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To identify target genes mediated by thyroid hormone/thyroid hormone receptor TRαA in Paralichthys olivaceus, the CDS region of TRαA gene was cloned by RT-PCR and constructed a recombinant eukaryotic expression vector p3×Flag-TRαA. The recombinant plasmid was transfected into HEK293T cells, and the results demonstrated that the TRαA of Paralichthys olivaceus was successfully expressed in the mammalian expression system. Cell lysates transfected with recombinant plasmid were purified and filtered by Flag affinity chromatography to obtain the pure fusion protein TRαA. The dual luciferase reporter assay was performed in HEK293T cells that p3×Flag-TRαA was co-transfected with the reporter gene expression vector pGL3-Pro-atoh8-1517/1333/708 containing the candidate target promoter. The results support that the receptor of TRαA binds to two TRE recognition sequence specific to the -1497--688 promoter region of the atoh8 gene to initiate the gene transcription, and that atoh8 is a target gene directly mediated by thyroid hormone via TRαA. This study provides the basis for further exploration of thyroid hormone-regulated thyroid hormone receptor TRαA -mediated signaling pathways.
To identify target genes mediated by thyroid hormone/thyroid hormone receptor TRαA in Paralichthys olivaceus, the CDS region of TRαA gene was cloned by RT-PCR and constructed a recombinant eukaryotic expression vector p3×Flag-TRαA. The recombinant plasmid was transfected into HEK293T cells, and the results demonstrated that the TRαA of Paralichthys olivaceus was successfully expressed in the mammalian expression system. Cell lysates transfected with recombinant plasmid were purified and filtered by Flag affinity chromatography to obtain the pure fusion protein TRαA. The dual luciferase reporter assay was performed in HEK293T cells that p3×Flag-TRαA was co-transfected with the reporter gene expression vector pGL3-Pro-atoh8-1517/1333/708 containing the candidate target promoter. The results support that the receptor of TRαA binds to two TRE recognition sequence specific to the -1497--688 promoter region of the atoh8 gene to initiate the gene transcription, and that atoh8 is a target gene directly mediated by thyroid hormone via TRαA. This study provides the basis for further exploration of thyroid hormone-regulated thyroid hormone receptor TRαA -mediated signaling pathways.
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Among the known subgroups of anoxygenic phototrophic bacteria, the Purple Nonsulfur Bacteria were widely investigated for their versatile metabolisms. This study isolated and identified an anoxygenic phototrophic bacterium of strain PUF1 from the East Lake, Wuhan using the colony morphology, cell ultrathin structure, characteristic absorption spectra and phylogenetic analysis. The isolated strain was identified as Rhodopseudomonas sp. The bacterial cells are straight or slightly curved rod-shaped, 3.05—10.06 µm in length, 0.32—0.68 µm in diameter, with laminar membranes. The bacterial culture appears dark purple-red with major pigments being Bchl. a and carotenoids. With an initial pH of 6.0 to 8.0 and light intensity of 500 to 3000 lux, cell biomass at the stationary phase measured by the optical density (OD) showed no obvious difference, but pH higher than 8.0 in the liquid culture indeed decreased the maximal quantum yield of PS II (Fv/Fm). PUF1 had inconstant protein contents in its growth with the highest protein content of more than 60% related to the cellular dry weight in the stationary growth phase. The activity of ATPase continuously declined over the culture time. A plot of Fv/Fm fitted the single peak Gauss model with peak values in the log phase that showed certain relationships between the Fv/Fm and bacterial growing status. These findings provide important references for the study of physiological and biochemical characteristics of phototrophic bacteria.
Among the known subgroups of anoxygenic phototrophic bacteria, the Purple Nonsulfur Bacteria were widely investigated for their versatile metabolisms. This study isolated and identified an anoxygenic phototrophic bacterium of strain PUF1 from the East Lake, Wuhan using the colony morphology, cell ultrathin structure, characteristic absorption spectra and phylogenetic analysis. The isolated strain was identified as Rhodopseudomonas sp. The bacterial cells are straight or slightly curved rod-shaped, 3.05—10.06 µm in length, 0.32—0.68 µm in diameter, with laminar membranes. The bacterial culture appears dark purple-red with major pigments being Bchl. a and carotenoids. With an initial pH of 6.0 to 8.0 and light intensity of 500 to 3000 lux, cell biomass at the stationary phase measured by the optical density (OD) showed no obvious difference, but pH higher than 8.0 in the liquid culture indeed decreased the maximal quantum yield of PS II (Fv/Fm). PUF1 had inconstant protein contents in its growth with the highest protein content of more than 60% related to the cellular dry weight in the stationary growth phase. The activity of ATPase continuously declined over the culture time. A plot of Fv/Fm fitted the single peak Gauss model with peak values in the log phase that showed certain relationships between the Fv/Fm and bacterial growing status. These findings provide important references for the study of physiological and biochemical characteristics of phototrophic bacteria.
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To study the effects of fluctuating light on algae, the growth of Microcystis aeruginosa, a typical water bloom alga, was studied under different light conditions using an experimental device with a light intensity control system based on a single-chip system. Four light conditions were applied in this research: three fluctuating light groups (10 min FL, 1 h FL and 6 h FL) with different fluctuation cycles and an average light group (AL). The experimental results show that the cell densities of Microcystis aeruginosa in the the 6 h FL, 1 h FL and 10 min FL groups were 28.3% (P<0.05), 18.2% (P<0.05) and 7.7% (P>0.05), respectively, which were higher than that in the AL group. It was also found that the specific growth rate, Fv/Fm and rETR of Microcystis aeruginosa in the three fluctuating light groups were significantly higher than those in the AL group (P<0.05), and each index significantly increased with the length of the fluctuating light cycle, but the mean NPQ and carotenoids per unit dry weight showed the opposite relationship to fluctuating light. The results also showed that Microcystis aeruginosa could better regulate their photosynthesis mechanism to utilize light energy under fluctuating light than under constant light when the average light intensity was low, and the longer the fluctuating period was, the better the utilization efficiency. This implies that fluctuating low-intensity light can be used as a means to increase algae production.
To study the effects of fluctuating light on algae, the growth of Microcystis aeruginosa, a typical water bloom alga, was studied under different light conditions using an experimental device with a light intensity control system based on a single-chip system. Four light conditions were applied in this research: three fluctuating light groups (10 min FL, 1 h FL and 6 h FL) with different fluctuation cycles and an average light group (AL). The experimental results show that the cell densities of Microcystis aeruginosa in the the 6 h FL, 1 h FL and 10 min FL groups were 28.3% (P<0.05), 18.2% (P<0.05) and 7.7% (P>0.05), respectively, which were higher than that in the AL group. It was also found that the specific growth rate, Fv/Fm and rETR of Microcystis aeruginosa in the three fluctuating light groups were significantly higher than those in the AL group (P<0.05), and each index significantly increased with the length of the fluctuating light cycle, but the mean NPQ and carotenoids per unit dry weight showed the opposite relationship to fluctuating light. The results also showed that Microcystis aeruginosa could better regulate their photosynthesis mechanism to utilize light energy under fluctuating light than under constant light when the average light intensity was low, and the longer the fluctuating period was, the better the utilization efficiency. This implies that fluctuating low-intensity light can be used as a means to increase algae production.
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In this study, we compared the utilization of different carbohydrates in Chinese perch and further explored the molecular mechanism of carbohydrate utilization in carnivorous fish. Water, plasma, liver and muscle samples were collected at 0, 1, 2, 3, 4, 8, 12 and 24 h after Chinese perch were fed glucose and dextrin at a 1670 mg/kg dose. The parameters urine sugar, blood glucose, blood triglycerides, blood insulin, and liver and muscle glycogen and the mRNA expression levels of glucose metabolism-related genes were detected. The results showed the following: (1) Within 1-12 h after feeding, the blood glucose level was significantly higher in the glucose group than in the dextrin group, while the blood glucose and insulin levels were not significantly different between the two groups. (2) The triglyceride content at 2-4 h was higher in the dextrin group than in the glucose group, and the liver glycogen content at 1 h was significantly higher in the dextrin group than in the glucose group. Furthermore, the muscle glycogen content at 24 h was significantly higher in the dextrin group than in the glucose group. (3) One hour after feeding, the mRNA expression levels of glucokinase (GK), fatty acid synthetase (FAS), acetyl-CoA carboxylase type I (ACC1) and citrate synthase (CS) were significantly higher in the dextran group than in the glucose group, and the expression levels of glycogen synthase (GS) and CS mRNA at 8h were significantly lower in the dextrin group than in the glucose group. These results demonstrated that the utilization efficiency of dextrin was better than that of dextrose and that the intake of dextrin could promote the synthesis of glycogen and fat.
In this study, we compared the utilization of different carbohydrates in Chinese perch and further explored the molecular mechanism of carbohydrate utilization in carnivorous fish. Water, plasma, liver and muscle samples were collected at 0, 1, 2, 3, 4, 8, 12 and 24 h after Chinese perch were fed glucose and dextrin at a 1670 mg/kg dose. The parameters urine sugar, blood glucose, blood triglycerides, blood insulin, and liver and muscle glycogen and the mRNA expression levels of glucose metabolism-related genes were detected. The results showed the following: (1) Within 1-12 h after feeding, the blood glucose level was significantly higher in the glucose group than in the dextrin group, while the blood glucose and insulin levels were not significantly different between the two groups. (2) The triglyceride content at 2-4 h was higher in the dextrin group than in the glucose group, and the liver glycogen content at 1 h was significantly higher in the dextrin group than in the glucose group. Furthermore, the muscle glycogen content at 24 h was significantly higher in the dextrin group than in the glucose group. (3) One hour after feeding, the mRNA expression levels of glucokinase (GK), fatty acid synthetase (FAS), acetyl-CoA carboxylase type I (ACC1) and citrate synthase (CS) were significantly higher in the dextran group than in the glucose group, and the expression levels of glycogen synthase (GS) and CS mRNA at 8h were significantly lower in the dextrin group than in the glucose group. These results demonstrated that the utilization efficiency of dextrin was better than that of dextrose and that the intake of dextrin could promote the synthesis of glycogen and fat.
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Pharyngeal myxosporidiosis caused by Myxobolus honghuensis is one of the most important limiting factors for the culture industry of the gibel carp, Carassius auratus gibelio (Bloch), in China. Pathogen abundance in the culture system directly determines the consequence of disease outbreaks in cultured aquatic animals. Therefore, a quantitative detection method to monitor the pathogen during the whole culture cycle will not only be applied in early diagnosis but also provide a technical basis for assessing disease risk and evaluating the effects of applied preventative and control measures. Here, a SYBR Green I real-time fluorescent quantitative PCR assay (QPCR) was developed to detect and monitor the abundance of M. honghuensis with a newly designed primer pair, HHF/R, which was based on the ITS loci. The specificity, sensitivity, repeatability and applicability of the assay were deeply evaluated. The results indicated that the developed method could specifically detect M. honghuensis without cross-reactivity with Henneguya doneci, Myxobolus nielii, Myxobolus pronini and Myxobolus wulii, a genetically similar pathogen causing hepatic myxosporidiosis of gibel carp. The lowest detection limit was 3.02×101 copies, which was 1000 times more sensitive than conventional PCR. The intraassay and interassay coefficients of variation were below 2%. Importantly, this method could detect all life cycle stages of M. honghuensis, which included its trophozoite and presporogonic stages, distributed not only in the tissue of infected fish but also in the water column and sediments. Therefore, the developed QPCR assay has high specificity, sensitivity and repeatability, which can be applied for quantitative monitoring of all life cycle stages of M. honghuensis distributed in a culture system during the whole culture cycle of gibel carp and will be the basis for the development of targeted and precise control strategies for pharyngeal myxosporidiosis of gibel carp.
Pharyngeal myxosporidiosis caused by Myxobolus honghuensis is one of the most important limiting factors for the culture industry of the gibel carp, Carassius auratus gibelio (Bloch), in China. Pathogen abundance in the culture system directly determines the consequence of disease outbreaks in cultured aquatic animals. Therefore, a quantitative detection method to monitor the pathogen during the whole culture cycle will not only be applied in early diagnosis but also provide a technical basis for assessing disease risk and evaluating the effects of applied preventative and control measures. Here, a SYBR Green I real-time fluorescent quantitative PCR assay (QPCR) was developed to detect and monitor the abundance of M. honghuensis with a newly designed primer pair, HHF/R, which was based on the ITS loci. The specificity, sensitivity, repeatability and applicability of the assay were deeply evaluated. The results indicated that the developed method could specifically detect M. honghuensis without cross-reactivity with Henneguya doneci, Myxobolus nielii, Myxobolus pronini and Myxobolus wulii, a genetically similar pathogen causing hepatic myxosporidiosis of gibel carp. The lowest detection limit was 3.02×101 copies, which was 1000 times more sensitive than conventional PCR. The intraassay and interassay coefficients of variation were below 2%. Importantly, this method could detect all life cycle stages of M. honghuensis, which included its trophozoite and presporogonic stages, distributed not only in the tissue of infected fish but also in the water column and sediments. Therefore, the developed QPCR assay has high specificity, sensitivity and repeatability, which can be applied for quantitative monitoring of all life cycle stages of M. honghuensis distributed in a culture system during the whole culture cycle of gibel carp and will be the basis for the development of targeted and precise control strategies for pharyngeal myxosporidiosis of gibel carp.
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Bdelloid rotifers, belonging to the subclass Bdelloidea (class Eurotatoria; phylum Rotifera), have become an important group attracting scholars in various fields because of their strict parthenogenesis and anhydrobiosis. A newly recorded species of bdelloid rotifer named Otostephanos torquatus Bryce, 1913 was found in moss samples collected from the Wanshan Islands in Zhuhai, Guangdong Province, China, in 2018. A detailed morphological description of this species is currently lacking. This paper describes the main taxonomic features of O. torquatus by describing the morphology of the body and scanning electron microscopy images of its trophi. This important classification of O. torquatus is based on the food pellets and trochi, including special rings, triangular upper lips and trophi with 7/7 major teeth. Food pellets are used to store food in the lumen, and the height of the upper lip is lower than that of the trochi. By comparing the COⅠgene sequence of O. torquatus and familiar species in the same family or genus, it is shown that O. torquatus belongs to the genetic position of the genus Otostephanos. By comparing research results about bdelloid rotifers in other countries and their important position in the study of evolution, Chinese scholars should strengthen the exploration and research on bdelloid rotifers.
Bdelloid rotifers, belonging to the subclass Bdelloidea (class Eurotatoria; phylum Rotifera), have become an important group attracting scholars in various fields because of their strict parthenogenesis and anhydrobiosis. A newly recorded species of bdelloid rotifer named Otostephanos torquatus Bryce, 1913 was found in moss samples collected from the Wanshan Islands in Zhuhai, Guangdong Province, China, in 2018. A detailed morphological description of this species is currently lacking. This paper describes the main taxonomic features of O. torquatus by describing the morphology of the body and scanning electron microscopy images of its trophi. This important classification of O. torquatus is based on the food pellets and trochi, including special rings, triangular upper lips and trophi with 7/7 major teeth. Food pellets are used to store food in the lumen, and the height of the upper lip is lower than that of the trochi. By comparing the COⅠgene sequence of O. torquatus and familiar species in the same family or genus, it is shown that O. torquatus belongs to the genetic position of the genus Otostephanos. By comparing research results about bdelloid rotifers in other countries and their important position in the study of evolution, Chinese scholars should strengthen the exploration and research on bdelloid rotifers.
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Sturgeon, one of the oldest chondrostei in the world, has no sexual dimorphic appearance. To understand the molecular characteristics of the gonad development of sturgeon under artificial culture, characteristics of mRNA levels between the testis and ovary of two-year-old Amur sturgeon (Acipenser schrenckii Brandt) were analyzed using transcriptome sequencing. A total of 19690 differentially expressed gene transcripts were found between the gonads, in which the sex-related genes mainly included three transcription factors (Dmrt1, Sox9 and Foxl2) and three transforming growth factors (Amh, Bmp15 and Gdf9). We found four significant enrichment KEGG pathways involved in the process of ovarian development: progesterone-mediated oocyte maturation, oocyte meiosis, ovarian steroidogenesis and the GnRH signaling pathway. The expression patterns of 18 differentially expressed genes in the ovarian steroidogenesis pathway were analyzed. The results suggest that estrogen biosynthesis is inhibited in the ovaries of two-year-old Amur sturgeon. However, androgen biosynthesis is not affected in the testis. This study provides a foundation for studies on gonadal differentiation, the development of sturgeon, and sex identification at the level of mRNA expression.
