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To reveal the relationships between spawning activities of pelagophil fish and environmental factors in the Three Gorges Reservoir (TGR), fish eggs and larvae were sampled at Zhongxian section, from May to July in 2016 and 2017. 60 fish species including 30 pelagophil fishes were sampled. Hemiculter bleekeri and Squalidus argentatus were the dominant species in eggs, and Hemiculter and Pseudolaubuca were abundant in larvae. In 2016, 7.041 billion eggs and 103.763 billion larvae drifted through the sampling section, and in 2017, 3.454 billion eggs and 34.427 billion larvae drifted through the sampling section. The amount of eggs and larvae of the four major Chinese carps reached 2.909 billion in 2016 and 2.117 billionin in 2017. Spawning activities of pelagophils fish varies temporally in different river reaches, which mainly occurred after early-June in the river reach from Zhongxian to Fuling but begun in mid-May in the river reach upstream of Changshou. Fish eggs and larvae from the river reach upstream of Changshou provided a large resource for recruitment to the fishery in TGR. Classification and regression trees (CART) analysis explored that spawning activities of the four major Chinese carps were favord when water discharge was rasing. But, spawning activities of Hemiculter bleekeri and Squalidus argentatus had no relationship with water discharge. In order to protect the spawning grounds and meet environmental requirements for natural reproduction of pelagophils fish, we propose ecological regulation of the cascade hydro-power projects in the Jinsha River and maintenance of large free-flowing stretches upstream of TGR.
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Phospholipase A2 plays a role in physiological and pathological processes such as phospholipid metabolism, inflammatory response, cell proliferation, and atherosclerosis. To investigate the biological function of sPLA2-III, five Ccpla2g3 paralogous genes located on different linkage groups were identified from the common carp (Cyprinus carpio) whole-genome using BLAST and synteny analysis performed by Genomicus, which named as Ccpla2g3a1, Ccpla2g3a2, Ccpla2g3b, Ccpla2g3c1 and Ccpla2g3c2, respectively. Gene structure and sequence analysis showed that Ccpla2g3as contained 7 exons, whereas Ccpla2g3b and Ccspla2g3cs contained 4 exons. These five genes respectively encoded 530, 525, 461, 752 and 753 amino acids, and all contained the PLA2_bee_venom_like region and characteristic sequences of sPLA2-III. Synteny analysis indicated that Ccpla2g3a1, Ccpla2g3a2, Ccpla2g3c1 and Ccpla2g3c2 were from the specific genome duplication of common carp. During evolution, the pla2g3a (b) in 2R (two rounds of genome duplication) fish, spotted gar (Lepisosteus oculatus) duplicated to pla2g3a and pla2g3b in 3R (fish-specific genome duplication, FSGD) fishes such as zebrafish (Danio rerio), but there was only one pla2g3c gene in 3R fishes because the other copy on the duplicated chromosome was lost. Homology analysis showed that the similarities of Pla2g3as, Pla2g3bs and Pla2g3cs of the analyzed fishes in orthologous proteins were 48.8%—93.2%, 37.6%—74.3% and 49.6%—97.6%, respectively, with the highest one between common carp and zebrafish. Phylogenetic analysis showed that Pla2g3cs of teleost’s and their ancestor, spotted gar, were grouped within the same branch with a bootstrap of 100; Pla2g3as and Pla2g3bs of spotted gar and teleost’s excluding common carp and zebrafish fell into one branch with a bootstrap of 96; Pla2g3bs of common carp and zebrafish formed a separate branch, demonstrating a larger variation of the gene during evolution. The expression of Ccpla2g3as was generally low during the whole early developmental stages of common carp, and it was higher in liver than other detected tissues (P<0.01) in adult fish; the expression level of Ccpla2g3b at 0.5h after fertilization was significantly higher than that of the later sampling points (P<0.05) with the highest level in ovary (P<0.01); the expression of Ccpla2g3cs reached the highest level at 120h, and it was higher in brain than in other parts. Generally, this study revealed the genetic structure, phylogeny and expression patterns of sPLA2-III in common carp.
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Stylonychia lemnae is a monocyte eukaryote with animal nutrition. It is also an important model protozoa to study cytology and genetics. Sterile pure culture is an important basis for the study of Stylonychia biology. In order to build a high-efficiency pure cultured system for Stylonychia, a Tetrahymena thermophila sterile pure cultured medium was referenced in this paper. And a response surface analysis was used to carried out single-factor and orthogonal experiments focused on the ratio of nitrogen source, carbon source and dipotassium hydrogen phosphate. A sterile pure cultured medium for Stylonychia was primarily established and some key cultured conditions were optimized including cultured temperature, initial pH, medium volume and initial cell density. Results showed that the securable maximum cell amount was about 3.0×103 cells and the best conditions were initial amount 100 cells, medium volume 10 mL, initial pH 7.0 and the cultured temperature 25℃
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This study analyzed the effects of dissolved oxygen content (DOC) and water temperature on the community and richness of bacteria in In-pond Raceway System (IPRS) from various viewpoints using Illumina Miseq high-throughput sequencing technology. The highest and lowest microbial richness was in September and October, respectively. In general, the microbial richness in lowest DOC was greater than that in highest DOC during the diurnal variation. The microbial richness in fecal collecting area was greater than that in aquaculture area. Proteobacteria, Actinobacteria, Bacteroidetes and Cyanobacteria were the 4 dominant species among July and November. At generic levels, Pseudomonas, Synechococcus and Flarobacterium were dominant species. Almost every bacterium had significant or extremely significant difference among different months. The richness of Pseudomonas was positively correlated to DOC (r=0.415, P<0.01), but negatively correlated to water temperature (r=–0.427, P<0.01). There was a significant correlation between Synechococcus, Cyanobacteria, CL500-29, Alpinimonas and water temperature (r=0.636, –0.448, 0.755, –0.428 respectively, P<0.01). The richness of Mycobacterium (r=0.488, P<0.01) and MNG7 were significantly correlated to DOC. Furthermore, there were significant or extremely significant relations among different bacterial communities. The microbial richness increased with the decreasing DOC level to reach peak level at 2.5 mg/L of DOC. These results suggest that stocking density, culture area, DOC, and season variety could regulate microbial richness.
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To investigate effects of dietary rapeseed meal on the growth performance, intestinal morphology, microflora, and the expression of small peptide transport related genes of grass carp (Ctenopharyngodon idellus), four isonitrogenous and isolipidic diets were formulated by adding 0, 5%, 10% and 15% fermented sesame meal to replace 0, 11.8%, 23.5% and 35.1% of rapeseed meal protein respectively, which were named as control group, trial group 1, trial group 2 and trial group 3. The experiment was carried out in an indoor recirculating system with three replicates in each group. Triplicates of 20 fish [initial body weight of (99.98±0.69) g] were fed to apparent satiation with four experiment diets twice a day for 45 days. The results showed no significant difference in weight gain rate (WGR), specific growth rate (SGR) and protein efficiency rate (PER) among all the groups, and WGR, SGR and PER of trial group 1 and 2 were slightly higher than those of the control group (P>0.05). Feed conversion ratio (FCR) of trial group 1 and 2 was slightly lower than that of the control group (P>0.05). The heights of intestinal villi in the trial groups were significantly higher than those of the control group (P<0.05), while the depth of crypt in the trial groups was significantly lower than that of the control group (P>0.05). The ratio of villi height to crypt depth (V/C) in the trial groups were significantly higher than that of the control group (P<0.05). Dietary fermented sesame meal significantly induced Lactobacillus and Bacillus (P<0.05) and significantly decreased Escherichia coli and Aeromonas (P<0.05). The expressions of CDX2, Sp1 and PepT1 genes increased significantly at first and then decreased with the increasing fermented sesame meal inclusion (P<0.05). These results suggest that the optimum proportion of fermented sesame meal replacement dietary rapeseed meal was 11.8%—23.5%.
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To investigate the effects of different forms of dietary methionine on rice field eel (Monopterus albus) [initial weight (30±0.45) g], Crystalline methionine (C-Met), encapsulated methionine (E-Met), methionine hydroxyl analog calcium salt (MHA-Ca) and methionine hydroxy analogue (MHA), whose effective Met content was 2 g/kg, were added in basal diet to form five experimental diets for a 10-week trial. Results showed that methionine in all forms improved weight gain rate and protein efficiency ratio and decreased feed conversion rate of rice field eels with significant change in groups of MHA-Ca and MHA compared with control group (P<0.05). Methionine addition significantly improved activity of trypsin, the contents of serum bile acid, total cholesterol, total protein, urea nitrogen and ammonia, muscle gumminess and adhesiveness (P<0.05). MHA-Ca and MHA addition improved the contents of serum glucose and HDL, activity of intestinal amylase, hepatosomatic GOT, crude protein of whole fish, muscle hardness, springiness and chewiness significantly (P<0.05), but reduced hepatosomatic index and serum glutamic oxalacetic transaminase activity significantly (P<0.05). The peak level of serum methionine appeared at 6h in control group after feeding, but at 9h in C-Met and MHA-Ca groups, at 12h in E-Met group, and at 3h and 9h in MHA group. These results revealed that methionine addition improved growth performance of rice field eels with better effects for MHA-Ca and MHA.
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To evaluate the water quality situation, this study investigated zooplankton species, density and biomass and the main water quality indexes like water temperature, conductivity, DO and pH in 12 cross-sections in the Wei River Basin in October of 2017 and June of 2018, respectively, using the biological diversity index method. 57 species of zooplankton species (11 species of protozoa, 33 species of rotifers, 7 species of cladocerans, 6 species of copepods) were identified, and the dominant species was Brachionus calyciflorus. During dry season, the density of zooplankton varied between 0.72—7.84 ind./L with the average density of (2.79±2.11) ind./L, and the biomass ranged 0.38[6.15 mg/L with the average biomass of (2.31±2.64) mg/L. The diversity indices of Shannon-Wiener and Margalef were 1.07 and 0.69, respectively. The canonical correspondence analysis indicated that the community structure of zooplankton in the Wei River Basin was primarily affected by the water environment including temperature, DO, altitude and conductivity. During wet season, the density of zooplankton varied between 0–179.02 ind./L with an average density of (16.66±49.18) ind./L, and the biomass ranged 0–2448.12 mg/L with an average biomass of (243.96±673.78) mg/L. The diversity indices of Shannon-Wiener and Margalef were 0.78 and 1.15, respectivly. The water quality of Wei River in Beidao and Linjiacun was moderately polluted, and the water qualities in Weijiabao were heavy pollution, and in Xianyang, Lintong, Huaxian the water qualities were light pollution. The water quality of Jing River in Yangjiaping, Yuluoping and Zhangjiashan was moderately polluted. The water quality of Beiluo River in Liujiahe, Jiaokouhe and Zhuangtou was moderately polluted.
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This study investigated growth performance and hypoxia tolerant ability of the yellow catfish and the hybrid catfish called " Huangyou No. 1” for an 8-week trial. The results showed that the average weight of the hybrid catfish was (19.60±0.88) g/tail at week 8, which was significantly higher than that of the yellow catfish was (15.74±0.42) g/tail (P<0.05) with a 24.52% increase. The feed coefficient of the hybrid catfish and the yellow catfish were 1.18±0.14 and 1.36±0.21, respectively. The survival rate of young hybrids catfish was 87.78±1.92, which was significantly higher than that of the yellow catfish at 67.78±1.92 (P<0.05). The survival rate of the hybrid catfish was 29.51% higher than that of the yellow catfish. The hybrid catfish and yellow catfish were placed in water with dissolved oxygen content of (1.48±0.27)mg/L and then hypoxia stress for 0, 6, 12 and 24h before collecting serum and liver for measurements. Hypoxia stress significantly regulated the LDH activity, SOD activity, CAT activity at 6h and the T-AOC at 12h in the serum and liver of both hybrid catfish and yellow catfish (P<0.05). The brain and liver HIF-1α mRNA level of both hybrid catfish and yellow catfish increased significantly by hypoxic stress (P<0.05) with higher level in hybrid catfish at 6, 12 and 24h. These results indicated that long-term hypoxic stress may cause oxidative damage to hybrid catfish and yellow catfish, but hypoxia tolerance of hybrid catfish is higher than that of yellow catfish.
Available online   , doi: 10.7541/2019.120
[Abstract](273) [FullText HTML](129) [PDF 662KB](11)
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To investigate the effects of ammonia exposure on amino acid metabolism, the Paramisgurnus dabryanus were exposed to 30 mmol/L NH4Cl solution to assess plasma, liver and muscle free amino acid contents. The free amino acid concentrations in plasma, liver and muscle of P. dabryanus were significantly affected by ammonia expo-sure (P<0.05). The plasma free alanine contents significantly increased with increased exposure time (P<0.05). The liver free glutamate contents increased significantly at 12h of ammonia exposure and then obviously decreased at 72h (P<0.05). While the liver free alanine contents remained constant during the first 24h of ammonia exposure, these va-lues remarkably increased at 72h (P<0.05). The muscle free glutamate increased significantly (P<0.05) at 12 hours and then rapidly decreased (P>0.05), and eventually significantly lower than that of the control group at both 72h and 96h (P<0.05). Two peak values of the muscle free alanine contents were found at the 12h and 48h, which were significantly higher than the control values (P<0.05). The remarkably decreased free glutamate values in plasma, liver and muscle of P. dabryanus and the significantly increased glutamine contents and glutamine synthetase activities during ammonia exposure suggest that the glutamate and \begin{document}${\rm{N}}{{\rm{H}}^ +_4}$\end{document} were synthesized into glutamine via glutamine synthetase under high environmental ammonia. With the increased exposure time, the accumulation of free alanine and significantly decreased free glutamate, arginine and proline revealed that P. dabryanus could use certain amino acid metabolism and the formation of alanine to inhibit the production of endogenous ammonia during ammonia exposure.
