Physiological responses associated with compensatory growth of Colossoma macropomum submitted to different feeding rates

Abstract

Colossoma macropomum, popularly known as tambaqui, is the most commercially cultivated native species in South America. Our study aimed to evaluate a series of endpoints related to growth response and physiological parameters in C. macropomum juveniles submitted to different feeding rates (FR) and subsequent refeeding. Fish were fed at five different FR (2%, 4%, 6%, 8%, and 10% of body weight per day) for 30 days (restricted feeding phase) and then refed until apparent satiation for another 30 days (refeeding phase). Growth parameters increased with increasing FR. The FR for maximum growth was estimated to be 8.98% day −1. The reduction in FR negatively affected the activity of digestive enzymes, intestinal histomorphometry, proximal composition, plasma metabolites, and antioxidant capacity. However, after refeeding, these physiological variables were mostly restored. Our results indicate that a FR of 6% day−1 provided the best growth and feed conversion, while the full compensatory growth was achieved at 4% day−1 after refeeding. Collectively, our data suggest that a FR of 2% day−1 can trigger the catabolism of endogenous reserves, an impeding factor for compensatory growth.