Coefficient of standardized ileal digestibility of amino acids in corn, soybean meal, corn gluten meal, high-protein distillers dried grains, and field peas fed to weanling pigs

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 (initial body weight: 10.3 ± 0.9 kg) 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 AA. An N-free diet used to calculate basal endogenous losses was also formulated. The CSID of all indispensable AA were greater (P<0.05) in SBM, CGM, and field peas than in HP DDG, except that no differences in the CSID of leucine, methionine, and tryptophan were observed between field peas and HP DDG. The CSID of methionine and tryptophan were greater (P<0.05) in SBM than in field peas, and the CSID of all indispensable AA were greater (P<0.05) in CGM than in field peas except for the CSID of arginine, histidine, lysine, and threonine. However, no differences in the CSID of all indispensable AA were observed between SBM and CGM. The CSID of arginine, histidine, and lysine in corn were less (P<0.05) than in SBM, but for all other indispensable AA, no differences between corn and SBM were observed. It is concluded that the CSID of all AA in CGM is similar to that in SBM, but HP DDG has lower CSID values than in corn, CGM, and SBM.