which are ink turtle, wild turtle, Huai River turtle, and T. japonicus. The results showed as follows: (1) the moisture contents in the muscles of four strains were 80.40%, 79.48%, 81.57% and 79.25%, respectively. The moisture contents in ink turtles and Huai River turtles were significantly higher than those in the wild turtle and T. japonicas (P<0.05). The crude protein contents in the four strains were 17.82%, 17.60%, 15.93% and 16.40%, respectively. The crude protein content in ink turtle was the highest, which was significantly higher than that in the Huai River turtle andT. japonicus (P<0.05). The crude fat contents were 0.42%, 1.43%, 0.65% and 1.06%, respectively. The crude fat content in ink turtles was significantly lower than that in other strains (P<0.05), while the ash showed no significant difference among each other (P>0.05). (2) The ink turtle had the highest contents of TAA and DAA in muscles. (3) The UFA in the four strains ofP. sinensis was 65.19%, 56.44%, 59.20% and 54.73%, respectively, which was significantly higher in the ink turtle than in other strains (P<0.05). The content of MUFA in ink turtle was significantly lower than in wild turtle, while the content of PUFA in ink turtle was significantly higher than in other strains (P<0.05). The contents of SFA in the four strains ofP. sinensis were 35.20%, 41.85%, 39.41% and 39.98%, respectively, which was significantly lower in ink turtle than that in other strains (P<0.05). (4) The contents of DHA and EPA in ink turtle were significantly higher than those in the Huai River turtle andT. japonicus , which had no significant difference with those in wild turtle. AA in muscles of ink turtle was significantly higher than that in other stains (P<0.05). (5) There was no obvious difference in the collagen content at calipash among the four strains ofP. sinensis (P>0.05). Therefore, the ink turtle is an indigenous strain with high nutritive value and delicious flavor.
2018, 42(4): 779-785
doi: 10.7541/2018.095
Abstract:
In this study, the cDNA sequence of Vitellogenin (Vtg) gene in Chinese sturgeon Acipenser sinensis was amplified with the rapid amplification of cDNA end (RACE) method, and its theoretical molecular mass is 196 kD. The antigenic site of the encoded amino acid sequence was cloned, which was used to construct recombinant plasmid and express recombinant protein. The polyclonal antiserum was obtained by immunizing rabbits with purified recombinant protein, and its specificity to Vtg was examined by western blotting. A competitive Enzyme-linked immunosorbent assay (ELISA) was established to detect Vtg in the serum of A. sinensis using antiserum of Vtg as antibody and the purified recombinant protein as antigen. The linear regression of the standard curve was y=–0.2916x+0.6794 (R2=0.9976). The sensitivity of this method was 4.12 μg/mL, and the lowest threshold for detection was 0.3 μg/mL. The inter- and intra-assay coefficients of variation was 2.52% (n=3) and 3.42% (n=3), respectively. The test results of blood sample for the female A. sinensis at different developmental stages showed that the method could be used to monitor the gonadal development of female Chinese sturgeon.
In this study, the cDNA sequence of Vitellogenin (Vtg) gene in Chinese sturgeon Acipenser sinensis was amplified with the rapid amplification of cDNA end (RACE) method, and its theoretical molecular mass is 196 kD. The antigenic site of the encoded amino acid sequence was cloned, which was used to construct recombinant plasmid and express recombinant protein. The polyclonal antiserum was obtained by immunizing rabbits with purified recombinant protein, and its specificity to Vtg was examined by western blotting. A competitive Enzyme-linked immunosorbent assay (ELISA) was established to detect Vtg in the serum of A. sinensis using antiserum of Vtg as antibody and the purified recombinant protein as antigen. The linear regression of the standard curve was y=–0.2916x+0.6794 (R2=0.9976). The sensitivity of this method was 4.12 μg/mL, and the lowest threshold for detection was 0.3 μg/mL. The inter- and intra-assay coefficients of variation was 2.52% (n=3) and 3.42% (n=3), respectively. The test results of blood sample for the female A. sinensis at different developmental stages showed that the method could be used to monitor the gonadal development of female Chinese sturgeon.
