• Volume 40,Issue 4,2016 Table of Contents
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    • Comparison of early growth in Sinonovacula constricta selection group and family

      2016, 40(4):603-611. DOI: 10.11964/jfc.20151010120

      Abstract (2624) HTML (510) PDF 1.32 M (2173) Comment (0) Favorites

      Abstract:To compare the early growth performance of the Sinonovacula constricta family group and colony group, we chose the excellent group from Leqing Bay to conduct the growth experiment. We established a selection group and 27 full-sib families(F1、F2...F30), because of the high mortality rate, the full-sib families F18, F24 and F28 are eliminated in the early days. For the selection group, the control group is breeding population group. For the full-sib families, single pair method is applied. And analyses were made about the fertility rate, the metamorphosis rate, the adhesive rate, the growth rate and size specification in different terms. By multiple comparison and variance analysis, it was indicated that there was no significant difference of the fertility rate, the metamorphosis rate, the size of D-type larva and the adhesive rate between different experimental groups. For all the experiment groups, the individual size and growth rate are different in different development periods. And the size and growth rate of group selection are greater than those of breeding population with significant difference. Among the full-sib families, there were also differences in the growth rate. Groups of F2, F7, F9, F13, F19, showed greater growth vigor than the control group with significant difference. Groups of F5, F6, F14, F25, F27 showed growth disadvantage compared with control group, also with significant difference. The paper conducted comprehensive comparison of early growth performance between family group and colony group, and obtained the excellent family and colony, providing basic data and excellent material for fine varieties breeding of S. constricta in the future.

    • Selection response in mass selection of golden shell Pacific oyster (Crassostrea gigas)

      2016, 40(4):612-617. DOI: 10.11964/jfc.20150409829

      Abstract (2531) HTML (513) PDF 1.25 M (2150) Comment (0) Favorites

      Abstract:The Pacific oyster (Crassostrea gigas) is a major global aquaculture species and a commercially important shellfish species in China. Beautiful shell color and fast growth are two important goals in Pacific oyster genetic breeding at present. We initiated selective breeding of shell color traits via family selection in 2010, and obtained four kinds of shell color strains including white shell, black shell, golden shell and purple shell. In the present study, the selection response, genetic gain and realized heritability of mass selection for shell height based on second-generation golden-shell families were analyzed. The results showed that shell height of the selected strain was greater than that of the control strain during the grow-out stage and the selected strain presented significant growth superiority after 350 d. The average selection response, genetic gain and realized heritability were 0.549±0.277, 3.717%±2.611%, 0.339±0.171 respectively, during larval stage, and were 0.436±0.138, 8.253%±1.014%, 0.270±0.086 during grow-out stage. In addition, golden shell and golden mantle proportion in the selected strain were increased by 22% and 10% compared with that of control strain, respectively. The information obtained in this study is of great significance for the selective breeding of golden shell Pacific oyster.

    • Polymorphism of MSTN-1 and the association with growth traits and muscle compositions of juvenile grass carp (Ctenopharyngodon idella)

      2016, 40(4):618-625. DOI: 10.11964/jfc.20150309749

      Abstract (2703) HTML (520) PDF 3.09 M (1554) Comment (0) Favorites

      Abstract:Previous studies suggested that the myostatin-1(MSTN-1) gene played as an important role in the growth and development of grass carp (Ctenopharyngodon idella). In order to determine whether the polymorphism of grass carp MSTN-1 gene was associated with growth traits and muscle compositions, 192 individuals from Yangtze River were used in this study. Three polymorphic loci were found in the 3824 bp MSTN-1 gene: C1799T, C1842T and TGAAGCGCTGGTTCT /2585-, which were named Locus 1 (wild-type EE/mutant EF), Locus 2 (wild-type HH/mutant HI) and Locus 3 (wild-type BB/deletion type BD), respectively. A general linear model was used to analyse the correlation between those three single nucleotide polymorphisms (SNPs) and grass carp traits. The results showed that two SNPs have a significant influence on grass carp growth traits. Whereas, none of those SNPs have a significant effect on grass carp muscle compositions. Multiple comparisons found that the body length and body weight of individuals with HI genotype were significantly higher than that of wide-type individuals, conversely, mutant individuals with BD genotype were significantly lower than wide-type individuals at body length and body weight in haplotype analysis; the groups with HI or BD genotype also had the similar results in fold type combinations analysis, while the body length of groups with BD genotype were not significantly lower than other groups. Results indicate that HI is a beneficial mutation on growth traits, while BD is a detrimental mutation on grass growth traits. Preliminary study indicated the MSTN-1 gene could be a candidate modifier gene in Molecular Marker-assisted Selection (MAS) of grass carp.

