Effect of dietary vitamin E on growth, fecundity, and leukocyte count in goldfish (carassius auratus)

Abstract

The effects of different levels of dietary vitamin E (0, 100, 200, 300, and 600 mg/kg diet) on growth, gonad weight, fecundity, and leukocyte count were studied in goldfish (Carassius auratus) for 120 days. Fish fed the 300 mg vitamin E/kg diet had the best feeding rate, weight gain, and specific growth rate. Fish fed the control diet lacking vitamin E began to develop gonads on day 60 and spawned only once, while those fed diets containing vitamin E began to develop gonads on day 40 and spawned twice. Females fed the 300 mg vitamin E/kg diet had significantly (p<0.01) heavier gonads and a higher number of eggs with better hatchability than those fed other diets. The second spawn was significantly (p<0.01) more prolific than the first in all groups. Egg weight and diameter and larvae weight and length were significantly (P<0.05) higher in fish fed 300 mg vitamin E than in fish fed the control diet but did not differ from other vitamin E treatments. Lymphocyte and monocyte populations were highest in fish fed 300 mg vitamin E. Thus, 300 mg vitamin E/kg diet is the optimum level for improving reproduction and immune response in C. auratus. The probable mechanism for the action of vitamin E on growth and reproduction is discussed.