Betaine can replace choline in diets for juvenile Nile Tilapia, Oreochromisniloticus

Abstract

An experiment was conducted to evaluate the ability of betaine to spare the choline requirement in juvenile tilapia. The basal diet contained 320 g crude protein/kg diet (101 g crude protein from casein and gelatin, and 219 g from a crystalline l-amino acid mixture). The total sulfur amino acid (TSAA) concentration of the basal diet was 5.0 g TSAA/kg diet, met:cys 89:11, the choline concentration was 3 g/kg dry diet and dietary phosphatidylcholine concentration was 15 g/kg dry diet. Varying concentrations of choline (3.0, 2.55, 2.10, 1.65, 1.20, 0.75, 0.30, or 0.0 g choline/kg dry diet) and betaine (0.0, 0.37, 0.75, 1.12, 1.49, 1.84, 2.24, or 2.49 g betaine/kg dry diet) were added to the basal diet resulting in eight experimental diets with choline:betaine ratio of 100:0, 85:15, 70:30, 55:45, 40:60, 25:75, 10:90 or 0:100, respectively. Feed consumption and weight gain were significantly affected by dietary choline:betaine ratios. Consumption of diets with a choline:betaine ratio of 40:60 was significantly higher than that of fish fed diets with a choline:betaine ratio of 100:0 and 85:15. Weight gain of fish fed diets with a choline:betaine ratio of 10:90 was significantly higher than fish fed diets with a choline:betaine ratio of 100:0 and 85:15, but not significantly different from fish fed the remaining diets. Feed efficiency and total liver lipid concentration were not significantly affected by dietary choline:betaine ratio. Based on these data, it appears that betaine spares the choline requirement in juvenile tilapia fed chemically defined diets and that dietary betaine substituted for choline increases feed consumption with no significant change in feed efficiency.