Apparent digestibility of juveniles of matrinxã Brycon amazonicus fed diets with different protein levels

ABSTRACT. The objective of the present study was to determine the apparent digestibility of juveniles of matrinxa Brycon amazonicus fed diets with different levels of protein. The experimental design was completely randomized, where the treatments consisted of four levels of protein in the diets (28, 32, 36 and 40%) and five replicates (water boxes) with 10 juveniles of matrinxa each. Diets were offered four times a day, and feces were collected twice a week, along 28 days, for digestibility analysis. Data collected were subjected to polynomial regression at 5% significance. Differences (p 0.05) in the digestibility of % ether extract. Digestibility of N, P, Ca, Mg, Cu and Zn presented linear positive (p < 0.05) behavior, in which the use of these minerals increased with the increase in the level of protein in the diets. However, the digestibility of K, Fe and Mn reduced (p < 0.05) with increasing protein levels in the diets. Thus, it can be concluded that the rise in protein level in diets for juveniles of matrinxa improves nutrient digestibility. The results of this study indicated that 40% crude protein in the diets provided better results.