Abstract:Ultrastructure of the spermatozoon of Sepia esculenta Hoyle was observed by scanning and transmission electron microscopy. The sperm is 191.84μm (n=10) long and consists of two parts, the head and the tail. The head is mainly composed of acrosome and nucleus, and the tail includes the middle piece, the principal piece, and the end piece. The acrosome was an inverted U-shaped cystid, and the subacrosomal space was ∩-shaped. The nucleus was long, slightly curved and cylindrical-shaped, and was filled with homogeneous texture with high electron density. The posterior nuclear fossa diverged from the center of the nucleus. The middle piece of the tail is very long and consists of mitochondria spur and flagellum incompletely encircled. The mitochondria spur includes two parts, the proximal part and the distal part. The proximal part contained a great amount of mitochondria, while the distal part contained no mitochondria. The principal piece of flagellum is slender, and is composed of a “9+2”axoneme surrounded by nine bundles of coarse fibers, and it formed the typical structure of “9+9+2”

Abstract:The annual ovarian maturation cycle of spotted halibut Verasper variegatus was studied by employing light microscopy and morphometric methods. The spotted halibut features asynchronous oocyte development and batch spawnings. In sexually matured female, the oocyte growth consisted five phases, and the ovary maturation cycle consisted five stages accordingly. Gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factor (CF) were all found to increase prior to, or during the peak phase of vitellogenic growth corresponding to the gonad development. The effective accumulated temperature for spotted halibut female broodstock is 1 050 d·℃. The results would highlight the reproductive cycle of captive female broodstocks of spotted halibut, and also serve as useful tools for broodstock breeding and determination of timing for hormone induced spawning.

Abstract:The annual ovarian maturation cycle and the variation of correlated plasma sex steroids levels were studied by employing light microscopy and morphometric methods combined with radioimmunoassay. In addition, the relationships between GSI, CF, HSI, sex steroids and temperature, photoperiod were investigated through statistical analysis. Results showed that barfin flounder features asynchronous oocyte development and batch spawnings. The oocyte growth included six phases, and six stages in ovary maturation cycle accordingly. Gonadosomatic index (GSI), hepatosomatic index (HSI) and condition factor (CF) were all found to increase prior to, or during the peak phase of vitellogenic growth corresponding to the gonad development. Statistical analysis revealed that GSI was positively correlated with CF while HSI showed negative relationship with CF. Temperature played more important role in regulating the gonad development compared with photoperiod based on the correlation analysis between GSI, temperature and photoperiod. During spawning the serum estradiol level began to increase in June (stage Ⅲ) and reached the first relatively lower peak in September and peaked in February. After the spawning, it dropped down to a relative low level and maintained until the next reproductive cycle. The testosterone level achieved the first relatively high peak in July and peaked in January, which was a month earlier than that of estradiol. A positive relationship was found between estradiol and testosterone level. Statistical analysis revealed that a positive relationship existed between photoperiod and estradiol level. In addition, the estradiol level showed positive correlations with GSI and CF. These results could highlight the reproductive cycle of captive barfin flounder females, and also serve as useful tools for broodstock breeding and determination of timing for hormone induced spawning.

Abstract:The basic characteristics of chondrichthyes mitochondrial genomes were fully revealed by comprehensive analysis of mitochondrial genomes in ten cartilaginous fishes. Mitochondrial genomes of cartilaginous fishes contain 37 standard metazoan genes and their gene order is identical. The Ka/Ks ratio of 13 mitochondrial proteincoding genes in the Carcharhiniformes and Rajiformes classes is much lower than 1 (0.019 1~0.156 4), indicating a strong purifying selection (negative selection).

Abstract:The effect of delayed feeding in early development stage on growth, survival and biochemical composition in tongue sole Cynoglossus semilaevis larvae was examined. Larvae were divided into four groups, each with 500 larvae (three replicates). At the water temperatures of 21~22 ℃ and salinity of 31.0, initial feeding of the control group with rotifer began at 3 days post-hatch (dph), the feeding of the other groups began at 4 dph (delayed feeding 1 day, D1), 5 dph (D2) and 6 dph (D3), respectively. The results showed that the mixed feeding stage for the larvae was at 3 dph. It was at 4 dph when the growth of larvae began accelerating. The yolk sac was almost completely absorbed at 5 dph, which suggested for an onset of complete exogenous feeding. After the 15d experiment, significant difference was observed only in dry weight between the control and the D1 larvae. The total length, dry weight, protein content and lipid content of D2 larvae were significantly lower than the control larvae (P<0.05). The survival rate of larvae decreased corresponding to the delay in initial feeding time. There was no significant difference found in mortality among all treatments within 4 days after mouth-opening. While 6 days after mouth-opening, the difference was much more significant. The morality of D3 larvae reached almost 100% at 10 dph.

