Assessment of the energy and protein requirements for tambaqui (Colossoma macropomum, Cuvier 1818) using the factorial approach

A factorial modeling approach was used to estimate digestible protein (DP) and digestible energy (DE) requirements of tambaqui ( Colossoma macropomum ) reared under pond culture conditions. The model integrates controlled laboratory experiments on maintenance requirements, nutrient digestibility, and protein and energy retention efficiencies with growth data from commercial pond farms spanning a wide range of body weights. Maintenance requirements were estimated as 0.2765 g DP kg⁻⁰·⁷⁵ day⁻¹ and 10.84 kJ DE kg⁻⁰·⁹⁵ day⁻¹ . Retention efficiencies for protein and energy were 30.82% and 33.47%, respectively, corresponding to deposition costs of 3.24 g DP g⁻¹ protein gain and 3.34 kJ DE kJ⁻¹ energy gain. The model predicts realistic feeding rates, feed intake (% body weight day⁻¹), and feed conversion ratios across growth stages, consistent with values reported for pond-cultured tambaqui under tropical conditions. Although the model tends to overestimate protein requirements at early growth stages, likely due to limitations in estimating protein retention efficiency, it provides coherent and biologically plausible indicators for nutritional management during grow-out. The proposed factorial framework is directly applicable to pond-based tambaqui production under typical tropical conditions and represents a robust decision-support tool for precision feeding and feed formulation, with potential for adaptation to other production systems when system-specific data are available. • Factorial modeling estimated digestible protein and energy requirements for tambaqui ( Colossoma macropomum ). • Retention efficiencies were 30.82% for protein and 33.47% for energy, supporting accurate growth requirement estimates. • Estimated maintenance requirements were 0.2765 g DP kg 0.75 day −1 and 10.84 kJ DE kg 1 .21 day −1 .