Tambacus (Colossoma macropomum x piaractus mesopotamicus) fed cassava and soybean meal artisanal feed

Abstract

The usage of artisanal feed is an alternative that is been discussed to support household fish culture in Amazonia. Employing this strategy, however, require the adoption of some criteria for adjusting feed nutrient balance. The purpose of this study was to investigate juvenile tambacu (Colossoma macropomum x Piaractus mesopotamicus) performance when fed cassava and soybean meal artisanal feed, as well to evaluate the need of its supplementation to fulfill fish amino acids, energy and macro minerals requirements. For this, 813 juveniles (48.49 ± 4.21 g) were stocked in 15 reinforced concrete ponds (earthen ground; 48.50 ± 3.61 m² x 0.8 m) and fed five different diets, in which four of them were artisanal, formulated to be isoproteic (25% CP), as follow: C1 (cassava + soybean meal + premix; as control), R1 (C1 + dicalcium phosphate), R2 (C1 + dicalcium phosphate + soybean oil), R3 (C1 + dicalcium phosphate + soybean oil + DL-methionine), and C2 (32%PB commertial extruded feed; as regional comparison parameter). After 75 days, a positive effect of dicalcium phosphate supplementation were detected (P<0.05) for weight gain, feed conversion, specific growth rate and protein efficiency ratio (PER). The effects of soybean oil or DL-methionine additions were not detected. Similarly, no significative differences were detected among the supplemented dicalcium phosphate artisanal feed (R1, R2 e R3) and C2, except for PER, that was lower for fish fed C2. These results have shown that there are no productive losses when juvenile tambacu are fed artisanal diets, containing only cassava, soybean meal, premix and dicalcium phosphate. © 2019, UCOPress. Cordoba University Press (UCOPress Editorial Universidad de Córdoba). All rights reserved.