We studied the feeding and vitality of adult Anthocidaris crassispina by using experimental ecology studies. The results show that A.crassispina had an obvious preference for Betaphycus gelatinum, followed by Sargassum hemiphyllum, Gelidium amansii and Ulva lactuca. Besides, the selection rate of Codium fragile was very low. The daily feed intake rate was affected by water temperature, seaweed species and body weight of A.crassispina. Both daily feed intake rate and vitality were at the best level of 23~27 ℃. And the daily feed intake rate of adult A.crassispina on U.lactuca, S.hemiphyllum and B.gelatinum were different. Under the optimum feeding water temperature, the daily feed intake rate of adult A.crassispina decreased with increasing body weight significantly.

Based on high throughput sequencing technology MiSeq, we analyzed the structure of intestinal bacterial colonies of Apostichopus japonicus cultured in Suspension cage of Fujian. The results show that the units of classification operation (OTUs) of the three samples were 124, 116 and 78, respectively. The abundance of species and dominant strains were rather different among these samples. The maximum of flora′s species abundance was 2.38 in foregut, followed by 2.22 in midgut and 1.24 in hindgut. The hindgut dominant bacteria was Formosa (87.3 8%) and Lactococcus (7.74%), while the dominance of foregut and midgut were Lactococcus and Bacillus. In addition, the percentages of Lactococcus in foregut and midgut were 59.68% and 11.8%, respectively, while the percentages of Bacillus were 62.45% and 12.07%, respectively. In respect of repeatability, the intestinal bacteria found in hindgut also existed in foregut and midgut, and foregut and midgut had six and four unique flora, respectively.

Six diet groups containing protein (44%, 48%, 52%) and small peptide (0.05% and 0.1%) were fed to groupers (Epinephelus akaara) to assess the effect on growth performance, digestive enzymes activities, serum biochemical and antioxidant abilities. The diets were named as D1 (44%, 0.05%), D2 (44%, 0.1%), D3 (48%, 0.05%), D4 (48%, 0.1%), D5 (52%, 0.05%) and D6 (52%, 0.1%). Each diet was fed to triplicate groups of fish with 15 fish [initial weight (42.16±0.23) g] which were randomly sorted into each rearing cubic fiberglass tanks and the experimental last for eight weeks. The results show that there was no effect on weight gain (WG), specific growth rate (SGR), muscle moisture, crude protein and ash contents. As protein level and small peptide concentration increased, the crude fats of grouper muscle, triglyceride (TG) and cholesterol (CHO) decreased (P < 0.05). The activity of pepsin was the highest in Group D2, and the activities of amylase, trypsin and lipase were the highest in Group D1.There were no significant difference among different groups (P > 0.05). The activities of malondialdehyde (MDA) and peroxidase (POD) were not significantly different among different groups (P > 0.05). The result shows that supplementation of small peptide at different protein levels can reduce protein requirement, promote fat metabolism and increase digestive enzymes activities.

To screen potential protective antigen genes for developing genetic engineering vaccine of Yersinia ruckeri, we amplified the outer membrane protein ompF gene of Y.ruckeri isolated from channel catfish (Ictalurus punctatus) with specific primers, followed by molecular cloning, bioinformatics analyses of ompF nucleotide and amino acid sequences with bioinformatics tools and online servers. Then we conducted prokaryotic expression and immunogenicity analysis of target recombinant protein ompF. The results show that ompF gene contained a complete opening reading frame of 1 095 bp (GenBank No. KP159420) in length and encoded 364 aa. Sequence homology analysis reveals that ompF amino acid sequence was highly conserved and shared a closest genetic relationship with ompF of Y.ruckeri (GenBank No.ADK27779.1), sharing sequence identity of 99.2% and was the same branch on the phylogenetic tree. The protein had a conserved gram-neg-porins domain, a signal peptide and a transmembrane region, which suggests that it was a transmembrane protein. Moreover, the ompF protein had 12 potential antigenic determinant regions which were related to protective immunity. In addition, the results of SDS-PAGE indicate that ompF recombinant protein mainly existed in sediment in form of inclusion body, and Western bolt results show that recombinant fusion protein ompF was constructed and expressed successfully, and had good immunogenicity against Y.ruckeri infection. The results indicate that ompF can be selected as a candidate protective antigen gene of Y.ruckeri genetic engineering vaccine.