Available online   , doi: 10.7541/2019.109
[Abstract](245) [FullText HTML](109) [PDF 714KB](35)
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The Yarlung Zangbo River (the upper Brahmaputa River) is the largest river on the Tibetan Plateau. The present study investigated the genetic diversity and population demography of Schizothorax molesworthi from the Motuo area of lower reaches of the Yarlung Zangbo River and Lohit River using mitochondrial DNA Cyt b gene sequences. The results showed that 21 haplotypes were identified for 167 individuals with relatively high haplotype diversity (h= 0.768) and low nucleotide diversity (π=0.00167). Phylogenetic trees and Network diagram based on haplotypes indicated all haplotypes from the lower reaches of the Yarlung Zangbo River and Lohit River were not clustered separately but mixed with each other according to the geographical distribution. Pairwise comparisons of genetic diffe-rentiation index (FST) among different populations ranged from –0.014 to 0.771 with highly significant genetic differentiations between the JZZB population and other populations (FST: 0.372—0.771). The analysis of molecular variance (AMOVA) showed that the largest mean FCT index was found between JZZB population and the group of other six populations. Neutral test, mismatch analysis and BSP (Bayesian skyline plot) analysis showed that overall S. molesworthi population from the lower reaches of the Yarlung Zangbo River and Lohit River experienced population expansion during the last glaciations BP (0—0.137 Ma).
Available online   , doi: 10.7541/2019.122
[Abstract](239) [FullText HTML](109) [PDF 843KB](22)
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Gymnocypris potanini Herzenstein, an endemic freshwater species in China, distributes in the upper reaches of the Minjiang River and the Lancang River and some plateau areas with low water temperature even in the summer. The present study investigated the morphological characteristics, formation period of increment, and hatching date of G. potanini. Larvae were identified by COⅠ sequences, which were caught in the Mengtun River at 2015 and 2016. Homology analysis showed that the COⅠ sequence of captured larvae and juvenile were genetically similar to G. potanini and then identified as the G. potanini. The shape of lapilli finally changed into mussel shape, whereas sagittae became wedge-shaped, the long ellipse shape, and eventually changed into long pointed. Then one increment of lapilli by marked temperature was formed every day. The number of marked increments on lapilli were linearly related to the age, and the slopes of the equations were closed to 1.0 (P>0.05). These results demonstrated a daily formation of otoliths increments. By counting the number of daily increment and confirming daily pattern of the increment deposition, the back-calculated hatching dates of the larvae were from 29 June to 15 July in 2015 and from 13 July to 18 August in 2016, indicating that G. potanini has a long spawning period in late summer. These results provided important information on the spawn time of estimation and the basic data for resources conservation of G. potanini.
Available online   , doi: 10.7541/2019.111
[Abstract](209) [FullText HTML](107) [PDF 474KB](15)
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Black carp Mylopharyngodon piceus, the most important freshwater fish in China, is widely distributed in the Yangtze River and along the Yangtze River. This study developed 12 highly polymorphic loci from 25 polymorphic microsatellite markers to analyze genetic diversity and population structure of 4 wild and 1 aquaculture populations in the Yangtze River system. The results showed that the polymorphic information content (PIC) of these 12 loci was between 0.660—0.923, indicating that all 12 loci were highly polymorphic (PIC>0.5). The allele number (Na) of the 5 populations was between 7.917—11.667 and the effective allele number (Ne) ranged from 4.837 to 6.035. The observed heterozygosity was between 0.713—0.861 and the expected heterozygosity was between 0.749—0.819. The ave-rage polymorphism information content was between 0.711—0.788. These results indicated the high genetic diversity in all 5 populations. The genetic distance between the 4 wild populations was relatively closer. The genetic distance between the cultured population and the 4 wild populations was much larger than that of the 4 wild populations. In the UPGMA phylogenetic tree, the Xiangjiang population and the Shishou population were first gathered together, and then clustered with the Hanjiang and Jiaxing populations, and finally together with the Wujiang culture population. The 12 microsatellite loci can be used for the assessment of germplasm resources and genetic diversity of different populations in black carp.
Available online   , doi: 10.7541/2019.130
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Aquaponics, a new type of sustainable, cyclic and zero-emission composite farming system, has become an effective method to solve the agricultural ecological crisis because of its good ecological environment effect and food safety guarantee. The 16S rRNA gene (V3-V5 region) of microorganisms in aquaculture environment and roots was sequenced by using Illumina high-throughput sequencing platform under the typical aquaculture pond mode in Northwest China. The comparison of microbial community structure and diversity showed that the total effective sequence of bacteria was 56444, and the average number of annotated OTU was 945. The dominant bacteria were phyla Proteobacteria, Bacteroidete, Firmicutes and Cyanobacteria. The dominant bacteria in MD.R and JH.R were phyla Bacteroidetes and Proteobacteria, respectively. There were 165 OTUs in the six samples with the highest OTU in JH.KX (137), the lowest one in JH.R (30), and the same OTU (85) in MD.R and JH.C. Rhizobia, fish pathogenic bacteria, cold-resistant bacteria and bacteria that decompose organism and reduce heavy metals and toxins were detected by annotating the OTUs. This study revealed the microbial community structure and its ecological regulation mechanism under the aquaponics model.
Available online   , doi: 10.7541/2019.115
[Abstract](199) [FullText HTML](106) [PDF 1545KB](6)
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To investigate the effect of temperature on transcripts and relative mRNA levels, high-throughput RNA sequencing were used for Yersinia ruckeri grown at 28℃ and 37℃. After the quality control, all differentially regulated genes were enriched and annotated by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and verified by Rockhopper software. The results showed that 173 differentially expressed genes were identified (P-value<0.05), including 58 up-regulated genes mainly enriched in several KEGG pathways: phosphotransferase system, starch and sucrose metabolism, galactose metabolism and other glycan degradation; and 115 down-regulated genes mainly enriched in several KEGG pathways: two-component system, thiamine metabolism and flagellar assembly. In summary, the SC09 had lower motility and weaker glucose metabolism at temperature of 37℃. The compensatory overexpression of some specific carbohydrate metabolism might play important roles for the survival of this bacterial under high temperature. This study provides an important basis for further research on the molecular mechanisms of SC09 in different temperatures.
Available online   , doi: 10.7541/2019.128
[Abstract](86) [FullText HTML](32) [PDF 795KB](2)
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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.
Available online   , doi: 10.7541/2019.113
[Abstract](168) [FullText HTML](74) [PDF 1355KB](4)
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Greb1 (Growth regulation by estrogen in breast cancer cell 1), an estrogen stimulated gene, plays critical roles in estrogen response. Previous study indicated that Greb1 was highly expressed in gibel carp (Carassius gibelio) pituitary. The current study cloned and characterized the expression of Carassius gibelio Greb1 (CgGreb1), and investi-gated its function in early embryonic development. The full length cDNA of CgGreb1 was 954 bp, encoding a deduced protein of 255 amino acids. Based on the NCBI database, most vertebrates contained at least one Greb1 isoforms, whose amino acid length ranged from 386-1988 and contained conserved N-terminus. Among those Greb1 homologues, CgGreb1 was the shortest one, locating in the N-terminus of other Greb1 homologues and sharing high identi-ties over 60%. CgGreb1 was dominantly expressed in pituitary, brains, liver and gonads with the highest level in pitui-tary. The expression of CgGreb1 was gradually increased by inducing spawning gibel carp females, peaked at 6 hours post induction, and then decreased and maintained at a relatively high level. During embryogenesis, the expression of CgGreb1 started from 50% epiboly, increased as embryogenesis progression, peaked at 24 hours post fertilization (hpf), and then gradually decreased and was undetectable at 48 hpf. WISH analysis showed that CgGreb1 signal was specifi-cally located in the embryonic margin during gastrulation, gradually distributed in the central neural system during somitogenesis, and was strongly expressed in many brain regions and notochord, but was gradually weakened from 30 hpf and was disappeared at 48 hpf. Knockdown of CgGreb1 specifically decreased the expression of tshβ, prl and gthα but not pomca in producing cells, suggesting that CgGreb1 played an important role in early pituitary development in gibel carp. Our present study provides insights into the molecular mechanism underlying pituitary development and growth regulation in gibel carp.
Available online   , doi: 10.7541/2019.114
[Abstract](219) [FullText HTML](103) [PDF 498KB](12)
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Growth traits are controlled by multiple genes to cause minor phenotypic effect. To understand the pyra-miding effect of advantage genotypes of growth-related molecular markers in largemouth bass (Micropterus salmoides), thirteen molecular markers related to growth traits were selected obtained on previous studies, which were loca-ted in PCK1, HSBP1, FOXO3b, MYH, HSC70-1, CTSB, HBP, POU1F1, PACAP, IGF-I, ghrelin, ApoproteinA and MSTN. The genotype of each marker in forty largemouth bass parents was analyzed and 2 families were constructed basing on pyramiding advantage genotypes. 305 and 266 individuals were sampled randomly from second filial generation of two families at nine month old, respectively. The results showed that the number of advantage genotypes was various in all offspring of family 1 with the number of individuals of each group 8, 26, 75, 74, 76, 35 and 11, respecti-vely. The average weight of advantage genotypes group was 185.03, 196.46, 198.73, 212.59, 222.66, 235.54 and 261.27 g, respectively. In the offspring of family 2, the number of advantage genotype ranged from one to six with the average weight 184.43, 213.17, 243.77, 249.98, 252.11 and 266.00 g, respectively. Correlation analysis showed that the pyramiding number of advantage genotype was correlated with growth traits. Our results present evidence to improve the growth trait of largemouth bass by utilizing the limited advantage genotypes. This study provided scientific basis for the application of molecular marker assisted breeding in largemouth bass.
Available online   , doi: 10.7541/2019.125
[Abstract](196) [FullText HTML](103) [PDF 816KB](6)
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Family selection has emerged as a crucial tool for selective breeding in aquaculture. The current artificial selection for Japanese scallop (Mizuhopecten yessoensis) predominantly focused on the apparent characters, e.g. growth, shell color and survival rate. Little studies of selective breeding were based on nutritional value of adductor muscle. The present study investigated the growth performance, the fatty acid composition, the content of carbon and nitrogen and C/N ratio of adductor muscle in distinct selective breeding families of M. yessoensis and explored the correla-tion between C/N ratio and fatty acid content. The results demonstrated that the growth features of the families 25#, 54# and 19# were superior to those of 32#, 87# and 93# (P<0.05). No significant difference of the total major fatty acids was observed between distinct families, but the relative abundance of the major fatty acids was obviously diffe-rent between distinct families as PUFA>SFA>MUFA. The amounts of EPA and DHA based on dry weight of adductor muscle in M. yessoensis varied from 3.59 to 4.09 mg/g, and from 3.03 to 3.46 mg/g, respectively. The relative abun-dance of both EPA and DHA ranged between 47.19 and 49.32% of the total fatty acids. Moreover,the content of carbon and nitrogen of adductor muscle in distinct families of M. yessoensis remained constantly with (39.21±0.04)% and (10.62±0.16)%, respectively. The C/N ratio was (3.70±0.06). The further correlation analysis showed that the C/N ratio was positively related to the growth of adductor muscle in distinct families. On the contrary, a prominently negative correlation existed between the C/N ratio and the content of TFA, SFA, PUFA, EPA or DHA with the most evident one between C/N ration with DHA. Our results indicated that the fatty acid composition, the content of C and N and the C/N ratio of adductor muscle could be used for selective breeding of M. yessoensis. These findings provide important implications for the broad development of the selective breeding in scallops.
Available online   , doi: 10.7541/2019.116
[Abstract](158) [FullText HTML](66) [PDF 770KB](2)
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In this study, open reading frame (ORF) of glycoprotein (1530 bp) was amplified by using RNA extracted from Spring Virernia of Carp Virus (SVCV). The SVCV G ORF was cloned into pYD1 vector to construct a recombi-nant plasmid pYD1-G and then transformed into competent yeast cells EBY100, and positive colonies were screened by colony PCR. The expression of G gene was induced by 2% glucose and detected by cell immunofluorescence and flow cytometry. The immunofluorescence staining observed increased EBY100-pYD1-G signal of induced yeast cells with increased induction time. Flow cytometry analysis observed significantly increased fluorescence intensities in prolonged induced EBY100-pYD1-G cells (P<0.05). These results indicated the SVCV G protein has been successfully expressed and localized on the surface of yeast cell. This study laid a foundation for the novel oral vaccine development against SVCV infection in carps in future.