Abstract:We examined the population genetic structure of three families including parents, backcross, and inbreeding families of Japanese flounder using 10 microsatellite markers. The results showed that among the 10 loci, the allele number (NA) was 1.7~3.0, the average allele number was 2.3, the effective allele number (Ne) was 1.553 2~2.887 8, the average effective allele number was 2.0541, the observed heterozygosity (Ho) was 0.307 0~0.664 8, the average observed heterozygosity (Ho) was 0.487 0, the expected heterozygosity (He) was 0.200 0~0.606 8, the average expected heterozygosity (He) was 0.606 8, the average polymorphism information content (PIC) was 0.233 4~0.579 4, and the average polymorphism information content (PIC) was 0.399 5. The polymorphism information content of the three families were at the medium level. The value of PIC from the largest to the smallest was: parents family, backcross family, and inbreeding family. The Poli194TUF was single in the inbreeding family. The genetic deviation index was 0.067 1, which indicated that 6.71% deviation was from families and the genetic deviation was not high inter-families. The genetic distance obtained from the clustering analysis of the three families by UPGMA indicated that the parents family and the inbreeding family was closer. The allele purification was faster in inbreeding family, and thus it was suitable for strains establishment.

Abstract:Danofloxacin, a third generation member of the quinolone family, it has been also used widely to prevent or treat bacterial diseases in fish farming in many countries. It has been studied in Paralichthys olivaceus, Acipenser schrenckii, and goldfish Carassius auratus Linnaeus, etc. However, to our knowledge, there are no studies concerning the pharmacokinetics of danofloxacin in turbot Scophthalmus maximus. In this study, the pharmacokinetics behavior of danofloxacin in turbot after intravenous and oral administration was investigated. Six fish were randomly selected from the tank (water temperature 16±0.6℃) and sampled at 15, 30min, and 1, 2, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96h after intravenous and oral administration, respectively. The concentrations of danofloxacin were determined by HPLC. The data were analyzed with the pharmacokinetic program DAS 2.0. The results showed that the relationship of plasma concentration versus time for danofloxacin were best described as a two-compartment open model, and the pharmacokinetic equations were: Civ=45.741e-1.927t＋7.332e-0.019t, Cpo=6.796e-0.05t＋3.135e-0.005t－9.931e-0.11t. After the intravenous and oral administration, the main pharmacokinetic parameters were as follows: t1/2β 36.336h and 129.228h, AUC0-96h 431.981 and 284.915 h·μg/ml, respectively. After oral administration, the concentration of danofloxacin in liver and kidney was higher than in muscle, but was similar with the concentration in plasma. According to the danofloxacin pharmacokinetics and the minimal inhibitory concentration of most fish bacterial pathogens, the dosage regime of danofloxacin for treatment of fish bacterial diseases was calculated as a daily dosage of 12.17mg/kg by oral administration.

Abstract:The morphological characteristics of Rhopilema esculenta from ephyra to juvenile jellyfish were described, the healing process of residual access mouth of gastrovascular cavity was observed for the first time, and the development phases of jellyfish were redefined. At the water temperature of 20±1℃, salinity 28~29, and pH 7.8~8.2, cultured ephyra（diameter 2~3mm）could grow to juvenile jellyfish (15~20mm) with clubbed subsidiary organ after 20d. The food consumption and growth characteristics (diameter and weight) from newly released ephyra to juvenile jellyfish were analyzed. It was found that the daily growth equation of juvenile jellyfish’s diameter（2～20mm）is y=2.748 8e0.101 8x. The relationship between weight and diameter, food consumption and diameter of juvenile jellyfish were y=6×10-5-0.5x3.547 5, y= 43.537x1.775 respectively.

