Abstract

ONO, Eduardo Akifumi et al. Apparent digestibility coefficient of practical diets with different energy: protein ratios for pirarucu juveniles. Pesq. agropec. bras. [online]. 2008, vol.43, n.2, pp. 249-254. ISSN 0100-204X.  http://dx.doi.org/10.1590/S0100-204X2008000200014.

The objective of this work was to determine the apparent digestibility of nutrients and energy of diets for pirarucu (Arapaima gigas) juveniles. Eight experimental diets containing four energy:protein ratios (11, 10.1, 9, 8 kcal digestible energy per gram of crude protein) and two non-protein energy sources (soybean oil and poultry fat) were tested in a 4x2 factorial scheme, in triplicates. Two hundred and forty pirarucu juveniles weighting 96.8±2.3 g were distributed in 24 cylindrical-conical fiberglass tanks, adapted for feces collection (modified Guelph system). Fish were fed twice a day to apparent satiation, with experimental diets containing 0.5% of chromium oxide as inert marker in order to determine the apparent digestibility coefficients. Diets containing an energy:protein ratio of 9 kcal digestible energy per gram of crude protein resulted in significantly lower apparent digestibility coefficient for dry matter, crude protein and non-nitrogenous extract. The highest apparent digestibility coefficients for crude fat was obtained with soybean oil. The dietary energy:protein ratio influences the nutrient and energy apparent digestibility coefficients to pirarucu juveniles.

Keywords : Arapaima gigas; crude energy; fish nutrition; proteins.