Effects of dietary vitamin E levels on growth and nonspecific immunity of red drum Sciaenops ocellatus

Abstract:

A single factor experiment was conducted to study the effects of dietary vitamin E on growth（feed efficiency ratio（FER），specific growth rate（SGR） and survival rate（SR））and nonspecific immunity（lysozyme activity，total complement activity and superoxide dismutase（SOD） activity） of red drum Sciaenops ocellatus L.， Five iso nitrogenous and iso energetic diets at levels of 0.1，25.3，51.0，102.8 and 203.2mg/kg vitamin E were fed twice a day（07∶30 and 16∶30）. Triplicated groups of 20 fish at initial body weight of about 151g were fed with the diets in the levels for 8 weeks. The experiment was done in floating net cages（1.5 m×1.0 m×1.0 m）. Results indicated that the feed efficiency ratio，specific growth rate and survival rate increased significantly with the increase of vitamin E supplement level in diet after 8 weeks of the feeding trial，the optimal vitamin E for growth of red drum was about 102.8mg/kg；the lysozyme activity and total complement activity of serum in red drum increased significantly with the increase of vitamin E supplement level in diet，and the red drum had the maximal level of lysozyme activity and total complement activity when fed by 102.8 and 25.3 mg/kg VE ，then the change of lysozyme and total complement activity were not significant；the SOD activity of serum in red drum increased significantly with the increase of vitamin E supplement level in diet，and the red drum had the maximal level of SOD activity when fed by 102.8mg/kg VE then decreased significantly.Ingeneral，it was showed that the optimal vitamin E for red drum growth was about 102.8mg/kg.