    • SNPs detection of ghrelin gene and its association with growth traits in largemouth bass (Micropterus salmoides)

      2016, 40(4):521-527. DOI: 10.11964/jfc.20150709989

      Abstract (2129) HTML (551) PDF 9.04 M (1972) Comment (0) Favorites

      Abstract:Ghrelin is one of the vital brain-gut peptides in vertebrates. In 1999, a noval 28-amino acid gut-brain peptide named ghrelin was first isolated from the mammalian stomach. Similar to the synthetic molecules of growth hormone secretagogues, ghrelin was proved to be an endogenous ligand for growth hormone secretagogue receptor and involved in growth hormone secretion, food intake, carbohydrate metabolism, and energy homeostasis. So, ghrelin gene is a potential candidate gene for fish growth traits. This study detected the polymorphism of the promoter of largemouth bass (Micropterus salmoides) ghrelin gene by DNA sequencing in 327 individuals, for exploring the association between the polymorphism of ghrelin and growth traits of largemouth bass. Two single nucleotide polymorphism (SNP) mutations were identified (S1:A-642C, S2:A-639C) of the gene. The genotype and gene frequency of 327 largemouth bass were further assayed with the method of SnaPshot, at site S1, there three kinds of genotypes named AA, AC and CC, the gene frequency were 0.067, 0.685 and 0.248 respectively. There were only two genotypes AA and AC on the locus of S2, of which gene frequency were 0.850 and 0.150 respectively. Genetic structure was analyzed by POPGENE32 software, the results showed that the two locus were in Hardy-Weinberg equilibrium, the effective number, expected heterozygosity and observed heterozygosity of S1 were 1.9362, 0.4843 and 0.6831 respectively, which of S2 were 1.1620, 0.1396 and 0.1508. The sites of S1 and S2 formed five diplotypes(D1, D2, D3, D4 and D5). Association analysis showed that individuals with genotype AC were significantly higher than those of individuals with genotype CC in body depth and total length at site S1. At site S2, the individuals of genotype with AA significantly showed a higher value on head length compared to the genotype of AC. The five diplotypes consisted of the two SNPs were different on some growth traits, the body weight, total length and body depth of diplotypes D1 showed significantly higher than those of D3. And diplotype D1 also showed a significantly higher value of body weight, body width and body depth compared with genotype D4. The SNP markers founded in ghrelin gene promoter would be candidate genetic markers, and it suggested that S1:A-642C and S2:A-639C could be two molecular markers for providing helps to the molecular marker assisted breeding of largemouth bass.

    • Effects of seven kinds of carbohydrate structure on the metabolism of Litopenaeus vannamei

      2016, 40(4):626-633. DOI: 10.11964/jfc.20150910075

      Abstract (2343) HTML (515) PDF 1.13 M (2163) Comment (0) Favorites

      Abstract:Litopenaeus vannamei [(0.14 ±0.01) g average weight] were fed with seven diets for 56 d to observe the effects of different carbohydrates on the growth performance, body composition and related metabolism in triplicate tanks (50 shrimps/tank) connected to a natural seawater (29) recirculating system. Seven formulated diets all contained about 20% carbohydrate content with different carbohydrate sources: glucose, fructose, glucose+fructose (1:1 weight ratio), sucrose, maltose, cornstarch and dextrin. Different carbohydrate sources had significant influence on the growth performance of shrimp when other requirements were met. The results showed that the shrimp fed polysaccharide are better than sucrose and others on the SGR and PER. And there was the lowest SGR and PER in glucose group. Different carbohydrate sources had no significant influence on the crude protein, moisture and ash of body, but had influence on the crude fat and glycogen of shrimp. Meanwhile, glycometabolism instead of fat and protein metabolism was affected by different carbohydrate sources in L. vannamei.

