• Volume 42,Issue 11,2018 Table of Contents
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    • Effects of acute ammonia exposure on gene involved in inflammation of mudskipper

      2018, 42(11):1704-1710. DOI: 10.11964/jfc.20170610858

      Abstract (1172) HTML (639) PDF 788.66 K (1196) Comment (0) Favorites

      Abstract:A study was carried out to test the effects of acute ammonia exposure on gene involved in inflammation of mudskipper Boleophthalmus pectinirostris. The mudskipper (15.14±0.05) g were randomly allocated to 2 groups (control group and exposure group) in triplicate for 96 h ammonia exposure. The 96 h lethal concentration 50 (LC50) of ammonia in mudskipper is 8.99 mg/L total ammonia nitrogen (TAN; 0.11 mg/L non-ionic ammonia); Fish exposed to ammonia showed the mRNA expression of TNF increased significantly by 2-fold for 96 h; The mRNA expression of IL-1 increased significantly by 6-fold for 12 h; And the mRNA expression of IL-6 increased significantly by 1.5 fold for 12 h and 96 h; however, the mRNA expression of IL-8 decreased significantly for 24 h. This study indicated that the 96 h LC50 of ammonia in mudskipper is 8.99 mg/L TAN; The mRNA expression of TNF, IL-1, IL-6, IL-8 increased significantly after fish exposed to ammonia for 48 h; The inflammation is considered as one of major causes of fish ammonia poisoning.

    • Comparative toxicity effect of nano-ZnO, bulk-ZnO, and ZnSO4 on oxidative stress in zebrafish(Danio rerio)

      2018, 42(11):1804-1816. DOI: 10.11964/jfc.20171211076

      Abstract (1211) HTML (632) PDF 1008.73 K (1156) Comment (0) Favorites

      Abstract:In order to explore the toxicity of nano ZnO and its relationship with the release of Zn2+ and its own characteristics, zebrafish were exposed to the nano-ZnO, bulk-ZnO, and ZnSO4 suspension for 4, 24 and 96 hours by using the acute toxicity test, and the glutathione-s-transferase (GST), catalase (CAT), and the levels of glutathione (GSH) and reactive oxygen species (ROS), the relative expression levels of Bax, Bcl-2, TNF- alpha and IL-6 in liver, intestine and gill of zebrafish were measured. The objective of this study was to compare the the strength of oxidative stress effects of nano-ZnO, bulk-ZnO and ZnSO4 in zebrafish, and discuss whether the toxicity of nano-ZnO is related to the releasing Zn2+ or nanoparticles itself. Results showed that nano-ZnO, bulk-ZnO, and ZnSO4 can cause oxidative stress in the tissues of zebrafish, and the nano-ZnO induced more oxidative damage than the other two forms of zinc. Consequently, we can conclude that the toxicity of nano-ZnO was higher than that of bulk-ZnO and ZnSO4 on oxidative stress in zebrafish and the toxicity of nano-ZnO was mainly attributed to the nanoparticles itself.

    • The diallel cross of Manila clam (Ruditapes philippinarum) populations from Fujian and Guangdong Provinces