Abstract:The main nutrients in the muscle, hepatopancreas， and gonade of Octopus variabilis were determined, and the amino acid, fatty acid， and mineral elements were also analyzed and evaluated. The results showed that the content of crude protein in the three tissues was 13.1%~14.7%, among which the highest content was found in dry muscle (6.69% higher than in gonad) (P<0.05). The content of crude fat in the three tissues was low and ranged from 0.9% in muscle to 1.2% in gonad. There were 18 kinds of amino acids found in three tissues. The ratio of EAA/TAA in muscle, hepatopancreas, and gonade was 41.06%, 40.34%, and 46.23%, respectively, which accorded with the amino acids mode recommended by WHO/FAO (1973). PUFA in muscle accounted for 51.9% in total fatty acids, among which C22∶6(DHA), C20∶5(EPA) and C20∶4(AA) in total accounted for 80.5%. The content of Fe and Zn was relatively high in the muscle tissue and amounted to 6.07mg/kg and 5.95mg/kg respectively. In general, the nutrients in O. ariabili muscle were rich and ideal as a food source of human beings

Abstract:We observed the changes of the pH, K value, TVB-N, total number of bacteria, sensory score, tissue structure, and rupture strength of Paralichthys olivaceus under the controlled freezing point storage, and also compared with the samples under refrigerated conditions. In the course of storage, the total number of bacteria, K value and TVB-N increased, while pH decreased first then increased and speeded up with the increasing temperature. At the end of the shelf life, the rupture strength decreased and the tissue structure deteriorated. Compared with the refrigerated samples, the controlled freezing point storage effectively inhibited the production of microorganisms, thus extended the storage time of P. Olivaceus.

Abstract:During starvation, changes of the contents of free amino acids (FAA) in the muscle of Litopenaeus vannamei at salinities of 0 and 30 were examined. The results showed that the concentrations of total FAA increased significantly at both salinities after 15d starvation. Among the free amino acids, the concentrations of taurine, threonine, proline, alanine, cysteine, valine, methionine, isoleucine, leucine, phenylalanine, lysine, histidine, and alanine decreased at different extent, and the concentration of proline declined to zero. The concentrations of taurine, threonine, alanine, cysteine, phenylalanine, and lysine also decreased significantly (P<0.05). However, the main free amino acids such as glycine, aspartic acid, tyrosine, and arginine increased greatly after 15d starvation, and as a result, the total concentration of FAA increased. The experiments also showed that the intensity of energy metabolism of FAA in the muscle of L. vannamei is different during starvation. Thus adding proline, arginine and lysine to the artificial food may promote the growth of L. vannamei

Abstract:By selecting 22 pairs of polymorphic microsatellite markers of Portunus trituberculatus, primers matching, and combinatorial testing, the multiplex PCR amplification system was built and the reaction conditions were optimized, including annealing temperature, Mg2+ concentration, dNTPs concentration and other parameters. Forty-seven combinations of double PCR, 15 combinations of triple PCR, and 3 quadruple PCR combinations were established. The establishment of this technology will provide a fast, effective molecular detecting tool for the P. trituberculatus breeding and germ-line assessment.

Abstract:Investigations were conducted on the microalgae community in high-level prawn ponds of Litopenaeus annamei. A total of 26 microalgae species were identified during the period of investigation. Of these, 10 species were Chlorophyta, 7 were Pyrrophyta, 4 were Euglenophyta, 2 each were Bacillariophyta and Cyanophyta, and 1 was Chrysophyceae. In high-level prawn ponds, Chlorella pyrenoidosa and Oscillatoria chlorine were the dominant species in the later phases of the culture period, contributing more than 90% of the total microalgae. The number of microalgae was in the range of 5.13×108~4.01×109 ind/L, biomass 42.92~181.73 mg/L. The averages of Shannon-Wiener index and biomass diversity index were 1.01~1.30 and 1.83~2.27, respectively. The three dominant groups of phytoplankton (Cyanophyta, Chlorophyta and Bacillariophyta) consisted of phytoplankton community structure in the final culture phases.

Abstract:In this study, three genomic DNA extraction methods including phenol-chloroform extraction, boiling lysis and reagent kit methods were compared in terms of extraction efficiency, DNA quantity, as well as the results of White Spot Syndrome Virus (WSSV) detection. The DNA extraction efficiency of three methods, was 101.5, 372.6 and 21.5 ng/μl, respectively. The ratios of OD260/OD280 were in the range of 1.979~2.175 (mean 2.070), 1.699~1.932 (mean 1.796) and 1.784~2.075 (mean 1.951), respectively. The positive rate of WSSV by OIE (Office International Des Epizooties) nested-PCR was 60% (DNA from phenol-chloroform extraction method), 50% (DNA from boiling lysis method) and 70% (DNA from kit method), while it was 100% by quantitative PCR (all DNA from three methods). The DNA copy number of WSSV detected by quantitative PCR ranged from 916.0 to 2.23×106, 63.3 to 1.78×106 and 479.7 to 2.70×106 copies/μl, respectively. The results would provide some reference for standardizing the detection of WSSV.