Available online   , doi: 10.7541/2019.118
[Abstract](171) [FullText HTML](70) [PDF 785KB](3)
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The effects of dietary Lactobacillus acidophilus on growth performance, digestive enzyme activities, premunition and related enzyme gene mRNA expression of Epinephelus coiodes were assessed in the current study. Seven hundred and twenty healthy fish with an average body weight of (5.60±0.05) g were randomly divided into 8 groups with 3 replicates per group and 30 fish per replicate. The fish were fed a basal diet and an experimental diet that were supplemented with L. acidophilus at the percentage of 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 and 1.2%) for 8 weeks, respecti-vely. The WGR and SGR increased first and then decreased with increased L. acidophilus, but they were significantly higher than those of the control group (P<0.05). The FCR reached the lowest value in 0.6% group that was signifi-cantly lower than other group (P<0.05). However, the PER level showed an opposite trend to the FCR. The activities of TRY and AMY in the liver and intestine tended to increase first and decrease thereafter. The liver TRY and AMY mRNA level of the experimental group were significantly higher than those in the control group (P<0.05). Among them, liver amylase and protease activity reached the maximum level at 0.6%, and intestinal protease and amylase activities reached the maximum level at 0.2% and 0.4%, respectively. The fish survival rate significantly increased with the increased Vibrio harvey for 7 days (P<0.05). These results reveal that 0.42% Lactobacillus acidophilus (0.72×108 cfu/mL) in the feed could significantly promote the growth and increase the digestive enzyme activity and disease resis-tance for juvenile grouper.
Available online   , doi: 10.7541/2019.132
[Abstract](282) [FullText HTML](121) [PDF 941KB](21)
Abstract:
This study analyzed the external morphology, vegetative and reproductive structure, growth process, biomass variation, mature individual proportion, R/T index, as well as the large subunit of ribulose-1, 5-bisphosphate carboxylase/oxygenase (rbcL) gene and the partial cytochrome coxidase Ⅰ (COⅠ) gene sequences of Gloiosiphonia capillaris (Hudson) Carmichael populations collected in the coast of Heishijiao, Fujiazhuang, Shicao, Jinshitan, Zhangzidao and Haiyangdao in Dalian. The results indicated that the gametophytes of G. capillaris were androgynous, solitary or caespitose habit, and that the main axes were erect, disciformi affixus, gelatinous in texture, red or purplish red. The length and width of thallus collected in Zhangzidao and Haiyangdao were significantly higher than those in other sites. Thallus was composed of cortex that had 6—10 cell layers and medulla that was consisted of many rhizoidal filaments. The size of mature cystocarp was small and protruded from the thallus. Cystocarps were spherical or hemispherical, and often became a group with 2—4 members. The maximum biomass of gametophyte appeared in June with an average value of 3.628 g/m2. The proportions of mature individuals increased gradually from March to June and got 100% in June. The gametophyte growth cycle was from March to July, and the temperature property was temperate. According to the phylogenetic tree of rbcL gene sequences, there was no sequence divergence among the 6 sites and clustered in a single monophyletic subclade with the sample from Canada. There was also no sequence divergence among the 6 sites based on the phylogenetic tree of COⅠ gene sequences. The samples were clustered in a single monophyletic subclade and identified as G. capillaris.
Available online   , doi: 10.7541/2019.112
[Abstract](82) [FullText HTML](31) [PDF 867KB](0)
Abstract:
To explore genetic structure of 164 Bombay duck (Harpadon nehereus), fishes from Qingdao, Nantong, Zhoushan, Sanmen, Ningde, Quanzhou and Zhanjiang in the coastal areas of the Yellow Sea, East China Sea and South China Sea were collected to sequence the mitochondrial DNA cytochrome b (Cyt b) gene fragment. Thirty-two mutation sites, including 27 single mutation sites and 1 simple mutation site were detected. The 164 sequences defined a total of 29 haplotypes. The average haplotype diversity (Hd) and nucleotide diversity (π) were (0.3026±0.0479) and (0.000371±0.000379), respectively, and both the lowest haplotype diversity and the lowest nucleotide diversity were Quanzhou population. The average genetic distance among different populations was 0.00035 and the genetic differentiation index FST value was less than 0.05, indicating no obvious genetic differentiation among the populations. The results of AMOVA showed that the genetic difference of Bombay duck populations was mainly from the variation among individuals within the population. The values of Tajima’s D and Fu’s Fs tests were both negatively and significantly deviated from neutral test. The nucleotide mismatch distribution showed distinct unimodal, indicating that Bombay duck experienced a population expansion event in history. We estimated that the population expansion occurred about 0.08—0.32 million years ago in the middle and late Quaternary Pleistocene based on the evolutionary rate of Cyt b gene 2%/Ma (millions years) in marine fishes.
Available online   , doi: 10.7541/2019.117
[Abstract](160) [FullText HTML](76) [PDF 1793KB](0)
Abstract:
To study effects of dietary carbohydrates and proteins on the growth of grass carp, we formulated a factorial design of 2×4 diets with medium-size (460 g) and large-size (1970 g) grass carp (Ctenopharyngodon idella). Two die-tary starch levels of 25% and 35% and four protein levels of 22%, 24%, 26% and 28%) were fed with medium-size grass carp for 56d with same quantity of food. Two dietary starch levels of 30% and 40% and four protein levels of 18%, 20%, 22% and 24% were fed large-size grass carp. The results showed that the growth performance of the medium-size grass carp increased significantly with increased protein level with the highest effect in the 28% protein group (P<0.05), and the growth performance of 35% wheat starch group was significantly higher than that of the 25% group (P<0.05). The growth performance of large-size grass carp increased significantly with the increased protein level with the peak level at 20% (P>0.05). The growth performance of the 40% wheat starch group was significantly higher than that of the 30% group (P<0.05). No significant negative effects on liver tissues were observed by adding 35% or 40% wheat starch in both groups of grass carp. These results reveal that grass carp can effectively utilize starch to save feed protein when the wheat starch level of the feed is below 35% and 40%, respectively.
Available online   , doi: 10.7541/2019.110
[Abstract](159) [FullText HTML](79) [PDF 814KB](8)
Abstract:
Natural resources of Barbatula toni have been seriously damaged in recent years due to habitat destruction and overfishing, which need urgent protection. The present study used mitochondrial DNA Cyt b and D-loop genes as molecular maker to perform the genetic diversity and phylogeographic analyses of three populations of B. toni from north China. 57 haplotypes were identified for 119 individuals of B. toni. No haplotype shared among different populations. Relatively high haplotype diversity (h=0.805—0.926) and low nucleotide diversity (π=0.00095—0.00458) were detected in three populations of B. toni. Haplotype Bayesian tree showed that B. toni from three river systems were separa-tely clustered as three clades. Analysis of molecular variance (AMOVA) indicated that the variation among populations (accounting for 79.45%) was the main source of variation. Differentiation index (FST) of three populations showed significant difference with FST >0.25 (P<0.01). Neutrality tests and mismatch distribution indicated the recent demographic expansion of B. toni. According to the average evolution rate of Cyt b of Cobitis melanoleuca from Siberia (0.68—0.84%/Ma), the divergence time of three populations of B. toni was 1.082—0.669 Ma, and recent demographic expansions time was at 0.071—0.047 Ma. Pleistocene climatic changes could be a key factor of the population dynamics.
Available online   , doi: 10.7541/2019.121
[Abstract](75) [FullText HTML](42) [PDF 1257KB](2)
Abstract:
This study investigated the morphological development and allometric growth pattern in early life cycle of Konosirus punctatus and illustrated their crucial ecological meanings for survival. Results showed that the average total length of larvae fish was (3.18±0.52) mm with water temperature at (21.5±0.5)℃. The morphological development of K. punctatus was divided into larvae stage (0-43 day age, from hatching to keeled scales appearing) and fry stage (44－55 day age, from keeled scales appearing to scales covering the body). Morphological changes and organ diffe-rentiations mainly occurred in the larval stage. Key morphological characteristics including rostrum length, trunk length, intestinal length, pectoral length and pelvic fin length exhibited allometric growth patterns, in which the growth infle-xion point were 42 day age (TL: 25.47 mm), 24 day age (TL: 15.57 mm), 31 day age (TL: 21.41 mm), 41 day age (TL: 25.47 mm), 42 day age (26.41 mm), respectively. The growth rate in rostrum length and pectoral length changed from the positive allometry (before inflexion point) to the same rate (after inflexion point); the growth rate in pelvic fin length changed from the positive allometry to the negative allometry. These variations could enhance the capacities of breathing, feeding and escaping. The growth rate in intestinal length changed from negative allometry to the same rate, which is related to the dietary conversion of K. punctatus. To adapt to the complex environments, key organs involved in growth and survival were preferentially developed at the early stage, which facilitated the survival rate of K. punctatus. All the findings provide a fundamental evidence for artificial breeding and seedling cultivation in the future.
Available online   , doi: 10.7541/2019.127
[Abstract](172) [FullText HTML](77) [PDF 1275KB](6)
Abstract:
To investigate pathological features of ichthyophthiriasis in Schizothoracine fishes, we performed a pathological comparison between Gymnocypris przewalskii przewalskii and Schizopygopsis pylzovi infected with Ichthyophthirius multifiliis. The infection of I. multifiliis resulted in high morbidity and mortality rate in G. p. przewalskii and S. pylzovi. The mortality rate of G. p. przewalskii and S. pylzovi increased dramatically at 3 dpi (day post infection) and then decreased gradually. All the infected G. p. przewalskii died after 8 dpi. The mortality rate of S. pylzovi was 97.3% with only two S. pylzovi survived after 14 dpi. There were lots of small white spots on the skin of both infected fish species but with significantly different Symptoms. A large amount of mucus were secreted in G. p. przewalskii to form gelatinous layer on the skin. Tomonts in different developmental stages were embedded in the gelatinous layer. In the infected S. pylzovi, necrosis and exfoliation occurred in the epithelium of the caudal fin and dorsal fin, and ulceration appeared due to the secondary infection by bacteria on the skin. The anatomic examination showed similar pathologi-cal changes in liver of G. p. przewalskii and S. pylzovi with the liver color from light red to faint yellow. Meanwhile, gallbladder was swollen and enlarged in both species. Histological sections and electron microscopy demonstrated the adhesion of gill filaments in infected G. p. przewalskii and S. pylzovi, and the gill lamellas and gill epithelia cells were exfoliated. In G. p. przewalskii, I. multifiliis parasite created huge cavities in the epidermis and altered the structure of the skin epidermis. Skin epidermal cells of infected S. pylzovi showed evident vacuolation, the original tight structure was completely lost, and boundaries between epidermis and tunicae propria was blurred. These results indicated simi-lar targeted organs by I. multifiliis infection but with different symptoms in G. p. przewalskii and S. pylzovi that may explain by the long-term adaptation to salt water and freshwater environments by G. p. przewalskii and S. pylzovi, which laid the foundation to study host-pathogen interaction in Tibetan highland fishes.
Available online   , doi: 10.7541/2019.134
[Abstract](151) [FullText HTML](79) [PDF 787KB](2)
Abstract:
This study explored the nitrogen-fixing microbial community structure, diversity and nitrogen fixation activity in urban landscape water body, and the nitrogen-fixing contribution of nitrogen-fixing cyanobacteria in water from Muye Lake and People’s Park in Xinxiang city. Physical and chemical indicators are eutrophic in these two lakes. This study measured 16S rDNA and Nitrogenase nifH gene of microorganism by high-throughput sequencing, and determined nitrogen fixation rate of nitrogen fixing microorganisms in two lakes by the acetylene reduction assay. A total of 32 phyla and 275 genera were detected in the prokaryote groups, and a total of 9 phyla and 66 genera were detected in the nitrogen-fixing microorganisms in Muye Lake. A total of 31 phyla and 238 genera were detected in the prokaryote groups; a total of 4 phyla and 13 genera were detected in the nitrogen-fixing microorganisms in the water column of the People’s Park. Nitrogen-fixing cyanobacteria accounted for 3% in the Muye Lake and 9.3% in People’s Park. The richness of Nitrogen-fixing microorganisms in Muye Lake is significantly higher than that of People’s Park. The nitrogen fixation activity in the two lakes was similar. It is speculated that nitrogen fixation activity may be inhibited in eutrophic water.
Available online   , doi: 10.7541/2019.129
[Abstract](218) [FullText HTML](95) [PDF 995KB](7)
Abstract:
Microcystis strains isolated from bloom-forming ponds were analyzed based on gvpA-C intergenic sequence and 16S rDNA. Several gvpA-C intergenic sequences shared an 172−176 bp extra sequence. An alignment of different types of 0.27 kb sequences, exclusive of the extra sequence, showed over 50 substitutions, whereas in a 0.69 kb hot spot region of 16S rDNA only 8 substitutions were identified. Compared to 16S rDNA, the gvpA-C intergenic sequence was generated by one-step PCR without contamination from co-existing bacteria and showed much higher variability, therefore should be useful in typing of Microcystis. Due to horizontal gene transfer, the two sets of types demonstrated an intersecting relationship. In addition, Microcystis gvpA-C intergenic sequences with or without the extra sequence formed two distinct clusters in a phylogenetic tree.