Sturgeon, one of the oldest chondrostei in the world, has no sexual dimorphic appearance. To understand the molecular characteristics of the gonad development of sturgeon under artificial culture, characteristics of mRNA levels between the testis and ovary of two-year-old Amur sturgeon (Acipenser schrenckii Brandt) were analyzed using transcriptome sequencing. A total of 19690 differentially expressed gene transcripts were found between the gonads, in which the sex-related genes mainly included three transcription factors (Dmrt1, Sox9 and Foxl2) and three transforming growth factors (Amh, Bmp15 and Gdf9). We found four significant enrichment KEGG pathways involved in the process of ovarian development: progesterone-mediated oocyte maturation, oocyte meiosis, ovarian steroidogenesis and the GnRH signaling pathway. The expression patterns of 18 differentially expressed genes in the ovarian steroidogenesis pathway were analyzed. The results suggest that estrogen biosynthesis is inhibited in the ovaries of two-year-old Amur sturgeon. However, androgen biosynthesis is not affected in the testis. This study provides a foundation for studies on gonadal differentiation, the development of sturgeon, and sex identification at the level of mRNA expression.
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The reproductive biology of Carassius auratus gibelio was studied with 546 fish collected from the lower reaches of the Irtysh River in Xinjiang Uygur Autonomous Region from April to October 2013. The overall sex ratio (F/M) was 10.84:1. The development of gonads can be divided into six periods according to their histological characteristics. The monthly variation in the proportion of gonads at each macroscopic maturity stage and gonadosomatic index (GSI) indicated that C. auratus gibelio spawns once a year and that its spawning season is from May to July, with peak spawning occurring in June. The estimated standard lengths (SL50) and ages (A50) at first sexual maturity for females and males were 161 and 135 mm and 2.3 and 1.9 years, respectively. The absolute fecundity (AF) of C. auratus gibelio was 42,453 eggs per fish, and the relative fecundity (RF) was 98.19 eggs per gram of body weight (BW). The absolute fecundity had a linear relationship with body length and a power function relationship with weight but no significant correlation with age or ovary weight. This study further enriches the biological data available for C. auratus gibelio and provides a scientific basis for the protection and sustainable utilization of C. auratus gibelio resources in the Irtysh River.
The reproductive biology of Carassius auratus gibelio was studied with 546 fish collected from the lower reaches of the Irtysh River in Xinjiang Uygur Autonomous Region from April to October 2013. The overall sex ratio (F/M) was 10.84:1. The development of gonads can be divided into six periods according to their histological characteristics. The monthly variation in the proportion of gonads at each macroscopic maturity stage and gonadosomatic index (GSI) indicated that C. auratus gibelio spawns once a year and that its spawning season is from May to July, with peak spawning occurring in June. The estimated standard lengths (SL50) and ages (A50) at first sexual maturity for females and males were 161 and 135 mm and 2.3 and 1.9 years, respectively. The absolute fecundity (AF) of C. auratus gibelio was 42,453 eggs per fish, and the relative fecundity (RF) was 98.19 eggs per gram of body weight (BW). The absolute fecundity had a linear relationship with body length and a power function relationship with weight but no significant correlation with age or ovary weight. This study further enriches the biological data available for C. auratus gibelio and provides a scientific basis for the protection and sustainable utilization of C. auratus gibelio resources in the Irtysh River.
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The effect of clove oil on the live transportation of bream was studied in this paper. Based on a single factor experiment, the optimum conditions for preservation during transportation was determined by orthogonal experiments, and the changes in water quality indicators and their effects on fish biochemical indicators during live transportation were detected and analyzed. The results showed that the optimum conditions for preservation and transportation were an anesthetic solution concentration of 15 mg/L, a water temperature of 9°C and a fish-water ratio of 1:3. The survival time was extended by up to 50h, and the fish survival rate was 100%. In terms of the water body indexes, there were no significant changes in pH and dissolved oxygen. The ammonia nitrogen level in the anesthesia group increased from 0.049 mg/L to 4.034 mg/L within 48h. The number of microorganisms in the water increased significantly within 24h. The increase in ammonia nitrogen and the growth of microorganisms affected the survival of fish. In terms of the biochemical indexes of the fish body, the glycogen content in the muscles of the anesthesia group fish decreased significantly within 24h. The content of lactic acid increased significantly and then decreased, and the pH decreased first and then increased, indicating that glycogen consumption produced lactic acid during the transportation of live fish. Among the blood indexes of the fish body, AST activity, LDH activity, urea and creatinine (CREA) increased after 12h and increased significantly after 36h (P<0.05), and then they were decreased in the anaesthetic group. The results showed that the metabolic levels of liver and kidney tissue were affected by the prolongation of the survival time.
The effect of clove oil on the live transportation of bream was studied in this paper. Based on a single factor experiment, the optimum conditions for preservation during transportation was determined by orthogonal experiments, and the changes in water quality indicators and their effects on fish biochemical indicators during live transportation were detected and analyzed. The results showed that the optimum conditions for preservation and transportation were an anesthetic solution concentration of 15 mg/L, a water temperature of 9°C and a fish-water ratio of 1:3. The survival time was extended by up to 50h, and the fish survival rate was 100%. In terms of the water body indexes, there were no significant changes in pH and dissolved oxygen. The ammonia nitrogen level in the anesthesia group increased from 0.049 mg/L to 4.034 mg/L within 48h. The number of microorganisms in the water increased significantly within 24h. The increase in ammonia nitrogen and the growth of microorganisms affected the survival of fish. In terms of the biochemical indexes of the fish body, the glycogen content in the muscles of the anesthesia group fish decreased significantly within 24h. The content of lactic acid increased significantly and then decreased, and the pH decreased first and then increased, indicating that glycogen consumption produced lactic acid during the transportation of live fish. Among the blood indexes of the fish body, AST activity, LDH activity, urea and creatinine (CREA) increased after 12h and increased significantly after 36h (P<0.05), and then they were decreased in the anaesthetic group. The results showed that the metabolic levels of liver and kidney tissue were affected by the prolongation of the survival time.
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The suppressor of cytokine signaling 3 (SOCS3) regulates the immune response. Here, we cloned the socs3b gene and investigated their role and distribution of socs3s in grass carp (Ctenopharyngodon Idella). Grass carp socs3b gene was 2126 bp in length, encoding 216 aa peptides. In adult fish, both orthologs were expressed in 11 tissues with slightly different among tissues. After Aerononas hydrophila injection, both socs3a and socs3b were significantly up-regulated in the liver, spleen, intestine and kidney tissues. These results suggest that socs3s may play important roles in tissue growth of grass carp and the modulation of bacteria-induced innate immune response. This study provides relevant reference for the follow-up study of the function of socs3s genes in grass carp.
The suppressor of cytokine signaling 3 (SOCS3) regulates the immune response. Here, we cloned the socs3b gene and investigated their role and distribution of socs3s in grass carp (Ctenopharyngodon Idella). Grass carp socs3b gene was 2126 bp in length, encoding 216 aa peptides. In adult fish, both orthologs were expressed in 11 tissues with slightly different among tissues. After Aerononas hydrophila injection, both socs3a and socs3b were significantly up-regulated in the liver, spleen, intestine and kidney tissues. These results suggest that socs3s may play important roles in tissue growth of grass carp and the modulation of bacteria-induced innate immune response. This study provides relevant reference for the follow-up study of the function of socs3s genes in grass carp.
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Previous studies have shown that Bacillus paralicheniformis FA6 strain (FA6), isolated from the intestine of grass carp, has a role in the degradation of various carbohydrates (e.g. amylase or cellulase activity). In order to study the putative mechanisms of action and explore its potential as a probiotic, we used the third-generation sequencing technology to determine its whole genome sequence. Genome assembly, gene prediction and functional annotation were performed using bioinformatics methods. Besides, we conducted structural and functional comparative genomic analyses between B. paralicheniformis FA6 and four other available Bacillus spp. genomes (two B. paralicheniformis and two B. licheniformis). Sequence analysis showed that the genome of B. paralicheniformis FA6 consists of a single chromosome, with the size of 4450579 base pairs, and the GC content of 45.9%. The B. paralicheniformis FA6 genome contains multiple food digestion-related genes, including 128 protease genes, 32 lipase genes and 72 glycoside hydrolase genes. In addition, the bacterial genome contains seven genes encoding for lantibiotics. Structural comparative analysis revealed that all five Bacillus spp. genomes share a collinear structural relationship, but genomic features of B. paralicheniformis FA6 are most similar to the two conspecifics. A comparison of metabolic pathways (KEGG) among the five Bacillus spp. strains showed that B. paralicheniformis FA6 has the largest number of genes involved in metabolic and environmental information processing. The numbers of genes in the B. paralicheniformis FA6 genome encoding cellulases, hemicellulases and amylases were 5, 7 and 5 respectively. This is higher than in other four strains, which indicates that B. paralicheniformis FA6 is better adapted for the digestion of plant cell wall polysaccharides. The results of this study indicate that B. paralicheniformis FA6 is highly adapted for the utilization of a broad range of plant metabolites, which may be a reflection of its adaptive evolution in the intestinal tract of grass carp. Moreover, the results of this study will provide a theoretical basis for the application of B. paralicheniformis FA6 as a dietary supplement to aquaculture feed.
Previous studies have shown that Bacillus paralicheniformis FA6 strain (FA6), isolated from the intestine of grass carp, has a role in the degradation of various carbohydrates (e.g. amylase or cellulase activity). In order to study the putative mechanisms of action and explore its potential as a probiotic, we used the third-generation sequencing technology to determine its whole genome sequence. Genome assembly, gene prediction and functional annotation were performed using bioinformatics methods. Besides, we conducted structural and functional comparative genomic analyses between B. paralicheniformis FA6 and four other available Bacillus spp. genomes (two B. paralicheniformis and two B. licheniformis). Sequence analysis showed that the genome of B. paralicheniformis FA6 consists of a single chromosome, with the size of 4450579 base pairs, and the GC content of 45.9%. The B. paralicheniformis FA6 genome contains multiple food digestion-related genes, including 128 protease genes, 32 lipase genes and 72 glycoside hydrolase genes. In addition, the bacterial genome contains seven genes encoding for lantibiotics. Structural comparative analysis revealed that all five Bacillus spp. genomes share a collinear structural relationship, but genomic features of B. paralicheniformis FA6 are most similar to the two conspecifics. A comparison of metabolic pathways (KEGG) among the five Bacillus spp. strains showed that B. paralicheniformis FA6 has the largest number of genes involved in metabolic and environmental information processing. The numbers of genes in the B. paralicheniformis FA6 genome encoding cellulases, hemicellulases and amylases were 5, 7 and 5 respectively. This is higher than in other four strains, which indicates that B. paralicheniformis FA6 is better adapted for the digestion of plant cell wall polysaccharides. The results of this study indicate that B. paralicheniformis FA6 is highly adapted for the utilization of a broad range of plant metabolites, which may be a reflection of its adaptive evolution in the intestinal tract of grass carp. Moreover, the results of this study will provide a theoretical basis for the application of B. paralicheniformis FA6 as a dietary supplement to aquaculture feed.
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To investigate the biological characteristics of grass carp dendritic cells (Ctenopharyngodon idellus) and the regulatory mechanisms of dendritic cells by Bacillus subtilis, we isolated and gained grass carp dendritic cells to analyze morphological features, unique biological functions and authorized surface molecular markers. The expression of immune-related cytokines of dendritic cell to Bacillus subtilis stimulation was analyzed by RT-PCR. Our results showed that DCs have classical dendritic morphological features to initiate T cell proliferation and migration ability. LPS stimulation promoted the maturation progress of dendritic cells by increasing the expression of surface molecular markers CD83 and CD80/86, suggest that grass carp DCs were morphological and functional homology to mammalian dendritic cells. The expression of anti-inflammatory factors Il-4 and Il-10 increased significantly after the stimulation of UV-killed Bacillus subtilis (P<0.05), and reached to the highest level at 12h, revealing that Bacillus subtilis can promote the expression of anti-inflammatory factors to regulate the immune functions of dendritic cell. In conclusion, these results explored the biological characteristics of teleost fish dendritic cells and characterized the influence of probiotics Bacillus subtilis on the immune functions.
To investigate the biological characteristics of grass carp dendritic cells (Ctenopharyngodon idellus) and the regulatory mechanisms of dendritic cells by Bacillus subtilis, we isolated and gained grass carp dendritic cells to analyze morphological features, unique biological functions and authorized surface molecular markers. The expression of immune-related cytokines of dendritic cell to Bacillus subtilis stimulation was analyzed by RT-PCR. Our results showed that DCs have classical dendritic morphological features to initiate T cell proliferation and migration ability. LPS stimulation promoted the maturation progress of dendritic cells by increasing the expression of surface molecular markers CD83 and CD80/86, suggest that grass carp DCs were morphological and functional homology to mammalian dendritic cells. The expression of anti-inflammatory factors Il-4 and Il-10 increased significantly after the stimulation of UV-killed Bacillus subtilis (P<0.05), and reached to the highest level at 12h, revealing that Bacillus subtilis can promote the expression of anti-inflammatory factors to regulate the immune functions of dendritic cell. In conclusion, these results explored the biological characteristics of teleost fish dendritic cells and characterized the influence of probiotics Bacillus subtilis on the immune functions.
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Often deep genetic divergence indicates potentially different species. However, exceptions are occasionally found. In this study, samples of Opsariichthys bidens from a tributary of the Yellow River (Yiluo River) were analyzed using the mitochondrial cytochrome b (Cyt b) gene, simple sequence repeats (SSR), and the method of stable isotope was used to explore their species status. Phylogenetic trees were reconstructed with the neighbor joining (NJ) and Bayesian inference (BI) methods based on the Cyt b gene sequences and two well supported clades were recovered. Shared haplotype was not detected between these two clades and the average genetic divergence of 3.1% between them seemed to reach the criterion of DNA barcoding for species identification. Nevertheless, analyses of SSR revealed no significant genetic differentiation between the clades (Fst=0.0012, P=1), with 99.88% of variation occurring among individuals. Besides, isotope composition of δ13C and δ15N demonstrated that the two clades shared a common diet with no nutrient niche separation between them. Analysis of SSR and stable isotopes indicated that the two mitochondrially well-separated clades of O. bidens could not be explained by cryptic species, although their deep genetic distances of the Cytb gene was derived from their ancestral populations.
Often deep genetic divergence indicates potentially different species. However, exceptions are occasionally found. In this study, samples of Opsariichthys bidens from a tributary of the Yellow River (Yiluo River) were analyzed using the mitochondrial cytochrome b (Cyt b) gene, simple sequence repeats (SSR), and the method of stable isotope was used to explore their species status. Phylogenetic trees were reconstructed with the neighbor joining (NJ) and Bayesian inference (BI) methods based on the Cyt b gene sequences and two well supported clades were recovered. Shared haplotype was not detected between these two clades and the average genetic divergence of 3.1% between them seemed to reach the criterion of DNA barcoding for species identification. Nevertheless, analyses of SSR revealed no significant genetic differentiation between the clades (Fst=0.0012, P=1), with 99.88% of variation occurring among individuals. Besides, isotope composition of δ13C and δ15N demonstrated that the two clades shared a common diet with no nutrient niche separation between them. Analysis of SSR and stable isotopes indicated that the two mitochondrially well-separated clades of O. bidens could not be explained by cryptic species, although their deep genetic distances of the Cytb gene was derived from their ancestral populations.