      2018, 42(11):1711-1718. DOI: 10.11964/jfc.20171011011

      Abstract (1121) HTML (629) PDF 499.29 K (1116) Comment (0) Favorites

      Abstract:In 2015, from Septemper to December, a diallel cross was conducted using two populations of Manila clam Ruditapes philippenarum from cultured Fujian stock and wild Guangdong stock which was F1 progeny. The growth, survival rate and heterosis at larval and juvenile periods were compared among the two reciprocal hybrid crosses and two parental crosses. The results indicated that all the four experimental groups had high fertilization and hatching rates, and did not show significant difference between each other. Totally, at larval period, maternal origin had significant effect on growth. While mating strategy was the major factor for growth hybrid effect during juvenile. In contrast, at larval period, mating strategy had significant effect on survival, while maternal origin was the major factor for survival during juvenile. This showed that gamete incompatibility and embryonic development disorders did not exist in interspecific hybridization between different geographical populations of R. philippenarum. At larval period, no growth or survival heteiosis was observed between two hybrid crosses and the two parental groups. In contrast, at juvenile period, the growth performances of two hybrid crosses were superior to the two parental groups, showing heteiosis in the characteristics of shell height and shell length after 30 days of age. Especially, at 40 days of age, heterosis values of shell height and shell length reached maximum, which were 25.64 and 27.00, respectively. This perhaps attributed to development difference of expression of heterosis. For survival rate, at larval period, the Fujian parental cross had the best performance which was 36.45%±1.85%. And the juvenile survival rate of the Guangdong parental cross was 52.27%±2.13%, which was higher than other three experimental crosses. In total, survival heterosis was not observed during the study. This was attributed to the fact that survival-related gene frequency of two geographic parental populations had no difference or detection was less often.

    • Pathology and PCR assay of Thelohanellus wuhanensis disease in Allogynogenetic crucian carp (Carassius auratus gibelio) in the periods of occurrence, development, fade and disappearance

      2018, 42(11):1817-1828. DOI: 10.11964/jfc.20171211082

      Abstract (1396) HTML (584) PDF 1.03 M (1108) Comment (0) Favorites

      Abstract:In order to explore the process and pathology of Thelohanellus wuhanensis diseased Allogynogenetic crucian carp (Carassius auratus gibelio), the disease was divided into four periods of occurrence, development, fade and disappearance according to whether there were mature spores and the degenerated degree of them or not. Pathological observation and analysis of nested PCR were made respectively. Results showed that in the period of occurrence, formed cysts on diseased fish were small and a little uplifted. The cysts were milk white in colour. Trophozoites increased by profilication and no mature spores appeared in the cysts. In the period of development, mature spores appeared in the cysts. Number and size of cysts increased. The cysts were gray black in the colour due to the increase of melanocytes. Diseased fish with higher infection would show death or deformity. In the period of fade, mature spores reduced by flowing out into water through the ruptured gap of cysts or by degenerating gradually until all of them degenerated. At the same time, cysts shrunk and melanocytes were more dense gradually. Diseased fish did not die in the present period due to relieved symptoms. In the period of disappearance, no mature spores and only degenerated materials were left in the flattened cysts. Melanocytes reduced gradually. Finally, the original part of cysts was replaced by connective tissue. Nested PCR analyses showed that the 1 584 bp and 853 bp in the first and second runs of nested PCR were respectively obtained in all of four periods of disease. However, in the late stage of the period of disappearance only 853 bp in the second run of nested PCR was obtained, which illustrated that its quantity reduced. No bands were obtained after late October. Present study not only revealed the pathology of T.wuhanensis infected sides in the four periods of disease, but also defined two ways of the disease fade and disappearance. One way was flow out of mature spores from ruptured cysts into water and another way discovered for the first time was degeneration of mature spores in the cysts.

    • Cloning and tissue expression of a novel hcSRCR1 gene in differential inner-shell color pearl mussel Hyriopsis cumingii

      2018, 42(11):1719-1728. DOI: 10.11964/jfc.20171211107

      Abstract (1216) HTML (614) PDF 927.03 K (1158) Comment (0) Favorites

      Abstract:As a superfamily of glycoproteins, scavenger receptors play a crucial role in the identification and assembly of chemically modified lipoproteins. In this study, cDNA of Hyriopsis cumingii scavenger receptor cysteine-rich gene (hcSRCR1) was cloned by using rapid amplification of cDNA ends (RACE) approaches, then the bioinformatics and expression profiles were analyzed. The complete hcSRCR1 cDNA consists of 1 000 nucleotides with a 819 bp open reading frame encoding 272 amino acid residues. The molecular weight of hcSRCR1 was 28.16 ku and pI was 5.55. It was also predicted that protein hcSRCR1 had two scavenger receptor cysteine rich domains and six conserved cysteine residues. qRT-PCR and Western blot showed that hcSRCR1 was constitutively expressed in a wide range of tissues with the highest expression level in the mantle. Moreover, differential expression analysis revealed that hcSRCR1 was more highly expressed in the mantle of purple line mussels compared to white line mussels. In situ hybridization investigations of the precise expression site of hcSRCR1 mRNA in the mantle showed that hcSRCR1 mRNA is specifically expressed in the inner epithelial cells of the outer fold mantle, as well as throughout the outer epithelium of the outer fold and ventral mantle. Our results suggest that hcSRCR1 play a role in the formation of shell and pearl color formation, and may provide useful information for further studies on regulation mechanism in the color formation of pearls.