Under semi-static water conditions, we studied the effects of single and joint toxicity of copper ion (Cu²⁺), cadmium ion (Cd²⁺) and mercury ion (Hg²⁺) on zebrafish embryonic development. The mortality rates at 48^th hour, 72^nd hour and 96^th hour as well as hatching inhibition rates at 72^nd hour, 96^th hour were used as end point of physiological toxicity, and the half lethal concentration (LC₅₀) was used as standard of toxicity evaluation. The results show that the LC₅₀s of Cu²⁺, Cd²⁺ and Hg²⁺on zebrafish embryos at 48^th hour were 0.58 mg·L^-1, 0.72 mg·L^-1 and 0.000 46 mg·L^-1; 72 h-LC₅₀s were 0.39 mg·L^-1, 1.15 mg·L^-1and 0.000 30 mg·L^-1; 96 h-LC₅₀s were 0.08 mg·L^-1, 0.19 mg·L^-1 and 0.000 18 mg·L^-1. The LC₅₀s of hatching inhibition rates of Cu²⁺, Cd²⁺ and Hg²⁺ at 72^nd hour were 0.05 mg·L^-1, 0.01 mg·L^-1 and 0.000 04 mg·L^-1, and were 0.06 mg·L^-1, 0.05 mg·L^-1 and 0.000 11 mg·L^-1 at 96^th hour, respectively. The toxicity of those heavy metal ions on zebrafish embryos was Hg²⁺ >Cu²⁺ >Cd²⁺.The toxicity of Cu²⁺, Cd²⁺and Hg²⁺on zebrafish embryos hatch inhibition rate or mortality had significant dose-response relationship, so hatching inhibition rate at 72^nd hour can be used as the most sensitive indicator for toxicity of zebrafish embryos. With a single toxic Cu²⁺, Cd²⁺ and Hg²⁺ of 96 h-LC₅₀ value, mixed unit 1 : 1 between two components at 48^th hour, 72^nd hour and 96^th hour, the combined toxicity showed synergies on zebrafish embryos; but mixed toxicity unit 1 : 1 : 1 coexistence of Cu²⁺, Cd²⁺ and Hg²⁺on zebrafish embryos at 48^th hour, 72^nd hour and 96^th hour showed toxicity antagonism.

We applied Wright's staining as well as cytochemical techniques and phagocytosis test to investigate morphological characterization and immune function of blood cells in "Youlu No.1" largemouth bass (Micropterus salmoides). Two types of blood cells were recognized: erythrocytes and leukocytes, including monocytes, thrombocytes, lymphocytes and granulocytes (Type Ⅰ, Ⅱand Ⅲ). Erythrocytes were the predominant blood cells, while leukocytes were relatively less. Lymphocytes were the most numerous among the leukocytes, accounting for 62.73%. Erythrocytes were negative by cytochemical properties of periodic acid Schiff (PAS), Sudan black B (SBB), acid and alkaline phosphatase (ACP and AKP), peroxidase (POX) and phenoloxidase (PO). All the leukocytes were positive for PAS, SBB, ACP and PO except for AKP and POX. Moreover, there were some differences in the degree of dyeing among the leukocytes. Thrombocytes were stained intensely with PAS, SBB, ACP and PO. Phagocytosis test reveals that erythrocytes show active phagocytic function with phagocytic rate of (16.17±1.08)%. Furthermore, thrombocytes, granulocytes (Type Ⅰ, Ⅱand Ⅲ) showed immune adherence function. Thrombocytes adhered to yeast, forming complex rosette, showing active immune adherence function which might be related with high degree of shape alterations and abundant PAS, SBB, ACP and PO that would influence phagocytosis of thrombocytes.

The characteristics of gonadal development of Holothuria scabra from Hainan Island were investigated by histological observation. Results show that gonadal development of H.scabra from Hainan Island were divided into five stages: recovery stage (Ⅰ), growing stage (Ⅱ), mature stage (Ⅲ), partly spawned stage (Ⅳ) and spent stage (Ⅴ). The characteristics of testis development are as follows: at StageⅠ, a few spermatogonias and spermatocytes started to grow along the germinal epithelium and the germ tube wall was the thickest. At Stage Ⅱ, the germinal epithelium became thinner and the longitudinal folds extended into the lumen. At Stage Ⅲ, lumens packed densely with mature spermatozoas, while at Stage Ⅳ, the germinal epithelium recovered into the original folding morphology. At Stage Ⅴ, a few of relic spermatozoa remained in the lumen. The characteristics of ovary development are as follows: at StageⅠ, oogonias and previtellogenic oocytes started to grow along the germinal epithelium. At Stage Ⅱ, central lumen contained numbers of vitellogenic oocytes, surrounded by oogonias and previtellogenic oocytes. At Stage Ⅲ, the lumen densely packed with vitellogenic oocytes. At Stage Ⅳ, the previtellogenic oocytes re-presented in germinal epithelium, and some nutritional phagocytes began to occur in lumen. At Stage Ⅴ, a few of relic vitellogenic oocytes were still in lumen.

