Effects of Dietary Vitamin A on Growth Performance, Blood Biochemical Indices and Body Composition of Juvenile Grass Carp (Ctenopharyngodon Idellus)

A 12-week growth study was conducted to investigate the effects of dietary vitamin A (VA) on growth performance, blood biochemical indices and body composition of grass carp. Six isonitrogenous and isoenergetic semi-purified diets were compounded with different VA level at 68, 328, 599, 1327, 2584 and 4769 IU/kg diet, respectively. The specific growth rate (SGR) increased significantly (P<0.05) with dietary VA level, and the highest SGR value was at 4769 IU/kg group. However, the feed conversion ratio (FCR), feeding rate (FR) and survival rate (SR) of juvenile grass carp were not significantly affected by dietary VA level (P>0.05). As the VA level increased, hepatosomatic index (HSI) increased significantly, peaked at the 1327 IU/kg group (P<0.05), and then showed a decreasing trend. Serum superoxide dismutase (SOD) activity in the control group was significantly lower than those in other groups and then increased with dietary VA level. Whereas, serum alkaline phosphatase (ALP) activity first increased and then decreased with dietary VA level, reaching the highest point at 1327 IU/kg group. No significant difference was observed on the whole body composition among treatments (P>0.05). In conclusion, appropriate dietary vitamin A supplementation could be helpful for the growth and antioxidant capacity of grass carp.