EFFECTS OF DIETARY VITAMIN E AND L-CARNOSINE ON GROWTH PERFORMANCE, ANTIOXIDANT STATUS, NON-SPECIFIC IMMUNITY AND SERUM BIOCHEMICAL INDICES IN JUVENILE TURBOT (SCOPHTHALMUS MAXIMUS)

A 2×4 factorial experiment (2 vitamin E×4 L-carnosine) was conducted to investigate the effects of dietary vitamin E (0 and 75 mg/kg) and L-carnosine (0, 50 mg/kg, 100 mg/kg and 200 mg/kg) on growth performance, antio-xidant status, non-specific immunity and serum biochemical indices in juvenile turbot. Eight diets were formulated and randomly allocated into triplicate groups of fishinitial body weight of (14.00±0.02) g in 24 cylindrical tanks (H:80 cm×Φ70 cm, water depth 50 cm) with 46 fish per tank for an 8-weeks trial. Results showed that fish weight gain rate (WGR) and specific growth rate (SGR) were significantly enhanced by dietary vitamin E (P < 0.05) but not by L-carnosine less than 100 mg/kg. However, WGR, SGR and protein efficiency ratio (PER) were depressed whereas feed conversion ratio (FCR) was elevated significantly by 200 mg/kg L-carnosine (P < 0.05). Statistical interactions between vitamin E and L-carnosine were observed in serum glutathione peroxidase (GSH-PX), catalase (CAT) activities, malondialdehyde (MDA) content, liver total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and MDA (P < 0.05). The highest GSH-PX activity was in the group of 50 mg/kg and 100 mg/kg L-carnosine, and the highest CAT activity was in the group of 100 mg/kg and 200 mg/kg L-carnosine and it showed no significant difference in group of 50 mg/kg (P>0.05). Liver T-AOC and SOD activities reached the top by 100 mg/kg L-carnosine and it showed no significant difference by 50 mg/kg L-carnosine (P>0.05) or the 75 mg/kg vitamin E. Main effects analysis show that serum T-AOC, SOD and liver CAT activities were significantly elevated by dietary vitamin E (P < 0.05), serum T-AOC was signifi-cantly elevated by dietary L-carnosine (P < 0.05). Statistical interactions between vitamin E and L-carnosine were observed in serum complement C3 and LZM activities (P < 0.05). Complement C3 reached the highest value in the group of 50 mg/kg L-carnosine and 75 mg/kg vitamin E (P < 0.05). Serum total protein (TP) was not significantly affected by dietary vitamin E and L-carnosine (P>0.05). Serum total cholesterol (TCHO) and triacyglycerol (TG) contents were decreased by vitamin E addition (P < 0.05). Comparatively, TG was reduced by dietary L-carnosine with the lowest level by 50 mg/kg L-carnosine (P < 0.05). These results suggest that 75 mg/kg vitamin E and 50 mg/kg L-carnosine is the best diet formulation (fish oil 70 g/kg, Soy lecithin 10 g/kg).