2018, 42(4): 786-793
doi: 10.7541/2018.096
Abstract:
This study conducted isolation, identification and drugs sensitivity of pathogen from sick Trionyx sinensis to provide a reference for control and prevention disease for Trionyx sinensis. The pathogenic bacteria were isolated and purified from skin, liver, kidney and spleen of Trionyx sinensis. The identification of the isolated pathogen was analyzed by biochemical reactions and 16S rRNA gene sequence. The artificial infection test was performed with intraperitoneal injection, and drugs susceptibility test was conducted by K-B method and double broth dilution method. The results showed that strain J22 was the pathogen of Trionyx sinensis, and the LD50 was 3.30×104 CFU/g. According to morphological and biochemical characteristics as well as 16S rRNA gene sequence analysis, strain J22 was identified as Chryseobacterium indologenes. Strain J22 was susceptible to neomycin, gentamicin and amoxicillin and other 9 antibiotics but resistant to florfenicol and doxycycline, etc. The chlorine dioxide, bleaching powder and potassium ferrate had great antiseptic effect on the isolated pathogeb. These results indicate that Strain J22-induced disease of Trionyx sinensis can be treat by drugs such as neomycin, gentamicin and amoxicillin for oral administration, and that chlorine dioxide, bleaching powder and potassium ferrate are suitable for external use in farming.
This study conducted isolation, identification and drugs sensitivity of pathogen from sick Trionyx sinensis to provide a reference for control and prevention disease for Trionyx sinensis. The pathogenic bacteria were isolated and purified from skin, liver, kidney and spleen of Trionyx sinensis. The identification of the isolated pathogen was analyzed by biochemical reactions and 16S rRNA gene sequence. The artificial infection test was performed with intraperitoneal injection, and drugs susceptibility test was conducted by K-B method and double broth dilution method. The results showed that strain J22 was the pathogen of Trionyx sinensis, and the LD50 was 3.30×104 CFU/g. According to morphological and biochemical characteristics as well as 16S rRNA gene sequence analysis, strain J22 was identified as Chryseobacterium indologenes. Strain J22 was susceptible to neomycin, gentamicin and amoxicillin and other 9 antibiotics but resistant to florfenicol and doxycycline, etc. The chlorine dioxide, bleaching powder and potassium ferrate had great antiseptic effect on the isolated pathogeb. These results indicate that Strain J22-induced disease of Trionyx sinensis can be treat by drugs such as neomycin, gentamicin and amoxicillin for oral administration, and that chlorine dioxide, bleaching powder and potassium ferrate are suitable for external use in farming.
2018, 42(4): 794-799
doi: 10.7541/2018.097
Abstract:
The Asian giant softshell turtle Pelochelys cantorii (Trionychidae) is seriously endangered and has designated as the first grade of protected animal in China in 1989. In 2000, it has been listed as endangered species by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, and put on par along with the Giant panda Ailuropoda melanoleuca and the white-flag dolphin Lipotes vexillifer. This animal typically suffers from gradual reduction in its total population because of inadequate safety, food, and health protections. Sparse data, extensively referred in the literature, emphasize on the reproductive for this species, in order to enhance individuals’ knowledge about the reproduction of P. cantorii. For this purpose, we attempted to study the nesting behavior, clutch size, egg size, incubation period, as well as other reproductive characteristics of 4 adults (2♂, 2♀) under captive conditions from 2015 to 2017. Oviposition season is commenced from May to August; the egg-laying behaviors are typically occurred at the night. Clutches are made up of eggs with spherical and rigid shells without parental care behaviors. All adult females laid 5—6 clutches [mean egg number=(42.6±5.3); (32—55); n=21] during the breeding season in 2015 and 2016. In 2016, the mean egg’s mass, egg’s diameter, and mass of the newly hatchings were (16.82±1.99) g (n=476), (3.10±0.18) cm (n=476), and (13.60±0.85) g (n=202), respectively. Analysis of reproductive data obtained by 2016 based on the size and mass of the eggs, which were positively correlated (r=0.916, P<0.01), showed that there was no significant difference in average size of clutch between these two females (Using analysis of variance (ANOVA),F1,9=0.442, P=0.283). The weight of female No. 1 was more than that of female No. 2, the mass of female No. 1’s egg and newly hatchings were both more than that of female No. 2 as well. The juveniles fed by live fish seedlings could be reared to (510.30±82.77) g in the greenhouse for one year. The achieved findings affiliated with reproduction traits in P. cantorii can shield some light, and those results might be used to improve the conservation of the species.
