Bovine plasma protein as an alternative protein source in extruded aquafeeds for Piaractus mesopotamicus (pacu) at two fattening stages

An 84-day feeding trial was conducted to evaluate the addition of bovine plasma protein concentrate (BPP) as a full replacement of fish meal (FM) in extruded aquafeeds for the fish Piaractus mesopotamicus at two fattening stages. Fish with an initial body weight of 105.55 +/- 13.48 g (1st fattening stage) and 564.50 +/- 88.02 g (2nd fattening stage) received two iso-nitrogenous and isocaloric diets with 130 g/kg of FM (FM diet-FMD) or with 130 g/kg of BPP (BPP diet-BPPD). No significant difference in growth performance was detected between dietary treatments. Fish from the 2nd fattening stage showed decreased intestinal pH and increased haemoglobin content. At the 1st fattening stage, fish fed with BPPD presented higher levels of plasma triglycerides and cholesterol, and hepatic and whole-body lipid content, while plasma glucose and muscular glycogen were lower at the 2nd fattening stage compared with FMD-fed fish. Fish fed with FMD showed an increase in the thiobarbituric acid reactive substances in liver at the 1st fattening stage and intestine at the 2nd one, accompanied by higher levels of hepatic catalase at the 1st fattening stage. Results suggest BPP could completely replace FM in diets for P. mesopotamicus without affecting growth performance, when FM represents 13% of the diet.