    • The induction of metamorphosis in Iwagaki oyster (Crassostrea nippona)

      2018, 42(11):1729-1736. DOI: 10.11964/jfc.20171211081

      Abstract (1342) HTML (818) PDF 821.93 K (1072) Comment (0) Favorites

      Abstract:The Iwagaki oyster Crassostrea nippona, is a large sessile oyster inhabiting intertidal hard grounds and reefs along the coast of East Asian. Because of its unique flavor, delicious taste and edibility during summer when other oyster species are unavailable, C. nippona is highly valued and has a broad market prospect. To obtain cultchless oyster with a regular shell shape and uniform size, epinephrine (EPI) was applied to C. nippona eye-spot larvae to induce cultchless metamorphosis. To determine optimum levels for C. nippona, the effect of EPI concentration, exposure time to EPI, and larval density were examined. The results demonstrate that EPI can significantly facilitate larval metamorphosis. 0.05 mmol/L and 1 h treatment were the optimum for single oyster seed production, and shell height and survival rates of cultchless spats showed a curve of descending with increasing EPI concentration and exposure time. However, there was no significant difference between EPI treatments at larval densities < 8 larvae/mL. The growth of C. nippona was also examined in the following days, which showed that shell height and spat survival rates were higher in 0.5-4 larvae/mL than those in 8 larvae/mL. Therefore, 8 larvae/mL was the optimum for single oyster seed production, while a density of no more than 4 larvae/ml was the best for cultchless spats cultivation.

    • Interaction between Litopenaeus vannamei Rab5B protein (LvRab5B) and IHHNV proteins

      2018, 42(11):1829-1839. DOI: 10.11964/jfc.20170810929

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      Abstract:To study the antiviral function of LvRab5B in the virus resistance of Litopenaeus vannamei, we constructed the fusion expression vectors of LvRab5B protein in insect cells and in yeast cells, respectively; studied the expression of LvRab5B protein in insect cells using immunofluorescence technique; studied the interaction between LvRab5B protein and IHHNV proteins using yeast two-hybrid technique; studied the expression of LvRab5B in different tissues of normal L. vannamei and the relative expression of LvRab5B at different time points after infection in L. vannamei infected with IHHNV or WSSV using qRT-PCR technique. The results showed that the fusion LvRab5B protein was able to express in insect cells. LvRab5B protein had no interaction with capsid protein (CP) of IHHNV, while it interacted with nonstructural protein (NS1) of IHHNV, and was weakly interacted with nonstructural protein (NS2) of IHHNV. qRT-PCR showed that LvRab5B was expressed in the heart, gills, intestine, stomach, hepatopancreas and muscle of normal L. vannamei, and the expression was the highest in the intestine, followed by the hepatopancreas. The relative expression of LvRab5B was different after viral infection. The expression decreased at the initial stage of infection, then increased rapidly, finally decreased at the end stage. This study shows that LvRab5B is involved in the innate immune process of L. vannamei against IHHNV or WSSV infection, which lays a foundation for further studies of the immune function and mechanism of LvRab5B protein in shrimp.