    • Preliminary proteomic analysis of the skin from crucian carp (Carassius auratus)

      2016, 40(4):528-536. DOI: 10.11964/jfc.20150709994

      Abstract (2197) HTML (484) PDF 2.32 M (1733) Comment (0) Favorites

      Abstract:Fish skin plays an important role in the mucosal immune response. In order to investigate the molecular mechanisms of mucosal immune responses in fish, the Crucian carp (Carassius auratus) were used as an animal model for fish skin immune system (FSIS), and proteomics analysis of protein expression in the skin of C. auratus was performed by using two-dimensional polyacrylamide gel electrophoresis (2-DE) combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) techniques. The results showed that 214 protein spots observed on 2-DE gels shared matching profiles of about 88% protein expression spots, while the 800 μg loading dose, and 18 cm pH3-10 IPG strips were used for isoelectric focusing (IEF) to 80 000 Vh. The 31 protein spots in the skin of fish were further identified as the 22 kinds of proteins by MS/MS analysis, namely myosin heavy chain, actin, keratin, zinc finger protein 585B, Rab15 effector protein, coiled-coil domain-containing protein 168, NCK1-associated protein, and creatine kinase M-type, enolase, pyruvate dehydrogenase E1 component subunit alpha, adenylate kinase isoenzyme 1, etc. Further analysis of protein functional classification based on Gene ontology (GO) showed 12 mainly biological processes, including metabolic process, cellular process, organism process, immune response, biological regulation and signaling etc.. The three of all biological processes such as metabolic, cellular and organism accounted for 24.7%, 19.5%, and 16.9% respectively, and immune response-related proteins included transformation/transcription domain-associated protein, keratin type I cytoskeletal 10, keratin type II cytoskeletal 8, and keratin type II cytoskeletal 6A. This is the first report on proteomics analysis of expressed proteins in the skin of C. auratus, and this study will help to understand the molecular mechanisms of mucosal immune responses at protein level in fish.

    • Research on Aeromonas hydrophila caused bacteria disease in spotted scat (Scatophagus argus)

      2016, 40(4):634-643. DOI: 10.11964/jfc.20150709976

      Abstract (2408) HTML (525) PDF 2.61 M (1690) Comment (0) Favorites

      Abstract:Spotted scat Scatophagus argus is popularized in South China as a new resource of marine aquaculture and ornamental fish in recent years. The research of S. argus was focused on biological characteristics, gonad development and reproduction, composition of muscle, artificial culture and the construction of a cell line, and so on. Until now, only three parasites, including Lenolopa huizhouensis, Metahaliotrema mizellei and M. gemiratohamula have been recorded to exist in the gut and gill of S. argus. In aquaculture, priority is given only to bacterial diseases caused by various aquatic pathogenic bacteria, which led to enormous economic loss in the aquatic animals, but the bacteria diseases were not reported in the S. argus. Therefore, the tasks of comprehensive study on the bacterial disease in S. argus become more urgent and important. In order to separate and identify the pathogen of fulminant disease in S. argus cultured in a laboratory in Shanghai Ocean University, we used the traditional method of pathogen isolation, virus and parasite were not detected, but we obtained a bacterial strain isolated from the diseased fish liver. And then, we observed the isolate strain by the electron microscope and tested the physiological and biochemical identification, and histopathological analysis was made in the natural incidence of fish, in addition, artificial infection was also implemented according to Koch's postulates. The results show that the isolate is a Gram-negative staining, cells straight with rounded ends, 0.8-1.0 μm ×1.0-2.0 μm, while observed by electron microscope, and consistent with A. hydrophila through physiological and biochemical characteristics. 16S rRNA gene sequence analysis by Blast in GenBank indicates that the isolate (accession number:KR006248) showed high levels of similarity to Ah ATCC7966 (99%). A phylogenetic tree of the isolate and other Ah strains formed a tight cluster. Histopathological analysis of diseased fish shows the pathological damages, including gill lamellae cells denudation and leukocytes infiltration in gills, abscission of intestinal villus, muscles loosening in intestine and a marked increase of pyknosis of glomerulus in kidney, infiltrating of hemocytes and inflammatory cells in liver. The healthy S. argus could be infected through artificial infection using the isolated bacteria. The half of lethal dose (LD50) to S. argus in 96 h is 7.35×107 CFU/mL. To conclude, the Ah201416 strain was identified as A. hydrophila which is the pathogen for S. argus. This study provides a theoretical basis for disease control and prevention and calls on people to pay more attention to the potential dangers caused by A. hydrophila against S. argus.

