Dietary supplementation of betaine improves growth performance and reduces lipid peroxidation in Nile tilapia.

In this study, we evaluated the growth performance, body composition and feed efficiency, muscle and gut histology, blood haematology and plasma biochemical parameters and the activity of antioxidant enzymes in the liver of Nile tilapia fed diets supplemented with betaine. Increasing doses (0.00, 0.50, 1.00 and 2.00 g kg−1) were added to a basal diet and randomly assigned to three groups, composed of 12 fish (27.76 ± 1.31 g) in each experimental units. The fish were fed to satiation four times a day during 100 days. Dietary inclusion of 0.50 g kg−1 of betaine resulted in greater results in weight gain, daily weight gain, specific growth rate, as well as energy retention rate. Dietary inclusion of betaine resulted in less height, width and thickness of the tunic of the gut folds. Fish fed 0.50 and 1.00 g kg−1 of dietary betaine showed higher plasma glucose. The concentration of substances reactive to thiobarbituric acid was lower in fish fed with 0.50 g kg−1 of dietary betaine, while those fed with 1.00 g kg−1 dietary betaine show greater activity of the catalase enzyme. The dietary inclusion of 0.50 g kg−1 of betaine improves growth performance probably by reducing lipid peroxidation. [ABSTRACT FROM AUTHOR]