Effect of supplemental dietary zinc sources on the growth and carbohydrate utilization of tilapia Smith 1840, Oreochromis niloticus × Oreochromis aureus

An 8-week feeding trial was conducted to investigate the effect of supplemental dietary zinc sources on the growth performance and carbohydrate utilization of juvenile tilapia Smith 1840, Oreochromis niloticus × O. aureus. The goal was to compare the bioavailability of two zinc sources, zinc sulphate (ZnSO4) or zinc methionine (ZnMet), by using two practical basal diets with 350 g kg−1 (C350) or 400 g kg−1 (C400) carbohydrates based on wheat as the carbohydrate source. The results showed that fish fed with a diet supplemented with 60 mg kg−1 Zn from either ZnSO4 or ZnMet had a significantly (P < 0.05) greater specific growth rate and protein efficiency ratio than those fed with the diets of ≤30 mg kg−1 Zn. The composition of tilapia carcass was also found to be influenced by various levels of dietary zinc from the two zinc sources. The G6P-DH in fish fed with the 20 mg kg−1 ZnMet diet and the PK levels in fish fed with 20 mg kg−1 ZnSO4 and 30 mg kg−1 ZnMet diet were significantly (P < 0.05) higher than those in fish fed with the C400 diet. The data suggest that supplemental dietary zinc from either ZnMet or ZnSO4 significantly affects the growth performance and carbohydrate utilization of tilapia.