Accurate determination of the amino acid content of selected feedstuffs.

The accurate determination of the amino acid content is important. In the present study, a least-squares non-linear regression model of the amino acid content determined over multiple hydrolysis times was used to accurately determine the content of amino acids in five different feedstuffs. These values were compared with 24-h hydrolysis values determined for the same feedstuffs. Overall, approximately two-thirds of the amino acids determined in this study (aspartic acid, threonine, glutamic acid, proline, glycine, alanine, leucine, tyrosine, phenylalanine and arginine) using 24-h hydrolysis were in good agreement (<3% difference). When examined across feedstuffs, the concentration of serine was underestimated by the 24-h hydrolysis method by 4.8%, while the concentrations of histidine and lysine were overestimated by 3.9% and 3.1%, respectively.