Quitosana na alimentação de alevinos de tilapia-do-Nilo (Oreochromis niloticus)

Abstract

This study aimed to evaluate the effects of increasing levels of chitosan derived from shrimp shell by-products in the diet of Nile tilapia (Oreochromis niloticus). A total of 300 fingerlings (initial mean weight 2,55±0,03 g) were randomly distributed into 20 tanks (80 L), with five replicates per treatment. The experiment was conducted over 45 days using a completely randomized design. Four diets were tested: a control diet without chitosan and three experimental diets containing 0,50%, 0,75%, and 1,0% chitosan. The best zootechnical performance was observed with 0,5% and 0,75% chitosan inclusion, with average weight gains of 61.56 g and 60.81 g, respectively, and the most efficient apparent feed conversion ratio (0,87) obtained with the 0,5% chitosan diet. Proximate composition analysis showed increased crude protein and reduced either extract in the 1,0% inclusion diet. Intestinal length and relative intestinal length were also positively influenced by the 0,75% inclusion level. Although some variables did not show significant differences, the inclusion of 0,5% chitosan proved effective, representing a balance between feed efficiency, growth, and carcass composition. These findings indicate its potential applicability in aquaculture to enhance the nutritional value of fish meat.