The Asian giant softshell turtle Pelochelys cantorii (Trionychidae) is seriously endangered and has designated as the first grade of protected animal in China in 1989. In 2000, it has been listed as endangered species by the International Union for Conservation of Nature (IUCN) Red List of Threatened Species, and put on par along with the Giant panda Ailuropoda melanoleuca and the white-flag dolphin Lipotes vexillifer. This animal typically suffers from gradual reduction in its total population because of inadequate safety, food, and health protections. Sparse data, extensively referred in the literature, emphasize on the reproductive for this species, in order to enhance individuals’ knowledge about the reproduction of P. cantorii. For this purpose, we attempted to study the nesting behavior, clutch size, egg size, incubation period, as well as other reproductive characteristics of 4 adults (2♂, 2♀) under captive conditions from 2015 to 2017. Oviposition season is commenced from May to August; the egg-laying behaviors are typically occurred at the night. Clutches are made up of eggs with spherical and rigid shells without parental care behaviors. All adult females laid 5—6 clutches [mean egg number=(42.6±5.3); (32—55); n=21] during the breeding season in 2015 and 2016. In 2016, the mean egg’s mass, egg’s diameter, and mass of the newly hatchings were (16.82±1.99) g (n=476), (3.10±0.18) cm (n=476), and (13.60±0.85) g (n=202), respectively. Analysis of reproductive data obtained by 2016 based on the size and mass of the eggs, which were positively correlated (r=0.916, P<0.01), showed that there was no significant difference in average size of clutch between these two females (Using analysis of variance (ANOVA),F1,9=0.442, P=0.283). The weight of female No. 1 was more than that of female No. 2, the mass of female No. 1’s egg and newly hatchings were both more than that of female No. 2 as well. The juveniles fed by live fish seedlings could be reared to (510.30±82.77) g in the greenhouse for one year. The achieved findings affiliated with reproduction traits in P. cantorii can shield some light, and those results might be used to improve the conservation of the species.
2018, 42(4): 800-810
doi: 10.7541/2018.098
Abstract:
Illex argentinus is one of the most important ommastrephid squids, due to its annual landing volume, and its key role as transient ‘biological pumps’ in southwest Atlantic ecosystem. In order to understand the fecundity characteristics of male ommastrephids, specimens of male I. argentinus, collected from December 2012 to March 2013, were used to analyze the fecundity and its relationship to reproductive development with biological statistics analysis. The results showed that the minimum biological size was 207.29 mm for mantle length (ML) and 162.55 g for body weight (BW). The effective fecundity (EF), defined as the sum of normal spermatophores in spermatophoric complex and spermatophoric sac, was in an average of (374±280.33) spermatophores. The mean value of relative effective fecundity by mantle length was (179.18±117.66) spermatophores per millimeter. The length of spermatophores (SL) varied from 6.34 to 33.14 mm, and its mean value was (21.57±4.17) mm, which was (10.22±1.82)% of mantle length. Both EF and SL significantly increased with the onset of sexual maturation (P<0.05). EF attained the maximum value at functionally maturity stage (Ⅵ), with a mean value of (811±181.34) spermatophores. SL increased up to the mating stage (Ⅶ), whereby it attained a mean value of (23.89±3.87) mm. Meanwhile, both EF and SL showed significantly linear relation with mantle length (EF=–581.92+4.56ML, R2=0.17, P<0.05;SL=5.77+0.075ML, R2=0.23, P<0.05) and body weight (EF=16.55+1.77BW, R2=0.37, P<0.05;SL=17.96+0.017BW, R2=0.17, P<0.05), indicating that individual with bigger size has larger EF and longer SL. Furthermore, the compare datasets of fitted model analysis revealed that there was no significant difference between the linear relationship of EF-ML and that of EF-BW (P>0.05). Based on multiple regression analysis, however, the influence on EF from body weight was more significant than that from mantle length (P<0.05). The compare datasets of fitted model analysis for SL showed that there was significant difference between the linear relationship of SL-ML and that of SL-BW (P<0.001), although the multiple regression analysis suggested a comparative influence on SL from both mantle length and body weight (P<0.001). These findings indicated that the EF of maleI. argentinus was a strategy of adaptability to its short lifespan by producing and accumulating spermatophores along with reproductive development and body growth, and the length of spermatophores will also increase with time.
