Effect of dietary glutathione supplementation on the biological value of rapeseed meal to juvenile grass carp, Ctenopharyngodon idellus

An 8‐week feeding trial was conducted to investigate the effects of dietary rapeseed meal (RM) and glutathione supplementation (400 mg kg−1) on growth and intestinal microbiota of grass carp (Ctenopharyngodon idellus). Dietary 450 g kg−1 RM decreased growth and feed intake, while increased the activities of serum alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine transaminase (ALT). The hepatic damages were also observed the significant lower condition factor (CF), hepatosomatic index (HSI) and the symbol of parenchymal damage. Glutathione supplementation increased weight gain and feed intake while significantly decreased the three serum biochemistry parameters compared with the RM group. In addition, HSI, CF and pathology reports revealed that glutathione supplementation alleviated the damage caused by RM on the fish liver. In addition, glutathione had a positive effect on the intestinal digestive capacity. PCR‐denaturing gradient gel electrophoresis (DGGE) analysis indicated a higher similarity between dietary glutathione supplementation and control group. In conclusion, we demonstrated dietary 450 g kg−1 rapeseed meal lead to negative health outcomes, while glutathione supplementation neutralize the adverse effect of rapeseed meal presented in aqua feed through alleviating the damage factors on the fish liver.