Nutritional Value of High Lysine Corn for the Broiler Chick

Two experiments were conducted using broiler chicks from one to 21 days (experiment 1) or to 28 days (experiment 2) of age to compare the nutritional value of high lysine, normal hybrid and sweet corn. Comparisons were made at varying dietary protein levels with the corns being substituted on an isonitrogenous basis within protein levels in corn-soybean meal diets. In experiment 1, only slight differences in performance of chicks fed high lysine or normal corn were observed at 14, 18 and 22% protein levels except that feed conversion at the 22% protein level was improved for chicks fed normal corn. For chicks fed sweet corn at the 22% protein level growth and feed conversion were significantly (P<.05) improved over that for chicks fed high lysine corn. At suboptimal protein levels performance was similar for chicks fed high lysine or sweet corn diets. Methionine supplementation gave a slight improvement in growth rate of chicks fed high lysine or normal corn diets at 18 and 22% protein levels, but depressed growth of chicks fed the normal corn diet at the 14% protein level. In experiment 2, at the optimal protein level (23%), chicks fed high lysine or normal corn performed similarly while at the suboptimal protein level (17%) growth rate of chicks fed normal corn was superior. Methionine supplementation significantly (P<.05) improved weight gain and feed conversion compared with the unsupplemented groups and the performance of chicks fed the methionine supplemented diets was similar between corns.