Illex argentinus is one of the most important ommastrephid squids, due to its annual landing volume, and its key role as transient ‘biological pumps’ in southwest Atlantic ecosystem. In order to understand the fecundity characteristics of male ommastrephids, specimens of male I. argentinus, collected from December 2012 to March 2013, were used to analyze the fecundity and its relationship to reproductive development with biological statistics analysis. The results showed that the minimum biological size was 207.29 mm for mantle length (ML) and 162.55 g for body weight (BW). The effective fecundity (EF), defined as the sum of normal spermatophores in spermatophoric complex and spermatophoric sac, was in an average of (374±280.33) spermatophores. The mean value of relative effective fecundity by mantle length was (179.18±117.66) spermatophores per millimeter. The length of spermatophores (SL) varied from 6.34 to 33.14 mm, and its mean value was (21.57±4.17) mm, which was (10.22±1.82)% of mantle length. Both EF and SL significantly increased with the onset of sexual maturation (P<0.05). EF attained the maximum value at functionally maturity stage (Ⅵ), with a mean value of (811±181.34) spermatophores. SL increased up to the mating stage (Ⅶ), whereby it attained a mean value of (23.89±3.87) mm. Meanwhile, both EF and SL showed significantly linear relation with mantle length (EF=–581.92+4.56ML, R2=0.17, P<0.05;SL=5.77+0.075ML, R2=0.23, P<0.05) and body weight (EF=16.55+1.77BW, R2=0.37, P<0.05;SL=17.96+0.017BW, R2=0.17, P<0.05), indicating that individual with bigger size has larger EF and longer SL. Furthermore, the compare datasets of fitted model analysis revealed that there was no significant difference between the linear relationship of EF-ML and that of EF-BW (P>0.05). Based on multiple regression analysis, however, the influence on EF from body weight was more significant than that from mantle length (P<0.05). The compare datasets of fitted model analysis for SL showed that there was significant difference between the linear relationship of SL-ML and that of SL-BW (P<0.001), although the multiple regression analysis suggested a comparative influence on SL from both mantle length and body weight (P<0.001). These findings indicated that the EF of maleI. argentinus was a strategy of adaptability to its short lifespan by producing and accumulating spermatophores along with reproductive development and body growth, and the length of spermatophores will also increase with time.
2018, 42(4): 811-818
doi: 10.7541/2018.099
Abstract:
In this study, an oil-producing alga was isolated and identified from soil at Pangquangou National Nature Reserve (Shanxi province, China), and cultivated under axenic conditions. Based on morphological observations, it was similar to the genus Chlorella. The phylogenetic analysis according to ribulose-bisphosphate carboxylase gene (rbcL) and 18S ribosomal RNA (18S rDNA) showed that it has the highest homology with Ch. vulgaris, so the strain was identified as Ch. vulgaris PQG67. It produced a lipid content within 30% after continuous culture with different light intensities, as well as more than 40% after affecting by salt (NaCl) stress. Fourier-transform infrared spectroscopy (FTIR) of the produced oil showed lipid band intensity from spectra vCO at 1634/cm, and continued to increase in Ch. vulgaris PQG67 cells during experimental test. The alga possessed high biomass and oil-producing potentials for utilization in biodiesel production.
In this study, an oil-producing alga was isolated and identified from soil at Pangquangou National Nature Reserve (Shanxi province, China), and cultivated under axenic conditions. Based on morphological observations, it was similar to the genus Chlorella. The phylogenetic analysis according to ribulose-bisphosphate carboxylase gene (rbcL) and 18S ribosomal RNA (18S rDNA) showed that it has the highest homology with Ch. vulgaris, so the strain was identified as Ch. vulgaris PQG67. It produced a lipid content within 30% after continuous culture with different light intensities, as well as more than 40% after affecting by salt (NaCl) stress. Fourier-transform infrared spectroscopy (FTIR) of the produced oil showed lipid band intensity from spectra vCO at 1634/cm, and continued to increase in Ch. vulgaris PQG67 cells during experimental test. The alga possessed high biomass and oil-producing potentials for utilization in biodiesel production.
2018, 42(4): 819-823
doi: 10.7541/2018.100
Abstract:
HSJ296, a Scenedesmus strain isolated and purified by this lab, can grow heterotrophically in the dark and contains a relatively high amount of α-linolenic acid. Comparisons of heterotrophic growth at different temperatures and concentrations of glucose, or with different nitrogen sources, indicated that the optimal culture conditions included 30℃, 4 g/L urea and 20—40 g/L glucose. As shown with fatty acid composition analyses under different conditions, the fatty acids of HSJ296 were mainly composed of hexadecanoic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2) and α-linolenic acid (α-C18:3), and the α-linolenic acid content in total lipids was between 35%—45% in independent experiments. The fermentation product of Scenedesmus HSJ296 may be used as a fish dietary supplement to supply α-linolenic acid and other nutrients.
HSJ296, a Scenedesmus strain isolated and purified by this lab, can grow heterotrophically in the dark and contains a relatively high amount of α-linolenic acid. Comparisons of heterotrophic growth at different temperatures and concentrations of glucose, or with different nitrogen sources, indicated that the optimal culture conditions included 30℃, 4 g/L urea and 20—40 g/L glucose. As shown with fatty acid composition analyses under different conditions, the fatty acids of HSJ296 were mainly composed of hexadecanoic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2) and α-linolenic acid (α-C18:3), and the α-linolenic acid content in total lipids was between 35%—45% in independent experiments. The fermentation product of Scenedesmus HSJ296 may be used as a fish dietary supplement to supply α-linolenic acid and other nutrients.
