COMPOSITION AND NUTRITIONAL-VALUE OF AN EXPERIMENTAL HIGH-PROTEIN CORN IN THE DIETS OF BROILERS AND LAYING HENS

Two samples of high-protein corn (HPC) containing 1.0 to 2.4% more CP than normal corn (NC) were evaluated in two experiments with broilers and one experiment with laying hens. Levels of Met, Ile, Leu, Phe, Val, Asp, Glu, and Ala, expressed as a percentage of protein on a DM basis, were consistently higher in the HPC samples than in samples of NC and sorghum (S). The Lys level expressed as a percentage of protein on a DM basis was slightly lower in HPC; however, Lys level expressed as a percentage of the grain (DM basis) was similar in HPC and NC. In Experiment 1, each grain source was fed at the same level (67.1%) in soybean meal diets with protein and amino acid levels restricted to approximately 80% of recommended requirements of the National Research Council in 1984. Broilers receiving the HPC diet from 1 to 21 days of age had greater weight gains (P < .01) and a better feed conversion (P < .02) than birds receiving NC. In Experiment 2, one sample of HPC, NC, and S were evaluated in broiler starter and grower diets formulated to be isoenergetic and isonitrogenous. Birds receiving the HPC diet had greater weight gains (P < .01) and better feed conversion (P < .04) than birds receiving the NC diet at 42 days. Higher levels of Met and other amino acids furnished by the HPC apparently stimulated these responses. In Experiment 3, two samples of HPC, NC, and S were fed at the same level (66.75%) in soybean meal diets to laying hens 43 to 67 wk of age. All diets were isoenergetic, but protein levels were higher (1.5 to 1.6%) in the HPC diets. Egg production rate and egg size were similar among hens receiving the four grains. However, hens receiving HPC consumed less feed (P < .05) and had better feed conversion (P < .01) than hens fed NC. Analytical data and the performance of broilers in the present study demonstrate that HPC has the potential to spare soybean meal or other protein supplements in poultry diets, and to improve performance.