LAUSR

Abstract The effects of dietary vitamin A level on the growth performance, immunity, oxidation resistance and lipid metabolism of juvenile Chinese mitten crab Eriocheir sinensis (0.84 ± 0.00 g) were determined in the present study. Six group of crabs (four replicate tanks per group with 40 crabs per tank) were respectively fed with 0 (control), 2322, 4511, 8478, 14,333 and 30,444 IU/kg dietary vitamin A for 8 weeks. The weight gain (WG) and specific growth rate (SGR) of juvenile crabs significantly increased in dietary vitamin A supplement groups compared with the control. Dietary vitamin A supplementation increased immunity and antioxidant capacity, hepatopancreas health and alleviated lipid peroxidation in the hepatopancreas of crabs. Moreover, total lipid content in the whole body and hepatopancreas, and triglyceride (TG) content in the hepatopancreas and serum of crabs showed a decreasing tendency with increasing inclusion of vitamin A. The hepatosomatic index (HSI) was lowest in crabs fed 30,444 IU/kg dietary vitamin A. Interestingly, the transcriptome sequencing data showed that the expression of genes related to immunity, antioxidant capacity, lipolysis and β-oxidation was up-regulated. In contrast, the expression of genes related to lipid synthesis was down-regulated in crabs fed 30,444 IU/kg dietary vitamin A compared with the control. This study indicates that dietary vitamin A requirement for E. sinensis is 5340 for WG and 5540 IU/kg for SGR based on the broken-line model.