The objective of this experiment was to determine the coefficient of standardized ileal digestibility (CSID) of amino acids (AA) in corn, soybean meal (SBM), corn gluten meal (CGM), high protein distillers dried grains (HP DDG), and field peas fed to weanling pigs. Twelve weanling barrows weighing about 10kg were prepared with a T-cannula in the distal ileum and randomly allotted to a replicated 6×6 Latin square design with 6 diets and 6 periods in each square. Five diets were formulated using corn, SBM, CGM, HP DDG, or field peas as the sole source of protein and amino acid. An N-free diet used to calculate basal endogenous losses was also formulated.

The CSID of all indispensable amino acids were greater (P<0.05) in SBM and CGM compared to HP DDG. No differences in the CSID of all indispensable amino acids were observed between SBM and CGM. The CSID of arginine, histidine, and lysine in SBM were greater (P<0.05) than in corn, but no differences between SBM and corn were observed for the other indispensable amino acids. The study found higher CSID values in corn, CGM, and SBM compared to HP DDG.