Dietary vitamin E enhances the growth, and immunity of snubnose pompano Trachinotus blochii juveniles

Abstract

Vitamin E is the most powerful antioxidant which prevents unsaturated fatty acid from oxidation and protects cell structure. The effects of vitamin E on the growth, body composition and innate immune response of snubnose pompano juveniles (Trachinotus blochii ) were assessed after ten weeks of feeding with dietary. Juveniles (360 individuals, mean initial weight 5.22 ± 0.28 g) were arbitrarily assigned equally into eighteen 200 L circular composite tanks and fed with one of six practical diets containing six levels of 2.31 (basal diet); 117.25; 189.03; 382.1; 758.54; 1,437.32 mg α-tocopherol acetate/kg. The results showed that final weight, weight gain, specific growth rate, protein efficiency ratio, hepatosomatic index, viscerosomatic index, ash, protein, lipid, hemoglobin (Hb), hematocrit (Hct), white blood cell count (WBCs) and lysozyme activity in fish fed with vitamin E supplement were considerably higher than those fed the vitamin E-free diet. Besides, feed conversion ratio and moisture in fish fed the basal diet were also higher than those fed the supplemented vitamin E diet. However, survival and red blood cell counts did not statistically differ among the experimental treatments. The results suggest that the suitable dietary vitamin E level for growth, composition and Hb, %Hct of this species were 117.25–189.03 mg/kg vitamin E supplementation, while dietary vitamin E concentration 382.1 mg/kg could be required to increase lysozyme activity and WBC numbers.