    • Effects of salinity on Crassostrea angulata sperm quality and fertilization using PI/Rh123 dual fluorescent staining and flow cytometry

      2018, 42(11):1737-1746. DOI: 10.11964/jfc.20180211171

      Abstract (1215) HTML (630) PDF 637.24 K (1188) Comment (0) Favorites

      Abstract:In this experiment, Crassostrea angulata sperm was used as the research object to study the effect of salinity stress on sperm quality and fertilization rate using PI/Rh123 dual fluorescent staining and flow cytometry (FCM). The results showed that sperm moving-time, survival rate and sperm activity increased first and then decreased with the increase of salinity. The suitable salinity range of C. angulata sperm was 20–35, and the salinity range was 25–35 with higher sperm activity. It was found that salinity stress caused damage to the sperm plasma membrane first and then damaged the mitochondrial activity by PI/Rh123 dual fluorescent staining and FCM. In addition, sperm were severely damaged under low salinity conditions (10, 15) and the damage ratio of sperm plasma membrane was 67.26%±2.35%, which was significantly different from the other groups. The artificial insemination experiment showed that fertilization rate and cleavage rate decreased significantly after low salinity stress (10, 15), and deformity and split stagnation were observed in cleavage stage, which shows that sperm quality not only seriously affects the process of fertilization, but also has a certain effect on cleavage. This experiment explored the feasibility of PI/Rh123 dual fluorescent staining and FCM to detect the function of plasma membrane and mitochondrial activity in oyster sperm, but also evaluated the sperm quality comprehensively, which provided a theoretical basis for the research of oyster sperm quality.

    • Isolation and cadmium adsorption mechanisms of cadmium-resistant bacteria strains in digestive gland of scallops

      2018, 42(11):1840-1847. DOI: 10.11964/jfc.20170910985

      Abstract (1212) HTML (724) PDF 735.41 K (1161) Comment (0) Favorites

      Abstract:In order to explore the relationship between the role of bacteria community and the high capacity for accumulation of Cd in the digestive tissues in scallops, two cadmium (Cd)-resistant bacterial strains (named A and B) were isolated from the digestive gland of scallop which were collected from the natural marine environment. Two bacterial strains were classified using 16S rDNA sequence analysis. And the ability of two bacterial strains for the accumulation of Cd and their adsorption characteristics of Cd were researched by the metal adsorption experiments. In addition, the combined technique of scanning electron microscopy (SEM) observation and transmission electron microscopy (TEM) observation was used to observe the cell morphology and inside structure of the bacterial strains under Cd exposure, and the cadmium precipitation and distribution outside and inside the cell were studied to explore the adsorption mechanism of Cd for two bacterial strains. Results showed that the two bacterial strains (A and B) could tolerate Cd2+ up to 100 mg/L and 80 mg/L in solid medium respectively. Based on 16S rDNA homology analysis, bacterial A sequences shared high similarities with Nitratireductor sp. and bacterial B was classified as Ruegeria sp. Their adsorption ability of 5 kinds of heavy metal ions (Cd2+, Cu2+, Mn2+, Zn2+ and Pb2+) were examined and both of them had higher adsorption of Cd than that of other four kinds of metals. In addition, bacterial strain A and B could accumulate Cd to 48.57 mg/g and 42.14 mg/g respectively in 50 mg/L liquid mediums and the accumulation factor for Cd was 971.4 and 842.8 respectively. Scanning electron microscopy (SEM) indicated that the amount of two strains both decreased and empty cavity occurred in some cells after Cd exposure. Obvious Cd precipitates appeared on A strain and more rough surface and irregular convex also appeared on B strain; therefore, extracellular precipitation might be an important way for two bacterial strains to resist and accumulate Cd.

    • Analysis and comparison of agglutinative activity and the molecular basis among 4 kinds of Litopenaeus vannamei hemocyanin based on different purification strategies