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To investigate the expression and function of Trachinotus ovatus cathepsin B (TroCatB) gene in response to bacterial stimulation, TroCatB cDNA was cloned by RT-PCR and RACE technology and it was 2181 bp in length with a 391 bp 5' UTR, a 797 bp 3'UTR and an 993 bp ORF encoding of 330 amino acid residues. The estimated molecular mass and theoretical isoelectric point were 36.37 kD and 5.73, respectively. The TroCatB protein has a signal peptide (1Met-18Ala), a precursor peptide (25Leu-64Gly) and a typical papain family cysteine domain, containing 107Cys, 277His, 297Asn catalytic activity sites. Homology analysis showed that the homology of the TroCatB protein with other vertebrates was 67.0—90.9%, and the homology of the mature peptide region with other vertebrates was 73.7—92.4%. The N-J phylogenetic tree revealed that the scorpionfish and other fish clustered together, closest to the corpus callosum. Real-time quantitative PCR indicated that TroCatB mRNA expressed in various tissues with the highest level in spleen. Vibrio alginolyticus infection significantly induced the expression of TroCatB gene in spleen with peak level at 6h and head kidney tissues (P<0.05) with peak level at 12h. These results indicated that the domain and catalytic active sites of TroCatB protein are conserved during genetic evolution. The TroCatB gene regulates the physiological activities of the organism against bacterial immunity, and plays an important role in the innate immune defense of ovate to elucidate the function of TroCatB in the immune process and the pathogenesis of pathogens.
To investigate the expression and function of Trachinotus ovatus cathepsin B (TroCatB) gene in response to bacterial stimulation, TroCatB cDNA was cloned by RT-PCR and RACE technology and it was 2181 bp in length with a 391 bp 5' UTR, a 797 bp 3'UTR and an 993 bp ORF encoding of 330 amino acid residues. The estimated molecular mass and theoretical isoelectric point were 36.37 kD and 5.73, respectively. The TroCatB protein has a signal peptide (1Met-18Ala), a precursor peptide (25Leu-64Gly) and a typical papain family cysteine domain, containing 107Cys, 277His, 297Asn catalytic activity sites. Homology analysis showed that the homology of the TroCatB protein with other vertebrates was 67.0—90.9%, and the homology of the mature peptide region with other vertebrates was 73.7—92.4%. The N-J phylogenetic tree revealed that the scorpionfish and other fish clustered together, closest to the corpus callosum. Real-time quantitative PCR indicated that TroCatB mRNA expressed in various tissues with the highest level in spleen. Vibrio alginolyticus infection significantly induced the expression of TroCatB gene in spleen with peak level at 6h and head kidney tissues (P<0.05) with peak level at 12h. These results indicated that the domain and catalytic active sites of TroCatB protein are conserved during genetic evolution. The TroCatB gene regulates the physiological activities of the organism against bacterial immunity, and plays an important role in the innate immune defense of ovate to elucidate the function of TroCatB in the immune process and the pathogenesis of pathogens.
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To investigate the epidemiology and etiology of eel viral diseases, and isolate, cultivate and identify the eel virus, a new cell line (EEK) was established by tissue explant method from european eel anguilla anguilla. EEK cells were fibroblast-like cells and were maintained and subcultured 38 generations over a 12-months period. The optimization of medium, serum concentration and temperature was conducted. EEK cells can grow and proliferate normally in DMEM/F12 and L15, but cannot proliferate in MEM. The growth rate enhanced with the increased Fetal Bovine Serum (FBS)in the range of 5%—15%, and it decreased with more than 20% FBS and less then 5% FBS. The cells grew well in a temperature range of 22—27℃, but the growth rate reduced at the temperature below 17℃ or above 32℃. The virus sensitivity test revealed that the cell line was susceptible to the infection of Anguillid herpesvirusv (AnHV) and has obvious cytopathic effect. The establishment of a kidney cell line from european eels has increased the variety of fish cell lines, providing important experimental material for the diagnosis of eel viral diseases, the study of viral etiology and the development of virus vaccine.
To investigate the epidemiology and etiology of eel viral diseases, and isolate, cultivate and identify the eel virus, a new cell line (EEK) was established by tissue explant method from european eel anguilla anguilla. EEK cells were fibroblast-like cells and were maintained and subcultured 38 generations over a 12-months period. The optimization of medium, serum concentration and temperature was conducted. EEK cells can grow and proliferate normally in DMEM/F12 and L15, but cannot proliferate in MEM. The growth rate enhanced with the increased Fetal Bovine Serum (FBS)in the range of 5%—15%, and it decreased with more than 20% FBS and less then 5% FBS. The cells grew well in a temperature range of 22—27℃, but the growth rate reduced at the temperature below 17℃ or above 32℃. The virus sensitivity test revealed that the cell line was susceptible to the infection of Anguillid herpesvirusv (AnHV) and has obvious cytopathic effect. The establishment of a kidney cell line from european eels has increased the variety of fish cell lines, providing important experimental material for the diagnosis of eel viral diseases, the study of viral etiology and the development of virus vaccine.
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The study was conducted to evaluate the effects of dietary protein on condition factors, body composition and serum biochemical indices of juvenile Sinilabeo decorus Tungting(Nichols).Five isolipidic and isoenergetic diets were formulated containing 32.57%, 37.58%, 42.76%, 47.83% and 52.22%, respectively. A total of 450 juvenile S. decorus Tungting with the average initial weight of (14.10 ± 1.08) g were randomly distributed into five groups with three replicates per group containing 30 juvenile S. decorus Tungting per replicate for 60 days. The results indicated that the survival ratio (SR) and the feed conversion ratio (FCR) had no significant differences among groups (P>0.05). Protein efficiency declined with increased dietary protein levels (P<0.05). The weight gain rate (WGR) and the specific growth rate (SGR) of 52.22% group were significantly lower than those of 32.57% and 42.76% groups (P<0.05). The condition factor (CF) and the intestine length ratio (ILR) decreased with increased dietary protein levels, in which 52.22% group were significantly lower than 32.57% group (P<0.05). There was no significant difference in body chemical composition, except muscle crude protein and ash. With the increase of dietary protein level, the muscle crude protein increased. Seventeen amino acids were found in fish muscle. The contents of Met, Ile,Leu,Asp, Ser,Glu, Ala, Arg, ƩEAA, ΣDAA and ΣTAA in dorsal muscle of 32.57% group were significantly lower than those in 52.22% group. With the increase of dietary protein level, the triglyceride (TG) and very low-density lipoprotein cholesterol(VLDL-c) in serum were increased, except the 37.58% group. The optimum level of dietary protein for juvenile S. decorus Tungting is estimated to 37.58%—42.76% under the current experimental condition. Broken-line of SGR estimated that protein requirements for the maximum growth was about 42.91% for juvenile S. decorus Tungting.
The study was conducted to evaluate the effects of dietary protein on condition factors, body composition and serum biochemical indices of juvenile Sinilabeo decorus Tungting(Nichols).Five isolipidic and isoenergetic diets were formulated containing 32.57%, 37.58%, 42.76%, 47.83% and 52.22%, respectively. A total of 450 juvenile S. decorus Tungting with the average initial weight of (14.10 ± 1.08) g were randomly distributed into five groups with three replicates per group containing 30 juvenile S. decorus Tungting per replicate for 60 days. The results indicated that the survival ratio (SR) and the feed conversion ratio (FCR) had no significant differences among groups (P>0.05). Protein efficiency declined with increased dietary protein levels (P<0.05). The weight gain rate (WGR) and the specific growth rate (SGR) of 52.22% group were significantly lower than those of 32.57% and 42.76% groups (P<0.05). The condition factor (CF) and the intestine length ratio (ILR) decreased with increased dietary protein levels, in which 52.22% group were significantly lower than 32.57% group (P<0.05). There was no significant difference in body chemical composition, except muscle crude protein and ash. With the increase of dietary protein level, the muscle crude protein increased. Seventeen amino acids were found in fish muscle. The contents of Met, Ile,Leu,Asp, Ser,Glu, Ala, Arg, ƩEAA, ΣDAA and ΣTAA in dorsal muscle of 32.57% group were significantly lower than those in 52.22% group. With the increase of dietary protein level, the triglyceride (TG) and very low-density lipoprotein cholesterol(VLDL-c) in serum were increased, except the 37.58% group. The optimum level of dietary protein for juvenile S. decorus Tungting is estimated to 37.58%—42.76% under the current experimental condition. Broken-line of SGR estimated that protein requirements for the maximum growth was about 42.91% for juvenile S. decorus Tungting.
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, doi: 10.7541/2019.128
Abstract:
This study re-described Myxobolus wulii (Wu & Li) Landsberg & Lom, 1991 and compared its strains in different sections of Yangtze River Basin (Chongqing strain, Hubei strain and Jiangsu strain) based on morphological and molecular (18S rDNA) data. The results showed that the spores and polar capsules of Chongqing strain were slightly smaller than those of Hubei strain, and that polar capsules and spores of Chongqing strain were equal in size while they were unequal for Hubei strain. The similarities and genetic distances among the three strains of M. wulii were 99.2%—99.9% and 0.002—0.007, respectively. Phylogenetic analysis showed that the sequences of M. wulii formed a poor geographical structure as well as poor host-original structure, but a strong parasitic site structure. The sequences of M. wulii clustered into two lineages: gill-parasites clade and hepatopancreas-parasites clade, indicating that the individuals of M. wulii have closer relationship with the same site of host. Moreover, the gill-parasites clade diverged earlier than hepatopancreas-parasites clade, which might be related to the evolution of external-parasites to internal-parasites. These data inferred that the gill-parasites population might be the earliest migrates of M. wulii.
This study re-described Myxobolus wulii (Wu & Li) Landsberg & Lom, 1991 and compared its strains in different sections of Yangtze River Basin (Chongqing strain, Hubei strain and Jiangsu strain) based on morphological and molecular (18S rDNA) data. The results showed that the spores and polar capsules of Chongqing strain were slightly smaller than those of Hubei strain, and that polar capsules and spores of Chongqing strain were equal in size while they were unequal for Hubei strain. The similarities and genetic distances among the three strains of M. wulii were 99.2%—99.9% and 0.002—0.007, respectively. Phylogenetic analysis showed that the sequences of M. wulii formed a poor geographical structure as well as poor host-original structure, but a strong parasitic site structure. The sequences of M. wulii clustered into two lineages: gill-parasites clade and hepatopancreas-parasites clade, indicating that the individuals of M. wulii have closer relationship with the same site of host. Moreover, the gill-parasites clade diverged earlier than hepatopancreas-parasites clade, which might be related to the evolution of external-parasites to internal-parasites. These data inferred that the gill-parasites population might be the earliest migrates of M. wulii.
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In order to prove up the spatial distribution patterns of Sgassum vachellianum in Northern Zhejiang nearshore typical reefs, investigations were conducted on three reef belts with 12 reefs from the end of May to the beginning of June, 2016. Researchers carried out vessel-mounted observations and collected samples with SCUBA (Self-Contained Underwater Breathing Apparatus) to find out and compare the differentia of horizontal and vertical distribution features of S. vachellianum in adult stages. The results showed that (1) at the area scale, water environment with high turbidity and high wave energy inhibited the growth and spread of S. vachellianum which could merely be found on the second narrow reef belt. According to the growth characteristics of minimum appropriate water temperature with 10 ℃, it can be inferred that the northernmost island of Zhoushan Archipelago is the northernmost spread limit of endemic S. vachellianum to China. (2) At the site scale, the factor of wave exposure might explain the reason why S. vachellianum were sparse in southeast and were rich in northwest of reefs. The average height of S. vachellianum was only 26.3 cm on the four reefs of the second reef belt, which indicates high wave energy is not suitable for its growth. (3) Within the site scale, the North Yushan Island on the second reef belt was with lowest turbidity so that S. vachellianum were widespread, which could even be found in depth of 6.4 m. However, coastal waters with high turbidity withheld vertical distribution of S. vachellianum. As the result showed the average height of S. vachellianum decreases with depth, which can be inferred that S. vachellianum were intolerance of intense light, but light is a major factor for its distribution. Compared with the vertical distribution of Sargassum horneri in this region, S. vachellianum were adaptive to the environment with high turbidity and high sediment. Therefore, the change of inhibited water environment has driven S. vachellianum to the edge of extinction. By studying the causes of the spatial distribution of S. vachellianum, the decline of algae fields and the trend of variation, the conclusion can be drawn that S. vachellianum are suitable for artificial transplantation in Northern Zhejiang coastal area. The findings can provide meaningful references for the protection and restoration of algae fields.
In order to prove up the spatial distribution patterns of Sgassum vachellianum in Northern Zhejiang nearshore typical reefs, investigations were conducted on three reef belts with 12 reefs from the end of May to the beginning of June, 2016. Researchers carried out vessel-mounted observations and collected samples with SCUBA (Self-Contained Underwater Breathing Apparatus) to find out and compare the differentia of horizontal and vertical distribution features of S. vachellianum in adult stages. The results showed that (1) at the area scale, water environment with high turbidity and high wave energy inhibited the growth and spread of S. vachellianum which could merely be found on the second narrow reef belt. According to the growth characteristics of minimum appropriate water temperature with 10 ℃, it can be inferred that the northernmost island of Zhoushan Archipelago is the northernmost spread limit of endemic S. vachellianum to China. (2) At the site scale, the factor of wave exposure might explain the reason why S. vachellianum were sparse in southeast and were rich in northwest of reefs. The average height of S. vachellianum was only 26.3 cm on the four reefs of the second reef belt, which indicates high wave energy is not suitable for its growth. (3) Within the site scale, the North Yushan Island on the second reef belt was with lowest turbidity so that S. vachellianum were widespread, which could even be found in depth of 6.4 m. However, coastal waters with high turbidity withheld vertical distribution of S. vachellianum. As the result showed the average height of S. vachellianum decreases with depth, which can be inferred that S. vachellianum were intolerance of intense light, but light is a major factor for its distribution. Compared with the vertical distribution of Sargassum horneri in this region, S. vachellianum were adaptive to the environment with high turbidity and high sediment. Therefore, the change of inhibited water environment has driven S. vachellianum to the edge of extinction. By studying the causes of the spatial distribution of S. vachellianum, the decline of algae fields and the trend of variation, the conclusion can be drawn that S. vachellianum are suitable for artificial transplantation in Northern Zhejiang coastal area. The findings can provide meaningful references for the protection and restoration of algae fields.
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To investigate the effects of enzymatic hydrolyzed soybean meal(ESBM)on growth performance, liver function and metabolism of largemouth bass (Micropterus salmoides), five isonitrogenous and isoenergetic diets were formulated by replacing fish meal with a plant-based protein source compound (enzymatic hydrolyzed soybean meal: corn gluten meal=10 鲶1) for a 67-days trial. The additions of ESBM in the feed were 0 (E0), 15% (E15), 20% (E20), 25% (E25), 30% (E30) to replace 0, 23.64%, 30.91%, 40%, 47.27% of the fish meal, respectively. In additional, two diets of soybean meal (SBM) and fermented soybean meal (FSBM) were used as the substitute for 20% ESBM, respectively. The results showed that the specific growth rate and weight gain rate of E25 and E30 were significantly higher than those of other groups (P<0.05), and that the feed coefficient ratio of each group had no significant difference (P>0.05). The survival rates of the E25 and E30 groups were lower than other groups. With the increase of ESBM, the viscerosomatic index, hepatic index and the lipid content of body decreased significantly (P<0.05). The specific growth rate of FSBM group was significantly lower than that of E20 group (P<0.05), and viscerosomatic index and hepatic index of FBSM were significantly higher than those of SBM and E20 (P<0.05). The activities of amylase and lipase of intestines increased first and then decreased with the increased ESBM, which were significantly higher than that of the control group (P<0.05). The activity of pepsin in E20 and E30 group was significantly higher than control group (P<0.05). The activity of amylase in FSBM group was significantly higher than SBM and E20 (P<0.05), while the change of intestinal lipase activity was opposite. The activities of liver total-antioxidant capacity (T-AOC), glutamic oxaloacetic transaminase (AST) and alanine aminotransferase (ALT) in all group except liver ALT in E30 group were significantly induced by ESBM (P<0.05), and ESBM significantly reduced liver malondialdehyde (MDA) (P<0.05). The liver MDA content and ALT activities of FSBM group was significantly lower than SBM and E20 group (P<0.05), and the liver AST activity was in the order of E20>FSBM>SBM. The oxygen consumption increased significantly with the increased ESBM, and the nitrogen excretion in E20, E25 and E30 were significantly higher than E0 group (P<0.05). The muscle nitrogen retention rates of E20 and E30 were higher than other groups. ESBM had significant effects on serum free fatty acid (NEFA), total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) of largemouth bass. Among E20, FSBM and SBM groups, the oxygen consumption in FSBM group was significantly lower than other two groups (P<0.05), while nitrogen excretion was opposite. The serum T-CHO of SBM group was significantly higher than other two groups (P<0.05), while serum LDL-C and muscle lipid were the contrary trend. The serum TG of E20 group was significantly lower than other two groups (P<0.05). These results indicate that the addition of ESBM up to 30% did not harm the growth, and reduced liver oxidative stress to enhance nutrients metabolism. ALL FSBM, SBM and ESBM have benefits to replace 30.91% fish meal with the best effects by ESBM.
