Estimations of Amino Acid Digestibility and Availability in Feedstuffs for Poultry

SummaryTotal amino acid composition of feedstuffs does not provide any information to the nutritionist concerning the degree to which amino acids are digestible and/or available for poultry. Several methods have been proposed for determining digestibility and availability of amino acids. The in vitro assays with the exception of chemical determination of available lysine have not been well accepted. The in vivo assays are not fully proven as reliable predictors for amino acid availability measurements. The faecal and ileal assays appear to be promising because the digestibility of all the amino acids in a feedstuff can be determined simultaneously. Until there is a reliable method for nutritional evaluation of the amino acids, faecal analysis is a more practical criterion from the point of view of applied poultry nutrition.