Effect of different carbohydrate-to-lipid ratios elicits growth, feed utilization, lipid deposition and lipogenic enzyme activity in striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878) fingerlings

This study evaluated the effects of diets containing various carbohydratetolipid (CHO L1) ratios on growth performance, nutrient utilization body indices and hepatic lipogenic enzyme (malic enzyme, 6phosphogluconate dehydrogenase and fatty acid synthase) activities. Triplicate groups of Pangasianodon hypophthalmus fingerlings were fed eight isoenergetic and isonitrogenous diets with different carbohydratetolipid ratios (0.51, 0.79, 1.12, 1.79, 2.41, 3.24, 4.43 and 7.62). Higher body fat deposition and lower growth performance were observed in P. hypophthalmus fingerlings fed with highlipid diet than those fed with highcarbohydrate diet. The fish fed the diet with 7.62 CHO L1 ratio exhibited significantly (p 0.05) higher hepatosomatic index compared to those fed higher lipid diets (0.51 and 0.79). High dietary carbohydrate level significantly increased (p 0.05) the activities of malic, 6phosphogluconate dehydrogenase and fatty acid synthase enzyme. Based on the secondorder polynomial regression analysis of weight gain, the optimal dietary carbohydrate and lipid contents for P. hypophthalmus fingerling were 304 and 103 g kg minus;1, respectively, which correspond to a dietary CHO L1 ratio of 2.95.