A Bioassay for Available Amino Acids and True Metabolizable Energy in Feedingstuffs

Abstract

An experiment was made to determine if the basic methodology of the bioassay for true metabolizable energy (TME) can be applied to the measurement of available amino acids (AAA) in feedingstuffs. Administration of graded levels of glucose (0–30 g) had no effect on the excretion of 13 AA by adult roosters. Feeding graded levels of soybean meal, alone or in combination with glucose, caused linear increases in AA excretion. Methods of measuring AAA are described and the importance of correcting for metabolic and endogenous AA excretion is discussed. A bioassay for AAA which may be combined with the measurement of TME is described.