Effects of three feeding strategies (self-feeders, automatic feeding and apparent satiety) on growth performance, haematological parameters, waste excretion and feed cost in Amazonian fish (Colossoma macropomum)

Abstract

A 127-day experiment was conducted to evaluate the effect of feeding strategies on juvenile tambaqui's (Colossoma macropomum) growth, body composition, haematological and biochemical parameters, excretion pattern and economic indices. Fifteen tanks randomly stocked 150 juvenile tambaqui (82.0 ± 0.8 g, mean ± SEM) subjected to three feeding strategies (n = 5): self-feeder system (T1); automatic-feeding with three set meals/day (T2) and apparent satiety with three meals/day (T3). The results revealed that fish T1 and T3 showed the best feed intake, feed conversion ratio, protein efficiency ratio and protein retention rate (p < 0.05). However, no significant differences were observed in growth, survival, haematological parameters, body composition and total ammonia nitrogen excretion among treatments (p > 0.05). Cortisol obtained a significantly higher value for fish T3 (122.92 ± 5.75 ng/ml), with a low water phosphorus value for fish T1 (0.43 ± 0.06 mg/L). Lastly, the feed cost based on the values deriving from diets revealed better indices (variable cost, unitary contribution margin and contribution margin index) for fish T1 and T3. In short, our findings suggest the benefits of using self-feeders for tambaqui aquaculture. © 2022 John Wiley & Sons Ltd.