2018, 42(4): 824-831
doi: 10.7541/2018.101
Abstract:
Thalassiosira Cleve is one of the most speciose marine diatom genera, that has been globally distributed. To assess the diversity of the genus Thalassiosira species, monoclonal strains were isolated and established from Chinese coast. The morphology was observed by using a light microscope (LM) and a scanning electron microscope (SEM). Sequences of the large subunit (LSU) and small subunit (SSU) of the nuclear rRNA-encoding genes (rDNA) were obtained to form a phylogenetic relationship. Among 14 established Thalassiosira allenii (T. allenii) Takano strains, morphological variation was found involving some with and without marginal ribs on the valve edge. After comparing with the original description of T. allenii, the strains without marginal ribs were assigned as a type of T. allenii, and those with marginal ribs were proposed as a new variety, T. allenii var. striata. Morphological divergence was supported by molecular data as well. On the phylogenetic trees inferred from both LSU and SSU of the nuclear rDNA, accordingly, T. allenii was clustered with var. striata, and formed as sister groups (Bayesian posterior probability (BPP) > 0.90), demonstrating their firm relationship. SSU sequences are totally identical, without any different base pair, between these two varieties. However, 11 different base pairs among 556 LSU base pair, which used for analysis, could be found, and divergence of distance among them is only 0.01.
Thalassiosira Cleve is one of the most speciose marine diatom genera, that has been globally distributed. To assess the diversity of the genus Thalassiosira species, monoclonal strains were isolated and established from Chinese coast. The morphology was observed by using a light microscope (LM) and a scanning electron microscope (SEM). Sequences of the large subunit (LSU) and small subunit (SSU) of the nuclear rRNA-encoding genes (rDNA) were obtained to form a phylogenetic relationship. Among 14 established Thalassiosira allenii (T. allenii) Takano strains, morphological variation was found involving some with and without marginal ribs on the valve edge. After comparing with the original description of T. allenii, the strains without marginal ribs were assigned as a type of T. allenii, and those with marginal ribs were proposed as a new variety, T. allenii var. striata. Morphological divergence was supported by molecular data as well. On the phylogenetic trees inferred from both LSU and SSU of the nuclear rDNA, accordingly, T. allenii was clustered with var. striata, and formed as sister groups (Bayesian posterior probability (BPP) > 0.90), demonstrating their firm relationship. SSU sequences are totally identical, without any different base pair, between these two varieties. However, 11 different base pairs among 556 LSU base pair, which used for analysis, could be found, and divergence of distance among them is only 0.01.
2018, 42(4): 832-838
doi: 10.7541/2018.102
Abstract:
In order to investigate the effects of indole-3-acetic acid (IAA) on physiological characteristics of Microcystis aeruginosa (M. aeruginosa), the growth, photosynthetic pigment content, chlorophyll fluorescence, lipid oxidation, and microcystin biosynthesis characteristics were studied. The achieved results showed that there was no significant variation in cell density, chlorophyll content, chlorophyll fluorescence characteristics, and microcystin contents at low concentrations of IAA (e.g., 0.04 and 0.2 mg/L). However the contents of phycocyanin, allophycocyanin, and malondialdehyde (MDA) decreased in comparison with the control group. High concentrations of IAA (0.04 and 0.2 mg/L) accelerate the algal growth and increased chlorophyll content, while that inhibited the contents of phycocyanin and allophycocyanin and reduced the peroxidation of membrane lipid peroxidation as well as synthetization of intracellular algal toxins. The findings also demonstrated that low concentrations of IAA have no clear influence on the growth and photosynthesis of M. aeruginosa CHAB-6301. However, high concentrations of IAA can promote the growth and photosynthesis of this alga, which may increase the possibility of formation of Microcystis-based water blooms.
In order to investigate the effects of indole-3-acetic acid (IAA) on physiological characteristics of Microcystis aeruginosa (M. aeruginosa), the growth, photosynthetic pigment content, chlorophyll fluorescence, lipid oxidation, and microcystin biosynthesis characteristics were studied. The achieved results showed that there was no significant variation in cell density, chlorophyll content, chlorophyll fluorescence characteristics, and microcystin contents at low concentrations of IAA (e.g., 0.04 and 0.2 mg/L). However the contents of phycocyanin, allophycocyanin, and malondialdehyde (MDA) decreased in comparison with the control group. High concentrations of IAA (0.04 and 0.2 mg/L) accelerate the algal growth and increased chlorophyll content, while that inhibited the contents of phycocyanin and allophycocyanin and reduced the peroxidation of membrane lipid peroxidation as well as synthetization of intracellular algal toxins. The findings also demonstrated that low concentrations of IAA have no clear influence on the growth and photosynthesis of M. aeruginosa CHAB-6301. However, high concentrations of IAA can promote the growth and photosynthesis of this alga, which may increase the possibility of formation of Microcystis-based water blooms.