    • Isolation and screeing of digestive enzyme producing probiotics from intestine of Litopenaeus vannamei

      2016, 40(4):537-546. DOI: 10.11964/jfc.20150309745

      Abstract (2706) HTML (533) PDF 2.06 M (2344) Comment (0) Favorites

      Abstract:To get safe digestive enzyme producing probiotics from intestine of healthy Litopenaeus vannamei, 576 bacteria strains were isolated. Those bacteria strains, extracellular protease, amylase, and lipase activities were detected through qualitative assay and quantittive assay. 11bacteria strains with three kinds of digestive enzyme and high capacity of enzyme production were screened. Secondly, susceptibility and hemolysis of the11strains were tested to identify their security. In this study, vegetative cell suspensions of 11strains in equal proportions were added in the rearing water of juvenile shrimp(L. vannamei). Then shrimps were challenged with Vibrio anguillarum. After the challeng test, real-time RT-PCR was employed to determine the relative expression of several immune genes. Through the difference of the relative expression we could detemine the protective effect of these strains on juvenile shrimp. Considering digestive enzyme activity, biological safety and protective effect, 4 strains were selected. Similarity analysis of 16S rDNA sequences indicated that NO.1, 2 and 4 showed 100% similarity to Bacillus sp. PCSAS 2-38, B. cereus strain N419 and B. thuringiensis strain EA26.1, respectively, and NO.9 showed 99% similarity to Rhodobacter capsulatus strain PSB-03. This laid the foundation for the probiotic development.

    • The life cycle of Thelohanellus wuhanensis from Carassius auratus involving an Aurantiactinomyxon-type actinospore

      2016, 40(4):644-651. DOI: 10.11964/jfc.20151210185

      Abstract (2504) HTML (542) PDF 9.51 M (1984) Comment (0) Favorites

      Abstract:Thelohanellus wuhanensis is an important parasite in crucian carp culture, forming numerous plasmodia on the skin, and causing massive mortality of juvenile fish in soil ponds. During the survey of actinosporeans in oligochaetes of fish pond in Liyang (31°18'N, 119°28'E), an Aurantiactinomyxon-type actinosporean was found from the oligochaete Branchiura sowerbyi. The actinospores are not connected with each other, and possess a style-less spore body with 3 almost equal-sized, elongate caudal processes. In apical view, the spore body is spherical and three polar capsules are positioned on the top of the spore body and close to each other. There is an above 100° angle between each process. Spore body average length (19.8±1.3)μm, width (18.2±1.1)μm polar capsules (4.53±0.4)μm long, (3.4±0.4)μm wide; caudal processes (195.0±15.7)μm long, (11.5±0.8)μm wide. Fresh spores floating in water were collected with 10 μL pipette tip under microscope and stored at -20℃. Genomic DNA was extracted with MagicMag Genomic DNA micro Kit (Sangon Biotech, China) following the instruction. Partial 18S rDNA sequence was amplified with primers MyxospecF and MyxospecR (Fiala 2006). Positive PCR products were sequenced with the primers in Sangon Biotech. Homologous sequences were determined by performing a BLASTN search at NCBI. DNA sequence similarities were calculated using the MEGA 6.0 software package. On the basis of 18S rDNA sequence analysis, the actinosporeans reported here were identified as T. wuhanensis, and showed 99.8%-100% sequence similarity with T. wuhanensis (HQ613410, JQ088179, JQ690370 and JQ968687) available in GenBank. Phylogenetic analysis revealed the actinsporean stages of most taxa in the clade Thelohanellus developed in alternative host Branchiura sowerbyi.

