Optimizing dietary protein and lipid levels for better growth performance, nutrient retention and flesh quality of grow-out striped catfish (Pangasianodon hypophthalmus).

This study evaluated the effects of dietary protein (DP) and lipid (DL) levels on the growth, nutrient retention, and flesh quality of striped catfish (Pangasianodon hypophthalmus). A 3 × 3 factorial design was used with three protein levels (28%, 30%, 32%) and three lipid levels (4%, 6%, 8%). Nine experimental diets were fed to fish (initial weight 167.91 ± 0.03 g) for 8 weeks. Results showed significant (p < 0.05) effects of DP and DL on growth performance and flesh quality. The DP28/DL4 diet yielded better growth, feed conversion ratio (FCR), and specific growth rate (SGR) while reducing intraperitoneal fat index (IPFI) and oxidative stress markers. Whole-body chemical analysis indicated higher protein retention (16.65 ± 0.04%) and lower lipid deposition (5.39 ± 0.07%) in the DP28/DL4 group. Flesh quality assessments revealed higher water-holding capacity (WHC), pH, and sensory attributes in DP28/DL4-fed fish. In contrast, higher lipid levels (6-8%) led to increased fat accumulation and oxidative instability. These findings highlight the importance of optimizing DP and DL levels for better growth, nutrient efficiency, and fish quality, supporting sustainable aquaculture and improved production efficiency.