      2018, 42(11):1747-1753. DOI: 10.11964/jfc.20170610873

      Abstract (1168) HTML (847) PDF 914.70 K (1192) Comment (0) Favorites

      Abstract:It has been confirmed that hemocyanin (HMC) is a kind of immunoglobulin superfamily (IgSF) protein with antiviral and antibacterial activity. But until now, the molecular basis of its functional diversity is not well understood. In this study, four kinds of HMC fractions from Litopenaeus vannamei, i.e. A-HMCs, A-HMCl, AL-HMCs and AL-HMCl, were purified by affinity chromatography and lectin chromatography, which possessed distinct agglutinative activities against different pathogens. Among them, the agglutination activities of AL-HMCs and AL-HMCl were significantly (about 2–32 times) stronger than those of A-HMCs and A-HMCl against Escherichia coli K12 and Vibrio parahaemolyticus. Furthermore, the protein component and glycosylation modification of the 4 HMCs were analyzed by 2-DE and 2-D lectin blotting. The results showed that they had 6-7 spots in the 2-DE map with significant difference in isoelectric point and molecular weight. In particular, these protein spots could bind with 4 lectins, including concanavalin A (ConA), peanut agglutinin (PNA), ulex europaeus agglutinin (UEA) and dolichos bifows agglutinin (DBA), to different degrees. Of these, all of the 6 protein spots from A-HMCl could bind to 4 kinds of lectins, while only 4 and 3 protein spots from A-HMCs showed positive to UEA and DBA, respectively. AL-HMCs and AL-HMCl could respectively react with PNA and UEA, to produce 3 spots out of 7 total protein spots and 2 spots out of 6 total protein spots, respectively. Collectively, our data demonstrated that the molecular basis of functional diversity of shrimp hemocyanin may be closely related to the diversity of protein composition and glycosylation.

    • Comparative analysis of image measurement technology and artificial measurement method based on three kinds of prawns

      2018, 42(11):1848-1854. DOI: 10.11964/jfc.20170910971

      Abstract (1094) HTML (776) PDF 698.91 K (1268) Comment (0) Favorites

      Abstract:The measurement of prawns’ morphological parameters was traditionally to use vernier caliper, but the error was great. In order to improve the intelligent level of prawns measurement, this paper first invented image measurement technique based on computer vision technology. Using this technique, we measured body length(BL), carapace length(CL) and carapace width(CW) of Marsupenaeus japonicus, Litopenaeus vannamei and Metapenaeus ensis, then compared these results with those from vernier calipers. We measured 421 prawns and obtained 15 156 data. Based on Bland-Altman mapping method and Intraclass Correlation Coefficient (ICC) to judge the consistency and repeatability. It turned out that: (1) More than 95% of the D-value between image measurement technique and vernier caliper method fell within the scope of LoA, and LoA CI was acceptable in professional sense, which showed that the consistency of the two methods was good. (2) For one individual, the results of identifying one angle by using image measurement technique were the same. The ICC of identifying three different angles were 0.996, 0.973, 0.957, which had no significant difference compared with that of 3 times measurements using vernier caliper by one person (ICC=0.997, 0.980, 0.965), but larger than three different persons (ICC=0.991, 0.952, 0.947). The result indicated that the repeatability of image measurement technique was related to shooting angle, and the same angle was the best. (3) The results of identifying one angle using image measurement technique were the closest to assumed truth value. Meanwhile, the degree of variation was minimal, the relative error was 1.52%, 2.37% and 3.74% respectively. In short, the consistency of image measurement technique and vernier caliper method was good, and the repeatability of the former was superior to the latter, with advantages in non-contact, fast measurement and wide application. Therefore, we could replace vernier caliper with image measurement technique to be applied in prawns morphological parameters measurement.

    • Study on otolith marking of larval common carp Cyprinus carpio by immersion in alizarin complexone

      2018, 42(11):1754-1765. DOI: 10.11964/jfc.20171211105

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      Abstract:The artificial release is one of successful approaches for natural fishery stock enhancement. Therefore, effective marking techniques are expected to be applied for assessment of the contribution of released fishes to the fishery resources. Because fish at larval stages are better for batch marking and releasing, in the present study, larval common carp Cyprinus carpio were immersed in the 100 mg/L of alizarin complexone (ALC) for 48 h, so as to compare and investigate the marking characteristics of this method among sagitta, asteriscus and lapillus, as well as the possible time lag between start/end of fish ALC immersion and corresponding start/end of the fluorescent signal on otolith. Results suggested that marking rings in aforementioned three types of otolith were significantly observed in both visible and fluorescent lights. As for the ALC marking effect, asteriscus (the best) and lapillus (the second) were relatively better than sagitta. One-day time lag was found, respectively, between start of fish immersion and corresponding start of otolith marking, as well as end of fish immersion and corresponding end of ALC marking in extended area on otolith. The otolith ALC marking rings could still be obviously noted, even the fish was reared for 50 days after end of immersion. This phenomenon showed that ALC marking ring could be preserved on otolith for quite a long period. Consequently, the present method of ALC immersion will have strong feasibility for otolith ecological marking of larval C. carpio.