To investigate the effects of enzymatic hydrolyzed soybean meal(ESBM)on growth performance, liver function and metabolism of largemouth bass (Micropterus salmoides), five isonitrogenous and isoenergetic diets were formulated by replacing fish meal with a plant-based protein source compound (enzymatic hydrolyzed soybean meal: corn gluten meal=10 鲶1) for a 67-days trial. The additions of ESBM in the feed were 0 (E0), 15% (E15), 20% (E20), 25% (E25), 30% (E30) to replace 0, 23.64%, 30.91%, 40%, 47.27% of the fish meal, respectively. In additional, two diets of soybean meal (SBM) and fermented soybean meal (FSBM) were used as the substitute for 20% ESBM, respectively. The results showed that the specific growth rate and weight gain rate of E25 and E30 were significantly higher than those of other groups (P<0.05), and that the feed coefficient ratio of each group had no significant difference (P>0.05). The survival rates of the E25 and E30 groups were lower than other groups. With the increase of ESBM, the viscerosomatic index, hepatic index and the lipid content of body decreased significantly (P<0.05). The specific growth rate of FSBM group was significantly lower than that of E20 group (P<0.05), and viscerosomatic index and hepatic index of FBSM were significantly higher than those of SBM and E20 (P<0.05). The activities of amylase and lipase of intestines increased first and then decreased with the increased ESBM, which were significantly higher than that of the control group (P<0.05). The activity of pepsin in E20 and E30 group was significantly higher than control group (P<0.05). The activity of amylase in FSBM group was significantly higher than SBM and E20 (P<0.05), while the change of intestinal lipase activity was opposite. The activities of liver total-antioxidant capacity (T-AOC), glutamic oxaloacetic transaminase (AST) and alanine aminotransferase (ALT) in all group except liver ALT in E30 group were significantly induced by ESBM (P<0.05), and ESBM significantly reduced liver malondialdehyde (MDA) (P<0.05). The liver MDA content and ALT activities of FSBM group was significantly lower than SBM and E20 group (P<0.05), and the liver AST activity was in the order of E20>FSBM>SBM. The oxygen consumption increased significantly with the increased ESBM, and the nitrogen excretion in E20, E25 and E30 were significantly higher than E0 group (P<0.05). The muscle nitrogen retention rates of E20 and E30 were higher than other groups. ESBM had significant effects on serum free fatty acid (NEFA), total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) of largemouth bass. Among E20, FSBM and SBM groups, the oxygen consumption in FSBM group was significantly lower than other two groups (P<0.05), while nitrogen excretion was opposite. The serum T-CHO of SBM group was significantly higher than other two groups (P<0.05), while serum LDL-C and muscle lipid were the contrary trend. The serum TG of E20 group was significantly lower than other two groups (P<0.05). These results indicate that the addition of ESBM up to 30% did not harm the growth, and reduced liver oxidative stress to enhance nutrients metabolism. ALL FSBM, SBM and ESBM have benefits to replace 30.91% fish meal with the best effects by ESBM.
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Available online
Abstract:
To investigate the effects of enzymatic hydrolyzed soybean meal(ESBM)on growth performance, liver function and metabolism of largemouth bass (Micropterus salmoides), five isonitrogenous and isoenergetic diets were formulated by replacing fish meal with a plant-based protein source compound (enzymatic hydrolyzed soybean meal: corn gluten meal=10 鲶1) for a 67-days trial. The additions of ESBM in the feed were 0 (E0), 15% (E15), 20% (E20), 25% (E25), 30% (E30) to replace 0, 23.64%, 30.91%, 40%, 47.27% of the fish meal, respectively. In additional, two diets of soybean meal (SBM) and fermented soybean meal (FSBM) were used as the substitute for 20% ESBM, respectively. The results showed that the specific growth rate and weight gain rate of E25 and E30 were significantly higher than those of other groups (P<0.05), and that the feed coefficient ratio of each group had no significant difference (P>0.05). The survival rates of the E25 and E30 groups were lower than other groups. With the increase of ESBM, the viscerosomatic index, hepatic index and the lipid content of body decreased significantly (P<0.05). The specific growth rate of FSBM group was significantly lower than that of E20 group (P<0.05), and viscerosomatic index and hepatic index of FBSM were significantly higher than those of SBM and E20 (P<0.05). The activities of amylase and lipase of intestines increased first and then decreased with the increased ESBM, which were significantly higher than that of the control group (P<0.05). The activity of pepsin in E20 and E30 group was significantly higher than control group (P<0.05). The activity of amylase in FSBM group was significantly higher than SBM and E20 (P<0.05), while the change of intestinal lipase activity was opposite. The activities of liver total-antioxidant capacity (T-AOC), glutamic oxaloacetic transaminase (AST) and alanine aminotransferase (ALT) in all group except liver ALT in E30 group were significantly induced by ESBM (P<0.05), and ESBM significantly reduced liver malondialdehyde (MDA) (P<0.05). The liver MDA content and ALT activities of FSBM group was significantly lower than SBM and E20 group (P<0.05), and the liver AST activity was in the order of E20>FSBM>SBM. The oxygen consumption increased significantly with the increased ESBM, and the nitrogen excretion in E20, E25 and E30 were significantly higher than E0 group (P<0.05). The muscle nitrogen retention rates of E20 and E30 were higher than other groups. ESBM had significant effects on serum free fatty acid (NEFA), total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) of largemouth bass. Among E20, FSBM and SBM groups, the oxygen consumption in FSBM group was significantly lower than other two groups (P<0.05), while nitrogen excretion was opposite. The serum T-CHO of SBM group was significantly higher than other two groups (P<0.05), while serum LDL-C and muscle lipid were the contrary trend. The serum TG of E20 group was significantly lower than other two groups (P<0.05). These results indicate that the addition of ESBM up to 30% did not harm the growth, and reduced liver oxidative stress to enhance nutrients metabolism. ALL FSBM, SBM and ESBM have benefits to replace 30.91% fish meal with the best effects by ESBM.
To investigate the effects of enzymatic hydrolyzed soybean meal(ESBM)on growth performance, liver function and metabolism of largemouth bass (Micropterus salmoides), five isonitrogenous and isoenergetic diets were formulated by replacing fish meal with a plant-based protein source compound (enzymatic hydrolyzed soybean meal: corn gluten meal=10 鲶1) for a 67-days trial. The additions of ESBM in the feed were 0 (E0), 15% (E15), 20% (E20), 25% (E25), 30% (E30) to replace 0, 23.64%, 30.91%, 40%, 47.27% of the fish meal, respectively. In additional, two diets of soybean meal (SBM) and fermented soybean meal (FSBM) were used as the substitute for 20% ESBM, respectively. The results showed that the specific growth rate and weight gain rate of E25 and E30 were significantly higher than those of other groups (P<0.05), and that the feed coefficient ratio of each group had no significant difference (P>0.05). The survival rates of the E25 and E30 groups were lower than other groups. With the increase of ESBM, the viscerosomatic index, hepatic index and the lipid content of body decreased significantly (P<0.05). The specific growth rate of FSBM group was significantly lower than that of E20 group (P<0.05), and viscerosomatic index and hepatic index of FBSM were significantly higher than those of SBM and E20 (P<0.05). The activities of amylase and lipase of intestines increased first and then decreased with the increased ESBM, which were significantly higher than that of the control group (P<0.05). The activity of pepsin in E20 and E30 group was significantly higher than control group (P<0.05). The activity of amylase in FSBM group was significantly higher than SBM and E20 (P<0.05), while the change of intestinal lipase activity was opposite. The activities of liver total-antioxidant capacity (T-AOC), glutamic oxaloacetic transaminase (AST) and alanine aminotransferase (ALT) in all group except liver ALT in E30 group were significantly induced by ESBM (P<0.05), and ESBM significantly reduced liver malondialdehyde (MDA) (P<0.05). The liver MDA content and ALT activities of FSBM group was significantly lower than SBM and E20 group (P<0.05), and the liver AST activity was in the order of E20>FSBM>SBM. The oxygen consumption increased significantly with the increased ESBM, and the nitrogen excretion in E20, E25 and E30 were significantly higher than E0 group (P<0.05). The muscle nitrogen retention rates of E20 and E30 were higher than other groups. ESBM had significant effects on serum free fatty acid (NEFA), total cholesterol (T-CHO), triglyceride (TG), and low density lipoprotein cholesterol (LDL-C) of largemouth bass. Among E20, FSBM and SBM groups, the oxygen consumption in FSBM group was significantly lower than other two groups (P<0.05), while nitrogen excretion was opposite. The serum T-CHO of SBM group was significantly higher than other two groups (P<0.05), while serum LDL-C and muscle lipid were the contrary trend. The serum TG of E20 group was significantly lower than other two groups (P<0.05). These results indicate that the addition of ESBM up to 30% did not harm the growth, and reduced liver oxidative stress to enhance nutrients metabolism. ALL FSBM, SBM and ESBM have benefits to replace 30.91% fish meal with the best effects by ESBM.
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2020, 44(1): 1 -9
doi: 10.7541/2020.001
Abstract:
Miniature inverted-repeat transposable elements (MITEs), a group of short and non-autonomous DNA transposons, are widely present in eukaryotic genomes. The location of the MITEs distribution would affect the host. In this study, MITEs in 33 fish genomes of the agnatha, chondrichthyes, sarcopterygii and actinopterygii were predicted and analyzed using bioinformatics approach. Ultimately, 2433 MITEs were identified in 33 fish genomes. MITEs content in 33 fish genomes varied from 0.11% to 21.18%, and MITEs content was positively correlated with fish genome size. MITEs were classified into 10 super families according to different terminal inverted repeats (TIRs) and target site duplications (TSDs) with the largest family of TC1-Mariner superfamily. The insertion of MITEs into the fish genome was mainly happened 4 million years ago to now, and most species had an explosive expansion between 2—0.5 million years ago. A number of fish MITEs were inserted into or near the genes, which may play an important role in the regulation of gene expression.
Miniature inverted-repeat transposable elements (MITEs), a group of short and non-autonomous DNA transposons, are widely present in eukaryotic genomes. The location of the MITEs distribution would affect the host. In this study, MITEs in 33 fish genomes of the agnatha, chondrichthyes, sarcopterygii and actinopterygii were predicted and analyzed using bioinformatics approach. Ultimately, 2433 MITEs were identified in 33 fish genomes. MITEs content in 33 fish genomes varied from 0.11% to 21.18%, and MITEs content was positively correlated with fish genome size. MITEs were classified into 10 super families according to different terminal inverted repeats (TIRs) and target site duplications (TSDs) with the largest family of TC1-Mariner superfamily. The insertion of MITEs into the fish genome was mainly happened 4 million years ago to now, and most species had an explosive expansion between 2—0.5 million years ago. A number of fish MITEs were inserted into or near the genes, which may play an important role in the regulation of gene expression.
2020, 44(1): 10 -19
doi: 10.7541/2020.002
Abstract:
Nitrite, a common pollutant in aquaculture, is an intermediate product of nitrogen cycle in ecosystem. To explore the mechanisms of sodium nitrite-induced cell apoptosis, grass carp liver cell (L8824) were exposed to four concentrations of sodium nitrite (0, 5 mg/L, 20 mg/L and 50 mg/L) with or without treatments of phosphoinositide receptor antagonist 2-APB and IRE1 inhibitors STF-083010. Cell apoptosis related gene expression of jnk, bcl-2, bax, caspase9, caspase3, ire1α, xbp1s and grp78 and the cytoplasmic calcium ion concentration were assessed. The results showed that nitrite significantly increased the apoptosis rate, cytoplasm calcium ion concentration and mRNA levels of jnk, bax, caspase9, caspase3, ire1α, xbp1s and grp78 and significantly decreased bcl-2 mRNA level, which were reversed by the STF-083010 treatment. Besides, both 2-APB and STF-083010 reduced the sodium nitrite-induced cytoplasmic calcium ion. These results indicate that endoplasmic reticulum stress-related IRE1 pathway plays pivotal role nitrite-mediated L8824 cell apoptosis and calcium dyshomeostasis.
Nitrite, a common pollutant in aquaculture, is an intermediate product of nitrogen cycle in ecosystem. To explore the mechanisms of sodium nitrite-induced cell apoptosis, grass carp liver cell (L8824) were exposed to four concentrations of sodium nitrite (0, 5 mg/L, 20 mg/L and 50 mg/L) with or without treatments of phosphoinositide receptor antagonist 2-APB and IRE1 inhibitors STF-083010. Cell apoptosis related gene expression of jnk, bcl-2, bax, caspase9, caspase3, ire1α, xbp1s and grp78 and the cytoplasmic calcium ion concentration were assessed. The results showed that nitrite significantly increased the apoptosis rate, cytoplasm calcium ion concentration and mRNA levels of jnk, bax, caspase9, caspase3, ire1α, xbp1s and grp78 and significantly decreased bcl-2 mRNA level, which were reversed by the STF-083010 treatment. Besides, both 2-APB and STF-083010 reduced the sodium nitrite-induced cytoplasmic calcium ion. These results indicate that endoplasmic reticulum stress-related IRE1 pathway plays pivotal role nitrite-mediated L8824 cell apoptosis and calcium dyshomeostasis.
2020, 44(1): 20 -25
doi: 10.7541/2020.003
Abstract:
To understand the role of zebrafish finTRIM in antiviral innate immunity, the zebrafish ftr56 gene was cloned and analyzed for its effect on the proliferation of spring viremia of carp virus (SVCV). Primers were designed according to the zebrafish FTR56 sequence. The FTR56 CDS region was amplified by PCR and ligated into the eukaryotic expression vector pcDNA4.0-His to construct the eukaryotic expression plasmid pcDNA4.0-FTR56-His and conducted bioinformatics analysis. Real-time quantitative PCR (qRT-PCR) was used to detect the expression of FTR56 mRNA in SVCV-infected zebrafish embryo fibroblasts (ZF4). Phylogenetic tree analysis showed that the zebrafish FTR56 was individually clustered. The amino acid sequence alignment showed that the similarites with TRIM56 of chimpanzees, cattle and mice were 22%—23%. The FTR56 secondary structure has one RING finger domain, one B-box domain, one coiled-coil region and one B30.0 domain. The FTR56 mRNA level increased significantly at 24h after SVCV infection. After overexpression of FTR56, the mRNA and protein levels of G protein of SVCV reduced significantly at 12h and 24h compared with the control group associated with significantly decreased SVCV titers in the culture supernatant, indicating that FTR56 inhibited SVCV proliferation. This study provide a reference for further revealing the immunoregulatory mechanism of finTRIM in fish viral diseases.
To understand the role of zebrafish finTRIM in antiviral innate immunity, the zebrafish ftr56 gene was cloned and analyzed for its effect on the proliferation of spring viremia of carp virus (SVCV). Primers were designed according to the zebrafish FTR56 sequence. The FTR56 CDS region was amplified by PCR and ligated into the eukaryotic expression vector pcDNA4.0-His to construct the eukaryotic expression plasmid pcDNA4.0-FTR56-His and conducted bioinformatics analysis. Real-time quantitative PCR (qRT-PCR) was used to detect the expression of FTR56 mRNA in SVCV-infected zebrafish embryo fibroblasts (ZF4). Phylogenetic tree analysis showed that the zebrafish FTR56 was individually clustered. The amino acid sequence alignment showed that the similarites with TRIM56 of chimpanzees, cattle and mice were 22%—23%. The FTR56 secondary structure has one RING finger domain, one B-box domain, one coiled-coil region and one B30.0 domain. The FTR56 mRNA level increased significantly at 24h after SVCV infection. After overexpression of FTR56, the mRNA and protein levels of G protein of SVCV reduced significantly at 12h and 24h compared with the control group associated with significantly decreased SVCV titers in the culture supernatant, indicating that FTR56 inhibited SVCV proliferation. This study provide a reference for further revealing the immunoregulatory mechanism of finTRIM in fish viral diseases.