    • Molecular cloning, bioinformatics analysis and expression pattern detection of α-tubulin gene during intestinal regeneration in the sea cucumber (Apostichopus japonicus)

      2016, 40(4):547-557. DOI: 10.11964/jfc.20150910083

      Abstract (2774) HTML (535) PDF 3.27 M (1963) Comment (0) Favorites

      Abstract:In this study, full-length cDNA of α-tubulin in sea cucumber Apostichopus japonicus was cloned for the first time by transcriptome data mining and rapid amplification of cDNA ends (RACE), and qRT-PCR was used to preliminarily reveal the biology function of α-tubulin in the process of intestine regeneration. The results showed that full-length cDNA of α-tubulin was 1641 bp, containing a 1362 bp open reading frame encoding a putative polypeptide of 453 amino acids residues. Bioinformatics analysis showed that the sequence of α-tubulin contains a 5'-untranslated region (UTR) of 153 bp, and a 3'-UTR of 126 bp. The predicted molecular mass of the deduced amino acid of α-tubulin was 50.33 ku, and the theoretical isoelectric point was 4.89. The amino acids inferred have a special sequence (GGGTGSG) which was a typical element in α-tubulin protein, belonging non-transmembrane and hydrophilic protein. Multiple sequence alignment analysis and phylogenetic analysis revealed that the α-tubulin in sea cucumber was very conservative with other eukaryotic organism and had 90% sequence identity with Notothenia coriiceps. Real-time quantitative PCR was carried out to measure the expression level of α-tubulin gene in different stages of sea cucumber intestine regeneration. The expression of α-tubulin was detected at all stages of intestine regeneration. The maximum and the minimum expression levels were found on 17th and 5th day, respectively. This study first obtained the structure information of α-tubulin gene in sea cucumber, and further certified the high homology of α-tubulin in eukaryote. In addition, our results indicated that α-tubulin plays an important role during intestinal regeneration in the sea cucumber A. japonicus.

    • Determination of antibiotic residues in fishery water environment by high performance liquid chromatography quadrupole time of flight mass spectrometry and its application

      2016, 40(4):652-663. DOI: 10.11964/jfc.20151110161

      Abstract (2563) HTML (521) PDF 1.16 M (2320) Comment (0) Favorites

      Abstract:Rapid screening method for 42 kinds of commonly used antibiotics residues in fishery water by High performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS) has been developed. Targeted antibiotics was extracted from samples on C18 Solid-phase extraction cartridges. Analytical separation was performed on a C18 reverse phase column by liquid chromatography with 1% acetic acid, formic acid, ammonium salt aqueous methanol solution as mobile phase. Positive ion source full scan patterns were used. The result showed that Limit of Quantity (S/N=10, LOQ) of 42 kinds of antibiotics were 0.010-0.120 μg/L. The average recovery for antibiotics was 60.7%-97.1%. The relative standard deviation (RSDs) was 0.58%-8.01%. The method is rapid and simple with high sensitivity. 60 fishery water samples were determined and sulfamethoxazole, sulfamonomethoxine, sulfapyridine, sulfachlorpyridazine, enrofloxacin were detected with the concentration from 25.6 to 106.7 ng/L. The method is sensitive, accurate and can be applied to the screening of antibiotic residues in fishery water environment.

    • Study on the isolation and primary culture of hepatocytes from liver of grouper (Epinephelus coioides)

      2016, 40(4):558-565. DOI: 10.11964/jfc.20150309796

      Abstract (3111) HTML (515) PDF 1.86 M (2215) Comment (0) Favorites

      Abstract:In order to explore the stable and reliable methods for isolation and primary culture of hepatocytes from Epinephelus coioides, we selected the hepatocytes of E. coioides and then cultivated them under different conditions. E. coioides hepatocytes were isolated by tissue separation and trypsin (0.25% with EDTA) digestion. The hepatocytes could be separated and purified by density gradient centrifugation. The harvested hepatocytes were then suspended in DMEM/F-12, M199, or L-15 (cultured with 5% CO2). The yield was determined by a hemocytometer. The viability was assessed by Trypan blue exclusion test. Proliferation of hepatocytes was tested by MTT assay. Function of hepatocytes was examined according to the levels of lactic acid dehydrogenase (LDH), albumin (ALB), and urea nitrogen (BUN)of supernatant at different time, respectively. Trypsin digestion method was better than tissue culture. Using 0.25% warm trypsin digestion, the cell yield was 1.6×108 cells per g(liver weight) and the viability was more than 95%. The cells growth were better cultured in L-15 medium than in DMEM/F-12 and M199 media. The liver function index showed that lactic acid dehydrogenase (LDH) significantly decreased, urea nitrogen (BUN) and albumin (ALB) significantly increased during 48-72 h with a strong proliferation. This study indicates that the best method of isolation was pancreatin digestion and the best medium was L-15. During 48 to 72 h in culture, the growth and metabolism of hepatocytes were thriving.

