Effect of dietary lipid level on growth performance, feed utilization and body composition by juvenile red spotted grouper (Epinephelus akaara)

This study was designed to determine the effect of dietary lipid level on growth performance, feed utilization and body composition of juvenile red spotted grouper, Epinephelus akaara. Triplicate groups of 12 fish (IBW = 2.51 g) with three isoenergetic and isonitrogenous experimental diets formulated by increasing lipid levels (5.98, 9.11 and 12.57 %) were fed to satiety for 8 weeks. At the end of the feeding trial, weight gain and specific growth rate were significantly higher for the fish fed diets with 9.11 and 12.57 % compared to the treatment which containing 5.98 % dietary lipid levels. With the increase of dietary lipid levels, feed conversion ratio decreased but protein efficiency ratio increased. As dietary lipid level increased, viscerosomatic index and intraperitoneal fat ratio increased dramatically, while no significant difference in hepatosomatic index was found in this experiment. In conclusion, under the experimental conditions, the increase of dietary lipid level beyond 9.11 % had no further beneficial effects.