Effects of dietary vitamin C on growth performance, hematology and muscle physiochemical indexes of juvenile Wuchang bream (〖WTHX〗Megalobrama amblycephala〖WTHZ〗)

Abstract:

A 90 days feeding trial was conducted to estimate the adequate dietary vitamin C (Vc) requirement of juvenile Wuchang bream (Megalobrama amblycephala) and its effect on growth, hematology and muscle physiochemical indexes. 450 healthy fish were selected and randomly divided into six groups for which Vc were supplemented at 0.2 ,33.4,65.8 ,133.7,251.5 and 501.5 mg/kg diet. After 90 days feeding, the growth performance, hematology and muscle physiochemical indexes were investigated. The results showed that the weight gains (WG) and specific growth rate (SGR) had an increasing trend with the increase of dietary vitamin C, the fish in 251.5 mg/kg and 501.5 mg/kg Vc group had significantly higher SGR that in the control group (P<0.05); while the feed coefficient reduced with increasing of dietary Vc, but no significant differences were observed among dietary treatments (P>0.05). The fish body indices were not significantly different among groups, except the viscerosomatic index in fish with 133.7 mg/kg Vc was significantly higher than that of the control group (P<0.05). Compared with the control, the contents of total leukocytes in fish with 65.8-501.5 mg/kg Vc, serum glutamic oxaloacetic transaminase in fish with 65.8 mg/kg Vc and serum glutamic pyruvic transaminase in fish with 133.7 mg/kg and 501.5 mg/kg Vc were significantly reduced (P<0.05). The contents of serum triglycerides in fish with 501.5 mg/kg Vc, superoxide dismutase activities in the muscle in fish with 133.7 mg/kg Vc were significantly improved (P<0.05). Other indices, such as survival rate，erythrocyte, hemoglobin, platelets,albumin and cooking loss of muscle were not significantly different among groups(P>0.05). Based on broken line model analyses in this study, the minimum dietary vitamin C level is 150 mg/kg to get optimal WG.