Amino acid ratios
Amino acid ratio is a means of expressing the requirements for amino acids relative to the requirement for lysine. Lysine is used as a reference because it is typically the first-limiting amino acid in most swine diets and the proper concentration of lysine and other amino acids is essential for protein synthesis. The amino acid ratios are often utilized because the requirements for amino acids remain relatively constant relative to lysine for a given stage of growth. In practice, the use of amino acid to lysine ratios makes establishing the levels for other amino acids relatively easy.