    • Feeding habits and growth characteristics of larvae and juvenile hybrid grouper (Epinephelus fuscoguttatus♀×E. polyphekadion♂)

      2018, 42(11):1766-1777. DOI: 10.11964/jfc.20170610856

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      Abstract:Hybridization is the most effective and thus widely used technique in the artificial breeding of grouper. Feeding habit is one of the most crucial variables for feeding strategy in early development stage of fish. Diet and feeding time with good feeding habit will increase the survival rate and the feed efficiency greatly. In order to understand the feeding characteristics of hybrid grouper(Epinephelus fuscoguttatus♀×E. polyphekadion♂) during the early development stage, feeding habits and growth of larvae and juveniles in condition of artificial culture were examined by using ecological method of simple random sampling at water temperature of 27.5–31 ℃. Results showed that hybrid grouper had already acquired good foraging capability at larvae stage. 3 days after hatch (DAH) opened its mouth and started to feed and feeding incidence was 40%. At 3 DAH, feeding incidence was 100% of larvae and juvenile. Feed intake of larvae and juvenile increased with the increase of body mass, which can be expressed by binomial equation. The fullness coefficient of stomach fluctuated in the range of 0.95%-11.26%. Larvae and juveniles could spend less than 1.5 h on feeding from empty to full in stomach, the larvae spend 0.5-1 h on digesting rotifers and 1-2 h on digesting copepods larvae, and the juveniles spend 1.5-3.5 h on digesting copepods adult. The daily feeding intake rates of hybrid grouper were 49.85%(5 DAH),22.55%(10 DAH) and 15.72%(24 DAH), which could be a reference for daily feeding of larvae and juvenile in artificial seedling. The feeding behavior of hybrid grouper larvae and juveniles mainly occurred at daytime. They had obvious circadian rhythm of feeding.The feeding rhythm of larvae (3 DAH and 10 DAH) exhibited feeding peak at 9:00 and 18:00, and the feeding peak of 24 DAH larvae was at 12:00. The average daily growth rate was 7.96% and the average daily weight gain was 28.73% during the 3-30 DAH larvae and juveniles. The relationship between total length, body weight and age (in days) can be expressed as exponential equation, respectively. The relationship between body weight (y) and total length (x) could be expressed to be y=0.037 3x2.537 8, b=2.537 8 is approximately equal to 3. It shows that the growth of lavae and juveniles of hybrid grouper belongs to the type of isokinetic growth.

    • Transcriptome analysis of high-temperature adaptation in large yellow croaker (Larimichthys crocea)

      2018, 42(11):1673-1683. DOI: 10.11964/jfc.20171111029

      Abstract (1412) HTML (1021) PDF 941.66 K (1580) Comment (0) Favorites

      Abstract:In order to investigate the variations of gene expression of Larimichthys crocea under high temperature stress, two libraries of high temperature treatment group and control group were constructed and sequenced using the Illumina HiSeq 2500 platform (paired-end). High temperature treatment group (heat1, heat2, heat3) and control group (control1, control2, control3) obtained 15.28 Gb and 13.92 Gb raw data respectively, and the average GC content of each library was 51%. After strict filtering, clean reads were then mapped to the Larimichthys crocea reference transcriptome using the Bowtie 2 software, the amount of gene expression were also estimated according to the reads mapped to genes. EdgeR software package was then used to determine the differential gene expression of 2 groups of samples with a threshold criteria FDR < 0.05 and |log2(FC)| > 2. Totally 1259 differentially expressed genes (DEGs) were identified under high temperature stress, among which 821 genes were up-regulated and 438 genes were down-regulated. Twelve DEGs were random selected for quantitative RT-PCR (qRT- PCR) analysis, and the results confirmed that the transcriptome analysis was reliable. Furthermore, the DEGs were subject to GO and KEGG enrichment analysis, the results showed that most of the DEGs were involved in oxidation-reduction, reduction reactions, protein folding and defolding, glucose and lipid metabolism, and the occurrence of certain diseases. The results above mentioned provide foundation information for further study on the molecular mechanism of high temperature tolerance in Larimichthys crocea.

