Rice ethanol distillery residue as a protein source in the diet of silver catfish (Rhamdia quelen)

Abstract

ABSTRACT The objective of the study was to evaluate the partial replacement of the protein of fish meal by the protein from the intermediate residue of rice ethanol distilleries in the proportions of 0%, 25%, and 50% in Rhamdia quelen. Three hundred and seventy-five fish (3.56 ± 0.6 g/7.07 ± 0.46 cm) were distributed in 15 tanks and fed three times a day for 60 days. At the end of the period, biometrics were performed to collect data and tissues, evaluating growth parameters, sonatic indices, digestive enzyme activity, plasma and hepatic metabolism, body nutrient composition, protein, and fat deposition. Fish fed the control diet showed higher feed intake (765.86 ± 53.86 g). The 50% replacement diet reduced final growth (14.27 ± 3.88 g), deposition of body protein (1.63 ± 0.05 g) and increased free liver amino acids (8.72 ± 0.41). The use of intermediate residue from rice ethanol distilleries in silver catfish diets was inefficient, requiring further studies to evaluate the protein quality of this ingredient.