Effects of different supplemental levels of dietary vitamin C on growth performance and antioxidant enzyme activity of Megalobrama terminalis larvae

WANG Xu; WANG Dongxue; LUO Yongcheng; LI Juan; QIN Wenjie

doi:10.13557/j.cnki.issn1002-2813.2025.02.015

Abstract：The study aimed to investigate the effects of different levels of vitamin C(VC)supplementation in feed on the growth performance and antioxidant enzyme activities of Megalobrama terminalis larvae.A total of 300 healthy,disease-free Megalobrama terminalis larvae with an initial weight of(6.0±1.5)g were selected and randomly divided into five groups,with three replicates per group and 20 fish per replicate.The control group was fed a basal diet,while groups C1,C2,C3,and C4 were fed diets supplemented with 200,400,800,and 1 600 mg/kg VC magnesium phosphate,respectively.The pre-trial period lasted for 10 days,followed by a formal trial period of 50 days.The results showed that the survival rates of all experimental groups was significantly higher than that of the control group(P＜0.05),with groups C2,C3,and C4 showing significantly higher survival rates than group C1(P＜0.05).The VC content in the fish tissues of all experimental groups was significantly higher than that of the control group(P＜0.05),with groups C3 and C4 having significantly higher VC content than the other groups(P＜0.05).The activities of catalase(CAT),total superoxide dismutase(T-SOD),and glutathione(GSH)in the hepatopancreas and muscle of the fish in all experimental groups were significantly higher than those in the control group(P＜0.05),while the malondialdehyde(MDA)content was significantly lower(P＜0.05),with group C3 having the lowest MDA content.The activities of alkaline phosphatase(AKP)and acid phosphatase(ACP)in the hepatopancreas and muscle of groups C2,C3,and C4 were significantly higher than those in the control group(P＜0.05).Based on regression equations,the optimal levels of VC supplementation in feed for maximizing T-SOD and CAT activities and minimizing MDA content were calculated to be 1 228.50,721.67,and 1 033.33 mg/kg,respectively.The study indicates that considering the survival rates and regression analysis,the recommended level of VC supplementation in the feed for Megalobrama terminalis larvae is 678～1 456 mg/kg.