2020, 44(1): 26 -35
doi: 10.7541/2020.004
Abstract:
Gibel carp (Carassius auratus gibelio Bloth) possesses a special ability to integrate exogenous sperm genome or chromosome fragments into its eggs for co-development, but the spontaneous formation probability is very low in allogynogenetic offspring. In this study, white crucian carp (C. cuvieri) sperm were treated by 0.25%, 0.5%, 1%, 2% and 4% trypsin solution for 10min, or by 1% trypsin solution for 5, 10, 15, 20 and 25min respectively, and then fertilized with mature eggs of allogynogenetic gibel carp clone A+. By comparing the changes of sperm structure and motility between control group and different treatment groups, also considering reproductive indexes, such as fertilization rate, hatching rate and survival rate, as well as occurrence rate of allo-octoploids, an effective method was established to integrate exogenous sperm genome into allogynogenetic gibel carp eggs to create allo-octoploids. The average survival rate and octoploid rate were (2.4±0.7)% and (16.3±0.5)% respectively when the eggs of gibel carp clone A+ were fertilized with white crucian carp sperm treated by 1% trypsin solution for 15min. The effective method developed in this study will be a valuable way for creating novel genetic resources with excellent economic traits in gibel carp genetic breeding. Subsequently, 57 allo-octoploid adults were obtained by batch processing and flow cytometry screening from 6-month-old offspring, which can be used as core population for breeding of novel gible carp varieties with faster growth and or higher disease-resistance.
Gibel carp (Carassius auratus gibelio Bloth) possesses a special ability to integrate exogenous sperm genome or chromosome fragments into its eggs for co-development, but the spontaneous formation probability is very low in allogynogenetic offspring. In this study, white crucian carp (C. cuvieri) sperm were treated by 0.25%, 0.5%, 1%, 2% and 4% trypsin solution for 10min, or by 1% trypsin solution for 5, 10, 15, 20 and 25min respectively, and then fertilized with mature eggs of allogynogenetic gibel carp clone A+. By comparing the changes of sperm structure and motility between control group and different treatment groups, also considering reproductive indexes, such as fertilization rate, hatching rate and survival rate, as well as occurrence rate of allo-octoploids, an effective method was established to integrate exogenous sperm genome into allogynogenetic gibel carp eggs to create allo-octoploids. The average survival rate and octoploid rate were (2.4±0.7)% and (16.3±0.5)% respectively when the eggs of gibel carp clone A+ were fertilized with white crucian carp sperm treated by 1% trypsin solution for 15min. The effective method developed in this study will be a valuable way for creating novel genetic resources with excellent economic traits in gibel carp genetic breeding. Subsequently, 57 allo-octoploid adults were obtained by batch processing and flow cytometry screening from 6-month-old offspring, which can be used as core population for breeding of novel gible carp varieties with faster growth and or higher disease-resistance.
2020, 44(1): 36 -43
doi: 10.7541/2020.005
Abstract:
Hucho taimen belong to endangered species. It is distributed in the Irtysh River basin and the Heilongjiang River basin, but the geographic isolation has existed between two basins chronically. Differences in the morphology and anatomy of Hucho in the two basins have been reported, yet the differences in gene sequences remain unclear. Several Hucho were collected from natural waters (Hucho BHB and Hucho BEJ), and introduced from Heilongjiang (Hucho HLJ). The morphological characteristics were described. The COⅠ gene was amplified and sequenced, and the phylogenetic tree was constructed by downloading the COⅠgenes from GenBank. The results indicated that Hucho BEJ and Hucho HLJ had the same morphological characteristics, and Hucho BHB differed from the other two species on body color and spot size. The phylogenetic tree based on the COⅠgene showed that the three different Hucho and H. taimen were clustered into one large branch, and that Hucho BEJ, Hucho HLJ and Russia’s Amur River (called the Heilongjiang River in China) were gathered into a common group, and Hucho BHB was another separate group. Based on the genetic matrix of the COⅠgene, Hucho BEJ and Hucho HLJ had similar genetic distance with the Russian Amur River (0—0.0044), and Hucho BHB was far away from Hucho BEJ, Hucho HLJ and Hucho of Russian Amur River (called the Heilong River in China) (0.0057—0.0082). These results indicated that Hucho BHB in morphology and gene sequence is quite different from Hucho HLJ and Russia’s Amur River (called the Heilongjiang River in China), which maybe belong to different ecological and geographical types. The almost identical morphology and gene sequence between Hucho BEJ and Hucho HLJ demonstrated that Hucho BEJ was a species released into the river or escaped from the farm.
Hucho taimen belong to endangered species. It is distributed in the Irtysh River basin and the Heilongjiang River basin, but the geographic isolation has existed between two basins chronically. Differences in the morphology and anatomy of Hucho in the two basins have been reported, yet the differences in gene sequences remain unclear. Several Hucho were collected from natural waters (Hucho BHB and Hucho BEJ), and introduced from Heilongjiang (Hucho HLJ). The morphological characteristics were described. The COⅠ gene was amplified and sequenced, and the phylogenetic tree was constructed by downloading the COⅠgenes from GenBank. The results indicated that Hucho BEJ and Hucho HLJ had the same morphological characteristics, and Hucho BHB differed from the other two species on body color and spot size. The phylogenetic tree based on the COⅠgene showed that the three different Hucho and H. taimen were clustered into one large branch, and that Hucho BEJ, Hucho HLJ and Russia’s Amur River (called the Heilongjiang River in China) were gathered into a common group, and Hucho BHB was another separate group. Based on the genetic matrix of the COⅠgene, Hucho BEJ and Hucho HLJ had similar genetic distance with the Russian Amur River (0—0.0044), and Hucho BHB was far away from Hucho BEJ, Hucho HLJ and Hucho of Russian Amur River (called the Heilong River in China) (0.0057—0.0082). These results indicated that Hucho BHB in morphology and gene sequence is quite different from Hucho HLJ and Russia’s Amur River (called the Heilongjiang River in China), which maybe belong to different ecological and geographical types. The almost identical morphology and gene sequence between Hucho BEJ and Hucho HLJ demonstrated that Hucho BEJ was a species released into the river or escaped from the farm.
2020, 44(1): 44 -49
doi: 10.7541/2020.006
Abstract:
Myostatin propetide (MSTNpp) of Macrobrachium nipponenese was expressed in Bacillus subtilis and its effect on the growth and creatine kinase activity was investigated. The MSTNpp gene sequence was optimized to synthesize BsMSTNpp according to the B. subtilis preference codon, and the recombinant expression plasmid pGJ105-BsMSTNpp was obtained. After the transformation and fermentation of recombinant B. subtilis, the supernatant was collected and identified by Western blot. The results showed that the molecular weight of the recombinant protein was 36.0 kD. The level of recombinant BsMSTNpp increased over time, and the expression level at 100h was 10 times than that in 24h. To verify the biological activity of the recombinant BsMSTNpp, the healthy freshwater shrimp with an average body weight of 1.52 g and average body length of 4.55 cm were randomly divided into 4 groups with 3 replicates per group and 200 shrimps per replicate for a 30d trial. The experimental group 1 and experimental group 2 were fed the basal diet supplemented with recombinant pGJ105-BsMSTNpp at the dose of 0.5×106 CFU/g and 1.0×106 CFU/g respectively. The control group 1 was fed the basal diet, and the control group 2 was fed the basal diet with pGJ105 at the dose of 1.0×106 CFU/g. The results showed that the growth ratios of the experimental groups were significantly higher than that of the control group 1 (P<0.05), and there was no significant difference between experimental groups and the control group 2. The creatine kinase activities of the experimental groups were higher than those of control groups (P<0.05). The results revealed that recombinant BsMSTNpp could enhance the activity of creatine kinase to improve the myocyte proliferation and differentiation to increase the muscle growth rate of Macrobrachium nipponenese. The results provide technical support to study the function of MSTNpp and its application in shrimp aquaculture.
Myostatin propetide (MSTNpp) of Macrobrachium nipponenese was expressed in Bacillus subtilis and its effect on the growth and creatine kinase activity was investigated. The MSTNpp gene sequence was optimized to synthesize BsMSTNpp according to the B. subtilis preference codon, and the recombinant expression plasmid pGJ105-BsMSTNpp was obtained. After the transformation and fermentation of recombinant B. subtilis, the supernatant was collected and identified by Western blot. The results showed that the molecular weight of the recombinant protein was 36.0 kD. The level of recombinant BsMSTNpp increased over time, and the expression level at 100h was 10 times than that in 24h. To verify the biological activity of the recombinant BsMSTNpp, the healthy freshwater shrimp with an average body weight of 1.52 g and average body length of 4.55 cm were randomly divided into 4 groups with 3 replicates per group and 200 shrimps per replicate for a 30d trial. The experimental group 1 and experimental group 2 were fed the basal diet supplemented with recombinant pGJ105-BsMSTNpp at the dose of 0.5×106 CFU/g and 1.0×106 CFU/g respectively. The control group 1 was fed the basal diet, and the control group 2 was fed the basal diet with pGJ105 at the dose of 1.0×106 CFU/g. The results showed that the growth ratios of the experimental groups were significantly higher than that of the control group 1 (P<0.05), and there was no significant difference between experimental groups and the control group 2. The creatine kinase activities of the experimental groups were higher than those of control groups (P<0.05). The results revealed that recombinant BsMSTNpp could enhance the activity of creatine kinase to improve the myocyte proliferation and differentiation to increase the muscle growth rate of Macrobrachium nipponenese. The results provide technical support to study the function of MSTNpp and its application in shrimp aquaculture.
2020, 44(1): 50 -58
doi: 10.7541/2020.007
Abstract:
This study used Sepiella japonica as the research object to establish and optimize the acquisition method of high-turbidity water DNA (environmental DNA, eDNA) in Zhoushan offshore by absolute quantitative technique. The results indicated that the eDNA yield by ethanol precipitation method is 1.76—2.53 times higher than that of filtrating method, but the limitations of the collection volume, treatment requirement and supporting equipment make the ethanol precipitation method difficult to employ in practice. Filter screen with small aperture have no filtering effect on sediment. The size of filter aperture has a great effect on eDNA yield only when small volume water samples were collected. Precipitation treatment to water sample enhanced the yield of eDNA, but it also increased the variation of eDNA yield. Cationic surfactant significantly inhibited eDNA degradation. The effect of the membrane removal method is better than the membrane method, and it is recommended to increase the centrifugation time when the membrane removal method was used. Although the phenol extraction method can not improve the eDNA yield, it can significantly improve the purity of the product. This study is the first to establish an optimal method for obtaining eDNA of macro-organisms from Zhoushan offshore water, which provides reference for water sample collection and eDNA extraction in similar waters.
This study used Sepiella japonica as the research object to establish and optimize the acquisition method of high-turbidity water DNA (environmental DNA, eDNA) in Zhoushan offshore by absolute quantitative technique. The results indicated that the eDNA yield by ethanol precipitation method is 1.76—2.53 times higher than that of filtrating method, but the limitations of the collection volume, treatment requirement and supporting equipment make the ethanol precipitation method difficult to employ in practice. Filter screen with small aperture have no filtering effect on sediment. The size of filter aperture has a great effect on eDNA yield only when small volume water samples were collected. Precipitation treatment to water sample enhanced the yield of eDNA, but it also increased the variation of eDNA yield. Cationic surfactant significantly inhibited eDNA degradation. The effect of the membrane removal method is better than the membrane method, and it is recommended to increase the centrifugation time when the membrane removal method was used. Although the phenol extraction method can not improve the eDNA yield, it can significantly improve the purity of the product. This study is the first to establish an optimal method for obtaining eDNA of macro-organisms from Zhoushan offshore water, which provides reference for water sample collection and eDNA extraction in similar waters.
2020, 44(1): 59 -66
doi: 10.7541/2020.008
Abstract:
To explore the microbial resources on control trichlorphon pollution, a potential trichlorphon-tolerant bacterium XR12 was isolated and screened from the aquaculture sediment according to the physiological-biochemical characteristics and 16S rRNA gene sequence analysis, and its antibiotic resistance and its safety and detoxification effect were evaluated. The results indicated that strain XR12 exhibited the maximum tolerance concentration of 7680 mg/L trichlorphon. The strain XR12 was identified as Rhodobacter sphaeroides through phenotypic characterization and phylogenetic analysis based on 16S rRNA sequences. Its 16S rRNA sequence had homology of 98%—100% with strains of R. sphaeroides from GenBank, and showed the closest relation to R. sphaeroides strain RSF1 (GenBank accession number: KF606891). In addition, XR12 exhibited high sensitivity to kanamycin, roxithromycin, pipram, amoxicillin, florfenicol, polymyxin B, neomycin, gentamycin, ofloxacin, enrofloxacin, norfloxacin, streptomycin, tetracycline, netilmicin, intermediate sensitivity to doxycycline and resistance to bacitracin, nalidixic acid and sulfamethoxazole. XR12 had a LC50 of >109 cfu/mL for zebra fish, and could significantly enhance the LC50 of trichlorfon to zebrafish from 26.06 to 59.51 mg/L, indicating a good detoxification effect on trichlorfon. This study indicated that XR12 had the potential for trichlorfon detoxification in aquaculture water.
To explore the microbial resources on control trichlorphon pollution, a potential trichlorphon-tolerant bacterium XR12 was isolated and screened from the aquaculture sediment according to the physiological-biochemical characteristics and 16S rRNA gene sequence analysis, and its antibiotic resistance and its safety and detoxification effect were evaluated. The results indicated that strain XR12 exhibited the maximum tolerance concentration of 7680 mg/L trichlorphon. The strain XR12 was identified as Rhodobacter sphaeroides through phenotypic characterization and phylogenetic analysis based on 16S rRNA sequences. Its 16S rRNA sequence had homology of 98%—100% with strains of R. sphaeroides from GenBank, and showed the closest relation to R. sphaeroides strain RSF1 (GenBank accession number: KF606891). In addition, XR12 exhibited high sensitivity to kanamycin, roxithromycin, pipram, amoxicillin, florfenicol, polymyxin B, neomycin, gentamycin, ofloxacin, enrofloxacin, norfloxacin, streptomycin, tetracycline, netilmicin, intermediate sensitivity to doxycycline and resistance to bacitracin, nalidixic acid and sulfamethoxazole. XR12 had a LC50 of >109 cfu/mL for zebra fish, and could significantly enhance the LC50 of trichlorfon to zebrafish from 26.06 to 59.51 mg/L, indicating a good detoxification effect on trichlorfon. This study indicated that XR12 had the potential for trichlorfon detoxification in aquaculture water.
2020, 44(1): 67 -74
doi: 10.7541/2020.009
Abstract:
The genetic diversity of fish is seriously inferred from human disturbance factors such as water pollution and habitat destruction. Recent studies on the genetic diversity of fishes in small and medium-sized rivers in eastern China have focused on simple species, but there has been less comprehensive evaluation of fish genetic diversity and its causes. In this study, Cao’e River was selected as the representation of middle and small rivers in East China to evaluate the general genetic diversities of its fishes using mitochondrial cytochrome b gene (Cyt b). The results showed that the haplotype diversity indices of Cyt b from the 21 species and 26 population were ranged from 0.074 to 0.987, and their nucleotide diversity indices were ranged from 0.00019 to 0.00520. The genetic diversities among different species were large. Comparing the genetic diversities of fishes in different sections of Cao’s River, the haplotype diversity indices of fishes decreased gradually from the estuary to upstream (P<0.05). The haplotype diversity indices in species populations from Cao’e River were significantly lower than that of same species from large rivers such as the Yangtze River and Yellow River (P<0.05). The haplotype diversity indices of sensitive fishes were significantly lower than those of middle tolerance fishes (P<0.05). Both the haplotype diversity indices and nucleotide diversity indices of three species, Pseudorasbora parva, Pelteobagrus nitidus and Mastacembelus aculeatus, in the populations from the upstream sampling site of Jinling were lower than those in the populations of same species from the sampling site of middle and lower reaches, Xianyan. This result implied that the overall genetic diversities of fishes from Cao’e River lied in middle or even low level, and that water pollution and overfishing might be the mainly reasons to reduce the genetic level of Cao’e River. In summary, our results provided an important theoretical basis for the management, protection, exploitation and utilization of fish resource of Cao’e River, and even of the middle and small rivers in East China.