2018, 42(4): 839-845
doi: 10.7541/2018.103
Abstract:
Metsulfuron-methyl is one of the sulfonylurea herbicides, which have been widely used throughout the world because of its significant advantages and safety. However, long-term use of Metsulfuron-methyl will impose a threat to aquatic ecosystems. Algae are frequently the major primary producers in aquatic ecosystems, often as an indicator to study water pollutants. In this study, dominant species of cyanobacteria (Microcystis aeruginosa PCC7806) were selected to deeply perceive the effect of Metsulfuron-methyl on the growth and photosynthetic of Microcystis aeruginosa. The achieved results showed that the growth of M. aeruginosa PCC7806 was significantly inhibited when the concentration of Metsulfuron-methyl exceeds 80 mg/L. The EC50 of the growth of M. aeruginosa PCC7806 was 81.998 mg/L by regression and Probit analysis. The results of cytochrome studies demonstrated that the content of chlorophyll a and carotenoids in unit cell of the treatment group on the 6th day was lower than that of in the control group, and when the concentration of Metsulfuron-methyl was 80 mg/L, the carotenoids content was remarkably lower than that of in the control group. The results of kinetics of chlorophyll fluorescence showed that the energy (ET0/RC) captured by the unit reaction center for electron transport (φE0) was used for quantum yield of photosynthetic of electron transport, which is extraordinary suppressed on the 6th day of the experiment. The results of chlorophyll fluorescence induction and cytochrome analysis showed that Metsulfuron-methyl could negatively affect the electronic properties of the electron acceptor in the photosynthetic reaction center. In summary, Metsulfuron-methyl may act on the electron acceptor side of the photosynthetic response center, thereby likely affecting the photosynthetic system of Microcystis aeruginosa.
Metsulfuron-methyl is one of the sulfonylurea herbicides, which have been widely used throughout the world because of its significant advantages and safety. However, long-term use of Metsulfuron-methyl will impose a threat to aquatic ecosystems. Algae are frequently the major primary producers in aquatic ecosystems, often as an indicator to study water pollutants. In this study, dominant species of cyanobacteria (Microcystis aeruginosa PCC7806) were selected to deeply perceive the effect of Metsulfuron-methyl on the growth and photosynthetic of Microcystis aeruginosa. The achieved results showed that the growth of M. aeruginosa PCC7806 was significantly inhibited when the concentration of Metsulfuron-methyl exceeds 80 mg/L. The EC50 of the growth of M. aeruginosa PCC7806 was 81.998 mg/L by regression and Probit analysis. The results of cytochrome studies demonstrated that the content of chlorophyll a and carotenoids in unit cell of the treatment group on the 6th day was lower than that of in the control group, and when the concentration of Metsulfuron-methyl was 80 mg/L, the carotenoids content was remarkably lower than that of in the control group. The results of kinetics of chlorophyll fluorescence showed that the energy (ET0/RC) captured by the unit reaction center for electron transport (φE0) was used for quantum yield of photosynthetic of electron transport, which is extraordinary suppressed on the 6th day of the experiment. The results of chlorophyll fluorescence induction and cytochrome analysis showed that Metsulfuron-methyl could negatively affect the electronic properties of the electron acceptor in the photosynthetic reaction center. In summary, Metsulfuron-methyl may act on the electron acceptor side of the photosynthetic response center, thereby likely affecting the photosynthetic system of Microcystis aeruginosa.