Available online   , doi: 10.7541/2019.123
[Abstract](172) [FullText HTML](80) [PDF 898KB](10)
Abstract:
This study provided technical support for its scientific protection and rational development through exploring the embryonic and larval development characteristics of Ptychobarbus dipogon. The result indicated that the egg diameter reached 3.7—3.9 mm, and egg diameter after water absorbed could reach to 5.1—5.3 mm. The hatching of egg taken 336.02 hours at temperature of 10℃. Based on external morphological characteristics, embryonic development were separated into 7 stages and 34 periods, including cleavage preparing stage, cleavage stage, blastula stage, gastrula stage, neural embryo stage, organ differentiation stage, hatching stage. Characteristics included newly hatching fry with body length 12.4 mm, 1 day fry after hatching with pectoral fin upwarp, operculum, pigment and underjaw primordial appearance, 3 day fry after hatching with hepatopancreas primordial and alimentary canal appearance, 4 day fry after hatching with gill raker and body pigment cell mass appearance, 5 day fry after hatching with stomatodeum and gill filament appearance, 6 day fry after hatching with pectoral fin fold, dorsal fin fold and pelvic fin fold appea-rance, 7 day fry after hatching with nose concave and astral form pigment group appearance, 9 day fry after hatching with swim bladder primordial appearance, 11 day fry after hatching with tail fin appearance with pectoral fin trembled, 13 day fry after hatching with swim bladder one room appearance, semicircular canal formed, 17 day fry after hatching with dorsal fin primordial and pectoral fins formed, 21 day fry after hatching with larger hyomandibular of pelvic fin fold, 28 day fry after hatching with spleen appearance, 33 day fry after hatching with pelvic fin appearance, 34 day fry after hatching with scale appearance, and no difference for the fish 85 day after hatching. Egg diameter of Ptychobarbus dipogon is the largest one among Schizothorax fishes, and its perivitelline space is smaller than four major Chinese carps, which may explain by cold environment at the plateau uplift.
Available online   , doi: 10.7541/2019.124
[Abstract](154) [FullText HTML](75) [PDF 597KB](7)
Abstract:
To evaluate effects of decontamination time on the nutrient composition, texture and water holding capacity, flavor components and volatile odor substances in bighead carp muscle, the micro-water purification aquaculture system was established in natural lakes for a 2-month trial. The contents of protein and fat in bighead carp muscle were decreased significantly, and the ash showed no significant difference. The content of volatile basic nitrogen and carbonyl in the muscle of bighead carp decreased significantly by prolonging purification time. The hardness of bighead carp muscle texture increased significantly with the extension of purification; the adhesion and chewing of bighead carp muscle were higher than that of the early purification, while the elasticity and recovery in bighead carp muscle were similar to the early experiment. The contents of water-soluble proteins and free amino acids in bighead carp muscle increased at day 20, and then began to decline. We inferred that micro-water purification treatment can significantly enhance the quality of bighead carp and improve the taste and flavor of fish.
Available online   , doi: 10.7541/2019.133
[Abstract](148) [FullText HTML](71) [PDF 1494KB](9)
Abstract:
To explore the species diversity of the marine diatom genus Thalassiosira Cleve, several monoclonal strains were established from Daya Bay, north coast of the South China Sea. The morphology of the cells was examined by light and scanning electron microscopy. The hypervariable D1-D3 region of the nuclear large-subunit ribosomal DNA and the relatively conserved region of the nuclear small-subunit ribosomal DNA were sequenced and used for phylogenetic relationship analysis. Combined the morphology and molecular data, a new species, T. flabellata sp. nov. X H Guo, Y Q Guo & Y Li was described. The cells normally form short chains or solitary. A central fultoportula, one ring of marginal fultoportulae and one marginal rimoportula are present on the valve face. This species is characterized by fasciculate areolae on the valve.
Available online   , doi: 10.7541/2019.126
[Abstract](234) [FullText HTML](93) [PDF 968KB](73)
Abstract:
To reveal the characteristics of external morphology and internal organ during the growth and development of larvae to juveniles of pearl oyster Pinctada fucata and the relationship between morphology, organs and motion, ingestion behavior, optical microscopy was used for observations and nonlinear regression parameters were used for descriptions. The results showed that during the normally larval rearing, the growth of shell length was accelerated positi-vely, the growth of shell height was decelerated positively, the growth of hinge length was accelerated negatively, the growth of shell height was faster than shell length, and the growth of hinge length was slower than shell length. When the larvae grown to a shell length of (209.26±9.22) μm, the internal organs began to change, the velum gradually degene-rated and developed into a gill, and the foot gradually formed. when the shell length reached (234.30±14.00) μm, the secondary shell appeared and the external morphology gradually changed to the juvenile. In the juvenile stage, the growth of gill filament length, gill filament distance and number of gill filament were slower than that of shell length. The larvae swim and filter microalgae by beating their cilia. When swimming, the double shells on the top of the larvae opened the umbo toward the bottom, and the velum projecting from back of the shell is used to propel the body. Larvae swim around clockwise with a certain radius in the vertical direction with a spiral either rising or falling. In the juvenile stage, the reciprocating expansion of the foot and the filtration of the sputum conducted the crawling and the feeding, respectively. During the metamorphosis of larvae stage, the velum is degraded, the motor function of the metamorphosis larvae is reduced, the feeding function has disappeared, larvae relied on reserved energy to complete growth and organ development, which is an important step in larval rearing.
Available online   , doi: 10.7541/2019.119
[Abstract](164) [FullText HTML](66) [PDF 930KB](0)
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 intes-tines 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.
Available online   , doi: 10.7541/2019.131
[Abstract](176) [FullText HTML](68) [PDF 951KB](7)
Abstract:
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.
Available online   , doi: 10.7541/2019.128
[Abstract](8) [PDF 795KB](1)
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.
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[Abstract](186) [FullText HTML](92) [PDF 634KB](8)
Abstract:
Habitat quality can directly affect population abundance and distribution of the Yangtze finless porpoise. This study investigated habitat status of both south and north banks of the main stem of the Yangtze River by taking high-resolution digital photos systematically during the 2017 Yangtze Freshwater Dolphin Expedition from November 10th to December 17th, 2017. The survey area covered the entire middle and lower reaches of the Yangtze River from Yichang to Shanghai (1669 km in length) and a total of 794 photo samples were collected. We recorded 318 sightings with 631 individuals of the Yangtze finless porpoise. The Chi-squared goodness of fit test revealed that proportions of observed frequency are significantly higher than the expected frequency in natural river banks (χ2=69.81, P<0.001). Whereas the result is opposite in the semi-natural and solidified river banks (χ2=39.26, P<0.001; χ2=12.15, P<0.001), indicating that the natural river banks were the preferred habitat of the Yangtze finless porpoise. The length of the semi-natural river and solidified banks accounted for 45.47% of the total length of the river bank, which intermingled with the patches of the natural river banks, demonstrating that the natural habitat was severely degraded and highly fragmented to impact the distribution of the Yangtze finless porpoise. Our study suggested that habitat degradation and fragmentation pose a significant threat to the survival of the Yangtze finless porpoise. Future conservation research and practice should focus on habitat restoration of the solidified river banks to reestablish and enhance habitat connectivity.
Available online
[Abstract](162) [FullText HTML](84) [PDF 951KB](0)
Abstract:
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.
Available online
[Abstract](165) [PDF 930KB](0)
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.
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[Abstract](150) [PDF 930KB](0)
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.
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[Abstract](158) [FullText HTML](80) [PDF 490KB](2)
Abstract:
We generally reviewed the distributions and potential risks of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) in the upper reaches of the Yangtze River based on recent studies. The distribution of heavy metals varied significantly with locations and types of mediums, and contents of some metals exceeded the limits in food. The contents of PAHs in the upper reaches of the Yangtze River were in line with those in the lower reaches. Low molecular weight PAHs were predominant in surface water, while high molecular weight PAHs were predominant in sediments, indicating low molecular PAHs may pose greater risks to aquatic ecosystems. DEHP and DBP were the predominant monomers of PAEs in surface water and sediments, and BBP and DBP ranked first and second respectively in fish bodies. The results of risk assessment also indicated that monomers such as DBP and DnBP had greater risk than DEHP. Over all, heavy metals and organic pollutants were widely distributed in the aquatic environment in the upper reaches of the Yangtze River, which may pose potential risks to the ecosystem.
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[Abstract](184) [FullText HTML](102) [PDF 690KB](18)
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The Chishui River, the only undammed first-order tributary of the upper Yangtze River Basin, is an important part of the " National Nature Reserve for Rare and Endemic Fishes of the Upper Yangtze River”, which plays important roles in fish conservation. To determine main environmental factors that affect the breeding activities of fishes with drifting eggs in this river, investigations on fish resources of early life stages were carried out in Chishui Reach from March to July in 2015 and April to August in 2016. A total of 27 species of fish early resources, belonging to 3 orders, 7 families and 22 genera, were collected during the investigation period. Nine of these species including Pseudolaubuca engraulis, Squalidus argentatus, Gobiobotia filifer, Botia superciliaris, Parabotia fasciata, Parabotia bimaculata, Leptobotia elongate, Leptobotia taeniops and Lepturichthys fimbriata laid drifting eggs in the running water. Canonical Correspondence Analysis (CCA) revealed various breeding environmental requirements for these species. Specially, B. superciliari, P. fasciata, P. bimaculata, L. elongate, L. taeniops and L. fimbriata tended to lay eggs when the water discharge was increasing, while P. engraulis and S. argentatus showed an opposite trend. Additionally, G. filifer preformed differently between 2015 and 2016. In the low flow year, their reproductive activities were positively associated with the water discharge. However, in the high flow year, no significant relation between the reproduction activities and water discharge was observed. These results strengthen our understanding of reproductive behavior of different fish species and provide valuable insights into fish conservation.
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[Abstract](171) [FullText HTML](83) [PDF 735KB](3)
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Eco-hydrological regulation of lakes have received more and more attentions in recent years, but systemic research on hydrological requirements of aquatic organisms still is limited. We systematically summarized the current status of aquatic plants and water level in the mid-lower Yangtze shallow lakes, influences of water level fluctuations on aquatic plants, and the requirement mode of water level fluctuation of aquatic plants. We also introduced a new method assessing ecological water level in shallow lakes based on aquatic plants, and provided corresponding strategies of water level regulations for lakes with different functions.
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[Abstract](247) [FullText HTML](119) [PDF 569KB](28)
Abstract:
Sinogastromyzon sichangensis is a small-size fish endemic to the upper Yangtze River mainly distributed in main stream and tributaries. Twenty-nine polymorphic microsatellite loci of the S. sichangensis were isolated by next-generation sequencing techniques. Four wild populations in Chishui River were amplified by 20 loci with mean alleles 14.5. The mean observed (Ho) and expected (He) heterozygosity were 0.620 and 0.882, respectively and the mean polymorphic information content (PIC) was 0.859. The Ho ranged from 0.520 (Maotai Town) to 0.669 (Chishui Town) and PIC ranged from 0.841 (Maotai Town) to 0.868 (Xishui River). The Fst value and analysis of population structure revealed a genetic differentiation between populations from Xishui River and the main stream of Chishui River. AMOVA showed that the genetic variation was 3.33% among populations while it was 96.67% within populations. These novel loci could use to investigate the population genetics and biological resource conservation strategy in S. sichangensis.
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[Abstract](374) [FullText HTML](146) [PDF 23157KB](46)
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We compiled the distribution and traits of 214 fish species and subspecies in the Jinsha River basin to investigate systematic and effective conservation planning in the basin. First, we modelled the distribution of widespread species throughout the basin with environmental factors such as climate, riverscape, land-use, and soil type; we used the occurrences as the distribution for other species. We planned the protected area (PA) network with the Marxan software to determine the species-specific conservation targets (grouped by mobility, distribution range, and conservation status) and evaluate the protection status of the current wetlands PAs. The best solution selected 486 planning units (47950 km2) that was 7.7% of the total planning units. The current wetlands PAs was not enough for fish conservation, which shelters 59.3% of all fishes (127 species) and 109 species require additional conservation area. The planning units’ area protected by the wetlands PA need to expand 55.9% to reach our conservation target.