The cathepsin L cDNA of Penaeus monodon (PmCatL) was cloned by rapid amplification of cDNA ends (RACE). The PmCatL cDNA included an open reading frame (ORF) of 1 026 bp encoding a polypeptide of 341 amino acids, which contained a typical signal peptide sequence (Met¹-Ala¹⁸), a prodomain (Val¹⁹-Gln¹²³) and a mature domain (Leu¹²⁴-Val³⁴¹). The preprocathepsin contained a potential N-glycosylation site (Asn⁹⁹), three catalytic sites (Cys¹⁴⁸, His²⁸⁷ and Asn³⁰⁸)and sequences E⁴⁵X₃RX₃F/WX₂NX₃IX₃N⁶⁴ and G¹⁸⁷CXGG¹⁹² were discovered in amino acid sequence. Homology analysis of PmCatL reveals that the PmCatL shared 36%~75% identity to other known cathepsin L sequences. The phylogenetic tree shows that the PmCatL clustered with the invertebrate cathepsin L cysteine proteases and was closely related to Macrobrachium rosenbergii cathepsin L. The expression levels of PmCatL in different tissues were analyzed by quantitative real-time PCR. Expression of PmCatL was detected in all tested tissues and the highest expression level was in lymph. The expression levels of PmCatL in different growth periods show that the expression levels of PmCatL with the highest expression level in post-larval, PmCatL might be associated with growth and development of P.monodon. PmCatL had the highest expression at Stage Ⅳ, which suggests that PmCatL might play an important role in ovary development in P.monodon.

To investigate immersion freezing (IF) effect on protein denaturation of prepared grass carp fillets (PGCFs) during frozen storage, we investigated the protein solubility, sulfhydryl of myofibrillar protein, Ca²⁺-ATPase activity, degradation of myofibril and secondary structure of myofibril. The results show that the solubility of myofibrillar protein, contents of total sulfhydryl and active sulfhydryl, activity of Ca²⁺-ATPase of PGCFs by using ICF were higher than those by using air freezing (AF). After frozen storage for 150 d, the contents of protein solubility, total sulfhydryl, active sulfhydryl and Ca²⁺-ATPase activity of PGCFs by using IF were increased by 17.51%, 14.20%, 4.86% and 28.73% than those by using AF, respectively. It is showed that IF was more advantageous to slow denaturation of protein. Moreover, the electrophoresis result show that the color of heavy chain from myosin of PGCFs by IF was deeper than that by AF, and the color of tropomyosin protein stripe was shallower than that by AF during frozen storage. Thus, IF reduced degradation of protein. The research of infrared spectrum shows that the decreased degree of α-helix content from PGCFs by using IF was less than that by using SAF. Conversely, the increase degree of β-fold, random coil and β-turn from PGCFs by using SAF were more obvious than that by using IF, which indicates that IF was more conducive to maintaining stability of secondary structure of myofibrillar protein during frozen storage. In general, IF was more beneficial to reducing the quality degradation of PGCFs due to protein denaturation.

In order to screen lactic acid bacterias with excellent antioxidant activity, we conducted the preliminary screening based on the requirements of salt toleranced, high and low temperature resistance, high acid production and its tolerance for hydrogen peroxide. Then antioxidant activity of the strains was evaluated in vitro tests including anti-lipid peroxidation assay, hydroxyl radical assay and reducing powder evaluation experiment. A series of experiments show that 15 of selected strains of lactic acid bacterias complied with the requirements. And the antioxidant activity of seven strains was of significant difference. Moreover, L4, L11 and L21 strains demonstrated better capacity on antioxidant activity than the others. VITEK -2 automation microbe system and 16S rDNA sequence analysis show that the three strains were Pediococcus pentosaceu, Lactobacillus plantarum and L.casei.

