Effects of different dietary lipid sources in the diet for Pangasius hypophthalmus (Sauvage, 1878) juvenile on growth performance, nutrient utilization, body indices and muscle and liver fatty acid composition

Abstract

Four isonitrogenous (300 g kg−1 crude protein), isoenergetic (21 kJ g−1) experimental diets were formulated to contain fish oil (FO), soybean oil (SBO), crude palm oil (CPO) and linseed oil (LO), respectively, as lipid sources each at inclusion level of 120 g kg−1 and fed to triplicate groups of 15 juvenile iridescent shark, Pangasius hypophthalmus (Sauvage, 1878) (mean weight 10.00 ± 0.70 g) to apparent satiation twice daily for 12 weeks. The results showed that survival of fish was consistently over 95% for all treatments whereas growth performance in the SBO and CPO treatments was similar and significantly (P < 0.05) higher than for fish fed the LO diet. However, fish fed all vegetable oil-based diets performed better than those fed the FO diet. Muscle and liver fatty acid composition for all treatments generally reflected the composition in the diet and the ratio of n-3/n-6 was found to play an important role in P. hypophthalmus, suggesting that excessive amounts of n-3 fatty acids reduce the overall growth performance. Results of this study thus suggests that P. hypophthalmus fed diets containing vegetable oils (especially CPO and SBO) produce better growth than those fed FO diet without showing any signs of nutrient deficiency.