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[Abstract](404) [FullText HTML](230) [PDF 818KB](64)
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The Yangtze River basin harbors a high degree of fish diversity, with 378 fish species distributing in the mainstream and its attached waters, and 149 of these species are endemic to this river. Meanwhile, the Yangtze River is an important fishery ground in China, contributing more than 60% of the total catch of freshwater fishery. Therefore, the Yangtze River plays important roles in both biodiversity conservation and capture fisheries. However, due to the increasing human activities in the past decades, fish resources in the Yangtze River have declined sharply. Firstly, more and more species have been assessed as threatened and the endangerment categories of many species have been upgraded. Secondly, the population size of many iconic species, such as Acipenser sinensis, the four famous Chinese carps and Coreius guichenoti, have declined continuously. Thirdly, the miniaturization tendencies of major fishing targets have become more and more obvious. Last but not the least, the total fishery catch reduced significantly. Overfishing, water projects construction, enclosing-lake cultivation, water pollution and alien invasion were the main reasons contributing to these changes. In most situations, these factors interacted together, which imposed more damage to the fish resources and increased the difficulty of conservation. In order to protect the fish resources in the Yangtze River effectively, following conservation strategies are suggested: establishing specialized nature reserve, banning commercial fishing completely, implementing river ecological restoration, strengthening scientific research and establishing comprehensive regulation mechanism.
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[Abstract](248) [FullText HTML](72) [PDF 696KB](12)
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Based on the Gini coefficient and Mann-Kendall test, the runoff variation in the Yichang reach of Yangtze River from 1982 to 2017 was evaluated, and its influence to the Chinese sturgeon spawning below the Gezhouba Dam was discussed under the cascaded hydropower operation. The results showed that the runoff and Gini coefficient decreased significantly after the construction of Gezhouba Dam, which synchronously decreased the flow and water levels in spawning days of the Chinese sturgeon. Water temperature had no significant change. The analysis of the abruption revealed great change of hydrological conditions in the spawning days and Gini coefficient in 2004 and 2009, which are coincided with time of the second and fourth phase impoundment of the Three Gorges Reservoir. The correlation analysis indicated that the higher runoff and Gini coefficient would induce Chinese sturgeon to spawn in days with high flow and water levels. These results suggest that the ecological operation of the Three Gorges-Gezhouba cascaded hydropower could enhance the runoff with large inequality and create long duration of high flow pulses during flood seasons.
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[Abstract](161) [FullText HTML](87) [PDF 599KB](14)
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Lake Dongting is the second largest floodplain lake along the Yangtze River basin. However, the study on fish communities in the Dongting Lake is limited, lacking systematic research on the spatio-temporal variations of fish assemblages in this area. Fish were sampled seasonally from December 2012 to October 2014 in the Dongting Lake. 80 fish species belonging to54 genera, 17 families, and 7 orders with dominant Cyprinidae accounting for 58.8% of the total species were collected. The species richness reduced by 36 in contrast with the historic records. The number and percentage of riverine and river-sea migratory species decreased by 13 (2.2%) and 4 (3.0%) respectively in comparison with historic records. We detected significant seasonal and regional differences in species composition and biodiversity. The diversity and evenness of fishes were significantly higher in summer and autumn than those in other seasons. Meanwhile, significantly lower diversity was observed in the east Dongting Lake than other regions. Our results indicated that seasonal flood pulses and, assisting by river-lake connectivity may play a fundamental role for the fish resources supplement in floodplain lakes. This study demonstrated significant spatio-temporal variations of fish assemblages in the Dongting Lake, which provided scientific foundations for fish conservation in this area.
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[Abstract](731) [FullText HTML](405) [PDF 760KB](69)
Abstract:
Three Gorges Reservoir (TGR) is the key project for the governance and development of the Yangtze River. TGR is an important region for the ecological and environmental protection in the Yangtze River economic belt. The hydrology and water environment have taken fundamental changes since the impoundment of TGR with some negative ecological and environmental problems. To address whether the aquatic ecosystem of TGR is healthy or not, the phytoplankton community index (PhyCoI) was used to assess the ecosystem health of TGR. Field survey was carried out on April 2015 in the whole region of TGR, including 23 tributary bays and 18 sections in the main channel of TGR with 174 sampling sites. A total of 61 phytoplankton taxa were identified, belonging to Cyanophyta, Chlorophyta, Bacillariophyta, Cryptophyta, Pyrrophyta, Euglenophyta, and Chrysophyta. Based on the scores of PhyCoI, the overall health status of TGR is good, with 68% sites in the status of very healthy (4≤PhyCoI<5) or healthy (3≤PhyCoI<4), 26% sites in sub-healthy (2≤PhyCoI<3), and 6% sites in general sick condition (1≤PhyCoI<2). Specifically, 96% sites in the main channel of TGR are healthy, and other 4% sites are in the status of sub-healthy. In the tributary bays, the ratios for the status of very healthy, healthy, sub-healthy, and general sick are 2%, 53%, 35%, and 9%, respectively. From the view of spatial distribution, overall health status of the main channel of TGR is good, and the health status of the main channel in Hubei Province is better than that in the Chongqing Province. In addition, the health status of sites in the Xiangxi Bay, Meixi Bay, and Xiaojiang Bay were highly variable. And in general, the health status of the bays near the dam of TGR is better than the bays far away from the dam. These results provide science and technology support for ecological and environmental protection of TGR.
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[Abstract](647) [FullText HTML](382) [PDF 1077KB](73)
Abstract:
The Yangtze River is the largest river in China. It is a priority conservation area for biodiversity of the world, with its main river, branches and wetlands. As an essential part of freshwater ecosystem, aquatic vegetation has been well studied by Chinese researchers since 1950s, but large-scaled analysis on the biodiversity pattern is lacked. Based on published studies, we analyzed spatial and temporal pattern of aquatic plant diversity in the Yangtze River Basin, and calculated the suitable habitat area and underlying influence of environmental factors using MaxEnt software. A total of 298 species are recognized, belonging to 121 genera in 52 families, which is 57.6% of the total aquatic vascular plants in China. The Yangtze River Basin is the key area for aquatic plant diversity of China, especially the subregions of middle reaches. The elevation and land use are the key environmental variables to the spatial pattern of aquatic plants. The separation among water systems have weak influence on the spatial pattern of diversity in aquatic vascular plants, but potamo-lacustrine habitats facilitated the species homogenization of the flora in a sub-basin scale. The network consists of Poyang Lake, Dongting Lake, Tai Lake, and the middle and lower mainstream is the suitable area for the aquatic plants based on the MaxEnt model. In the past half century, the decline or loss of aquatic vegetation occurred in plenty of lakes in the Yangtze River Basin. We suggested that the protection of aquatic vegetation should be incorporated into the integrated conservation of the middle and lower Yangtze River.
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[Abstract](548) [FullText HTML](310) [PDF 681KB](15)
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PAEs have been proved to be one of the major organic pollutants. The present study determined the level of PAEs using surface water samples from the upper reaches of the Yangtze River. The results showed that DEHP contributed the most to PAEs pollution, followed by DBP. Risk Quotients of PAEs were used for preliminary screening, and DEHP and BBP were identified as potential risk factors with RQ of 310 and 70.7. The MOS10 of DEHP and BBP were 1.40 and 1.32×105, respectively, indicating that BBP may pose little risk to aquatic organisms. The potential risk of DEHP was further analyzed with joint probabilistic curves. Among different biological groups, fish and zoobenthos were two major groups sensitive to DEHP-induced damage under current concentrations with 99.4% and 98.3% for 5% species of each group. While among the toxicity endpoints, reproduction may be more sensitive than others. The 5% and 10% aquatic species were suffered from reproductive damages by 100% and 97.8%, respectively. Overall, our results indicated that DEHP in the surface water of the upper Yangtze River may pose potential risk to aquatic organisms, especially on their reproduction. Therefore, more concerns should be paid in species protection and environmental management.
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[Abstract](444) [FullText HTML](259) [PDF 766KB](43)
Abstract:
To better understand zooplankton distribution and its relationship with the physical-chemical factors in middle Yangtze River, we collected 20 zooplankton samples from segments at Yichang, Jingzhou, Yueyang, Wuhan and Hukou in October, 2016. A total of 23 species that belong to 13 families and 14 genera were identified, among which 16 species belong to Rotifera, 4 to Copepoda and 3 to Cladocera. Among the five segments, the highest number of zooplankton species was detected at Hukou (9 species), while the lowest was at Yueyang (5 species). The average density at Wuhan (10.94±5.81) ind./L was higher than that at Hukou and the other segments. Rotifers (3.41±0.21) ind./L were dominant in the zooplanktonic community, and Keratella valga, Synchacta atylata and Keratella cochlearis were the dominant species. The average density of copepods (mainly nauplius) was (0.75±0.07) ind./L. Cladocera had the lowest average density. Similarly, the zooplankton biomass at Wuhan was also higher than that at Hukou and the other three segments. Comparing with studies at other segments of Yangtze River, we detected lower zooplankton diversity in our investigation. Spearman correlations indicated that the biomass and diversity of zooplankton were significantly and positively correlated (P<0.05) to chlorophyll a.
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[Abstract](435) [FullText HTML](255) [PDF 507KB](49)
Abstract:
The Yangtze floodplain is one of the most important wetlands in the world. For decades, many lakes in this region have suffered from multiple stressors, such as over-exploitation fishery resources and cultural eutrophication. To solve these problems, it is necessary to establish a quantitative lake ecosystem management platform at a regional scale. Recognizing the lack of regional scale zoobenthos models with high predictive power, we carried out 105 lake-time investigations on 46 small-to medium-sized lakes along the mid-lower Yangtze River in this study. The results showed that the density and biomass of zoobenthos of these lakes were (847±248) ind./m2 (mean±SE) and (29.41±3.97) g/m2, respectively. The density and biomass of oligochaetes, gastropods and chironomids were (403±225) ind./m2 and (1.12±0.39) g/m2, (82±20) ind./m2 and (26.38±3.99) g/m2, and (356±62) ind./m2 and (1.86±0.58) g/m2, respectively. Further analyses showed that water depth, Secchi depth, water temperature, total phosphorus, phytoplankton chlorophyll a, and submersed macrophyte biomass were the important factors affecting the standing crops of zoobenthos. A series of models were therefore established. The explanation of variations in zoobenthos density among lakes was generally better than that of biomass. The explantion percentage of simple regression models were between 18%—33% for density and 7%—18% for biomass. In the multiple regression models, the explanation percentage was 46%—49% for density and 16%—55% for biomass. Considering the large sampling size of this study, the explanation of these research models was significantly higher than that of previous studies. When comparing the percentage predictive errors (PPE), the simple models and multiple models showed similar results: PPE was 76%—171% for density and 115%—1034% for biomass in simple models, and 88%—114% for density and 141%—1015% for biomass in multiple models. Therefore, these simple regression model with relatively few variables and good predictive power are suggested in practical application.

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2019, 43(4): 693 -700   doi: 10.7541/2019.082
[Abstract](456) [FullText HTML](159) [PDF 539KB](47)
Abstract:
A 66-day feeding trial was conducted to investigate the effects of different protein sources on growth, body composition and PEPT1 gene expression in the foreintestine and TOR gene expression in the liver of juvenile darkbarbel catfish [initial weight (2.90 ± 0.01) g]. Four isoproteic (39.0% crude protein) and isolipidic (9.0% crude lipid) diets were formulated with fish meal (FM), soy protein concentrate (SPC), fish hydrolysate (FH) and crystal amino acids (CAA) as the main protein source. No significant difference was observed in the survival rate among dietary treatments (P>0.05). Dietary protein had a significant effect on SGR. SPC group had lower SGR than that of the FM groups, while SPC group had higher SGR than FH and CAA group (P<0.05). The crude protein of SPC group was only lower than the FM group, while the crude lipid of SPC group was higher than the FM group (P<0.05). Dietary protein had a significant effect on PEPT1 mRNA expression. The PEPT1 mRNA expression in SPC group was significantly lower than the FM group, but significantly higher than the FH and CAA group at day 35. However, the PEPT1 mRNA expression of SPC group was significantly higher than the FM group at day 66 (P<0.05). Dietary protein source had no effect on TOR gene expression. These results suggested that juvenile darkbarbel catfish of SPC group had better growth performance than FH and CAA group, which might be attributed to the higher foregut PEPT1 mRNA expression.