The genetic diversity of fish is seriously inferred from human disturbance factors such as water pollution and habitat destruction. Recent studies on the genetic diversity of fishes in small and medium-sized rivers in eastern China have focused on simple species, but there has been less comprehensive evaluation of fish genetic diversity and its causes. In this study, Cao’e River was selected as the representation of middle and small rivers in East China to evaluate the general genetic diversities of its fishes using mitochondrial cytochrome b gene (Cyt b). The results showed that the haplotype diversity indices of Cyt b from the 21 species and 26 population were ranged from 0.074 to 0.987, and their nucleotide diversity indices were ranged from 0.00019 to 0.00520. The genetic diversities among different species were large. Comparing the genetic diversities of fishes in different sections of Cao’s River, the haplotype diversity indices of fishes decreased gradually from the estuary to upstream (P<0.05). The haplotype diversity indices in species populations from Cao’e River were significantly lower than that of same species from large rivers such as the Yangtze River and Yellow River (P<0.05). The haplotype diversity indices of sensitive fishes were significantly lower than those of middle tolerance fishes (P<0.05). Both the haplotype diversity indices and nucleotide diversity indices of three species, Pseudorasbora parva, Pelteobagrus nitidus and Mastacembelus aculeatus, in the populations from the upstream sampling site of Jinling were lower than those in the populations of same species from the sampling site of middle and lower reaches, Xianyan. This result implied that the overall genetic diversities of fishes from Cao’e River lied in middle or even low level, and that water pollution and overfishing might be the mainly reasons to reduce the genetic level of Cao’e River. In summary, our results provided an important theoretical basis for the management, protection, exploitation and utilization of fish resource of Cao’e River, and even of the middle and small rivers in East China.
2020, 44(1): 75 -84
doi: 10.7541/2020.010
Abstract:
To study the effects of fishmeal level and stocking density on the growth and immunity of juvenile black carp, a two-factor design of fishmeal level (10%, 20%) × culture density (50, 100, 200 tails/box) was applied. The young black carp (2.50±0.02) g were divided into 6 groups of L50, L100, L200, H50, H100 and H200 with 3 replicates in each group using reservoir cages (1.5 m×1.5 m×1.5 m). In the early stage of experiment (week 8), the weight gain rate of black carp increased at first and then decreased with the increase of the stocking density, and the weight gain rate of the H200 group was higher than that of the L200 group (P>0.05), while it was significantly lower than that of the L200 group in the later stage (week 16) (P<0.05). The survival rate of the L200 group was lower than that of the L50 group (P>0.05). The stocking density and fishmeal levels showed an interactive effect on the survival rate and the weight gain rate (P<0.05). In the early stage, levels of lysozyme (LSZ) and serum glucose (GLU) of the low-fishmeal group decreased firstly and then increased with the increase of density, and intestinal secretory immunoglobulin A (S-IgA) increased. The levels of LSZ, complement 4 (C4), immunoglobulin M (IgM), S-IgA and cortisol (COR) of the H200 group were higher than those of the L200 group, while the GLU of the H200 group was lower than that of the L200 group (P>0.05). In the later stage, the level of C4 in the high and low fishmeal groups decreased at first and then increased with the increase of density (P>0.05). In the H200 group, the IgM and COR levels were higher than those of the L200 group, and the level of GLU was lower than that of the L200 group (P>0.05). In summary, high-density culture negatively regulate the growth performance, body’s immunity and anti-stress ability. The increased fishmeal level reversed the effects of high-density culture on growth performance, the immunity and anti-stress ability in the early stage. However, in the later stage, the increased fishmeal level only reduce high-density culture-mediated the survival rate without rescuing the growth performance and immune function.
To study the effects of fishmeal level and stocking density on the growth and immunity of juvenile black carp, a two-factor design of fishmeal level (10%, 20%) × culture density (50, 100, 200 tails/box) was applied. The young black carp (2.50±0.02) g were divided into 6 groups of L50, L100, L200, H50, H100 and H200 with 3 replicates in each group using reservoir cages (1.5 m×1.5 m×1.5 m). In the early stage of experiment (week 8), the weight gain rate of black carp increased at first and then decreased with the increase of the stocking density, and the weight gain rate of the H200 group was higher than that of the L200 group (P>0.05), while it was significantly lower than that of the L200 group in the later stage (week 16) (P<0.05). The survival rate of the L200 group was lower than that of the L50 group (P>0.05). The stocking density and fishmeal levels showed an interactive effect on the survival rate and the weight gain rate (P<0.05). In the early stage, levels of lysozyme (LSZ) and serum glucose (GLU) of the low-fishmeal group decreased firstly and then increased with the increase of density, and intestinal secretory immunoglobulin A (S-IgA) increased. The levels of LSZ, complement 4 (C4), immunoglobulin M (IgM), S-IgA and cortisol (COR) of the H200 group were higher than those of the L200 group, while the GLU of the H200 group was lower than that of the L200 group (P>0.05). In the later stage, the level of C4 in the high and low fishmeal groups decreased at first and then increased with the increase of density (P>0.05). In the H200 group, the IgM and COR levels were higher than those of the L200 group, and the level of GLU was lower than that of the L200 group (P>0.05). In summary, high-density culture negatively regulate the growth performance, body’s immunity and anti-stress ability. The increased fishmeal level reversed the effects of high-density culture on growth performance, the immunity and anti-stress ability in the early stage. However, in the later stage, the increased fishmeal level only reduce high-density culture-mediated the survival rate without rescuing the growth performance and immune function.
2020, 44(1): 85 -94
doi: 10.7541/2020.011
Abstract:
An 8-week growth experiment was conducted to investigate the effect of dietary replacement of fish meal protein with meat and bone meal (MBM) on growth performance, feed utilization, blood physiological and biochemical indices, muscle chemical composition and texture characteristics in juvenile Furong crucian carp (Furong carp♀× red crucian carp♂) [initial body weight of (17.47±2.56) g]. Three isonitrogenous (crude protein: 38%) and isolipidic (Crude lipid: 6.5%) diets were formulated with 0, 50% and 100% dietary fish meal protein replaced by MBM (designated FM, T1 and T2). The results showed that, no significant differences were found in weight gain rate (WGR), specific growth rate (SGR) and feeding rate (FR) among the FM, T1 and T2 groups (P>0.05), while the feed conversion ratio (FCR) of the FM group was significantly higher than that of the T2 group (P<0.05). There was no significant difference in blood physiological and serum biochemical indices, except for the hemoglobin (HGB) and aspartic amino transferase (AST). The HGB content in the T1 and T2 groups, was significantly higher than that in the FM group (P<0.05). On the other hand, AST showed a downward trend with the increasing proportion of dietary MBM, and the AST of the T2 group was significantly higher than that of the FM group. The crude lipid content of the dorsal muscle in the T1 group was significantly lower than that in the FM group. Meanwhile, with the replacement of dietary fish meal with MBM, the Asp, Glu, Gly, Ala, Val, Met, Ile, Leu, Tyr, Phe, ΣEAA, ΣDAA and ΣTAA contents of dorsal muscle were decreased, while the elasticity and adhesion of dorsal muscle were increased. In summary, MBM is an acceptable alternative animal protein source for Furong crucian carp, and 100% dietary fish meal could be replaced by MBM without significantly adverse effects on the growth of Furong crucian carp.
An 8-week growth experiment was conducted to investigate the effect of dietary replacement of fish meal protein with meat and bone meal (MBM) on growth performance, feed utilization, blood physiological and biochemical indices, muscle chemical composition and texture characteristics in juvenile Furong crucian carp (Furong carp♀× red crucian carp♂) [initial body weight of (17.47±2.56) g]. Three isonitrogenous (crude protein: 38%) and isolipidic (Crude lipid: 6.5%) diets were formulated with 0, 50% and 100% dietary fish meal protein replaced by MBM (designated FM, T1 and T2). The results showed that, no significant differences were found in weight gain rate (WGR), specific growth rate (SGR) and feeding rate (FR) among the FM, T1 and T2 groups (P>0.05), while the feed conversion ratio (FCR) of the FM group was significantly higher than that of the T2 group (P<0.05). There was no significant difference in blood physiological and serum biochemical indices, except for the hemoglobin (HGB) and aspartic amino transferase (AST). The HGB content in the T1 and T2 groups, was significantly higher than that in the FM group (P<0.05). On the other hand, AST showed a downward trend with the increasing proportion of dietary MBM, and the AST of the T2 group was significantly higher than that of the FM group. The crude lipid content of the dorsal muscle in the T1 group was significantly lower than that in the FM group. Meanwhile, with the replacement of dietary fish meal with MBM, the Asp, Glu, Gly, Ala, Val, Met, Ile, Leu, Tyr, Phe, ΣEAA, ΣDAA and ΣTAA contents of dorsal muscle were decreased, while the elasticity and adhesion of dorsal muscle were increased. In summary, MBM is an acceptable alternative animal protein source for Furong crucian carp, and 100% dietary fish meal could be replaced by MBM without significantly adverse effects on the growth of Furong crucian carp.
2020, 44(1): 95 -103
doi: 10.7541/2020.012
Abstract:
To investigate the effects of heavy metals (copper and cadmium) on Oryzias melastigma, the relationships among indicators were analyzed. Three concentration gradients of copper and cadmium were used according to the seawater quality standard, and five physiological and biochemical indicators [lactic acid (LA), lactate dehydrogenase (LDH), testosterone (T), follicle stimulating hormone (FSH), luteinizing hormone (LH) and fecundity] were determined. The LA content of O. melastigma decreased significantly with the prolongation of copper exposure time, and increased with the increase of cadmium concentration. The activity of LDH did not change much under copper poisoning, but increased slightly with the prolongation of cadmium exposure time. The content of T increased with short-term copper treatment, but it decreased significantly with the prolongation of the time. The content of T increased with the enhanced cadmium toxic concentration and prolonged time. The content of FSH and LH decreased significantly with the increase of copper poisoning, and decreased with the increase of cadmium concentration, and the contents of both FSH and LH were closely related to T change. The fecundity of O. melastigm showed a significant downward trend with the prolongation of copper exposure time and the increased concentration. These results indicated that copper and cadmium poisoning could cause physiological and biochemical changes of O. melastigm with a pattern of gender differences, and that female fish can be selected for related pollution monitoring.
To investigate the effects of heavy metals (copper and cadmium) on Oryzias melastigma, the relationships among indicators were analyzed. Three concentration gradients of copper and cadmium were used according to the seawater quality standard, and five physiological and biochemical indicators [lactic acid (LA), lactate dehydrogenase (LDH), testosterone (T), follicle stimulating hormone (FSH), luteinizing hormone (LH) and fecundity] were determined. The LA content of O. melastigma decreased significantly with the prolongation of copper exposure time, and increased with the increase of cadmium concentration. The activity of LDH did not change much under copper poisoning, but increased slightly with the prolongation of cadmium exposure time. The content of T increased with short-term copper treatment, but it decreased significantly with the prolongation of the time. The content of T increased with the enhanced cadmium toxic concentration and prolonged time. The content of FSH and LH decreased significantly with the increase of copper poisoning, and decreased with the increase of cadmium concentration, and the contents of both FSH and LH were closely related to T change. The fecundity of O. melastigm showed a significant downward trend with the prolongation of copper exposure time and the increased concentration. These results indicated that copper and cadmium poisoning could cause physiological and biochemical changes of O. melastigm with a pattern of gender differences, and that female fish can be selected for related pollution monitoring.
2020, 44(1): 104 -111
doi: 10.7541/2020.013
Abstract:
Intermuscular bones (IBs) are common in the lower teleost and its morphology types and numbers are varied among different fish species. In this study, we documented the number, morphology, and distribution of IBs in Coilia nasus. The morphology of IBs in C. nasus was not different with Cyprinidae species; however, the distribution of IBs was quite different. Besides epineurals, epicentrals, and epipleurals, we found two others categories of IBs in C. nasus, which are located in the dorsal and ventral parts on both sides of the vertebrae. According to the reference, we called them dorsal and ventral myorhabdoi, respectively. These types of IBs were also identified in C. brachygnathus. The morphology of these IBs showed non-forked type (“1” or “(”). The number of IBs in C. nasus ranged from 492 to 543, and the number of epineurals, epicentrals, epipleurals, dorsal myorhabdoiand ventral myorhabdoi ranged from 114 to 142 (\begin{document}$\bar x$\end{document} ![]()
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Intermuscular bones (IBs) are common in the lower teleost and its morphology types and numbers are varied among different fish species. In this study, we documented the number, morphology, and distribution of IBs in Coilia nasus. The morphology of IBs in C. nasus was not different with Cyprinidae species; however, the distribution of IBs was quite different. Besides epineurals, epicentrals, and epipleurals, we found two others categories of IBs in C. nasus, which are located in the dorsal and ventral parts on both sides of the vertebrae. According to the reference, we called them dorsal and ventral myorhabdoi, respectively. These types of IBs were also identified in C. brachygnathus. The morphology of these IBs showed non-forked type (“1” or “(”). The number of IBs in C. nasus ranged from 492 to 543, and the number of epineurals, epicentrals, epipleurals, dorsal myorhabdoiand ventral myorhabdoi ranged from 114 to 142 (
2020, 44(1): 112 -121
doi: 10.7541/2020.014
Abstract:
Sinibotia reevesae, an endemic fish, lives only in the upper reaches of the Yangtze River. This study explored the structure characteristics of Sinibotia reevesae brain and effects of the ecological habits on the central nervous system. The results showed that S. reevesae brain was composed of five parts of telencephalon, diencephalon, mesencephalon, cerebellum and myelecephalon. The olfactory lobe was a typical spindle shape and the preoptic nucleus of the brain was arranged in a cord-like manner without large preoptic nucleus and small cell group. The corpus mamillare and parasympathetic nucleus were visible in the diencephalon, meanwhile, saccus vasculosus and inferior lobeis were well developed. There were five layers in the tectum opticum of the mesencephalon and three layers in the cerebellum. The myelecephalon located in the end of the brain and differentiated into facial lobes and developed vagal lobes. Histological observations revealed that olfactory, auditory, tactile sensation, taste, motor centers and athletic ability of S. reevesae were well-developed. To sum up, the S. reevesae mainly depend on the sense of smell, hearing, touch, and taste to forage and to evade the natural enemies.
Sinibotia reevesae, an endemic fish, lives only in the upper reaches of the Yangtze River. This study explored the structure characteristics of Sinibotia reevesae brain and effects of the ecological habits on the central nervous system. The results showed that S. reevesae brain was composed of five parts of telencephalon, diencephalon, mesencephalon, cerebellum and myelecephalon. The olfactory lobe was a typical spindle shape and the preoptic nucleus of the brain was arranged in a cord-like manner without large preoptic nucleus and small cell group. The corpus mamillare and parasympathetic nucleus were visible in the diencephalon, meanwhile, saccus vasculosus and inferior lobeis were well developed. There were five layers in the tectum opticum of the mesencephalon and three layers in the cerebellum. The myelecephalon located in the end of the brain and differentiated into facial lobes and developed vagal lobes. Histological observations revealed that olfactory, auditory, tactile sensation, taste, motor centers and athletic ability of S. reevesae were well-developed. To sum up, the S. reevesae mainly depend on the sense of smell, hearing, touch, and taste to forage and to evade the natural enemies.
2020, 44(1): 122 -132
doi: 10.7541/2020.015
Abstract:
This study investigated annual variations of fish communities in different sections along the longitudinal gradient of the near-natural river based on the data collected from 2007 to 2016. A total of 133 fish species, belonged to 7 orders, 20 families and 84 genera, were collected. Among these species, Acipenser dabryanus and Myxocyprinus asiaticus have been enlisted as class Ⅰ and II protected species in China, while other 36 species endemic to the upper Yangtze River. The number of fish species increased along the longitudinal gradient, which increased from 47 in Chishui Town Section to 90 in the Chishui City Section and to 120 in the Hejiang County Section. Cluster analysis and non-metric multidimensional scaling (nMDS) ordination analysis revealed that the fish communities in all sections were varied significantly over time. The relative abundance of large and medium-sized economic fishes, such as S. sinensis and O. sima, declined continuously, while the small-sized fishes such as H. labeo, S. argentatus and R. giurinus showed the opposite trends. Additionally, the abundance of some endemic fish species, such as H. tchangi and C. guichenoti, declined markedly. The induced reasons included local overfishing, navigation, channel regulation and hydropower development, as well as changes of aquatic environment in the mainstream of the upper Yangtze River. In order to effectively protect fish stocks, it is recommended to strictly manage fisheries and water activities. Further strengthen long-term monitoring and timely detect changes in fish mix structure.
