Effects of varying dietary energy levels on growth performance and wholebody composition in Gattan

Study was conducted to investigate the effects of various energy levels on growth performance, food conversion ratio (FCR) and whole body composition in Gattan, Barbus xanthopterus fingerlings (12.12±0.28 g) for 8 week. Feeding trial was conducted using 3 semipurfied diets containing 3 levels of digestible energy (DE 2.5, 3 and 3.5 kcal/g) and same protein level 35%, in a flow-through system (1L/min) at 26.2 ± 0.460C. Triplicate groups of 15 fish (12.12±0.22 g) each, were stocked in 300-L circular polyethylene tanks and fish were fed to satiety thrice daily throughout the feeding trial. The best of total weight gain (146.67 g), FCR (2.21), protein efficiency ratio (1.31), apparent net protein utilization (ANPU%) (34.69) and condition factor (CF) (1.26) were observed in diet containing 3 kcal/g DE. The viscerosomatic index (VSI) and hepatosomatic index (HSI) did not show any significant difference between treatments (P>0.05). The final whole body moisture content decreased significantly with increasing energy levels in diets (P<0.05). Although whole body lipid and protein contents did not show significant variation among treatments (P>0.05), but the highest lipid and protein deposition were observed in diets containing 3.5 and 3kcal/g DE, respectively. Comparison between varying levels of dietary energy on the growth, feed utilization and whole body composition of Gattan indicated that 3 kcal g-1 DE could be the preferential dietary energy levels in fingerlings of this species.