Lysine: Amino acid requirements of broiler breeders.

Because feed intake is controlled in broiler breeders, amino acid supply is determined by the composition of the feed and the level of feed intake. Controlling amino acid supply during the laying cycle can be facilitated by the use of a model for calculating requirements. A possible model is outlined and the various components discussed. Typical calculations suggest that the model can provide a useful basis for practical feeding decisions. Model elements include: levels of animal performance; utilization of amino acids for egg production, maintenance, and tissue growth; population structure; and the variation of feed intake and the covariance between feed intake and requirements.