2018, 42(4): 846-853
doi: 10.7541/2018.104
Abstract:
Submerged macrophytes have an important effect on the restoration of the degraded aquatic ecosystem, and the light intensity is the main limiting factor for its growth and development. This study investigated 7 different light intensities (100%, 60%, 40%, 20%, 10%, 5% and 1% of natural light) on the morphological index (plant height, leaf number) and physiological index (chlorophyll, root activity, antioxidant enzyme activity and malondialdehyde), of Potamogeton crispus to provide the theoretical basis for the construction of eutrophic water plant community. The results showed: (1) With the increase of light intensity, the plant heights, leaf numbers and biomass growth rate increased significantly, but the growth was inhibited in high light intensity (CK group) and the low intensity (1% group). (2) The chlorophyll content of P. crispus increased first and then decreased with the increase of light intensity. The contents of Chl. a, Chl. b, Chl. a + b and Car in 1% and CK groups were lower than those of the others. (3) With the extension of the test time, the root activity increased first and then decreased with higher root activity in the group of 20%, 40% and 60%. (4) The activity of SOD, POD and CAT increased first and then decreased during the whole experiment, and in the later stage of experiment, 1% and CK groups had higher content of SOD but lower content of POD and CAT. The content of MDA of leaf increased during the experiment associated with reduced growth of P. crispus. The best growth conditions of P. crispus were the 20%—60% of natural light, and the sustained weak light stress would cause the metabolism disorders of active oxygen, cells damage, and ultimate death.
Submerged macrophytes have an important effect on the restoration of the degraded aquatic ecosystem, and the light intensity is the main limiting factor for its growth and development. This study investigated 7 different light intensities (100%, 60%, 40%, 20%, 10%, 5% and 1% of natural light) on the morphological index (plant height, leaf number) and physiological index (chlorophyll, root activity, antioxidant enzyme activity and malondialdehyde), of Potamogeton crispus to provide the theoretical basis for the construction of eutrophic water plant community. The results showed: (1) With the increase of light intensity, the plant heights, leaf numbers and biomass growth rate increased significantly, but the growth was inhibited in high light intensity (CK group) and the low intensity (1% group). (2) The chlorophyll content of P. crispus increased first and then decreased with the increase of light intensity. The contents of Chl. a, Chl. b, Chl. a + b and Car in 1% and CK groups were lower than those of the others. (3) With the extension of the test time, the root activity increased first and then decreased with higher root activity in the group of 20%, 40% and 60%. (4) The activity of SOD, POD and CAT increased first and then decreased during the whole experiment, and in the later stage of experiment, 1% and CK groups had higher content of SOD but lower content of POD and CAT. The content of MDA of leaf increased during the experiment associated with reduced growth of P. crispus. The best growth conditions of P. crispus were the 20%—60% of natural light, and the sustained weak light stress would cause the metabolism disorders of active oxygen, cells damage, and ultimate death.
2018, 42(4): 854-864
doi: 10.7541/2018.105
Abstract:
In order to comprehensively evaluate the eutrophication status in China lakes, this study scientifically analyzed the eutrophication and its regional heterogeneity in 22 representative lakes of China, and the quantitative relationship between TP and eutrophication was also studied. The results showed that 59.1% of the surviving lakes are in different eutrophication status from 2010 to 2011. Among them, Yunnan-Guizhou Lake area has the highest eutrophication level, but Menggu-Xinjiang Lake area has a bipolar levels. The lakes at Northeast Mountain and Plain area, and also the lakes at eastern area generally have a level between middle nutrition to mild eutrophication. The lowest eutrophication level is at the area of Qinghai-Tibet Plateau. Based on the relationship between sunshine amount, frost-free period, temperature, water depth, altitude, precipitation and lake nutrition status, it reveals that the geographical location of lakes is the fundamental factor affecting lake eutrophication and its regional distribution. The results of comprehensive analysis showed that there is a significant correlation between chlorophyll a and total phosphorus concentrations in lakes nationwide. Cubic curve regression equation fits the relation between chlorophyll a and total phosphorus concentrations at the areas of eastern plain, northeastern plain-mountain, Qinghai-Tibet Plateau and Yun-Gui Plateau. S-curve equation fits the relation between concentrations of chlorophyll a and total phosphorus in the Menggu-Xinjiang Lake area. With the increase of total phosphorus concentration, there was a minimum value of chlorophyll concentration in the lake areas of eastern plain, northeastern plain-mountain, Qinghai-Tibet Plateau at the beginning, and then followed by a maximum value. The minimum concentrations of total phosphorus in the three lake areas were 0.054 mg/L, 0.089 mg/L and 0.072 mg/L, respectively. This study can provide information for the control of lake eutrophication in future.