    • Using stable isotopes to estimate the effects of different carbon/nitrogen feeds on feeding habit of Procambarus clarkii in the rice-crayfish co-culture system

      2018, 42(11):1778-1786. DOI: 10.11964/jfc.20171211115

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      Abstract:In the rice-crayfish co-culture system, natural resources and primary productivity of rice fields are abundant, which provides abundant natural baits for Procambarus clarkii. At present, there is no report about the utilization of rice fields with P. clarkii. In this paper, C/N was increased by adding carbon source to feed, which makes nitrogen utilization increase and enriches the density of natural baits in rice fields. We designed three feeding modes as group A (formulated diet C/N: 8), group B (formulated diet and bran C/N: 12) and group C (formulated diet, bran and glucose C/N: 16). Stable isotope techniques were used for analyzing the feeding habits of P. clarkii. The results showed that: ①The δ13C and δ15N values of muscles in different dietary C/N groups were significantly lower than the juvenile P. clarkii muscle, and the δ13C values of adult P. clarkii muscle decreased with the increase of C/N. While the δ15N values of P. clarkii muscle in group B with different sizes were higher than the other two groups. In the same C/N treatment, the δ13C and δ15N value of crayfish muscle of a small size crayfish were the highest. ②According to the analysis of diet, formulated feed was the first food source of P. clarkii with different sizes in group A, accounting for 38.03%-44.17%. Formulated feed was still the first contribution of crayfish diet with different sizes in group B but dropped to 22.13%-25.35%. In group C, the organic debris for the diet of small size P. clarkii accounted for 19.93% was the first food source. Formulated feed which was the first food source of middle and large size P. clarkii declined further to 18.85% and 19.4% respectively. The natural food proportions including zooplankton, algae and Alternanthera philoxeroides were significantly increased in groups B and C compared with group A. The results indicate that by increasing the C/N of feed of rice-crayfish co-culture system, the utilization rate of natural food in the rice fields can be increased, and the excessive use and waste of the feed can be avoided, and it is beneficial to realize the rational utilization of rice fields resources.

    • Development of SNPs related to bait domestication based on largemouth bass (Micropterus salmoides) transcriptome and association analysis with growth traits

      2018, 42(11):1684-1692. DOI: 10.11964/jfc.20171010987

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      Abstract:Micropterus salmoides is a species of carnivorous teleost. Annually, a large amount of forage fish were used as food for M. salmoides. The residual forage fish not only increase the culture costs, but also pollute environment seriously. In order to protect the environment and cut down culture costs, it is necessary to breed the strain which can digest and absorb formulated feed efficiently to reduce the utilization of forage fish. In this study, for promoting selective breeding of the M. salmoides strain suitable for formulated feeds, bait domestication was carried out in juvenile M. salmoides of breeding group and non-breeding guoup. On the 14th day and the 16th day after bait domestication, the growth traits including body weight, total length and body height were measured. At the same time, seven candidate Unigenes related to energy metabolism with SNPs were selected from the transcriptome of M. salmoides. The SNP sites were genotyped by using of SNaPshot in a bulked segregate analysis (BSA) population with 129 minimax individuals, and the association analysis between genotypes and growth traits were detected. After analysis by using of SPSS 19.0 software, the results showed that, among the seven SNP sites, C1332G in Unigene031044, A741G in Unigene085384, A284G in Unigene022319, were significantly associated with body weight, full length and body height. By BLAST analysis, Unigene031044, Unigene085384 and Unigene022319 were predicted as hydroxysteroid 17-beta dehydrogenase 12-B (hsd17b12b), Acyl-CoA synthetase long-chain family member 1 (acsl1) and Succinate dehydrogenase complex assembly factor 2 (sdhaf2). The results indicated that the SNP sites in above three genes probably play the roles of regulating lipid metabolism and three carboxylic acid cycle, and help M. salmoides to improve the capacity to digest, absorb and utilize formulated feed. The current three SNPs can be used as candidate markers for breeding M. salmoides suitable for formulated feeds.

