Growth performance and feed utilization of keureling (Tor tambra) fingerlings fed a formulated diet with different doses of vitamin E (alpha-tocopherol)

The objective of the present study was to determine the optimum dosage of vitamin E (alpha-tocopherol) in the diet of keureling, Tor tambra (Val.) fingerlings for optimal growth performance and feed utilization. Five doses of vitamin E were tested: 0 mg kg⁻¹ feed (control); 150 mg kg⁻¹ feed; 300 mg kg⁻¹ feed; 450 mg kg⁻¹ feed; 600 mg kg⁻¹. The feed ratio was 5% body weight, which was delivered twice daily at 08:00 and 17:00 for 60 days. The results showed that higher growth performance, feeding conversion ratios, feed efficiency, protein retention, and protein digestibility were obtained at 600 mg kg⁻¹ feed, but the value was not significantly different from the other doses. The optimal dose in terms of the hepatosomatic index and survival rate was 300 mg kg⁻¹. Hence, it was concluded that the optimum, most economical dose of vitamin E supplement for keureling (T. tambra) was 150 mg kg⁻¹ feed, because this value was not significantly different from the doses of 300 and 600 mg kg⁻¹ feed.