Abstract: For optimal performance, it is important to formulate diets that meet the nutrient requirements for poultry while minimizing the excretion of excess nutrients into the environment. With respect to protein feed ingredients, apparent ileal digestibility is widely used to reflect its bioavailability. If diet formulations are based on apparent ileal digestibility values, the digestibility of amino acid in feedstuffs will be underestimated and may result in an increased level of nutrient excretion. The concept of standardized digestibility system in which corrections are made for basal endogenous amino acid losses as a mean of overcoming the limitations of apparent digestibility estimates is proposed. Standardized ileal amino acid digestibility and the method of evaluating basal endogenous amino acid losses are discussed. The application of standardized ileal amino acid digestibility in amino acid nutrient evaluation of feed ingredients in broilers are reviewed in this article.

Key words: standardized ileal amino acid digestibility; basal losses; broilers; feed ingredients