Effects of dietary carbohydrate/lipid ratios on growth, body composition, and nutrient utilization of hybrid catfish (Pseudoplatystoma reticulatum x Leiarius marmoratus)

Background: farming of hybrid catfish is relatively recent in Brazil; consequently, it is necessary to develop practical diet formulations for this fish. Objective: to evaluate the influence of different carbohydrate/lipid ratios (CHO:L) on growth performance, body composition and nutrient utilization of hybrid catfish (Pseudoplatystoma reticulatum x Leiarius marmoratus). Methods: four isonitrogenous diets were formulated with increasing lipid levels, using the following CHO:L ratios: 1.3:1 (diet 1); 1.1:1 (diet 2); 0.9:1 (diet 3), and 0.8:1 (diet 4). Fish were fed 5% of BW/day (dry-weight basis) in triplicate groups of 6 fish each (18 ± 1.5 g) for 2 months. Results: though final weight and absolute weight gain decreased with increasing dietary lipid (p0.05). Moreover, viscerosomatic index and hepatosomatic index showed no statistical difference among dietary treatments. Body lipid increase for fish fed diet 4. Lipid and energy efficiency retentions were higher at 0.8:1 CHO:L group. Conclusion: CHO:L ratios around 1.3:1 produced large benefit by best growth performance in the studied hybrid model