Compensatory growth of fingerlings of pacú (Piaractus mesopotamicus Holmberg, 1887) in severals systems of feeding

Abstract

Compensatory growth of young fishes of pacu (Piaractus mesopotamicus) was evaluated through four cycles of "no-feeding/re-feeding†(NA/RA). The experimental test was made with three groups of fishes having initial average weights of 0.19, 0.54 and 2.11 g, which were considered as blocks. Two experimental treatments versus a control were compared with cycles of: 2 days NA/3 days RA (treatment A); 3 days NA/2 days RA (treatment B) and Continuous feed (control). Differences for the average weight throughout all the experiment were not observed. The General Specific Growth Rate showed significant differences: treatment B produced a growth smaller than that of the control. The analysis by cycles allowed detecting that the control presented greater growth than both experimental treatments in the second cycle and, respect to treatment B, in the fourth cycle; differences between blocks were evident only in both first cycles in favor of the fish of greater size. The Protein Efficiency Rate did not show differences when it was analyzed in general form; nevertheless, it could be observed that in the second period, treatment B was minor respect to the control. The effect of blocks showed a similar result to those obtained for the Specific Growth Rate. The results suggest the existence of compensatory response in young fishes of pacu and that the size affects the performance of these fishes during the compensation stage.