Influence of different feed restriction regimes on compensatory response and individual variability in juvenile Brycon amazonicus

In aquaculture systems, feed management represents one of the main production costs. Intermittent feed restriction may reduce feed consumption; however, its effects on growth and stock uniformity should be carefully evaluated. This study investigated the influence of different feed restriction regimes on feed consumption and growth of juvenile Brycon amazonicus. A total of 600 juveniles (initial body weight of 12.2 ± 2.3 g) were randomly distributed among 12 masonry tanks (0.7 m³) with continuous water flow. The control group (CG) was continuously fed for 56 days. The experimental groups were subjected to two feeding regimes during the first 28 days (Phase 1): one day of fasting followed by one day of refeeding (J1R1), and three days of fasting followed by four days of refeeding (J3R4). After this period, fish in the experimental groups were fed daily for an additional 28 days (Phase 2). Throughout the experiment, all fish were fed a commercial diet containing 36% crude protein to apparent satiation. Standard length (SL), total weight (TW), weight coefficient of variation (CVw), and mean individual feed intake (FI) were measured at the end of each phase. The absence of significant differences in the evaluated parameters at 56 days indicates the occurrence of complete compensatory growth. Since no significant increase in feed intake was observed during the refeeding period, the results suggest that growth compensation occurred mainly through improved nutrient utilization efficiency rather than compensatory hyperphagia. In addition, the J1R1 protocol showed a tendency toward greater stock uniformity at the end of the experiment, as evidenced by the lower coefficient of variation in body weight, although this difference was not statistically significant (p > 0.05). Therefore, although the evaluated feed restriction strategy promoted homogeneous compensatory growth in juvenile B. amazonicus, further studies are needed to determine the most appropriate feed restriction protocol, considering its effects on performance, stock uniformity, and fish health.