We studied the effects of salting time, dry process and intermittent vacuum wine lees pickling technology on the quality of drunk fish (Oreochromis mossambicus). Results indicate that the quality of drunk fish was the best when being salted for 13 h, dried at 50 ℃ for 11 h and vacuumed at 25 ℃ for 6 d in rice wine lees of 0.095 MPa. The total sugar, total acid and amino acid nitrogen of drunk fish with best quality were (596.93±1.6) μg·g^-1, (123.95±15.22) mg·g^-1 and (1.98±0.15)g·kg^-1, respectively, which is better in quality than the products obtained under other conditions.

The paper studies the high voltage electrostatic field combined with modified atmosphere packaging technology effect on tilapia fillets stored at temperature of controlled freezing-point, analyzes and compares the influence of 3.8 kV, 1.8 kV and 0 V high-voltage electrostatic on tilapia meat quality indexes. Changes in sensory, chromatic aberration, total bacterial counts, pH, TVB-N, TBA and drip loss of tilapia fillets were monitored during storage. Results show that high voltage electrostatic field can improve the quality of fish significantly, storing up to 30 d. The sample was good without peculiar smell. High voltage electrostatic field can inhibit the drip loss significantly and inhibit the growth of microbes and volatile base nitrogen effectively, inhibiting fat oxidation in the fish. In general, the effect of 3.8 kV high-voltage electrostatic, which can prolong the shelf life of tilapia fillets to 30 d, was better than that of 1.8 kV on tilapia fillets.

Bordetella bronchiseptica were extracted with methanol-0.1%formic acid water (volume ratio 3:7) under ultrasonication, purified by solid phase extraction column, and blowed with nitrogen gas. Then we used B.bronchiseptica to detect the residues after the concentration of samples. Results show that colistin in the muscle tissue of aquatic products ranged from 0.4 μg·mL^-1 to 2.4 μg·mL^-1, with good linearity between drug concentration logarithm and the diameter of bacteriostatic (R²> 0.990 0). Colistin in muscle was fortified at 0.20 μg·g^-1, 0.40 μg·g^-1 and 0.60 μg·g^-1, and the average recovery was 70.59%~70.59%, while the coefficient of variation was 3.22%~14.01%. The limits of determination were 100 μg·kg^-1 in grass carp and prawn muscles, 75 μg·kg^-1 in turtle and eel muscles, and 125 μg·kg^-1 in crab muscle. The cylinder plate method for determination of colistin residues is good. All minimum detection of drugs meet the national standard of residue limits issued by Ministry of Agriculture of China.

To determine the etiology of Pseudobagrus ussuriensis with skin ulcer, bacteriology was conducted from the edge of ulcer, the spleen and the kidney. Besides, wet mounts from gill, skin mucus and intestinal content were checked to exclude parasites. Pathological characteristics, target organs and visible pathogens were determined by histopathology. The results show that BHI is not a good medium for the first time bacteria isolation and culture from fish. No obvious bacteria were seen on the medium. The target organs were skin and muscle, spleen, head kidney and trunk kidney. All the fish mainly expressed necrotizing ulcerative dermatitis and panniculitis, splenitis and interstitial nephritis. Moreover, mild focal branchitis was also found. No obvious change was obversed in eye, brain, liver, heart, digestive tract and gas bladder. After re-staining the slides with Gimsa, we found long filamentous and hair-like bacteria in muscle tissue. Furthermore, fungal hyphae were also seen in muscle tissue. The etiology of this case was considered a co-infection of bacteria and fungi. The findings support the importance of histopathology in diagnosis.

An experiment was conducted to explore the effect of ingestion and digestion of pearl oyster (Pinctada fucata) on microalgae of different types and concentrations from aspects of particle size, surface structure, biochemical composition and feed concentration. The mixture of Chaetoceros muelleri and Dicrateria zhanjiangensis with similar size and the mixture of Platymonas subcordiformis and Marine chlorella with different sizes were fed to pearl oysters. Cells count was detected in the remaining mixture microalgae. C.muelleri, D.zhanjiangensis, P.subcordiformis and M.chlorella of different concentrations were fed to pearl oyster to compare the digestion of microalgae in feces. The results show that selective feeding was not significantly different (P>0.05) between microalge with similar size, while the ingestion rate raised with increasing size (P < 0.05). The digestion rate decreased with increase of diet concentration.

Pharmaceutical and personal care products (PPCPs), which are ubiquitous in environment, are a series of emerging contaminants presenting potential risks to fishery ecology, aquatic products as well as human health. This paper summarizes the pollution and detection methods of PPCPs in fishery environment and aquatic products as well as introduces the current study on toxicity and risk assessment of PPCPs. In the end, the direction of future research is provided.