This study investigated annual variations of fish communities in different sections along the longitudinal gradient of the near-natural river based on the data collected from 2007 to 2016. A total of 133 fish species, belonged to 7 orders, 20 families and 84 genera, were collected. Among these species, Acipenser dabryanus and Myxocyprinus asiaticus have been enlisted as class Ⅰ and II protected species in China, while other 36 species endemic to the upper Yangtze River. The number of fish species increased along the longitudinal gradient, which increased from 47 in Chishui Town Section to 90 in the Chishui City Section and to 120 in the Hejiang County Section. Cluster analysis and non-metric multidimensional scaling (nMDS) ordination analysis revealed that the fish communities in all sections were varied significantly over time. The relative abundance of large and medium-sized economic fishes, such as S. sinensis and O. sima, declined continuously, while the small-sized fishes such as H. labeo, S. argentatus and R. giurinus showed the opposite trends. Additionally, the abundance of some endemic fish species, such as H. tchangi and C. guichenoti, declined markedly. The induced reasons included local overfishing, navigation, channel regulation and hydropower development, as well as changes of aquatic environment in the mainstream of the upper Yangtze River. In order to effectively protect fish stocks, it is recommended to strictly manage fisheries and water activities. Further strengthen long-term monitoring and timely detect changes in fish mix structure.
2020, 44(1): 133 -142
doi: 10.7541/2020.016
Abstract:
In order to explore the food composition of Procambarus clarkia and the food web structure in two different systems (crayfish-only system and integrated rice-crayfish symbiosis farming (IRCSF) system), we analyzed carbon and nitrogen stable isotope ratios (δ13C and δ15N) of sources and consumers, food web structure by SIBER and the food composition of P. clarkia by SIAR. The results showed that among the 19 collected species, the δ13C value of the consumer was between –34.22‰ to –25.34‰, the δ15N value was between 2.33‰ to 8.05‰, and the trophic level was between 1.46 to 3.64. The trophic level of P. clarkia in crayfish-only system was higher than that in IRCSF system. The metrics of food web reflected that the isotope niches in two systems using P. clarkia were similar. In IRCSF system, the trophic diversity in the food web was higher than that in crayfish-only system, and the niche overlap of each species and trophic redundancy in food web were lower than those in crayfish-only system. The significant positive correlation between the body length/weight and δ15N value of P. clarkia mean that P. clarkia prefer animal baits in two systems. The food contribution for P. clarkia was uniform and the proportion of plant baits was higher in IRCSF system compared with the crayfish-only system. The results indicated that the transfer loss of energy from sources to P. clarkia is higher in crayfish-only system, and the P. clarkia in IRCSF system was more herbivorous.
In order to explore the food composition of Procambarus clarkia and the food web structure in two different systems (crayfish-only system and integrated rice-crayfish symbiosis farming (IRCSF) system), we analyzed carbon and nitrogen stable isotope ratios (δ13C and δ15N) of sources and consumers, food web structure by SIBER and the food composition of P. clarkia by SIAR. The results showed that among the 19 collected species, the δ13C value of the consumer was between –34.22‰ to –25.34‰, the δ15N value was between 2.33‰ to 8.05‰, and the trophic level was between 1.46 to 3.64. The trophic level of P. clarkia in crayfish-only system was higher than that in IRCSF system. The metrics of food web reflected that the isotope niches in two systems using P. clarkia were similar. In IRCSF system, the trophic diversity in the food web was higher than that in crayfish-only system, and the niche overlap of each species and trophic redundancy in food web were lower than those in crayfish-only system. The significant positive correlation between the body length/weight and δ15N value of P. clarkia mean that P. clarkia prefer animal baits in two systems. The food contribution for P. clarkia was uniform and the proportion of plant baits was higher in IRCSF system compared with the crayfish-only system. The results indicated that the transfer loss of energy from sources to P. clarkia is higher in crayfish-only system, and the P. clarkia in IRCSF system was more herbivorous.
2020, 44(1): 143 -152
doi: 10.7541/2020.017
Abstract:
To discover the causes of sick black seabass, bacterial strain ZS201807 was isolated from the cultured Centropristis striata with the symptoms of white spots in gill and visceral organs. The biochemical and physiological characteristics of the isolated strain were studied by using conventional method, such as API 20 and 16S rDNA gene sequence. The bacteria were identified as Edwardsiella tarda. The artificial infection experiment indicated that the strain was the causative agent of sick Centropristis striata. Histopathological analysis revealed that the spleen and kidney were the main target organs with serious infection, such as a large number of erythrocyte infiltration in the spleen tissue, serious blood stasis, gill filaments capillary dilation, renal tubular cavity stenosis, glomerular enlargement, epithelial cell swelling and cell cavitation. Ultrastructural pathology showed that there was a large accumulation of rod bacteria in the spleen and head kidney tissue of the sick fish. The drug susceptibility test showed that the bacterium was sensitive to 14 kinds of drugs such as ciprofloxacin (per 5 μg), tetracycline (per 30 μg) and enrofloxacin (per 5 μg), and resistant to 13 kinds of drugs such as penicillin (per 10 U), azithromycin (per 15 μg) and amikacin (per 30 μg). It was confirmed that the pathogen of the disease and death of the black seabass was slow Edwardsiella tarda.
To discover the causes of sick black seabass, bacterial strain ZS201807 was isolated from the cultured Centropristis striata with the symptoms of white spots in gill and visceral organs. The biochemical and physiological characteristics of the isolated strain were studied by using conventional method, such as API 20 and 16S rDNA gene sequence. The bacteria were identified as Edwardsiella tarda. The artificial infection experiment indicated that the strain was the causative agent of sick Centropristis striata. Histopathological analysis revealed that the spleen and kidney were the main target organs with serious infection, such as a large number of erythrocyte infiltration in the spleen tissue, serious blood stasis, gill filaments capillary dilation, renal tubular cavity stenosis, glomerular enlargement, epithelial cell swelling and cell cavitation. Ultrastructural pathology showed that there was a large accumulation of rod bacteria in the spleen and head kidney tissue of the sick fish. The drug susceptibility test showed that the bacterium was sensitive to 14 kinds of drugs such as ciprofloxacin (per 5 μg), tetracycline (per 30 μg) and enrofloxacin (per 5 μg), and resistant to 13 kinds of drugs such as penicillin (per 10 U), azithromycin (per 15 μg) and amikacin (per 30 μg). It was confirmed that the pathogen of the disease and death of the black seabass was slow Edwardsiella tarda.
2020, 44(1): 153 -161
doi: 10.7541/2020.018
Abstract:
Largemouth bronze gudgeon (Coreius guichenoti) is a potamodromous and endemic fish in the upper reaches of Yangtze River. An epidemic was found in largemouth bronze gudgeon at a farm in Luzhou, Sichuan province, southwest China, at the end of March 2012. In this study, we reported the first observation of furunculosis found in largemouth bronze gudgeon. One dominant bacteria strain, YTL1, was isolated from the liver of diseased largemouth bronze gudgeon, and a series of methods including morphological observation, biochemical tests, and phylogenetic analysis of 16S rRNA and six housekeeping genes were used to identify the pathogen. The strain was finally identified as A. salmonicida subsp. salmonicida based on the results. Antimicrobial susceptibility tests were carried out by the standard Kirby-Bauer disc diffusion method to screen effective drugs for the therapy of the disease, with results showing that YTL1 was sensitive to thirteen antibiotics such as florfenicol, norfloxacin, and ampicillin, resistant to 6 antibiotics such as bacitracin, streptomycin, and kanamycin, and mid-sensitive to erythromycin. Accordingly, florfenicol was added into diets to control furunculosis in largemouth bronze gudgeon with a good result. Artificial infection experiments in grass carp fingerlings and zebrafish resulted in the similar symptoms as diseased largemouth bronze gudgeon. In conclusion, our study demonstrated that multilocus sequence typing based on six housekeeping genes is an effective method to identify A. salmonicida strains to the subspecies level, confirmed that A. salmonicida infection is one of the greatest threats to artificial breeding and aquaculture of largemouth bronze gudgeon, and has expanded the susceptible hosts of A. salmonicida subsp. salmonicida to more cyprinid fishes.
Largemouth bronze gudgeon (Coreius guichenoti) is a potamodromous and endemic fish in the upper reaches of Yangtze River. An epidemic was found in largemouth bronze gudgeon at a farm in Luzhou, Sichuan province, southwest China, at the end of March 2012. In this study, we reported the first observation of furunculosis found in largemouth bronze gudgeon. One dominant bacteria strain, YTL1, was isolated from the liver of diseased largemouth bronze gudgeon, and a series of methods including morphological observation, biochemical tests, and phylogenetic analysis of 16S rRNA and six housekeeping genes were used to identify the pathogen. The strain was finally identified as A. salmonicida subsp. salmonicida based on the results. Antimicrobial susceptibility tests were carried out by the standard Kirby-Bauer disc diffusion method to screen effective drugs for the therapy of the disease, with results showing that YTL1 was sensitive to thirteen antibiotics such as florfenicol, norfloxacin, and ampicillin, resistant to 6 antibiotics such as bacitracin, streptomycin, and kanamycin, and mid-sensitive to erythromycin. Accordingly, florfenicol was added into diets to control furunculosis in largemouth bronze gudgeon with a good result. Artificial infection experiments in grass carp fingerlings and zebrafish resulted in the similar symptoms as diseased largemouth bronze gudgeon. In conclusion, our study demonstrated that multilocus sequence typing based on six housekeeping genes is an effective method to identify A. salmonicida strains to the subspecies level, confirmed that A. salmonicida infection is one of the greatest threats to artificial breeding and aquaculture of largemouth bronze gudgeon, and has expanded the susceptible hosts of A. salmonicida subsp. salmonicida to more cyprinid fishes.
2020, 44(1): 162 -169
doi: 10.7541/2020.019
Abstract:
To study the individual biology of chum salmon, 447 samples were collected in Dongning section of the Suifen River from 2012 to 2017. The results showed that the age groups of samples were 1+—5+, of which 3+ and 2+ age are dominant for females and males respectively. The relationships between body weight and body length of male and female salmon were as follows: W=0.0082×L3.0604; W=0.0076×L3.0746, which were all belonged to the type of uniform growth. Von Bertalanffy growth function was used in simulating the fork length growth of chum salmon. The fork length growth equations of male and female chum salmon aged 3+ years were Lt,F=141.64×e–0.11·(t+1.55) and Lt,M= 119.51×e–0.13·(t+1.45), respectively. The fork length growth rate of chum salmon was inversely proportional to the age of sexual maturity. The total fork length of 50% male and female individuals reaching sexual maturity (L50) was estimated by logistic moderating function with 42.15 cm for male and 51.53 cm for female. ARSS analysis revealed a significant difference between male and female individuals for L50. Results showed that the average of absolute fecundity (F) and relative fecundity (FL and FW) were 3412 eggs, 52.42 eggs/cm and 1.17 eggs/g respectively. The positive correlation between F and fork length, body weight, and gonad weight of female chum salmon was significant, while the significant positive correlation between GSI and fork length, body weight, F was found. The power exponential equation was used to simulate the relationships of F and fork length, body weight respectively, and the regression function as follow: F=0.0311×L2.7745(R2=0.638); F=1.946×W0.9374(R2=0.704). This study will provide basic information for the conservation of chum salmon.
To study the individual biology of chum salmon, 447 samples were collected in Dongning section of the Suifen River from 2012 to 2017. The results showed that the age groups of samples were 1+—5+, of which 3+ and 2+ age are dominant for females and males respectively. The relationships between body weight and body length of male and female salmon were as follows: W=0.0082×L3.0604; W=0.0076×L3.0746, which were all belonged to the type of uniform growth. Von Bertalanffy growth function was used in simulating the fork length growth of chum salmon. The fork length growth equations of male and female chum salmon aged 3+ years were Lt,F=141.64×e–0.11·(t+1.55) and Lt,M= 119.51×e–0.13·(t+1.45), respectively. The fork length growth rate of chum salmon was inversely proportional to the age of sexual maturity. The total fork length of 50% male and female individuals reaching sexual maturity (L50) was estimated by logistic moderating function with 42.15 cm for male and 51.53 cm for female. ARSS analysis revealed a significant difference between male and female individuals for L50. Results showed that the average of absolute fecundity (F) and relative fecundity (FL and FW) were 3412 eggs, 52.42 eggs/cm and 1.17 eggs/g respectively. The positive correlation between F and fork length, body weight, and gonad weight of female chum salmon was significant, while the significant positive correlation between GSI and fork length, body weight, F was found. The power exponential equation was used to simulate the relationships of F and fork length, body weight respectively, and the regression function as follow: F=0.0311×L2.7745(R2=0.638); F=1.946×W0.9374(R2=0.704). This study will provide basic information for the conservation of chum salmon.
2020, 44(1): 170 -179
doi: 10.7541/2020.020
Abstract:
Ptychobarbus dipogon is endemic to China and has been threatened by overfishing and biological invasion. To examine 956 individuals collected from Lhaze to Nyemo of Yarlung Zangbo River, the population resources and fishery management policies of this species were studied by using per-recruit models from October 2008 to September 2009, April 2012 to July 2012 and in March 2013 respectively. The total instantaneous annual mortality (Z) of female and male P. dipogon were 0.52/year and 0.70/year, respectively. The range of natural mortality (M) of female and male P. dipogon were 0.10—0.17/year and 0.14—0.24/year, respectively. The range of current fishing mortality (Fcur) was 0.35—0.42/year for females and 0.46—0.56/year for males. The range of spawning potential ratio of P. dipogon was 3.1%—6.7% for females and 9.8%—18.2% for males, both of which were all significantly lower than the threshold reference point (25%). These results indicated that the stock of P. dipogon had been over-exploited under the current fishery management policy. To evaluate protective effect of capture age and seasonal closure, 14 different fishery management policies were simulated. The results show that raising the fishing age to not less than 15 years or setting the season closure time from February to June can effectively protect the population of the diagonal nematode.
Ptychobarbus dipogon is endemic to China and has been threatened by overfishing and biological invasion. To examine 956 individuals collected from Lhaze to Nyemo of Yarlung Zangbo River, the population resources and fishery management policies of this species were studied by using per-recruit models from October 2008 to September 2009, April 2012 to July 2012 and in March 2013 respectively. The total instantaneous annual mortality (Z) of female and male P. dipogon were 0.52/year and 0.70/year, respectively. The range of natural mortality (M) of female and male P. dipogon were 0.10—0.17/year and 0.14—0.24/year, respectively. The range of current fishing mortality (Fcur) was 0.35—0.42/year for females and 0.46—0.56/year for males. The range of spawning potential ratio of P. dipogon was 3.1%—6.7% for females and 9.8%—18.2% for males, both of which were all significantly lower than the threshold reference point (25%). These results indicated that the stock of P. dipogon had been over-exploited under the current fishery management policy. To evaluate protective effect of capture age and seasonal closure, 14 different fishery management policies were simulated. The results show that raising the fishing age to not less than 15 years or setting the season closure time from February to June can effectively protect the population of the diagonal nematode.
2020, 44(1): 180 -186
doi: 10.7541/2020.021
Abstract:
To search suitable reference genes for normalization of quantitative Real-Time PCR (qRT-PCR) in Moina macrocopa, we tested three reference genes of β-actin, 16S rRNA and 12S rRNA by using four analysis methods: (1) expression level of the genes (cycle threshold value); (2) GeNorm; (3) NormFinder; and (4) BestKeeper. The results showed that the Ct values of the β-actin, 16S rRNA and 12S rRNA genes remained unchanged in M. macrocopa treated with different concentrations of phenol, and the order of the stability was 16S rRNA>12S rRNA>β-actin. GeNorm analysis revealed that the order of the stability was 16S rRNA=β-actin>12S rRNA. Both NormFinder and Bestkeeper software analysis demonstrated that the order of the stability was 16S rRNA>β-actin>12S rRNA. These results indicated that 16S rRNA was the best-fit reference gene for qRT-PCR in M. macrocopa, at least under phenol treatment, which provide useful information for future functional investigations of target gene expressions in M. macrocopa in response to environmental stress.
