Ileal Digestibility of Crude Protein and Amino Acids in Bakery and Biscuit Byproducts Fed to Growing Pigs

This study evaluated the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AAs) in three bakery and biscuit byproducts fed to growing pigs. Five crossbred barrows fitted with a T-cannula at the distal ileum were allotted to a 5 × 5 Latin square design. The AID of CP was higher in the plain bread meal (PB) and sweet bread meal (SB) than in corn (CN) and biscuit meal (BC) (p < 0.05), while the AID of most indispensable AAs was higher in CN and PB than in BC (p < 0.05), reflecting the dietary CP and total AA concentrations. After correction for basal endogenous AA losses, the SID of CP separated the ingredients more clearly, with PB and SB higher than CN, and CN higher than BC (p < 0.05). The SID of lysine, methionine, threonine, and tryptophan did not differ among the four ingredients, indicating that the digestible supply of these limiting AAs was maintained when corn was replaced with these ingredients. These SID values provide ingredient-level information for incorporating bakery and biscuit byproducts into growing pig diets as alternative feed ingredients alongside corn.