Objective: Study the effects of adding betaine into broiler chick rations in order to reducing methionine requirement. Design: Randomized completely design.
Animals: Seven hundred day- old male Ross 208 broiler chicks.
Procedure: The chicks were randomly divided into five dietary treatments. Each treatment was contained four replicate floor pens of 35. One treatment (as control) fed diet included methionine
content according to NRC (1994) recommendation. In other dietary treatments, the level of methionine lowered by 10% (as low- methionine diets) and 0, .02, .04, and .08% of betaine were added into diets respectively. Body weight, feed consumption feed conversion ratio and mortality were evaluated at 21, 42, and 49
days of age. Statistical analysis: Data for all response variables were subjected to ANOVA. Variable means for treatments showing significant differences in the ANOVA were compared using Tukey’s test.
Results: At the age of 21 days, adding .04% betainc (not .02 or
.08%) into low-methionine diet caused significant increase in body weight, in comparison with control and other treatments (P = .002). There were no significant differences among feed conversion ratio •
in dietary treatments. Feeding diets containing low level of
methionine without betaine or supplemented with .02% betaine increased feed conversion ratio significantly (P .02), at 42 days of age. At the end of experimental period (49 days of age), no
significant differences observed among body weights and feed
conversion ratios in dietary treatments, however adding .04% betaine into low-methionine diet improved body weight and feed
efficiency slightly compared with control and other treatments. Conclusion: According to obtained results in this feeding trial it could be concluded that although adding different levels of betaine
(.02, .04, and .08%) into low-methionine diets did not affect body weight and feed conversion ratio, but it seems supplementation low-methionine diet with .04% betaine could compensate marginally
deficiency of methionine in broiler chick rations.