Effect of dietary carbohydrate level on growth performance and body composition of juvenile Amphiprion ocellaris

To investigate the effect of different carbohydrate (CHO) levels in diets on the growth performance, feed efficiency and body composition of juvenile Amphiprion ocellaris, we fed the fish with 4.4%, 8.4%, 12.2%, 16.1%, 20.5%, 24.5% and 28.4% CHO.The results show that the weight gain (WG) and special growth ratio (SGR) increased first and then decreased with increasing carbohydrate level.The regression analysis shows that the WG and SGR reached the maximum when CHO levels were 16.49% and 16.73%, respectively.Moreover, with increasing carbohydrate level, the feed coefficient (FCR) increased first and then showed a declining trend, while the trends of efficiency of protein (PER), protein retention ratio (PRR) and lipid retention ratio (LRR) were just the opposite.The regression analysis shows that the minimum FCR was at 9.20% CHO level; the maximum PER was at 8.57% CHO level; the maximum PRR was at 10.97% CHO level; and the maximum LRR was at 14.12% CHO level.The whole body fish crude fat content increased with increasing CHO levels first, and then decreased slightly after reaching the maximum value at 20.5% CHO level.Based on the second order polynomial regression analysis of growth parameter and CHO level, 16.49%~16.73% dietary CHO level provided the maximum growth of juvenile A.ocellaris.Based on the second order polynomial regression analysis of feed efficiency parameters and CHO level, 8.57%~14.12% dietary CHO level provided the maximum feed efficiency for juvenile A.ocellaris.