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 matrinxã 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 matrinxã 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) were observed in dry matter digestibility, with higher digestibility according to increasing levels of protein in the diets. This behavior was directly expressed in the digestibility of nutrients by juveniles of matrinxã, such as % ash, % crude protein, apparent digestible energy, % digestibility of apparent digestible energy and energy: protein ratio. However, this was not observed (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 matrinxã improves nutrient digestibility. The results of this study indicated that 40% crude protein in the diets provided better results.