The growth of aquaculture production is due to the intensification of routine practices, including the increase in food supply, which can have negative consequences for fish and the environment. Restriction and refeeding cycles thus become an important protocol, since during fasting, fish reduce energy use and prioritize maintenance mechanisms and during refeeding they activate compensatory mechanisms, leading to compensatory weight gain. This study evaluated the performance (weight gain/GP and feed conversion/CA) of pacu (P. mesopotamicus) with alternating food restriction and refeeding, using controlled food supply or until satiety.
240 fish (45.67 ± 12.94g) were subjected to cycles of 3 days of restriction and two days of refeeding (3r2rf) for 30 days or 21 days of restriction (r) followed by 9 days of refeeding, fed at 3% of live weight [3r2rf (3%), r (3%)] or until apparent satiety [3r2rf (AL), r (AL)]. Two groups of fish were fed daily, one with a controlled supply [fd (3%)] and the other to satiety [fd (AL)]. At the end, feed consumption was calculated and the fish were weighed for weight (WG) and feed conversion (FC) calculations.
At 21 days, GP was higher in fd fish (3%) compared to 3r2rf fish (3%), r fish (3%) and fd fish (AL). At 30 days, GP was higher in fd fish than in 3r2ra fish, which did not differ from fish fed for 9 days (r). Re-feeding made the GP of r fish (3% and AL) equal to the GP of 3r2fr fish, especially in fish fed 3% (p<0.0001).
At 21 days, feed conversion (FC) differed between feed offerings (3% of body weight and to satiety) in ad fish (p<0.0001) and the profile was similar in 3r2ra fish.
Compensatory growth was partial, probably due to the short feedback time (9 days), but the compensatory process was taking place. In the compensatory process, the organism allocates the available energy to stabilize vital survival processes. The results showed that food restriction modulated energy reserves during the 21 days of food restriction, and after 9 days of refeeding it promoted compensatory growth and the recovery of energy reserves.