The effects of different dietary carbohydrate inclusion levels on the growth performance of tambatinga (Colossoma macropomum × Piaractus brachypomus)

The optimization of feeding management is crucial for improving growth performance, as it directly influences growth rates and the economic viability of aquaculture systems. Carbohydrates (CHO) represent a low-cost source of energy and are therefore essential nutrients in the formulation of commercial diets for fish. This study aimed to evaluate the effects of including different CHO levels in the diet of tambatinga (Colossoma macropomum × Piaractus brachypomus), an omnivorous fish, on growth performance and metabolic responses. Five diets were formulated with graded CHO levels (230, 260, 290, 320, and 350 g kg⁻¹) and fed to fish (initial weight: ~10.00 g) distributed in 15 1,000-L tanks (triplicate groups; n = 8 fish per tank) to apparent satiety for 45 days. Data were analyzed using analysis of variance (ANOVA) and linear and quadratic regression analyses, with statistical significance set at p < 0.05. Diets containing 230 and 260 g kg⁻¹ of CHO resulted in greater weight gain, higher specific growth rate, and lower feed conversion ratio compared with the other dietary treatments. Plasma cholesterol levels showed that lower dietary CHO levels resulted in higher concentrations. No significant differences were observed in plasma glucose, triglyceride, total protein, or albumin levels. Overall, the inclusion level of 230 g kg⁻¹ demonstrated considerable potential as the optimal dietary carbohydrate requirement for tambatinga by promoting superior growth performance and supporting metabolic regulation.