2019, 43(4): 701 -707   doi: 10.7541/2019.083
[Abstract](310) [FullText HTML](64) [PDF 847KB](32)
Abstract:
To elucidate the role of intestinal fatty acid binding protein (Ifabp) in the regulation of lipids metabolism, unigenes were obtained from transcriptome of liver in spotted scat, Scatophagus argus. Two subtypes of ifabp genes (ssifabp2a and ssifabp2b) were isolated and analyzed in the female and male S. argus, respectively. Tissue distributions and changes of ssifabp2a and ssifabp2b in fast feeding and re-feeding were also observed. Phylogenetic tree results showed that ssIfabp2a was clustered with other Ifabp2a, Ifabp or IfabpX1, while ssIifabp2b was clustered with Ifabp2b or Ifabp-like in Osteichthyes. Homology analysis revealed that the sequence identity of ssifabp2a was 78.8%—87.9% with other Osteichthyes Ifabp2a, Ifabp or IfabpX1. The sequence identity of ssifabp2b was 79.5%—87.9% with other Osteichthyes Ifabp2b or Ifabp-like. The sequence identity was 73.5% between ssifabp2a and ssifabp2b. RT-PCR showed that ssifabp2a was the highest in intestine, and had a moderate level in kidney and liver. And ssifabp2b was also the highest in intestine, but had a moderate level in liver, stomach and hypothalamus in male. However, the expression of ssifabp2a was the highest in stomach, and moderate in kidney, liver and hypothalamus, with a weak expression level in other tissues and no expression in pituitary. The ssifabp2b was expressed strongly in hypothalamus, ovary, heart and intestine, and weakly in other tissues, but had no expression in gill of females. In the intestine, the expression of ssifabp2a decreased significantly, but there was no significant change of ssifabp2b after 2d of food deprivation. The expression of ssifabp2a decreased significantly compared with the control group, but there was no significant difference on the expression of ssifabp2b within the 7 day fasting group. The expressions of ssifabp2a and ssifabp2b increased significantly with refeeding 3-h after the scheduled feeding time. In liver, the expression of ssifabp2a was not changed, but the expression of ssifabp2b increased significantly after 2-day of food deprivation. However, the ssifabp2a and ssifabp2b were all increased during the 7-day fasting, and decreased significantly with refeeding 3-h after the scheduled feeding time. In summary, ssIfabp2a and ssIfabp2b are involved in the regulation of lipids metabolism at liver and intestine in Scatophagus argus.
2019, 43(4): 708 -722   doi: 10.7541/2019.084
[Abstract](301) [FullText HTML](143) [PDF 846KB](21)
Abstract:
A 65-day trial was conducted to investigate effects of CLA on cytological morphology, activity of antioxidant enzymes, and gene expressions of lipid metabolism in the liver and muscle of grass carp. Seven isonitrogenous (crude protein: 36 g/100 g) and isolipidic (crude lipid: 4.5 g/100 g) diets were formulated: 0 CLA (control), 0.5% (CLA0.5), 1% (CLA1), 1.5 (CLA1.5), 2 (CLA2), 2.5 (CLA2.5), and 3% CLA (CLA3). Three biological replicates of fish were assigned to each diet with the initial body weight at (5.08±0.08) g. Endoplasmic reticulum in the liver, and loose sarcolemma of myocyte and degradation of myofibril in the muscle when compared with the control fish. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx), and the total antioxidant capacity (T-AOC) both in the liver and muscle of CLA1.5-CLA2.5 groups significantly (P<0.05) increased compared with control group. The activities of catalase (CAT) in the liver of CLA1.5-CLA3 groups were significantly (P<0.05) higher than that of control group, however, there was no significant (P>0.05) change in the glutathione reductase (GR) activity in the liver. The MDA contents in the liver of fish fed with CLA1.5-CLA2 diets were significantly (P<0.05) lower than that of control group, however, the MDA contents in the liver of fish fed with CLA2.5-CLA3 diets significantly (P<0.05) increased compared with control group. In contrast, fish fed with CLA3 had significantly higher MDA contents in the muscle (P<0.05) compared with control group. Compared with the control fish, the mRNA level of acetyl-CoA carboxylase (ACC) both in the liver and muscle of fish fed with CLA1.5-CLA2.5 diets were significantly (P<0.05) down-regulated; the mRNA levels of lipoprotein lipase (LPL), hormone-sensitive lipase (HSL), and peroxisome proliferator-activated receptor alpha (PPARα) of fish fed with CLA1.5-CLA2.5 diets were significantly (P<0.05) up-regulated; the mRNA levels of fatty acid desaturase 2 (FAD2) in the liver of fish fed with CLA2-CLA3 diets and in the muscle of fish fed with CLA1.5-CLA2 and CLA3 diets were significantly (P<0.05) up-regulated; the mRNA level of peroxisome proliferator-activated receptor gamma (PPARγ) in the liver of fish fed with CLA1-CLA3 diets was significantly (P<0.05) down-regulated. Conversely, there was no significant (P>0.05) difference for the PPARγ mRNA level in the muscle of fish fed with CLA0.5-CLA3 diets. In conclusion, supplementation of 2% CLA could significantly decrease the lipid contents in the liver and muscle without affecting cytological morphology of liver and muscle, the growth and feed utilization of grass carp by improving the antioxidant capacities in the liver and muscle.
2019, 43(4): 723 -730   doi: 10.7541/2019.085
[Abstract](292) [FullText HTML](150) [PDF 683KB](23)
Abstract:
A 84-day feeding trial was conducted to evaluate the effects of dietary aflatoxin B1 (AFB1) on growth, physiological responses, histological changes, and accumulation in juvenile grass carp (Ctenopharyngodon idellus). Triplicate groups of grass carp [(2.90±0.16) g] were fed with six semipurified diets formulated with isonitrogenous (crude protein: 32.96%), isocaloric (gross energy: 14.55 kJ/g) containing 0, 10, 20, 100, 1000 and 5000 μg/kg AFB1. AFB1 did not significantly impact behavior, the survival rate, final body weight (FBW), feeding rate (FR), specific growth rate (SGR) or feed efficiency (FE). No significant differences were found in hepatosomatic index (HSI) and viscera index (VSI) among all groups. AFB1 had no significant effect in activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). No significant histological lesions in hepatopancreas and kidney were identified between the control and increasing AFB1 treatments. No AFB1 residue was detected in muscles when fish fed with AFB1 up to 1000 μg/kg, however, tiny dose [(1.21±0.18) μg/kg] of AFB1 were detected in muscles in the group with 5000 μg/kg AFB1, which was below the safety limitation of FDA. The results indicated that juvenile grass carp is a little susceptible species to AFB1 exposure up to approximately 5000 μg/kg diet (determined level was 4979.2 μg/kg diet), at least for 84 days.
2019, 43(4): 731 -738   doi: 10.7541/2019.086
[Abstract](263) [FullText HTML](160) [PDF 614KB](22)
Abstract:
To explore effects of stickwater (SW) on bile acid metabolism, 4 isonitrogenous and isoenergetic diets including the control diet containing 30% fish meal (FM) and three experimental diets without fish meal but with 8% (SW8), 17% (SW17), 25% (SW25) stickwater (dry matter) were fromulated to feed the yellow catfish with the initial body weight of (15.67±0.11) g for 60 days in pond cage farming. Compared with FM group, fat content of whole fish of SW25 group decreased observably (P<0.05), and liver fat content of SW17 and SW25 group reduced significantly (P<0.05); Cholesterol in serum of SW17 and SW25 groups decreased from 11.9% to 16.6%, and triglyceride decreased from 32.5% to 47.9% (P<0.05). Liver bile acid of SW25 group decreased by 76.3% (P<0.05) compared with FM group, but serum and intestine bile acid increased by 125.7% and 123.3% (P<0.05). The liver CYP7A1 at mRNA level had no significant difference among five groups, but the expression of BSEP, ABCC4, and NTCP increased by stickwater with 16.9%, 68.2% and 222.8%, respectively, in SW25 group. The mRNA level of ABCC4 and NTCP varied significantly (P<0.05). The results indicated that addition of 25% stickwater (dry matter) in diets without fish meal had no effect in liver bile acid synthesis, but it promoted transferring bile acid to serum and intestine to improve fat metabolism and reduce fat deposition in yellow catfish.
2019, 43(4): 739 -747   doi: 10.7541/2019.087
[Abstract](287) [FullText HTML](140) [PDF 608KB](26)
Abstract:
This study evaluated the effects of dietary copper sulfate (CuSO4), glycine chelated copper (Cu-Gly), copper hydroxymethionine (Cu-MHA) on growth, antioxidant enzymes and intestinal morphology of juvenile pearl gentian grouper (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀). Juvenile pearl gentian grouper with the average body weight of (9.00±0.00) g were randomly divided into 3 groups with 3 replicates in each group and 30 fish in each replicate to feed isonitrogenous and isolipidic experimental diets with 3 different copper sources for 8 weeks. (1) The weight gain ratio (WGR), survival ratio (SR) in Cu-Gly and Cu-HMA groups were significantly higher than those in CuSO4 group (P<0.05). (2) The hepatosomatic index (HSI) and viscerosomatic index (VSI) in Cu-HMA group was significantly higher than those in CuSO4 and Cu-Gly groups (P<0.05). There was no significant difference in condition factor (CF) among all groups (P>0.05). (3) Cu contents of vertebrae in Cu-Gly and Cu-HMA groups were significantly higher than that in CuSO4 group (P<0.05). (4) The serum concentrations of triglyceride (TG) and low-density lipoprotein cholesterot (LDLC) in CuSO4 group was significantly higher than those in Cu-Gly and Cu-HMA groups (P<0.05). The serum concentration of high-density lipoproteot cholesterin (HDLC) in CuSO4 group was significantly lower than that in Cu-Gly and Cu-HMA groups (P<0.05). (5) The activity of serum ceruloplasmin (CP) in CuSO4 group was significantly higher than that in Cu-Gly and Cu-HMA groups (P<0.05). (6) The plica height (PH) of midgut and hindgut in Cu-HMA group were significantly higher than those in CuSO4 and Cu-Gly groups (P<0.05). These results revealed that dietary adding Cu-Gly and Cu-HMA could improve intestinal morphology and serum lipid metabolism to ameliorate growth of juvenile pearl gentian grouper.
2019, 43(4): 748 -756   doi: 10.7541/2019.088
[Abstract](227) [FullText HTML](52) [PDF 721KB](25)
Abstract:
The interplay between intestinal microorganism and their host has received extensive scientific attention, however, there is no study about the response of intestinal microorganism of the Chinese mitten crab in the hunger state. In the present study, 16S rRNA sequencing was used to investigate intestinal microorganism in Chinese mitten crab during the period of starvation and refeeding. The results showed that the Alpha diversity index of the intestinal microorganisms decreased by starvation, and re-feeding did not change the descending trend of the intestinal microbial diversity index. Besides, there was no significant difference comparing to the control group (P>0.05). In terms of the bacterial phyla composition, starvation gradually increased the proportions of the Proteobacteria, Firmicutes and Bacteroidetes and reduced the proportion of Tenericutes. Re-feeding restored Proteobacteria, Firmicutes, Bacteroidetes and Tenericutes to the level of control group. By comparing different strains under different conditions, 8 strains with significant differences (P<0.05) were sifted at the family and genus level. Among them, Candidatus bacilloplasma was characterized by high abundance of bacteria and significant response to starvation and refeeding, and its specific function of the flora needs further investigation. This study first reported the changes of intestinal flora of the crabs after starvation and refeeding, which could provide basic knowledge for the further exploration of the specific functions of the flora.
2019, 43(4): 757 -762   doi: 10.7541/2019.089
[Abstract](374) [FullText HTML](123) [PDF 492KB](29)
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In order to study the molecular regulation mechanism of the soft intermuscular bones in Rice flower carp, the intermuscular bones of Rice flower carp and Jian carp were collected for high-throughput sequencing of microRNAs (miRNAs) and bioinformatics analysis. 25474895 and 24625715 high quality sequences of 18—32 nt, as well as 595 and 570 known mature miRNAs were obtained from the small RNA library of Rice flower carp and Jian carp intermuscular bone, respectively. Compared with Jian carp, 84 miRNAs were up-regulated and 267 were down-regulated in the intermuscular bone of Rice flower carp. Seven of the down-regulated miRNAs in Rice flower carp were reported as promoting human osteogenesis. Six of the up-regulated miRNAs were reported as inhibit human osteogenesis. These results indicated that Rice flower carp may inhibit the process of osteogenesis by down-regulating the expression of osteogenic miRNAs and up-regulating the expression of osteogenesis inhibiting miRNAs. Therefore it can maintain its intermuscular bone small and soft characteristics. This study laid the groundwork for the study of molecular regulation mechanism of intermuscular bone development.
2019, 43(4): 763 -770   doi: 10.7541/2019.090
[Abstract](262) [FullText HTML](122) [PDF 612KB](23)
Abstract:
This study cloned the full-length of complement C7 cDNA by RACE (rapid-amplification of cDNA ends) from Russian sturgeon (Acipenser gueldenstaedti). It contained 3103 bp, including a 2502 bp open reading frame (ORF) encoding 833 dedueced amino acids, a 44 bp 5′-UTR and a 554 bp 3′-UTR. Multiple sequence alignment revealed that AgC7 proteins were well conserved with the typical structural motifs such as TSP1, LDLa, FIMAC, MACPF and had the sequence identity with Lepisosteus oculatus (56%), Ictalurus punctatus (46%), Danio rerio (49%), Salmo salar (49%) and Oreochromis niloticus (47%), respectively. AgC7 gene is constitutively expressed in all evaluated tissues with the highest expression in intestine and the weakest level in muscle. Chitosan oligosaccharide induced the expression of AgC7 gene to a certain degrees in all tissues with the highest increase in intestine (1.51 times). After infection with Aeromonas hydrophila, AgC7 gene exhibited distinct time-dependent response patterns in tested tissues with most obvious induction in gills and the maximum expression at 6h after infection (41.30 times). The expression of AgC7 gene decreased rapidly and returned to normal level after 12h. These results suggest that C7 of Russian sturgeon might play an important role in the immune defenses against bacterial infection.
