REPLACEMENT VALUE OF BETAINE FOR DL-METHIONINE IN MALE BROILER CHICKS

The effect of DL-methionine and betaine supplementation on growth perf ormance of 2,400 male broilers in the age period of 1 to 38 d, and on carcass composition of a subsample of 384 birds was examined. Three do se levels of DL-methionine (0, 0.05, and 0.10%) and two doses of betai ne (0 and 0.04%) were supplemented in different combinations to methio nine-deficient diets. Two types of diets were fed as starters and grow ers: either corn-soybean diets or practical diets typical for the Dutc h broiler industry. All diets were fortified with 220 ppm choline in o rder to avoid a deficiency in methyl groups. Increasing DL-methionine supplementation significantly improved daily weight gain and feed conv ersion efficiency. Supplemental betaine did not affect bird growth. Be taine slightly improved feed conversion in diets without supplemental DL-methionine, but did not affect this parameter in diets with added D L-methionine. Breast meat yield was significantly increased by about 1 .5 percentage points by the addition of 0.05% DL-methionine, whereas 0 .04% betaine only tended to increase breast meat yield in the range of 0.3 to 0.6 percentage points. The type of diet did not have any effec t on the responses obtained. In summary, there was no evidence for bet aine to spare DL-methionine as an essential amino acid supplement in b roiler diets.