Quality Assessment of Frozen Solenocera crassicornis Treated with Sodium Metabisulphite by Soaking or Spraying

The present work was carried out to evaluate the safety of shrimp(Solenocera crassicornis)treated with different concentrations of sodium metabisulfite(SMB)by soaking or spraying during frozen storage.Shrimps soaked in higher concentrations of SMB showed higher sensory scores,lower total color differences,and better anti-melanosis effects than shrimps in the control and other treatment groups throughout frozen storage(−18℃).Lower total volatile basic nitrogen and thiobarbituric acid reactive substances and higher salt soluble protein contents were detected in shrimp soaked with high doses of SMB compared with other samples.In addition,lower counts of total aerobic plates and psychrotrophic bacteria were observed in shrimp treated by soaking with higher doses of SMB than those in control shrimp and shrimp treated with other methods during frozen storage(−18℃).However,the SO2 content of 5%SMB-soaked samples exceeded the maximum allowable limit of 100mgkg−1.Overall,the use of 1.5%SMB soaking to treat shrimp results in good antioxidant and antimicrobial effects and,thus,may be suggested to preserve S.crassicornis under frozen conditions.The results of this study present important guidance on the use of SMB to maintain the quality of marine-trawling shrimp from manufacturing to consumption.

Study on the Release of Grouper Epinephelus for Stock Enhancement

Two methods, tagging and ink injection, are used in the grouper releasing experiment. The studied fishes are the juvenile of Epinephelus akaara and Epinephelus awoara both artificially cultivated and caught from natural waters, and their wild adults. Experimental results show that the inhabiting behaviours for both juvenile and adult fishes show distinct regionality, which move within an area of 2 n mile diameter 651 days and 48 days after being released, respectively. With the tagging method, the tagged fishes could only be recaptured in the year of release while, with the injection method, they could be caught in the 1st, 2nd and 3rd years. It is confirmed that in the cement tank, the tagged fishes lose their 1/3 tags. That means that the tagging method is not fit for the release research while the injection method is. Generally, the recaptured rates of injected fishes are 1.4 ~ 4.5 %, 3.1 ~ 13.4 % and 2.7 % for the 1st, 2nd and 3rd years, respectively.

Genetic identification of two species of Pleuronichthys by DNA barcoding

DNA barcoding is a new method for biological taxonomy, offering the ability to identify species from fragments in any life-history stage. Pleuronichthys cornutus and P. japonicus are two morphologically similar species. Pleuronichthys japonicus has never been found previously in China. However, in this study, we identified both species using DNA barcoding （cytochrome c oxidase subunit I （COI））, the mtDNA control region and cytochrome b. The results reveal that： l） intraspecific variation in the DNA barcode is much less than interspecific variation; 2） the two morphologically similar species were placed into separate clades distinguishable by high bootstrap values; 3） COI barcodes are more powerful for identifying the two species than the other two mtDNA fragments.

Molecular cloning and transcriptional analysis of a NPY receptor-like in common Chinese cuttlefish Sepiella japonica

Neuropeptide Y(NPY) has a pivotal role in the regulation of many physiological processes. In this study, the gene encoding a NPY receptor-like from the common Chinese cuttlefish Sepiella japonica( SjNPYR-like) was identified and characterized. The full-length SjNPYR-like cDNA was cloned containing a 492-bp of 5′ untranslated region(UTR), 1 182 bp open reading frame(ORF) encoding a protein of 393 amino acid residues, and 228 bp of 3′ UTR. The putative protein was predicted to have a molecular weight of 45.54 kDa and an isoelectric point(pI) of 8.13. By informatic analyses, SjNPYR-like was identified as belonging to the class A G protein coupled receptor(GPCR) family(the rhodopsin-type). The amino acid sequence contained 12 potential phosphorylation sites and five predicted N-linked glycosylation sites. Multiple sequence alignment and 3D structure modeling were conducted to clarify SjNPYR bioinformatics characteristics. Phylogenetic analysis identifies it as an NPYR with identity of 33% to Lymnaea stagnalis NPFR. Transmembrane properties of SjNPYR-like were demonstrated in vitro using HEK293 cells and the p EGFP-N1 plasmid. Relative quantifi cation of SjNPYR-like mRNA level confi rmed a high level expression and broad distribution of SjNPYR-like in various tissues of female S. japonica. In addition, the transcriptional profile of SjNPYR-like in the brain, liver, and ovary during gonadal development was analyzed. The results provide basic understanding on the molecular characteristics of SjNPYR-like and its potentially physical functions.

Biochemical Composition and Nutritional Value of the Muscle Tissue of Yellowback Seabream, Evynnis Tumifrons, from the East China Sea

Biochemical composition and nutritional value of muscle tissue of wild-caught yellowback seabream （Evynnis tumifrons） from the East China Sea were determined. The yellowback seabream muscle contained 18.30% crude protein and 0.47% crude lipid. The contents of biochemical, moisture, crude protein, crude lipid, and ash were analyzed using AOAC standard methods. The compositions and contents of amino-acid and fatty-acid were determined by Amino Acid 20 Analyzer and Agilent 6890 Gas Chromatograph. The total essential amino acids （EAA; those required by humans） accounts for 46.96% of the total amino acids in E. tumifrons, higher than FAO/WHO standard but lower than whole-egg protein standard. In E. tumifrons, the first limiting amino acids were threonine （Thr）, based on amino acid score （AAS）, and methionine （Met） and cysteine （Cys）, based on chemical score （CS）. A total of 19 fatty acids were identified; together, eicosapentaenoic acid （EPA） and docosahexaenoic acid （DHA） contributed 22.65% of the total fatty-acid content, with 17.25% from DHA. The nutritional-requirement characteristics of this fish, which tumifrons mariculture. composition data provided useful information on the food quality and may facilitate the development of appropriate feed formulation in E.