2019, 43(4): 771 -777   doi: 10.7541/2019.091
[Abstract](135) [FullText HTML](43) [PDF 615KB](11)
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To investigate the effect of low salinity stress on Glucose-6-Phosphate Isomerase (GPI) in Takifugu rubripes, we cloned GPI and analyzed its expressions in tissues with and without acute low-salinity stress using RT-PCR and real-time quantitative PCR (qPCR) techniques. The results showed that the GPI cDNA of the T. rubripes was 1736 bp in length containing an Open Reading Frame of 1662 nucleotides that encodes 553 amino acids. The predicted amino acid sequence contains two Sugar Isomerase Domains without signal peptide and transmembrane domains. Results of multiple sequence alignment showed that GPI was highly conserved among species. qPCR results showed that GPI mRNA was expressed in all the tested tissues, with the highest expression level in muscle. Under low-salinity stress, the relative mRNA expression of GPI in gill increased firstly, then decreased and increased again in all low-salinity groups, and the relative mRNA expression of GPI in kidney differed among low-salinity groups. Therefore, it was speculated that GPI play a role in the response of T. rubripes to acute low-salinity stress.
2019, 43(4): 778 -785   doi: 10.7541/2019.092
[Abstract](295) [FullText HTML](156) [PDF 714KB](14)
Abstract:
sCAP could stimulate heart movement and contraction of muscle and fallopian tube, enhance posterior bowel contraction and participate in biological molting. This study identified the sCAP gene (GenBank accession No. MG779491) from Sepiella japonica as SjsCAP. We cloned a 696 bp full-length cDNA sequence of SjsCAP gene by RT-PCR and RACE techniques including 111 bp 5′ untranslated region (UTR), 324 bp 3′UTR, and 261 bp open reading frame (ORF) encoding a protein with 86 amino acids. The molecular weight of the protein was 9.331 kD and its pI was 8.52. The prediction of signal peptides and transmembrane domain indicated that SjsCAP might play an important role in extracellular. The protein is hydrophilic. Phylogenetics analysis based on SjsCAP amino acid sequences demonstrated that S. japonica has the closest relationship with Sepia officinalis with a 90% similarity. Expression analysis of SjsCAP gene in male and female individuals showed that it mainly expressed in optic lobe and also has the high expression in the brain. The expression level in male was obviously higher than that of female cuttlefish. The results of in situ hybridization assay showed that significant positive hybridization signals were detected in the optic lobe of the brain tissue of S. japonica, the vertical lobe, subvertical lobe, peduncle lobe, dorsolateral lobe of the esophageal nerve mass, and optic gland. These results provide some theoretical basis for genetic resource conservation and development of S. japonica.
2019, 43(4): 786 -796   doi: 10.7541/2019.093
[Abstract](236) [FullText HTML](56) [PDF 956KB](16)
Abstract:
In order to explore the formation process, water purification effect, microbial structure and function of three types of biofloc in the water with Litopenaeus vannamei during hatchery period, the content of flocs and water quality index were measured, and Illumina MiSeq high-throughput sequencing technique was applied to compare the characte-ristics of biofloc in three groups with glucose, starch and sucrose, respectively. The results indicated that the biofloc formed in each group could effectively regulate water quality and reduce the levels of ammonia and nitrite. The concentrations of ammonia, nitrite and nitrate in the water samples from three experimental groups were significantly lower than those in the control group (P<0.05). The concentrations of ammonia, nitrite and nitrate in starch group were significantly higher than those in the glucose group and sucrose group (P<0.05). Moreover, the BFV in starch group was significantly lower than that in the glucose group (P<0.05), and the sucrose group possessed the highest BFV. The particle size of three groups was: sucrose group > glucose group > starch group. The quantity of 553, 515 and 542 OTUs was measured in the three groups respectively. Tthe microbial abundance index Chao1 and Shannon value implied the relationship in the three groups was: glucose group > sucrose group > starch group. Furthermore, regarding the phylum level, Proteobacteriae, Bacteroidetes and Planctomycetes were the dominant phylum in each group, and the proportion of three phylums in each group was 91.7%, 97.6% and 88.7%, respectively. However, in the genus level, Oceanicella was the dominant genus in glucose group, with the highest proportion of 18.4%, and the Muricauda and Cyclobacterium had the highest proportion in starch group, which were 9.8% and 5.9% respectively, and higher than those in glucose group and sucrose group. Rhodopirellula in sucrose group was 1.8% and 4.1% higher than that in the glucose group and starch group, respectively. Cell metabolism, genetic information processing and environmental information processing were detected in the three groups by Tax4Fun method. The gene function abundance in glucose group was higher than that in the sucrose and starch group. All of the results implied that biofloc in the breeding water with Litopenaeus vannamei could not only purify water quality, but also improve the microbial diversity, among which the glucose was the most effective carbon source. Nevertheless, biofloc technology is of essential to maintain the balance between water quality and water ecosystem.
2019, 43(4): 797 -804   doi: 10.7541/2019.094
[Abstract](121) [FullText HTML](51) [PDF 893KB](16)
Abstract:
This study investigated the isolation and purification of spermatogonial stem cells (SSCs) by single cell suspensions after enzyme digestion using testes of various months old tiger puffer. SSCs were enriched by Percoll discontinuous gradient. The SSCs were identified by optical observation and immunolocalization of Vasa protein. The majo-rity of SSCs at 14-month-old fish was type A spermatagonial cells that were significantly higher than those of the 22-month-old males (P<0.05). SSCs were mainly enriched in 10%—30% Percoll gradient belt, where the germ cells were mainly distributed at 14-month-old fish. These results indicate that 14-month-old male fish is a great source for SSCs using the current isolation method.
2019, 43(4): 805 -813   doi: 10.7541/2019.095
[Abstract](206) [FullText HTML](56) [PDF 1158KB](14)
Abstract:
The microscopic structure and cytochemical characteristics of peripheral blood cells in Megalobrama amblycephala were observed by routine Wright staining and cytochemical staining. Six types of cells were distinguished in the peripheral blood cells in Megalobrama amblycephala: erythrocytes, lymphocytes, monocytes, neutrophils, eosinophils and thrombocytes. The lymphocytes are the most abundant blood cells except erythrocytes, followed by thrombocytes, monocytes, neutrophils and eosinophils. The mature erythrocytes are mostly oval with smooth surface, oval or round nuclei whose chromatin is denser. The lymphocytes are usually round, with less cytoplasm, and the nucleus is usually eccentrically located. The monocytes are mostly round, the nucleus is round or oval, and vacuoles can be observed in the cytoplasm. Neutrophils are nearly round, and their nuclei are usually eccentrically located, lobed, kidney or oval shaped, with clear nucleoplasm boundaries. Eeosinophils are usually round, with reniform or oval nuclei, and the cytoplasm is filled with purple granules. Thrombocytes have various forms, most of which are oval, spindle, long-rod shaped or teardrop shaped, and their nucleo-cytoplasmic ratio is large. The lymphocytes were positive for periodic acid-Schiff reaction (PAS), weakly positive for naphythol AS-D chloroacetate esterase (AS-DCE) and α-naphthol ace-tate esterase (ANAE), and negative for Sudan black B (SBB), acid phosphatase (ACP), alkaline phosphatase (AKP) and peroxidase (POX). The monocytes were strongly positive for POX and ACP, while PAS, positive for SBB, AS-DCE and ANAE were and negative for AKP. Except weakly positive for PAS and ANAE, the cytochemical staining pattern of neutrophils were the same as those of monocytes. Eosinophils showed strong positive for POX and ANAE, positive for SBB and ACP, weak positive for PAS and AS-DCE, and negative for AKP. The thrombocytes were weakly posi-tive for PAS, AS-DCE and ANAE and negative for SBB, ACP, AKP and POX. The microstructural and cytochemical characteristics of peripheral blood cells in Megalobrama amblycephala were similar to those of other fishes, but also had obvious species specificity. The results of this investigation can be used as a basis for monitoring the health status of Megalobrama amblycephala and provide basic data for its farming and pathological diagnosis.
2019, 43(4): 814 -824   doi: 10.7541/2019.096
[Abstract](299) [FullText HTML](153) [PDF 1200KB](23)
Abstract:
Lamprey is of considerable model organism to subject of vertebrate evolution and developmental biology. The current study investigated the morphological characteristics and the growth pattern of embryos, yolk-sac larva and ammocoate of Lampetra morii. The results indicated that the cleavage of lamprey zygote was holoblastic cleavage and the embryology had been subdivided into cleavage, blastula, gastrula, neural plate and groove, head protrusion, prehatching and hatching. The newly-hatched larva breaks through the fertilization membrane at 11—12 day-post-fertilization at water temperature of (18±1)℃. The newly-hatched larva had body weight with (0.00032±0.00002) g and total length with (0.29±0.02) cm. During yolk-sac stage, the body weight and total length of larva generally increased over time. The snout length, eye length, postocular length, disc length, prebranchial length, branchial length, head length, trunk length, tail length and cloacal slit length exhibited allometric growth. The ammocoete stage reached when yolk extruded from the anus and the digestive tract completed at 15 day-post-hatch. In 5 months after hatching, the body weight and total length of ammocoete generally increased over time. The melanophores were extensively distributed and increased in ammocoete. The 5-momth old ammocoete had body weight of (0.07±0.01) g and total length of (3.87±0.32) cm. The early development of L. morii is the basic data for artificial culture and developmental biology, which is the basis for the model organism.
2019, 43(4): 825 -831   doi: 10.7541/2019.097
[Abstract](344) [FullText HTML](60) [PDF 623KB](41)
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Coregonus ussuriensis, one coldwater fish, is an important economic fishery species in the Heilong River basin. The resources of Coregonus ussuriensis have been seriously impacted by anthropogenic influences such as pollution, habitat degradation and overfishing. Knowing the characteristics of life history at the important stage helps to better protect the Coregonus ussuriensis. Otolith element fingerprint could objectively and specifically reflect the character of the water which fish experienced. The element Sr and Ca microchemistry patterns have been used to reflect the water type which the fish lived in. To study the characteristics of life history for Coregonus ussuriensis, an electron probe microanalyzer (EMPA) was used to analyze the element Sr and Ca microchemistry patterns in otoliths for Coregonus ussuriensis collected from Suibin and Jiejinkou section of the Heilong River main stream and Tangyuan section of the Songhua River main stream from December 2013 to January 2014. Results of line transect analysis indicated the value of Sr/Ca significantly fluctuated including a low ration (<5) responded to freshwater life and some high rations (>10) responded to seawater life, revealing they had experienced an anadromous migration. The results of X-ray mapping analysis of EMPA reflected the same feature of anadromous migration. The annual ring of otolith characters analysis showed the bright and dark belt in the otolith match with the low and high Sr/Ca ratio areas well. It revealed that Coregonus ussuriensis migrate seasonally. Some species migrate to seawater in summer and return back to freshwater in winter regularly, and other species may not have significant regularity. The time of in fresh water and sea water is inconsistent. This study first reported the migratory characteristics of Coregonus ussuriensis, which can provide an important basis for further study on the life history.
2019, 43(4): 832 -840   doi: 10.7541/2019.098
[Abstract](217) [FullText HTML](54) [PDF 689KB](13)
Abstract:
Dali Nor lake, one of the four lakes in Inner Mongolia Autonomous Region, China, is a typical saline-alkaline lake with high concentrations of carbonate salts (alkalinity up to 60 mmol/L, pH 9.6 and salinity 6‰). Amur ide (Leuciscus waleckii) is one of the only two existing economic fish in the Dali Nor Lake with the character of spawning migration. To investigate the osmotic and ionic regulation mechanism of the L. waleckii during spawning migration form Dali Nor lake to Gongger river, we analyzed serum ionic (Na+, K+, Cl, Ca2+ and Mg2+) and hormone (PRL, GH and IGF-1) levels, Na+/K+-ATPase activities in gills, intestinal and kidney, Ca2+/Mg2+-ATPase activities in gills and structure of gills in L. waleckii collected form Dali Nor lake and Gongger river. In addition, above parameters were studied in L. waleckii during 24-h transfer from lake to river water. Compared to lake fish, river fish had decreased Na+, significantly increased Cl in serum as well as significantly increased Na+/K+-ATPase activities in kidney and intestinal while no significant change in gills. There were no significant differences of K+, Ca2+, Mg2+ and hormone (GH, IGF-1 and PRL) levels in serum between lake and river fishes. During 24-h lake-to-river water transfer, Cl increased and K+ decreased significantly in serum, Na+/K+-ATPase activities in gills, intestinal and kidney and Ca2+/Mg2+-ATPase activi-ties in gills, as well as PRL and IGF-1 levels all increased significantly (P<0.05). Histology of gills showed that mucous cell counts were significantly higher in lake fish compared to that of river fish, while branchial chloride cells (CCs) counts have no obvious difference between lake and river fish, but the size of branchial CCs on filaments slightly increased in river fish. It is concluded that L. waleckii could maintain high serum ionic levels though endocrine control of Na+, K+-ATPase in osmotic regulatory tissues during spawning migration form Dali Nor lake to Gongger river.
