Nutritional evaluation of meat meals for poultry. VI. Association of growth promotion, protein digestibility, and hot-water-soluble protein content, and effect of amino acid supplementation

Abstract

Despite considerable variation in digestibility (from 68 to 83%) and in the hot-water solubility (from 14 to 27%), of the protein of meat meals, these parameters were not significantly correlated with chick growth on diets based on wheat, skim milk, and the meat meals. Although growth rates on both high and low quality meals were increased by addition of arginine, lysine, methionine, and tryptophan, with the major part of the response due to lysine, methionine, or both, differences in growth rates on high and low quality meals were not eliminated. However, with high levels of the amino acids and additional minerals, vitamins, and antibiotic, growth rates on some low quality meals were similar to those on the supplemented high quality meat meals. It is concluded that differences in the available essential amino acid content of the meat meals were the main cause of variation in growth-promoting ability, but that when amino acid deficiency was corrected a second limiting factor could be one or more of vitamins, minerals, and antibiotic.