Dietary beta-carotene improves growth performance and antioxidant status of juvenile Piaractus mesopotamicus

This study was conducted to investigate the effects of dietary synthetic beta-carotene on growth performance, haematological and immunological parameters, energy reserves and antioxidant status of juvenile fish Piaractus mesopotamicus. Two hundred and ten fish (12.24 +/- 2.98 g) were fed with a control extruded feed (CEF) and the same diet supplemented with beta-carotene (BEF) for 90 days. A higher weight gain and specific growth rate were found in fish fed BEF in comparison with those fed CEF. In addition, BEF-fed fish showed lower liver somatic index and a higher percentage of eosinophils. No statistical differences were found in energy reserves, except for plasma triglycerides which decreased in fish fed with BEF. Regarding oxidative stress markers, decreased activities of antioxidant enzymes were found in intestine and gills of BEF-fed fish (SOD and GST, respectively). In the liver, both LPO levels and CAT activity decreased in fish fed with BEF. Additionally, lower brain LPO levels without changes in the antioxidant enzymes were observed in BEF-fed fish. The inclusion of dietary synthetic beta-carotene improved growth and antioxidant status, and had a plasma triglyceride-lowering effect in juvenile P. mesopotamicus.