2019, 43(4): 841 -846   doi: 10.7541/2019.099
[Abstract](227) [FullText HTML](51) [PDF 662KB](19)
Abstract:
We investigated larval and eggs resource of Botia robusta at Laibin section in the Hongshuihe River from mid of April 2017 to August, and found that Botia robusta was the dominant species of collected eggs. We studied the ontogeny of Botia robusta from the Tail bud to Juvenile phase and described the features of 14 developmental stages respectively. The egg membrane was non-adhesive, averaging 6.8 mm. One chamber air bladder was 7.1 mm in total length and the muscle nodes were about 33 pairs. It took 20d to finish the Yolk-sac larva phase stage, spawning mainly from May to June. The total number of the eggs laid at Laibin section in 2017 was about 2.23×108. The correlation analysis between oviposition and major environmental factors found significant correlation between the water temperature with the spawning dynamics (P<0.05).
2019, 43(4): 847 -853   doi: 10.7541/2019.100
[Abstract](308) [FullText HTML](167) [PDF 757KB](57)
Abstract:
This study analyzed the resources status and spatial distribution of Anguilla japonica and Anguilla marmo-rata in the Pearl River based on the data collected from 2015 to 2017. A total of 41 Anguilla japonica individuals with the average age of (4.2 ± 1.3) years were collected in these three years, and 93% individuals were sexually immature. A total of 12 Anguilla marmorata individuals with the average age of (4.3 ± 1.0) years were collected and 83% individuals were sexually immature. Anguilla japonica could migrate to the Heshan section of the Hongshuihe River with the percentages in individuals and in weight both less than one percent. Anguilla marmorata could migrate to the Shilong section of the Xijiang River with an occurrence rate less than one in 200. This indicated that the wild Anguilla spp. resources in the Pearl River are extremely rare and need to be protected. Redundancy analysis shown that river fractals and river width play important roles in spatial distribution for Anguilla japonica, while river width and river depth play important roles for Anguilla marmorata. This study is a part of a long-term investigation for the wild Anguilla resources of the Pearl River, and the results could be instructive to the conservation and management of Anguilla resources.
2019, 43(4): 854 -860   doi: 10.7541/2019.101
[Abstract](216) [FullText HTML](49) [PDF 696KB](23)
Abstract:
The target strength (TS) of fish and its relationship with body length is one of the core contents of research and application in fishery acoustic technology. The current study measured target strengths of two widespread commercial cyprinid fish species, Cyprinus carpio and Aristichthys nobilis with hydroacoustics experiment with tethering method and Simrad EY60 echosounder (120 kHz) under swimming status (26 individuals of C. carpio and 26 of A. nobilis) in an undisturbed cage in the Geheyan Reservoir (Yichang City, Hubei Province) from 1 May — 20 May, 2017. The total length of C. carpio and A. nobilis were from 19.9 to 29.6 cm and 49.2 to 74.2 cm, respectively. The body weight of them were from 175 to 461 g and 1200 to 4700 g, and their TS were from –59.35 to –45.20 dB and –34.22 to –17.49 dB, respectively. The regression relationship between target strength (TS, dB) and total length (TL, cm) for the two species were TS = 29.84×lgTL – 95.23 (R2 = 0.74, P < 0.01) for C. carpio, and TS = 35.88×lgTL – 90.33 (R2 = 0.83, P < 0.01) for A. nobilis. The TS-TL equation of A. nobilis was used to assess the total fish biomass of a small enclosed water body (Lake Yanlong) to 89.36 ton (i.e. 40.1 g/m2), which is close to the real total catch (73.61 tons) of this area, supporting the rationality of in method to evaluate fish target strengths and their relationship with body length. Exploring target strength for the two most common fish should benefit the development of hydroacoustics techniques in China’s inland waters.
2019, 43(4): 861 -868   doi: 10.7541/2019.102
[Abstract](119) [FullText HTML](53) [PDF 777KB](6)
Abstract:
Resveratrol (Res) is an important active ingredient in Chinese herbal medicines such as rhubarb and polygonum cuspidatum with antibacterial, anti-inflammatory and antioxidant properties. To explore its application value in the prevention and treatment of bacterial diseases in aquatic animals, we explored the antibacterial activity of resveratrol against Aeromonas hydrophila, an important bacterial pathogen in freshwater aquaculture. The growth, biofilm formation, hemolysis inhibition, and virulence related gene expression of A. hydrophila under different resveratrol concentrations were detected. The in-vivo protection of resveratrol was confirmed by artificially infecting crucian carp with A. hydrophila. The results showed that the minimal inhibitory concentration (MIC) of resveratrol against A. hydrophila was above 1024 μg/mL, and the concentration less than 64 μg/mL did not affect the growth ratio of A. hydrophila. Resveratrol with more than 32 μg/mL significantly inhibited the biofilm formation and hemolytic activity of A. hydrophila (P<0.05) in a dose-dependent pattern. Resveratrol mediated heavy moisture of bacterium group sense of regulation and of QS system by inducing luxR and reucing luxS gene expression. The expression of omp was significantly down-regulated by resveratrol. Artificial infections showed that the mortality rate of allogynogenetic crucian carp infection in the 25—100 mg/kg resveratrol-treated group was significantly lower than that of the control group, and the expression of TNF-α and IFN-γ mRNA was significantly decreased. This study showed that resveratrol can effectively inhibit the viru-lence of A. hydrophila and reduce the inflammatory response at 2500 mg/kg on fish infected with A. hydrophila.
2019, 43(4): 869 -874   doi: 10.7541/2019.103
[Abstract](225) [FullText HTML](128) [PDF 495KB](9)
Abstract:
To assess tissues distribution and elimination of robenidine hydrochloride in Ictalurus punctatus, single and 5-day continuous oral administration (20 mg/kg) of robenidine hydrochloride has been conducted in healthy Ictalurus punctatus at (28±1)℃. The concentration-time curve of robenidine hydrochloride in plasma was a two-compartment model for the single oral administration with the kinetic equation: C= 7.69e–0.02t + 0.13e–0.01t–7.82e–0.27t. The T(peak) and Cmax in the plasma, muscle, skin, gill, liver and kidney of channel catfish were 10.03, 15.79, 11.10, 2.61, 12.89, 7.87 and 5.76 μg/mL, 2.91, 2.90, 3.05, 3.04 and 0.42 mg/kg, respectively. The elimination half-life and drug-time curve AUC were 58.63, 23.57, 35.37, 19.74, 29.34, 43.30h and 326.74 (μg/mL)/h, 157.58, 183.72, 95.09, 174.82, 29.85 (mg/kg)/h, respectively. For the 5-day continuous oral administration at 20 mg/kg, the highest and lowest concentration of robenidine hydrochloride was the intestines and the muscle, respectively. The elimination rate of robenidine hydrochloride in each tissue from fast to slow was plasma, gill, brain, muscle, skin, liver, kidney and intestines. If the maxi-mum residue limit (MRL) of robenidine hydrochloride in edible tissue is 10 μg/kg, the withdraw period should not be less than 23 days under this experimental condition.
2019, 43(4): 875 -883   doi: 10.7541/2019.104
[Abstract](249) [FullText HTML](118) [PDF 739KB](18)
Abstract:
Excessive ammonia nitrogen in the aquaculture waters can impact immunity, growth, and morbidity and mortality of the cultured animals. The ammonia nitrogen in aquaculture waters is mainly removed by microbial degrada-tion. In this study, two ammonium removal strains were screened from a mixture of water and sediment in variety aquaculture ponds and identified as Bacillus coagulans. The degradation rate of the two strains were 97.8% and 98.5%, respectively. Two strains could adapt high pH value and C/N range, and have high resistance to high temperature and high salt. The oral administration trials verified that the two strains were safe for cultured aquatic animals. The two screened strains and the previously obtained mutagenic strain B38 in our lab were mixed with 1 鲶1 鲶1 ratio to make a probiotics complex, and its effects on the amount of ammonia nitrogen, nitrite and algae were evaluated by 18 days farming trials. Compared with the four commercial probiotics (Photosynthetic Bacteria, Yeast, EM and Bacillus), ammonia nitrogen decreased greatly in the ponds using probiotics complex. The number of algae in the ponds using probiotics complex and Bacillus from the 9th day was higher than other groups, and the amount of algae were about twice as much as the other groups on the 14th day. The probiotics complex can reduce ammonia nitrogen and increase the number of algae. This study provides a foundation for the development of complex probiotics.
2019, 43(4): 884 -891   doi: 10.7541/2019.105
[Abstract](315) [FullText HTML](160) [PDF 816KB](27)
Abstract:
This study analyzed the characteristics of algal blooms based on the spring algal blooms data collected from the tributaries of Three Gorges Reservoir from 2004 to 2015. Results showed that the algal blooms had occurred in 26 tributaries of Three Gorges Reservoir (TGR) with the highest rate in Xiangxi River. The dominant species of the algal blooms were Bacillariophyta and Dinophyta. The probability of Dinoflagellate blooms increased correspondently with the increased impounded level, but the occurrence rate of Diatom blooms increased after several years while reserving water level was up to 175 m. The concentrations of algae density, chlorophyll a and trophic state were low when the reservoir water level was below 175 meters, and then increased sharply when the reservoir water level raised to 175 meters with a trend of gradual decrease after years of reservoir impounding to 175 meters. The principal components analysis (PCA) showed that the algae density, chlorophyll a concentration, total phosphorus (TP), total nitrogen (TN) and permanganate index were classified into the same cluster. Algal density and chlorophyll a concentration were significantly positively correlated with TP, dissolved oxygen, permanganate index and pH. With the impounded level of Three Gorges Reservoir, the mean flow velocity of the tributaries decreased, which might result in the algal blooms at the tributaries of Three Gorges Reservoir under proper temperatures.
2019, 43(4): 892 -899   doi: 10.7541/2019.106
[Abstract](238) [FullText HTML](126) [PDF 703KB](9)
Abstract:
Potamogeton crispus plays an important role in maintaining the balance of lake ecosystem in winter-early spring. Maternal environment can influence life-history and offspring performance traits of aquatic plant. Understanding maternal environmental effects could predict the response mechanism of aquatic plant life-history traits to climate warming. In this study, P. crispus was used to explore the response to warming with three heated modes by investigating morphology, stoichiometry and early germination strategy of turions. We found that warming had no effect on tu-rion wet weight, but extreme warming significantly increased turion length and width. The results of stoichiometry indicate that maternal extreme warming significantly increased N concentrations in turions, but significantly decreased C 鲶N ratio. And maternal warming accelerated the germination of turions and seedling growth. In summary, maternal warming significantly affected turion morphology, stoichiometry and germination.
2019, 43(4): 900 -909   doi: 10.7541/2019.107
[Abstract](379) [FullText HTML](152) [PDF 858KB](17)
Abstract:
The oligotrich ciliates are important components of the marine microplankton. Many studies have been carried out on the taxonomy of these taxa in the past one and a half centuries. However, ambiguities concerning their identification have been accumulated due to lacking key morphological characters. Ten poorly known oligotrichs, Strombi-dium apolatum Wilbert & Song, 2005, Strombidium capitatum (Leegaard, 1995) Kahl, 1932, Strombidium guangdongense Liu, et al., 2016, Strombidium paracalkinsi (Lei, et al., 1999) Agatha, 2004, Strombidium parastylifer Song, et al., 2009, Strombidium suzukii Song, et al., 2009, Spirostrombidium cinctum (Kahl, 1932) Petz, et al., 1995, Paralle-lostrombidium jankowski (Song, et al., 2009) Song, et al., 2018, Parallelostrombidium kahli (Song, et al., 2009) Song, et al., 2018, Strombidinopsis minima (Gruber, 1884) Song & Bradbury, 1998 were investigated using live observation and protargol impregnation methods. Based on the present populations, much more information particularly with respect to their morphological features in vivo as well as original morphometric data were provided. Compared with previous population, some variable characters of these species were recorded.
2019, 43(4): 910 -922   doi: 10.7541/2019.108
[Abstract](129) [FullText HTML](48) [PDF 1138KB](5)
Abstract:
5 genera 13 taxa of Staurosiraceae (Bacillariophyta) were collected from Mugecuo Scenic Area, Sichuan province, China. Among them, 2 genera of Pseudostaurosiropsis Morales and Stauroforma Flower, Jones & Round were newly recorded in China, and there are 7 newly recorded species of China: Staurosirella frigida Van de Vijver & Morales, S. martyi (Héribaud-Joseph) Morales, Pseudostaurosira cataractarum (Hustedt) Wetzel, Morales & Ector, P. pseudoconstruens (Marciniak) Williams and Round, P. trainorii Morales, Pseudostaurosiropsis connecticutensis Morales and Stauroforma exiguiformis (Lange-Bertalot) Flower Jones & Round. The detailed morphology, habitat characteristics and geographical distribution of each taxon were given. Moreover, according to new classification system, Staurosiraceae species were revised in Algarum Sinicarum Aquae Dulcis (Tomus X).

### 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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