In order to comprehensively evaluate the eutrophication status in China lakes, this study scientifically analyzed the eutrophication and its regional heterogeneity in 22 representative lakes of China, and the quantitative relationship between TP and eutrophication was also studied. The results showed that 59.1% of the surviving lakes are in different eutrophication status from 2010 to 2011. Among them, Yunnan-Guizhou Lake area has the highest eutrophication level, but Menggu-Xinjiang Lake area has a bipolar levels. The lakes at Northeast Mountain and Plain area, and also the lakes at eastern area generally have a level between middle nutrition to mild eutrophication. The lowest eutrophication level is at the area of Qinghai-Tibet Plateau. Based on the relationship between sunshine amount, frost-free period, temperature, water depth, altitude, precipitation and lake nutrition status, it reveals that the geographical location of lakes is the fundamental factor affecting lake eutrophication and its regional distribution. The results of comprehensive analysis showed that there is a significant correlation between chlorophyll a and total phosphorus concentrations in lakes nationwide. Cubic curve regression equation fits the relation between chlorophyll a and total phosphorus concentrations at the areas of eastern plain, northeastern plain-mountain, Qinghai-Tibet Plateau and Yun-Gui Plateau. S-curve equation fits the relation between concentrations of chlorophyll a and total phosphorus in the Menggu-Xinjiang Lake area. With the increase of total phosphorus concentration, there was a minimum value of chlorophyll concentration in the lake areas of eastern plain, northeastern plain-mountain, Qinghai-Tibet Plateau at the beginning, and then followed by a maximum value. The minimum concentrations of total phosphorus in the three lake areas were 0.054 mg/L, 0.089 mg/L and 0.072 mg/L, respectively. This study can provide information for the control of lake eutrophication in future.
2018, 42(4): 865-870
doi: 10.7541/2018.106
Abstract:
Food quality can significantly affect the phosphorus content, growth, reproduction, as well as physiological behavior of zooplankton, leading to regulate the energy transfer efficiency at the primary producer-consumer interface. However, the elemental coupling between zooplankton and food is scarcely observed at the community level. In this study, the elemental coupling and the elemental imbalances between seston and mesozooplankton assemblage in addition to the ecological impacts of such imbalances on zooplankton-phytoplankton interaction were detailed by analyzing the compositions of carbon, nitrogen, and phosphorus in seston and mesozooplankton assemblage derived from 13 samples containing water bodies in the Hubei province, China. The achieved results showed that both C﹕N and C﹕P ratios in mesozooplankton were positively correlated with the corresponding ratios in seston. Besides, the elemental imbalances between seston and mesozooplankton were positively correlated with the corresponding seston ratio (C﹕N,r=0.97, P<0.001; C﹕P,r=0.81, P=0.001). Further analysis also revealed that the energy transfer efficiency between zooplankton and phytoplankton declined with the increase of elemental imbalance in C﹕P ratio (r= –0.58, P=0.037). Moreover, a similar decline in zooplankton biomass was found as well as increase of imbalance in C﹕P ratio (r= –0.59, P=0.033). These results indicated that seston stoichiometry could remarkably impact the elemental stoichiometry of mesozooplankton assemblage, and the elemental imbalances tended to be greater with the increase of seston stoichiometry; consequently, the energy transferred to mesozooplankton was decreased as well.
Food quality can significantly affect the phosphorus content, growth, reproduction, as well as physiological behavior of zooplankton, leading to regulate the energy transfer efficiency at the primary producer-consumer interface. However, the elemental coupling between zooplankton and food is scarcely observed at the community level. In this study, the elemental coupling and the elemental imbalances between seston and mesozooplankton assemblage in addition to the ecological impacts of such imbalances on zooplankton-phytoplankton interaction were detailed by analyzing the compositions of carbon, nitrogen, and phosphorus in seston and mesozooplankton assemblage derived from 13 samples containing water bodies in the Hubei province, China. The achieved results showed that both C﹕N and C﹕P ratios in mesozooplankton were positively correlated with the corresponding ratios in seston. Besides, the elemental imbalances between seston and mesozooplankton were positively correlated with the corresponding seston ratio (C﹕N,r=0.97, P<0.001; C﹕P,r=0.81, P=0.001). Further analysis also revealed that the energy transfer efficiency between zooplankton and phytoplankton declined with the increase of elemental imbalance in C﹕P ratio (r= –0.58, P=0.037). Moreover, a similar decline in zooplankton biomass was found as well as increase of imbalance in C﹕P ratio (r= –0.59, P=0.033). These results indicated that seston stoichiometry could remarkably impact the elemental stoichiometry of mesozooplankton assemblage, and the elemental imbalances tended to be greater with the increase of seston stoichiometry; consequently, the energy transferred to mesozooplankton was decreased as well.
Journal Introduction
- Establishment Time：1955 Bimonthly
- Competent unit：Chinese Academy of Sciences
- Host unit：Institute of Hydrobiology, Chinese Academy of Sciences ; Chinese Society for Oceanology and Limnology
- Editor-in-Chief：GUI Jian-Fang
- ISSN 1000-3207
- CN 42-1230/Q
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