The objective of this study was to evaluate the effects of the inclusion of extruded soybean in diets for piavuçu (Leporinus macrocephalus L.) juveniles with different levels of digestible energy. A hundred fish with initial weight of 5.06 ± 0.61 g were distributed into 20 aquarium (80 L), in a entirely randomized design with five treatments (0.00, 20.00, 35.00, 50.00 and 67.5% full fat soybean in the diets) and four replications. Isonitrogenous, isocalcium, isophosphorus, isoaminoacids for methionine diets with different digestible energy values (3,193; 3,326; 3,413; 3,510 and 3,621 kcal/kg) were given to fish for seventy days. The criteria evaluated were weight gain, length increment, daily feed intake, feed gain, protein efficiency ratio and survival rate. No differences (P>0.05) were observed among treatments regarding the performance criteria. We concluded that the inclusion of full fat soybean in piavuçu juveniles diet is a viable option, and it may partially or totally replace soybean meal, without decreasing performance, while providing greater deposition of fat in the carcass.
alternative feedstuff; digestible energy; fish production; Glycine max L; nutrition