Dietary supplementation of sodium butyrate may benefit growth performance and intestinal function in juvenile grass carp (Ctenopharyngodon idellus)

A 49-days feeding trial was conducted to study the effects of sodium butyrate on growth performance, gut morphology of juvenile grass carp. Five isoenergetic and isonitrogenous experimental diets were compounded by the supplementation in the basal diet with gradient sodium butyrate at 0, 500, 1000, 2000, 3000mgkg(-1) respectively. A total of 375 juvenile grass carp (with initial body weight of 3.8g) were randomly allocated into five diet treatments, and each treatment has three replicates. The results showed that the specific growth rate (SGR) of SB1000 and SB2000 group was significantly higher (P<0.05) than that of the other groups. Moreover, the lowest SGR was observed in SB3000 group. Feeding rate and the whole-body proximate composition including moisture, crude lipid, crude protein and crude ash were not affected by sodium butyrate (P>0.05). Total superoxide dismutase activities in hepatopancreas in the experimental groups were significantly higher than those in the control group (P<0.05). Glutathione peroxidase activity in hepatopancreas was significantly upregulated by dietary sodium butyrate level (P<0.05). However, the activity of total antioxidant capacity and the contents of malondialdehyde were not significantly different among groups. The expression levels of mRNA encoding PepT1 and LAT2 in the foregut both showed a first increasing and then decreasing tendency as dietary sodium butyrate level increased (P<0.05), and peaked in SB1000 and SB2000 groups respectively. The results indicated that appropriate dietary supplementation of sodium butyrate at 2000mgkg(-1) could improve the growth, antioxidant ability and intestinal absorption capacity of the juvenile grass carp.