Abstract:o investigate the prevalence of pathogenic Vibrio. and Aeromonas hydrophila in aquaculture animals in flowing through systems in Nanchang, animals were sampled over an 18-month period between March 2009 and September 2010. Seven pairs of primers were designed for toxin sub-unit A (ctxA) gene, O139 special gene, O1 special gene, tcpA gene, toxR gene, haemolytic gene, vvhA gene and aerolysin(aerA) gene. Specific PCR was established to simultaneously detect these 7 genes. Strains of Vibrio cholerae, V. parahaemolyticus, V. vulnificus and Aeromonas hydrophila can be detected and differentiated by the size and numbers of specific PCR products through electrophoresis bands examination. In 1 440 tested samples, 17 samples were Vibrio parahaemolyticus positive (1.74%), 25 samples were Vibrio cholerae positive (1.18%), and no Aeromonas hydrophila and Vibrio vulnificus were found in the samples. The results of PCR detection were consistent with those of the traditional culture methods. The results indicated that the levels of pathogenic Vibrio in Nanchang area were very low, while the levels of pathogenic Vibrio in Amyda Sincnsis and Rana catesbeiana were relatively high.

Abstract:Nutritional compositions of fish protein hydrolysate (FPH), ultramembrane filtered fish protein hydrolysate (UF） FPH, fishmeal, casein, and soybean meal were analyzed and compared in this study. The results showed that the content of protein in ultramembrane filtered fish protein hydrolysate was significantly higher than that in fish protein hydrolysate without ultrafiltration. The lipid content in fish protein hydrolysate was reduced by ultrafiltration and the ash content was increased. The total amino acid in fish protein hydrolysate, ultramembrane filtered fish protein hydrolysate, fishmeal, casein, and soybean meal were 62.24, 62.34, 50.78, 74.33, 37.36 mg/100mg, respectively, and the percentage of essential amino acids to the total amino acids (EAA/TAA) were 47.41%, 49.47%, 49.90%, 48.41%, 49.25%, respectively. Taurine is rich in fish protein hydrolysate. Fish protein hydrolysate and fishmeal also have abundant iodine, selenium and vitamin B2, B5. In conclusion, fish protein hydrolysate is a high quality protein material with balanced amino acids, relatively high contents of vitamin B2 and B5, and abundant microelements of iodine and selenium.

Abstract:Rapid detection of Lactobacillus fermentum was established by using polymerase chain reaction (PCR) and denaturing high-performance liquid chromatography (DHPLC). The primers were designed and the PCR system was optimized with the elongation factor (EF-Tu) of L. fermentum as the target gene. Twenty-six strains including L. gasseri were tested with specific detection. The sensitivity of various diluted standard strains were determined. The results indicated that the PCR-DHPLC method was specific and sensitive with a detection limit of 100 CFU/ml.

Abstract:With the rapid development of aquaculture industry,the pattern of mariculture is transfering gradually from the traditional methods to the intensive farming culture in China.All of that,one of the key issues is water treatment.This paper illustrates that the solid wastes from the waste water can be effectively removed by the arc screen.The conclusion is drawn on the comparison of several key parameters of water before and after filtering through the arc screen.The results showed that the arc screen played an important role in the removal of the suspended substances at a removal rate of 90%.At the same time,the arc screen filtration process also increased pH and the concentration of the dissolved oxygen,and reduced the chemical oxygen demand,which would relieve the load of water treatment.

Abstract:The single factor test and the orthogonal test results showed that the optimum alkali extraction process was: 2 volumes of 6% NaOH were added, followed by stirring in water bath at 40℃ for 4h. The orthogonal test results indicated that the optimum enzymolysis procedure was as follows: 0.5% pancreatin was added to the extraction solution adjusted to pH 8.6, and kept at 50℃ for 3h for hydrolysis, and then 0.3% pepsin was added to the solution adjusted to pH 5.7 and kept at 40℃ for 2h. The single factors test results of ethanol solution revealed that the best procedure was as follows: after adjusting pH of the obtained hydrolysate to 6.5, 95% ethanol was added to adjust the consistency of precipitation system to 70%. The quality of the product met the standard requirement of WS1-C3-0030-2000 (Chondroitin sulfate tablets) and WS-10001-(HD-0892)-2002 (Chondroitin sulfate injection).