Growth performance and intestinal histology of juvenile pirarucu fed with increasing levels of soybean meal

Abstract

The aim of this study was to evaluate the inclusion of different levels of soybean meal in pirarucu’s diet. 200 pirarucu juveniles (152.15 ± 0.8 g) were distributed in 20 polyethylene tanks with a continuous water flow system. A completely randomized experimental design was used, with five treatments (n = 4) containing 0, 10, 20, 30 and 40% of soybean meal inclusion levels. Growth performance was measured as specific growth rate, feed conversion, weight gain and survival. Body composition, protein retention rate and histopathological changes in the intestine were analyzed. The different treatments did not affect weight gain, specific growth rate and survival. The body composition of the fish was affected by treatments for ash and ether extract and the IHS was also affected. The diet with 40% soybean meal compromised feed conversion rate. Additionally, the distal intestine of fish fed with the same diet showed a reduction in the height of mucosal folds and a loss of supranuclear vacuolation in enterocytes. Based on these results, the inclusion of up to 30% of soybean meal in the diet of juvenile pirarucu is possible without negative effects on performance and enteric morphology.