Efeitos da restrição alimentar e realimentação sobre características intrínsecas de juvenis de pacu (Piaractus mesopotamicus) cultivados em tanques-rede no Reservatório de Itaipu Binacional

Abstract

This research aimed to evaluate the effect of different feeding strategies, of a restrictive nature, on the zootechnical performance of juveniles of the species Piaractus mesopotamicus, the pacu, cultivated in an intensive system of net-tanks. The experiment lasted a total of 120 days, using 400 specimens of the species with an average weight of 154.0±38.3 g, randomly distributed in 20 net-tanks with a useful volume of 0.8 m3, totalizing 20 fish/tank. The adopted feeding practices were: A (daily feeding); B (food from Monday to Friday); C (feeding on alternate days); D (food Monday, Wednesday and Friday); E (two days of feeding and one day without). Extruded commercial feed (33.9% CP; 3.904 kcal/g) was used, provided in a single daily portion, at a rate calculated as a function of body weight, obtained by biometry. It was observed that fish fed daily (A), on alternate days (C) or fed every two days, followed by one without food (E), showed higher final weight, weight gain, specific growth rate, biomass final, and final length, differing (P<0.05) from the other feeding strategies. However, fish fed on Mondays, Wednesdays and Fridays (D) showed better responses of their intrinsic characteristics related to: (%) HDL (186.55), lipids (5.61) and crude protein (19.33), being more adequate and balanced than the other treatments, including those of group (A). These individuals fit into a higher quality group than the others of their species, as specimens were obtained with a lower percentage of fat than the other proposals in the study and this affects their speed of oxidation and deterioration in the post mortem, thus increasing their shelf life, in addition to making it a less caloric food, which consequently makes it more attractive to the consumer.