L-Threonine for Poultry: A Review

The costs of protein and energy have fluctuated dramatically for the feed industry during the last few years. As a consequence, feed formulation practices are directed toward economic analysis rather than optimal bird performance. In addition, use of alternate ingredients and amino acid formulation on a digestible bases has become more common in the United States. The industrial production of methionine and lysine has resulted in poultry nutritionists reducing the level of dietary crude protein while maintaining bird performance and profitability. Indeed, the commercial availability of other amino acids may allow nutritionists to further decrease crude protein while more effectively meeting the birds’ amino acid requirements for maintenance and tissue accretion. This review examines poultry literature on L-threonine and makes extrapolations relating to commercial situations. Functions of L-threonine in metabolism and threonine's content in feedstuffs are discussed.