Lysine An essential amino acid , molecular weight (146.2) found in protein. Lysine is generally the most limiting amino acid in the food supply of both animals and humans. It is produced commercially as L-lysine·HCl, L-lysine·SO4, or L-lysine free base. Virtually all cereal grains and their by-products are firstlimiting in lysine, and most oilseed meals, with the exception of soybean meal, are deficient in lysine. In addition to its use in protein synthesis, lysine, as protein-bound trimethyl-lysine, is a precursor of carnitine in the body. Both protein-bound lysine and free lysine can react with free carbonyl groups such as those existing on reducing sugars to form Maillard reaction products. Heat and humidity promote the Maillard reaction in stored feeds and feed ingredients. Also, under alkaline conditions and heat, lysine in feeds or feed ingredients can react with dehydroalanine (produced from serine) to form the cross-linked amino acid lysinoalanine. Neither lysinoalanine nor Maillard-bound lysine have lysine bioactivity.
Lysine deficiency in chickens can lead to slow growth, weight loss, poor feathering, and reduced egg production. In severe cases, it might cause appetite loss and leg problems. A lack of lysine also lowers resistance to diseases