Vitamin E Deficiency could Increase the Optimum Dietary Vitamin C Requirement in Juvenile Olive Flounder, Paralichthys olivaceus

A 12-week feeding trial was conducted to evaluate the effects of deficiency of vitamin E (αtocopherol) on the optimal vitamin C (L-ascorbic acid, AA) requirement in diets for juvenile Olive flounder (Paralichthys olivaceus). Ten diets were formulated to contain two dietary vitamin E levels of 0 (E₀) and 200 (E₂₀₀) mg dl-tocopheryl acetate (TA) and five graded levels (0, 100, 300, 1000 and 3000 mg/kg diet) of AA in the form of L-ascorbyl-2-monophosphate (AMP). Fish averaging 4.81±0.06 g (mean ±SD) were distributed randomly to each aquarium as a group of 25 fishes. Increasing vitamin C levels from 0 to 100 mg/kg diets had significantly improved survival, weight gain and feed efficiency of fish, being particularly evident with vitamin E deficient diet (E₀). Broken-line regression analysis indicated that the optimum dietary vitamin C level could be 114.99 mg ascorbic acid (AA)/kg diet in vitamin E deficiency diets (E₀) and of 92.16 mg AA/kg diet in vitamin E supplemented diets (E₂₀₀). The results indicated that vitamin E deficiency could increase the optimum dietary vitamin C level in juvenile Olive flounder.