    • Quantitative description of body composition in grass carp (Ctenopharyngodon idella)

      2016, 40(4):566-576. DOI: 10.11964/jfc.20150709984

      Abstract (2717) HTML (508) PDF 2.39 M (1884) Comment (0) Favorites

      Abstract:To quantify the body cmposition of grass carp,about 3700 datasets were adopted from 51 studies regarding body composition and morphological parameters of grass carp with body weights ranging from 1.52 to 694.80 g after data searching and collecting from academic database. Through data classification,correlation analysis and linear regression analysis,the overall results in the present experiment suggested that close linear relationships of whole-body protein content and viscera weight (y, g) with body weight of grass carp (x, g) were obtained respectively: y=0.1604x-0.3645, R2=0.994; y=0.1059x-0.3097, R2=0.9875. With an increase of body weight,whole-body lipid and ash contents (especially the lipid content) of grass carp are more susceptible to dietary manipulations. Deposition of 1 g protein resulted in a retention of 4.57 g moisture,while accumulation of 1 g lipid entailed a decrease of 0.95 g moisture in the whole-body of grass carp. In the liver,deposition of 1 g lipid entailed a decrease of 0.66 g moisture,suggesting that the loss rate of moisture driven by lipid deposition is tissue specific in grass carp. The present study also demonstrated that mesentery is an important site for lipid deposition in grass carp,and an increase of lipid accumulation in mesentery,liver and muscle contributes to whole-body lipid deposition. In addition,an increase of whole-body lipid content is accompanied by increased viscera weight. The results in this study are helpful to quantify the body composition of grass carp and provide scientific guidance for its practical production.

    • Effects of enrichment with different nitrogen sources on growth, photosynthetic carbon fixation and nitrogen uptake of Saccharina japonica

      2016, 40(4):577-584. DOI: 10.11964/jfc.20150709962

      Abstract (2763) HTML (565) PDF 1.32 M (2367) Comment (0) Favorites

      Abstract:To investigate physiological characteristics of Saccharina japonica cultured in enriched media with different nitrogen sources, kelp were cultured for 7 days in three nitrogen conditions, including natural seawater, enrichment of ammonia and nitrate, and then growth rate, photosynthesis at different carbon levels (P-Ci curve) and nitrogen uptake rate were determined, respectively. The results showed that both enrichments of ammonia and nitrate remarkably enhanced growth of kelp, but no significant difference between the two treatments. P-Ci curve conformed to the saturated kinetics equation, and both the maximal photosynthetic rate (Vmax) and half saturated constant (Ks) were notably raised by enriched nitrogen. However, Vmax showed no significant difference between the two nitrogen enrichment, while Ks exhibited a higher value in ammonia than in nitrate enrichment. Compared to natural seawater, the ratio of Vmax/Ks increased in enrichment of nitrate and kept no change in enrichment of ammonia. Contents of Chl.α and Car were enhanced by enrichment of nitrogen, with no significant difference between the two nitrogen sources enrichments. Content of soluble sugar was decreased by enriched nitrogen, and showed a lower value in enrichment of ammonia than nitrate. Compared with natural seawater, ammonia enrichment enhanced ammonia uptake and inhibited nitrate uptake, while enrichment of nitrate increased nitrate uptake and had no remarkable effect on ammonia uptake. In conclusion, enrichments with both two nitrogen sources could enhance uptake of carbon and nitrogen, but ammonia enrichment had advantage in nitrogen uptake, while nitrate enrichment showed more remarkable influence on carbon fixation. Therefore, the balance of carbon and nitrogen utilization affected by enrichment of ammonia or nitrate resulted in no significant difference in growth rate between the two treatments.