To search suitable reference genes for normalization of quantitative Real-Time PCR (qRT-PCR) in Moina macrocopa, we tested three reference genes of β-actin, 16S rRNA and 12S rRNA by using four analysis methods: (1) expression level of the genes (cycle threshold value); (2) GeNorm; (3) NormFinder; and (4) BestKeeper. The results showed that the Ct values of the β-actin, 16S rRNA and 12S rRNA genes remained unchanged in M. macrocopa treated with different concentrations of phenol, and the order of the stability was 16S rRNA>12S rRNA>β-actin. GeNorm analysis revealed that the order of the stability was 16S rRNA=β-actin>12S rRNA. Both NormFinder and Bestkeeper software analysis demonstrated that the order of the stability was 16S rRNA>β-actin>12S rRNA. These results indicated that 16S rRNA was the best-fit reference gene for qRT-PCR in M. macrocopa, at least under phenol treatment, which provide useful information for future functional investigations of target gene expressions in M. macrocopa in response to environmental stress.
2020, 44(1): 187 -196
doi: 10.7541/2020.022
Abstract:
To analyze the molecular diversity of planktonic microbial eukaryotes as well as relationships between the community structures and physicochemical factors based on the terminal restriction fragment length polymorphism (T-RFLP), water samples were collected from 43 sites in Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River during wet season and dry season, respectively. The results revealed that water bodies of Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River were seriously polluted by nitrogen and phosphorus, and the water were in poor quality. The diversity indexes of planktonic microbial eukaryotes in Guangdong Reach of Xijiang River were higher than those in Guangzhou Reach of Pearl River. The Shannon-Wiener indexes of samples collected in wet season were lower than those in dry season. There were significant differences in community structures of microbial eukaryotes from different seasons and regions. The community structures of planktonic microbial eukaryotes in Pearl River were affected by chemical oxygen demand, permanganate index, ammonia nitrogen, total nitrogen and total phosphorus. However, correlation coefficients between community structures and physicochemical factors were different depending on seasons and regions. In addition, one T-RF and six T-RFs were selected as possible sensitive species (Cystobasidium sp. or Protostelium nocturnum) and pollution-tolerant species (Acanthamoeba hatchetti, Babesia bicornis, Blastocystis sp., Botryosphaerella sudetica, Candida caryicola, Coccomyxa simplex, Cryptomonas ovata, Filos agilis, Stenophora robusta, Sulfonecta uniserialis and Theileria sp. etc.), respectively.
To analyze the molecular diversity of planktonic microbial eukaryotes as well as relationships between the community structures and physicochemical factors based on the terminal restriction fragment length polymorphism (T-RFLP), water samples were collected from 43 sites in Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River during wet season and dry season, respectively. The results revealed that water bodies of Guangzhou Reach of Pearl River and Guangdong Reach of Xijiang River were seriously polluted by nitrogen and phosphorus, and the water were in poor quality. The diversity indexes of planktonic microbial eukaryotes in Guangdong Reach of Xijiang River were higher than those in Guangzhou Reach of Pearl River. The Shannon-Wiener indexes of samples collected in wet season were lower than those in dry season. There were significant differences in community structures of microbial eukaryotes from different seasons and regions. The community structures of planktonic microbial eukaryotes in Pearl River were affected by chemical oxygen demand, permanganate index, ammonia nitrogen, total nitrogen and total phosphorus. However, correlation coefficients between community structures and physicochemical factors were different depending on seasons and regions. In addition, one T-RF and six T-RFs were selected as possible sensitive species (Cystobasidium sp. or Protostelium nocturnum) and pollution-tolerant species (Acanthamoeba hatchetti, Babesia bicornis, Blastocystis sp., Botryosphaerella sudetica, Candida caryicola, Coccomyxa simplex, Cryptomonas ovata, Filos agilis, Stenophora robusta, Sulfonecta uniserialis and Theileria sp. etc.), respectively.
2020, 44(1): 197 -205
doi: 10.7541/2020.023
Abstract:
We used living observation, protargol impregnation and silver staining methods to investigate the nuclei morphology and position, infraciliature, and oral apparatus of two oligohymenophorean ciliates: Paramecium primaurelia and Tetrahymena mimbres, which collected from hot springs of Tibet Autonomous Region. SSU rDNA and COXⅠ genes of these two species were sequenced, and the phylogenetic analysis revealed that P. primaurelia is clustered in Paramecium aurelia complex, and T. mimbres is clustered in Tetrahymena borealis group. These two species are newly recorded in China from the hot springs of Tibet Autonomous Region. The study of these two newly recorded species not only provides new methods and insights for the discovery of protozoa resources in the Tibetan hot springs, but also provides basic information for the study of protozoa environmental adaptation.
We used living observation, protargol impregnation and silver staining methods to investigate the nuclei morphology and position, infraciliature, and oral apparatus of two oligohymenophorean ciliates: Paramecium primaurelia and Tetrahymena mimbres, which collected from hot springs of Tibet Autonomous Region. SSU rDNA and COXⅠ genes of these two species were sequenced, and the phylogenetic analysis revealed that P. primaurelia is clustered in Paramecium aurelia complex, and T. mimbres is clustered in Tetrahymena borealis group. These two species are newly recorded in China from the hot springs of Tibet Autonomous Region. The study of these two newly recorded species not only provides new methods and insights for the discovery of protozoa resources in the Tibetan hot springs, but also provides basic information for the study of protozoa environmental adaptation.
2020, 44(1): 206 -212
doi: 10.7541/2020.024
Abstract:
To investigate the effects of two strains of Microcystis aeruginosa (microcystin-producing and microcystin-free) at different concentrations on the life table parameters of Brachionus calyciflorus, we conducted a life-table study at 25℃ and investigated the responses of life table parameters of B. calyciflorus to microcystin-producing M. aeruginosa concentrations at five temperature gradients. The results showed that both M. aeruginosa toxicity and concentration significantly mediated the net reproduction rate (R0; F=31.83, P<0.01; F=30.36, P<0.01) and intrinsic growth rate (rm; F=34.67, P<0.01; F=18.73, P<0.01) of B. calyciflorus with a significant interactive effect, and that temperature and microcystin-producing M. aeruginosa concentration had significant independent and interactive effects on the net reproduction rate (R0; F=13.51, P<0.01) and intrinsic growth rate (rm; F=12.99, P<0.01) of B. calyciflorus. Microcystin-free M. aeruginosa promoted the rotifer population and it could be used as a food source for rotifers at low concentration (1×104 cells/mL), but its food quality was low due to the lack of fatty acids and other nutrients. High concentration of Microcystin-free M. aeruginosa (1×105 cells/mL and 5×105 cells/mL) obviously inhibited the growth of rotifers because rotifers prefer microcystin-free M. aeruginosa. The net reproductive rate and intrinsic growth rate of B. calyciflorus increased significantly by increasing concentration of microcystin-producing M. aeruginosa. Moreover, high temperature (30℃ and 35℃) accelerated their reproduction and growth rate, shorten the generation time, and promoted inhibitory effect of microcystin-free M. aeruginosa on rotifers.
To investigate the effects of two strains of Microcystis aeruginosa (microcystin-producing and microcystin-free) at different concentrations on the life table parameters of Brachionus calyciflorus, we conducted a life-table study at 25℃ and investigated the responses of life table parameters of B. calyciflorus to microcystin-producing M. aeruginosa concentrations at five temperature gradients. The results showed that both M. aeruginosa toxicity and concentration significantly mediated the net reproduction rate (R0; F=31.83, P<0.01; F=30.36, P<0.01) and intrinsic growth rate (rm; F=34.67, P<0.01; F=18.73, P<0.01) of B. calyciflorus with a significant interactive effect, and that temperature and microcystin-producing M. aeruginosa concentration had significant independent and interactive effects on the net reproduction rate (R0; F=13.51, P<0.01) and intrinsic growth rate (rm; F=12.99, P<0.01) of B. calyciflorus. Microcystin-free M. aeruginosa promoted the rotifer population and it could be used as a food source for rotifers at low concentration (1×104 cells/mL), but its food quality was low due to the lack of fatty acids and other nutrients. High concentration of Microcystin-free M. aeruginosa (1×105 cells/mL and 5×105 cells/mL) obviously inhibited the growth of rotifers because rotifers prefer microcystin-free M. aeruginosa. The net reproductive rate and intrinsic growth rate of B. calyciflorus increased significantly by increasing concentration of microcystin-producing M. aeruginosa. Moreover, high temperature (30℃ and 35℃) accelerated their reproduction and growth rate, shorten the generation time, and promoted inhibitory effect of microcystin-free M. aeruginosa on rotifers.
2020, 44(1): 213 -221
doi: 10.7541/2020.025
Abstract:
As a representative lake in Momoge Wetland Reserve, White Crane Lake is facing the risk of salinization and eutrophication.In order to slow down the salinization trend and provide research basis for the restoration of submerged vegetation and survival of species diversity of White Crane Lake, this study investigated physiological indexes of Ceratophyllum demersum in different alkalinity (0, 7, 10 and 17 mmol/L) and mixed saline-alkaline (salinity of 0.3, 0.6, 1, 2 and 4 g/L, corresponding alkalinity of 1.9, 3.8, 6.3, 12.6 and 25.2 mmol/L). The results showed that when the salinity was below 1.5 g/L, alkalinity had no effect on C. demersum. Within the range of the alkalinity gradient set in the experiment, C. demersum grown normally. Although C. demersum peroxidase (POD) and proline showed gradient change, C. demersum was still able to tolerate the alkalinity conditions below 17 mmol/L. With the increase of mixed saline-alkaline concentration, the growth of C. demersum showed a trend from flourish to decline. Under the condition of salinity of 0.6 g/L and alkalinity of 3.8 mmol/L, C. demersum had the best growth with the high-promoting and low-inhibiting ability. With the increase of salinity to 2 g/L and alkalinity to 12.6 mmol/L, C. demersum were under stress and survived partially, and the POD content increased sharply and the difference between plants was large. When salinity increased to 4 g/L and alkalinity reached 25.2 mmol/L, all C. demersum died after 21 days explained by the high concentration of mixed saline-alkaline and the low removal rate of nitrogen and phosphorus that are negatively correlated. This study provides reference for the restoration of submerged vegetation in salinized lakes.
As a representative lake in Momoge Wetland Reserve, White Crane Lake is facing the risk of salinization and eutrophication.In order to slow down the salinization trend and provide research basis for the restoration of submerged vegetation and survival of species diversity of White Crane Lake, this study investigated physiological indexes of Ceratophyllum demersum in different alkalinity (0, 7, 10 and 17 mmol/L) and mixed saline-alkaline (salinity of 0.3, 0.6, 1, 2 and 4 g/L, corresponding alkalinity of 1.9, 3.8, 6.3, 12.6 and 25.2 mmol/L). The results showed that when the salinity was below 1.5 g/L, alkalinity had no effect on C. demersum. Within the range of the alkalinity gradient set in the experiment, C. demersum grown normally. Although C. demersum peroxidase (POD) and proline showed gradient change, C. demersum was still able to tolerate the alkalinity conditions below 17 mmol/L. With the increase of mixed saline-alkaline concentration, the growth of C. demersum showed a trend from flourish to decline. Under the condition of salinity of 0.6 g/L and alkalinity of 3.8 mmol/L, C. demersum had the best growth with the high-promoting and low-inhibiting ability. With the increase of salinity to 2 g/L and alkalinity to 12.6 mmol/L, C. demersum were under stress and survived partially, and the POD content increased sharply and the difference between plants was large. When salinity increased to 4 g/L and alkalinity reached 25.2 mmol/L, all C. demersum died after 21 days explained by the high concentration of mixed saline-alkaline and the low removal rate of nitrogen and phosphorus that are negatively correlated. This study provides reference for the restoration of submerged vegetation in salinized lakes.
2020, 44(1): 222 -230
doi: 10.7541/2020.026
Abstract:
The growth and propagation of aquatic plants will be greatly suppressed if the water level rises promptly. Some aquatic plants, especially for some emergent plants, can form floating mats to avoid the effects of deep flooding. We studied the species composition and distribution pattern of floating mat to find which species could form floating mats more easily and survive in the process of increasing water level in Lake Erhai in 2017. A total of 26 aquatic species (attached to 15 families and 19 genera) were recorded. The concentrations of total nitrogen (TN), total phosphorus (TP) and total dissolved phosphorus (TDP) in the water under the floating mat were greater than those in the open water, while the concentration of dissolved oxygen (DO) was vice versa. The results showed that both species richness and biomass of the floating mat were positively correlated with the area of floating mat (P<0.01), and the mean biomass of the floating mat was not significantly correlated with the area of floating mat (P>0.05). The longest root of the floating mat was significantly correlated with the area of floating mat in summer (P<0.01) but not in winter (P>0.05). Most of the floating mats distributed in the region within an offshore distance of 60 m and the water depth less than 2 m. The area of the most floating mats was less than 600 m2 (87% for summer and 95% for winter), and the number of species in the floating mats is less than 10, the longest root in the floating mats ranged from 40 to 120 cm. The frequency and relative biomass of Zizania latifolia were the greatest among all recorded species on the floating mats in two seasons (frequency: 73.33% in summer and 66.67% in winter; relative biomass: 43.38% in summer and 41.91% in winter). These results indicated that Z. latifolia was easier to form floating mats in escape of the stress of deep water than the other emergent species to explain its sino-dominance in the emergent community. The mechanism that Z. latifolia is easier to form floating mats than the other emergent plants deserves further investigations.
The growth and propagation of aquatic plants will be greatly suppressed if the water level rises promptly. Some aquatic plants, especially for some emergent plants, can form floating mats to avoid the effects of deep flooding. We studied the species composition and distribution pattern of floating mat to find which species could form floating mats more easily and survive in the process of increasing water level in Lake Erhai in 2017. A total of 26 aquatic species (attached to 15 families and 19 genera) were recorded. The concentrations of total nitrogen (TN), total phosphorus (TP) and total dissolved phosphorus (TDP) in the water under the floating mat were greater than those in the open water, while the concentration of dissolved oxygen (DO) was vice versa. The results showed that both species richness and biomass of the floating mat were positively correlated with the area of floating mat (P<0.01), and the mean biomass of the floating mat was not significantly correlated with the area of floating mat (P>0.05). The longest root of the floating mat was significantly correlated with the area of floating mat in summer (P<0.01) but not in winter (P>0.05). Most of the floating mats distributed in the region within an offshore distance of 60 m and the water depth less than 2 m. The area of the most floating mats was less than 600 m2 (87% for summer and 95% for winter), and the number of species in the floating mats is less than 10, the longest root in the floating mats ranged from 40 to 120 cm. The frequency and relative biomass of Zizania latifolia were the greatest among all recorded species on the floating mats in two seasons (frequency: 73.33% in summer and 66.67% in winter; relative biomass: 43.38% in summer and 41.91% in winter). These results indicated that Z. latifolia was easier to form floating mats in escape of the stress of deep water than the other emergent species to explain its sino-dominance in the emergent community. The mechanism that Z. latifolia is easier to form floating mats than the other emergent plants deserves further investigations.
2020, 44(1): 231 -236
doi: 10.7541/2020.027
Abstract:
Licorice (Glycyrrhiza cyrrhiza uralensis Fiseh) is known as the “king of all herbs” because of its characteristics of harmonizing various medicines. It is a common cheap medicine in China and is therefore used in aquaculture. It’s main active components are polysaccharides, glycosides, alkaloids, organic acids and volatile oil. In aquaculture, the common methods of licorice administration include feeding, perfusing, injecting, soaking and sprinkling, by which way are used for immune conditioning, disease control and other purposes for aquatic animals. However, there are also some problems in use of licorice, such as unstable quality of medicinal materials, extensive use methods, less standardized prescriptions, and inaccurate naming and description. In this paper, the fishery value of licorice was reviewed.
Licorice (Glycyrrhiza cyrrhiza uralensis Fiseh) is known as the “king of all herbs” because of its characteristics of harmonizing various medicines. It is a common cheap medicine in China and is therefore used in aquaculture. It’s main active components are polysaccharides, glycosides, alkaloids, organic acids and volatile oil. In aquaculture, the common methods of licorice administration include feeding, perfusing, injecting, soaking and sprinkling, by which way are used for immune conditioning, disease control and other purposes for aquatic animals. However, there are also some problems in use of licorice, such as unstable quality of medicinal materials, extensive use methods, less standardized prescriptions, and inaccurate naming and description. In this paper, the fishery value of licorice was reviewed.
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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