COMPARISON OF WHEAT CULTIVARS IN DIETS OF DIFFERENT PROTEIN CONTENTS WITH AND WITHOUT SUPPLEMENTAL L-LYSINE FOR BROILER CHICKS

Abstract

Four experiments were conducted to compare wheat cultivars of wide genetic base in chick diets of different protein contents with and without supplemental L-lysine. In the first experiment, 24 wheat cultivars were compared with corn. The 28-day body weights of chicks fed a 22.0%-protein Neepawa wheat were significantly lower than those fed the other grains. In the second experiment, body weights were significantly higher, and feed-to-gain ratios and mortality significantly lower for chicks fed 22% protein diets than for those fed the 18% diets. In the next two experiments, chicks fed 18 or 22% protein diets supplemented with 0.3% L-lysine had significantly higher body weights and lower feed-to-gain ratios than those fed diets without supplemental L-lysine. In each of the last three experiments, differences among cultivars were significant as were the cultivar × dietary protein level and cultivar × L-lysine interactions. Correlation coefficients between grain protein levels and chick body weights in all diets of different protein content and different L-lysine supplementation revealed that a large proportion of the difference among chick body weights was probably due to the various lysine levels of the diets that resulted from the different proportions of grain and soybean meal in the diets.