Impacts of different feeding modes on the gonadal development, total edible yield, and nutritional composition of male Chinese mitten crab (Eriocheir sinensis)

This study analyzed the tissue indices,proximate composition,fatty acid and amino acid composition of edible tissues of male E.sinensis under three feeding modes(formulated diets(FD),natural diets(ND),and traditional diets(TD)).The results showed that different feeding modes had no impacts on the overall gonadal development,as no significant difference was found in gonadsomatic index among three treatments.For edible yield,three modes all had similar levels of the meat yield,hepatosomatic index,and total edible yield.Although different feeding modes did not affect the individual edible yield and gonadal development,significant differences were detected in the nutritional composition of males from three modes.For proximate composition,significant differences were found in the total lipids of gonads and the carbohydrate of hepatopancreas and meat.For fatty acids,crabs from ND had a higher proportion of monounsaturated fatty acids.In gonads and hepatopancreas,FD had a higher proportion of long-chain polyunsaturated fatty acids.For amino acids,FD had higher amino acid contents,while ND had the lowest.Except tryptophan,the essential amino acids scores of the meat were all greater than 100.As there was no significant difference on meat quality and meat yields between three feeding modes,this study suggests that the formulated diet could replace the natural diet and traditional diet towards sustainable crab farming in future.

Hemocytes transcriptome profile of the Chinese mitten crab(Eriocheir sinensis)

The Chinese mitten crab(Eriocheir sinensis)possesses an open circulatory system,in which hemolymph moves through interconnected sinuses or spaces surrounding organs called hemocoels.The hemocytes are classified into hyalinocytes,semigranulocytes,and granulocytes;and limited transcriptomics research is available.In this study,the transcriptome of the crab E.sinensis hemocytes was characterized.A total of 14,380,229 clean reads representing a total of 4.31 Gb nucleotides dataset were produced.A total of 67,047 contigs were obtained and 12.49%(8375)and 9.74%(6533)of the contigs were matched to data publicly available from the GenBank nr nucleotide and Uniprot databases,respectively.Among these contigs,4344 contigs belong to three categories of Gene Ontology,126 contigs to 21 subcategories of KEGG,and 4962 contigs to 25 categories of the COG database.A total of 508,379 and 345 transcripts of the E.sinensis showed>40%sequence similarity with transcripts expressed in the vertebrate blood cells from tilapia(Oreochromis niloticus),Chinese softshell turtle(Trionyx sinensis)and chicken(Gallus gallus)respectively.A total of 53,077 single nucleotide polymorphisms were identified and 9912 SSRs for microsatellite mining were found.The most frequent repeat motifs detected were dinucleotide repeats,accounting for 37.52%of the total repeats.Our data provides an important gene resource for the exploitation of molecular marker-assisted breeding,immune mechanisms and conservation of germplasm in the crab E.sinensis.