    • The relationship between phytoplankton community structure and water quality factors in the pond of Litopenaeus vannamei

      2018, 42(11):1787-1803. DOI: 10.11964/jfc.20171211087

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      Abstract:In order to study the correlations between the change of water quality and phytoplankton community structure during the process of Litopenaeus vannamei aquaculture, the water quality was tested and the changes of phytoplankton community structure were analyzed from April 2016 to September 2016 in an aquaculture farm in Fengxian District, Shanghai, and then the correlations between phytoplankton community structure and water quality factors were analyzed. The results showed that there were 7 phyla, 59 genera, 113 species (including 20 unnamed species), Chlorophyta > Bacillariophyta > Cyanophyta > Euglenophyta > Xanthophyta > Chrysophyta > Pyrrophyta, and 18 dominant species (including 3 unnamed species)——there were 10 dominant species (including 1 unnamed species) in the first season and 14 dominant species (including 2 unnamed species) in the second season. Dominant species were Bacillariophyta at beginning, then Chlorophyta and finally Cyanophyta. According to CCA analyzing, Chlorophyta is mainly affected by pH and nitrogen (including ammonia nitrogen, nitrate nitrogen, nitrite nitrogen), Cyanophyta by phosphorus (including total phosphorus and active phosphorus), and Bacillariophyta by temperature, so we should pay more attention to temperature, pH, nitrogen and phosphorus.

    • Genome-wide identification, phylogeny, and expression of IL17 receptor genes in common carp (Cyprinus carpio) and grass carp (Ctenopharyngodon idella)

      2018, 42(11):1693-1703. DOI: 10.11964/jfc.20180311198

      Abstract (1339) HTML (627) PDF 812.07 K (1277) Comment (0) Favorites

      Abstract:To gain a better understanding of the evolution and action mode of the IL17R family in common carp (Cyprinus carpio) and grass carp (Ctenopharyngodon idellus), the two representative species of Cyprinidae, we analyzed them with the method of comparative genomics and bioinformatics. Sequence alignment and annotation were conducted in the genome database of common carp and grass carp as well as the analysis of genetic structure and phylogeny respectively. Finally, gene expression analysis was performed in 12 different tissues of these two species. We identified and characterized nine and five IL17R homologues. Along with genes annotation and nomenclature, phylogenetic analysis built on amino acid sequences of the IL17R proteins in 12 species showed highly conservative and no specific genes in teleosts. Comparative genomics showed that there was no significant increase in IL17 receptor genes in most teleosts compared with tetrapods. Nevertheless, except for IL17RB genes, all of the members showed extensive gene duplications, leading to nine IL17R genes in common carp. Expression analysis of different tissues showed that the functions of different gene copies were differentiated after the whole genome duplication. Studies have shown that an additional round of duplication, also named teleost-specific (TS) WGD, or the 3R WGD, took place in the common ancestor of all extant teleosts. After duplication, one of the two redundant copies of a gene should theoretically have the freedom to degenerate and become lost from the genome without consequence. Also, it was generally hypothesized that, compared to other teleost, common carp had undergone additional whole genome duplication (the 4R WGD). The comprehensive estimation based on whole genome datasets suggested that the latest WGD event occurred around 8.2 MYA. Therefore, we postulated that the significant expansion of IL17R genes in the common carp genome may be the result of this additional WGD, which could have caused a sudden doubling of the IL17R genes and the IL17RB had been lost in their evolution history with the reason that the functions of genes were redundant and conservative. Expression profiling showed that most of the IL17R genes were expressed in a more-or-less tissue-specific fashion.

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