Fattening with Formulated Diets Improves the Immune Response and Lipid Accumulation in the Gonads of Male Chinese Mitten Crab (Eriocheir Sinensis)

Abstract

To improve the yield and quality of Chinese mitten crabs and ensure environmental sustainability, it has become an inevitable trend to replace iced trash fish (Trash) with formulated feeds (Feed) during farming. However, the effect of feeds on fattening male crabs remains unclear. Hence, this experiment aimed to assess the alternative function of feed fattening by a comparative analysis of growth and physiological metabolism. The results suggested no statistical difference in the growth and development of male crabs fattened on the feeds. The diet potentiated the immune response and repressed apoptosis in the gonads during fattening. Cholesterol accumulation and augmented fatty acid catabolism in the gonads were observed in the Feed group. Additionally, feed fattening diminished protein deposition. Metabolomic analysis indicated that feed fattening promoted lysine degradation and purine metabolism in the gonads. A further lipidomic study discovered that feed fattening mostly contributed to the boosting of phosphatidylcholines (PCs) that contain unsaturated fatty acids via the glycerophospholipid pathway compared to the trash fish group. To summarize, the formulated diets effectively substituted trash fish for fattening and were superior in immunological promotion and lipid accumulation, however, the enhanced lysine degradation and purine metabolism may compromise the flavor and quality of the male crab gonads. Our results provide novel perspectives into the formulation design and application of the formulated feeds in the process of fattening.

Keywords: Eriocheir sinensis, Formulated feed fattening, Gonads, Lipid accumulation, Phosphatidylcholine