Zootechnical and growth performance of tambaqui (Colossoma macropomum) under different productive models of...

The objective of this study was to evaluate the zootechnical performance of tambaqui (Colossoma macropomum) for fattening (> 2 kg) under three management strategies on nine fish farms, which were equally distributed as follows: Low Productive Efficiency (LPE) - 6-8 tons year-1 without aeration; Medium Productive Efficiency (MPE) - 9-14 tons year-1 with emergency aeration and High Productive Efficiency (HPE) - 15-22 tons year-1 with supplemental aeration. Tank management data were collected and water quality parameters were monitored. Performance indices were evaluated through monthly biometrics until the end of the cycle; growth curves (von Bertalanffy) and instantaneous growth rate (IGR) were also calculated for comparison. Analysis of variance was applied to test the effect of the productive efficiency of the models on zootechnical performance. There was a difference (p<0,05) between the production strategies in relation to storage, density and productivity. Water quality indicators of oxygen (4.49-4.99 mg L-1), pH (6.51-6.77), temperature (31.12-33.81 °C), conductivity (43.37-55.63 µS cm-1), transparency (23.04-26.92 cm), nitrite (0.06-0.08 mg L-1) and nitrate (0.36-0.42 mg L-1) were within the cultivation standards. Phosphorus (0.37-0.48 mg L-1) and TSS (65.85-91.12 mg L-1) parameters suggest higher nutrient loads promoted by high densities. Differences between systems (p<0,05) demonstrate better overall results for HPE in final weight (2,726.53 ± 136.99 g), weight gain (2,719.98 ± 133.84 g) and apparent feed conversion (1.82 ± 0.02). The growth curves and IGR revealed differences in performances, indicating that production strategies alter the way fish grow. Systems with higher productivity demonstrate, based on their better results, greater care in the management.