    • Study on feeding ecology of fish community in Laoshan Bay during summer using stable carbon and nitrogen isotopes

      2016, 40(4):585-594. DOI: 10.11964/jfc.20150709965

      Abstract (2596) HTML (532) PDF 2.96 M (1906) Comment (0) Favorites

      Abstract:Laoshan Bay is one of numerous gulfs of the Yellow Sea and an important fish enhancement and release area. It is vital for the Yellow Sea fishery resources that carry out proliferation and implement effective fisheries conservation and management in Laoshan Bay ecosystem. Based on bottom trawl survey conducted in Laoshan Bay in June and August 2014, the dominant fish species of fish community during summer were analyzed and their feeding ecology was studied by stable carbon and nitrogen isotopes method. The stable carbon isotope ratio (δ13C) is often used to assess basal sources in food web with a slight enrichment, while the stable nitrogen isotope ratio (δ15N) is indicator of trophic level, as a major increase with each trophic level. In terms of the index of relative importance (IRI), there were 10 dominant species of fish community in Laoshan Bay during summer, including Amblychaeturichthys hexanema, Ctenotrypauchen chinensis, Odontamblyopus rubicundus, Johnius belengerii, Argyrosomus argentatus, Lanmichthys polyactis, Chelidonichthys kumu, Cynoglossus joyneri, Clupanodon punctatus and Thrissa kammalensis. There were significant differences in dominant fish species composition of fish community between two months in summer. The range of δ13C of dominant fish species ranged from -20.66‰ to -17.53‰ in June and from -21.06‰ to -17.33‰ in August. There were significant differences in δ13C between dominant fish species. According to δ13C of this research, combining with results of stomach contents analysis, the results show that the main food source of fish community was benthic prey in June, but the food source of fish community was more extensive in August. The range of δ15N of dominant fish species was 10.86‰~15.47‰ in June and 9.40‰-13.10‰ in August. There were significant differences in δ15N between dominant fish species and the biggest difference were 4.61‰ and 3.70‰, respectively. The dominant species of fish community in Laoshan Bay in June included fish with middle trophic level and high trophic level, the mean trophic level of fish community was 3.90, and was mainly benthivores. The dominant species of fish community in Laoshan Bay in August included fish with middle trophic level and low trophic level, the mean trophic level of fish community was 3.37, including zooplankivores and benthivores, mainly benthivores. Linear regression analysis showed that in addition to J. belengerii, C. punctatus, C. joyneri and C. kumu, whose trophic level showed not linear correlation with the length, and the trophic level of rest of the dominant species was significantly positive correlation with the body length. This was mainly because with the increase of body length, they increase feeding on prey with high trophic level, but reduce feeding on prey with low trophic level, and their trophic level also increases.

    • Genetic parameters for growth and survival traits in the Pacific white shrimp (Litopenaeus vannamei) cultured using the zero water exchange system

      2016, 40(4):595-602. DOI: 10.11964/jfc.20150709985

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      Abstract:Heritabilities and genotype by environment interaction effect for growth and survival traits were estimated in the G2 generation of the Pacific white shrimp (Litopenaeus vannamei) under the zero water exchange system and large water exchange system. A total of 51 Pacific white shrimp full-sib families were established by artificial fertilization and directional mating technology. After communally rearing for 52 d in zero water exchange system, body weight, body length, and sex of the 3822 shrimps in two concrete tanks were recorded. The variance components for growth and survival traits were estimated using the linear (generalized linear) mixed model and REML method. The results showed that body weight and survival rate had a high coefficient of variation. The heritabilities estimated for body weight and body length were 0.49±0.08 and 0.43±0.07, respectively. Both of them were high heritability estimates (h2≥0.15). The heritability estimated for survival was 0.11±0.03, which was a low heritability estimate (h2<0.15). There was a high genetic correlation between body weight and body length (0.98±0.01). The genetic correlation between body weight and survival was 0.31±0.15. The genetic correlation between body length and survival was 0.34±0.15. For body weight and survival traits, the genetic correlations between zero and large water exchange systems were 0.62±0.11 and 0.65±0.11, respectively. This implied that there were great genotypes by environment interaction effect between the two systems (K>0.5). In conclusion, there was high genetic variation for body weight of this population in the zero water exchange system. However, a separate selection line should be established to improve growth and survival for shrimp reared in the zero water exchange system because high re-ranking of families occurred between zero and large water exchange systems.

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