Diâmetro do ingrediente e a digestibilidade aparente de rações por duas espécies de peixes tropicais

This research was carried out at the Aquatic Organisms Nutrition Research Laboratory, FMVZ - Unesp - Campus of Botucatu, a unit of Aquaculture Center of Unesp (Universidade Estadual de Sao Paulo) - Brazil. The objective was to evaluate the ingredient diameter influence (0.5; 1.0; 1.5; 2.0 and 2.5 mm), using the apparent digestibility of diets by Nile tilapia, Oreochromis niloticus L. (Perciformes cichlidae) and pacu, Piaractus mesopotamicus (Holmberg) Characiformes, Characidae). The coefficients were determined according to dry matter, crude protein and ether extract. These treatments were analyzed by variance analysis in the factorial design 2 x 5 (two fish species and five diameters). The result showed that there is significant interaction between ingredient diamater and species and that, the most appropriate ingredient diameter to manufacture fish diets is between 1.0 and 2.0 mm to pacu and 1.5 mm to Nile tilapia.