Crescimento compensatório de alevinos de tilápia do Nilo (Oreochromis niloticus) submetidos a restrição alimentar e realimentação

Abstract

This study aimed to evaluate the effect of different starvation and re-feeding periods on compensatory growth in juvenile Nile Tilapia (Oreochromis niloticus). A total of 108 juvenile Nile tilapia were randomly distributed to 12 tanks with capacity of 15 L each, maintained in a recirculating water system. The experiment lasted 55 days and was conducted in a completely randomized experimental design with four replications. The experimental treatments consisted of: Control: fish were fed to apparent satiation throughout the experimental period; Starvation 10: fish were fed to apparent satiation for the first 15 days, followed by 10 days of starvation and re-feeding to apparent satiation for 30 days; and Starvation 15: fish were fed to the satiation for the first 15 days, followed by 15 days of starvation and re-feeding to apparent satiation for 25 days. Animal performance was evaluated through determination of feed intake, total length, individual body weight, specific growth rate, survival rate, condition factor and muscle growth. Water quality parameters, including pH, dissolved oxygen and electric conductivity remained within values considered to favor fish development. Unsatisfactory performance results were reported in fish submitted to 15 days of starvation (treatment starvation 15 - P<0,05). Feeding strategies with cycles of restriction and re-feeding have been used to promote compensatory growth performance in fish. However, in this study, positive results for compensatory growth performance were reported only in fish submitted to 10 days of starvation followed by 30 days of re-feeding (treatment Starvation 10). Growth of muscle fibers with diameter smaller than 20 µm was directly impacted (P<0,05) by feed restriction. Fish submitted to starvation for 15 days (treatment starvation 15) had the lower frequency on muscle fibers with diameter smaller than 20 µm. In conclusion, feeding restriction in the juvenile phase is compensated by at least 30 days of re feeding after the starvation period.