Growth, Yield, and Feed Utilization Responses of Pangasius (Pangasius bocourti) Fingerlings to Different Dietary Lipid Levels

Understanding the nutrient requirements of farmed fish species is crucial for formulating a well-balanced diet, especially considering that feed represents a significant portion of aquaculture production costs. Lipids, in particular, are an important source of energy. Thus, this study aimed to determine the optimal dietary lipid level for Pangasius bocourti. Three isonitrogenous diets were formulated using protein sources to provide 30% protein, with lipid levels set at 5, 7, and 9%. A total of 315 fingerlings, with an average weight of 1.75g, were used in the experiment. The fish were randomly distributed across nine tanks, with each tank housing 35 fish and three replicates per dietary treatment. The feeding trial lasted for 75 days. At the end of the experiment, final body weight (FBW), daily weight gain (DWG), weight gain (WG), specific growth rate (SGR), relative body weight gain (RBW), final biomass (FBM), and net yield (NY) were all higher in the group fed the 9% lipid diet, although these differences were not statistically significant (P> 0.05). In contrast, feed conversion ratio (FCR), protein efficiency ratio (PER), and feed efficiency (FE) showed significant improvements (P< 0.05) in the group receiving the 9% lipid diet. No significant differences were observed in the moisture, protein, or ash content of the fish bodies, except for ether extract, which increased with higher dietary lipid levels. These findings suggest that a diet containing 9% lipids is optimal for enhancing growth performance and net yield in Pangasius bocourti.