The aim of this study was to evaluate the requirement of crude protein (CP) and digestible energy (DE) in piavuçu fingerlings (Leporinus macrocephalus), for a period of 45 days. It was used 150 fingerlings with average weight of 0.40 ± 0.08g, distributed in 30 aquariums (30L) in a completely randomized design in a 3x 2 two-factorial scheme composed of three levels of crude protein (25, 30 and 35% of crude protein) and two levels of digestible energy (3,250 and 3,500 kcal of DE/kg), totaling six diets and five replicates. The rations were given four times a day. Weight gain linearly increased while feed conversion decreased, also in a linear fashion, according to crude protein levels. Digestible energy only influenced weight gain whose best result was observed on animals fed diets containing 3,500 kcal digestyble energy. Feed conversion was not affected by levels of digestible energy. A significant interaction occurred among CP and DE levels for body composition in moisture, protein and lipids. Levels of 35% of CP and 3,500 kcal of DE provide better zootechnical results without affecting chemical composition of carcass of piavuçu fingerlings, so the suggested energy:protein ratio is 10 kcal/g CP.
fish nutrition; larval rearing; native fish; nutritional requirement
