Effect of taurine supplementation on growth, nutrient utilization, antioxidant status, digestive enzyme activity, and metabolic enzyme activity in Striped Catfish <i>Pangasianodon hypophthalmus</i> fed fish-meal- and plant-protein-based diets

ABSTRACT Objective The study contrasts the effects of dietary taurine in plant-based and fish-meal (FM)-based diets for Striped Catfish Pangasianodon hypophthalmus. Methods Four isoproteic (∼300 g/kg crude protein) and isolipidic (∼60 g/kg crude lipid) diets were prepared containing FM without (FMF) and with addition of 15 g taurine per kilogram of feed (FMT) and plant ingredients without (PPF) and with addition of 15 g taurine per kilogram feed (PPT). In total, 16 tubs with 100-L capacity were used and four tubs were allocated under each dietary treatment. Fifteen Striped Catfish (average weight 6.3 ± 0.04 g) were randomly distributed in the tubs and fed twice daily up to satiation for a period of 60 d. Results The fish that were fed with the FMT diet showed significantly higher (P &amp;lt; 0.05) final weight and weight gain among the treatments, followed by FMF and PPT, which exhibited similar final weight and weight gain. Feed conversion ratios for FMF and PPT were alike and significantly (P &amp;lt; 0.05) lower than those for the PPF diet. The whole-body crude protein and ash were higher in the FMT group. The serum parameters such as hemoglobulin, total protein, albumin, and globulin were significantly (P &amp;lt; 0.05) higher in the FMT group, followed by the FMF and PPT diets, which showed similar activity. Taurine supplementation in both FM- and plant-based diets increased antioxidant enzyme activity in fish liver and intestine. The lowest lipid peroxidation activity was observed in the FMT diet. Digestive enzyme levels in the PPT diet were comparable to those with the FMF diet but significantly lower than those with the FMT diet. Taurine-enriched plant diets showed metabolic enzyme activity levels that were similar to those observed in the FM diets. Conclusions The study highlights that the blend of plant ingredients and taurine matches FM-based diets in supporting growth, nutrient utilization, antioxidant and digestive enzyme activity, and metabolic function in pangasius.