Role of dietary methionine in poultry production

Abstract

Synthetic DL-methionine (DLM) supplements poultry diets to enhance production. The bioe$cacy of liquid methionine is generally lower than that of powder methionine; however, if the level of total sulfur amino acids (TSAA) is set to the commercial recommendation, the bioe$cacy of liquid methionine seems to be equal to that of powder methionine (equimolar basis). Absorption and transportation in the segment of the jejunum di#er between liquid and powder methionine because multiple systems are involved. Methionine supplementation in a low-protein diet alleviates the negative e#ects of heat stress. The supplementation improves the amino acid balance and consequently promotes growth performance by enhancing feed e$ciency, increases protein synthesis and decreases fat synthesis. Methionine supplementation also improves the immune response through direct e#ects (protein synthesis and breakdown) and indirect e#ects (derivatives of methionine). As various factors influence the methionine requirement, the requirements of commercial strains are higher than those recommended by NRC (1994.). Moreover, the methionine requirement expressed as a percentage of diet declines during the starter and grower phases, while the requirement related to lysine is little changed (tends to increase).© 2009, Japan Poultry Science Association.