Use of the ideal, protein concept for precision formulation of amino acid levels in broiler diets

Ideal amino acid ratios for chicks during the early growth period (0 to 21 days) are well documented by empirical evidence, but suggested rations for older birds are in need of confirmation. Based on best empirical estimates of lysine, SAA, and threonine requirements of broiler chicks during 0 to 21, 21 to 42, and 42 to 56 days of age, together with new knowledge of maintenance contributions to the total requirement for these amino acids, it appears that the ideal ratio of SAA and threonine to lysine may change very little as birds advance in age and weight toward a 56-day market weight. This paper presents regression equations that predict both digestible and total lysine, SAA, and threonine requirements at any age or weight between hatching and 56 days.