LAUSR

Abstract An experiment was conducted to test the hypothesis that the standardized ileal digestibility of crude protein (CP) and amino acids (AA) in threonine biomass (Thr-BM) and 2 sources of tryptophan biomass (Trp-BM1 and Trp-BM2) were greater than in soybean meal (SBM). Twelve weanling barrows (11.08 ± 1.06 kg) that had a T-cannula installed in the distal ileum were allotted to a replicated 6 × 6 Latin square design with 6 diets and 6 periods. A nitrogen-free diet, a diet based on SBM, and a diet based on a combination of SBM and Thr-BM were formulated. Two additional diets were formulated based on a combination of SBM and the 2 sources of tryptophan biomass. The last diet was not related to this work. Diets were fed to pigs for 7 days, and ileal digesta were collected on days 6 and 7 of each period. Results indicated that concentrations of CP and AA were greater in biomass products than in SBM, and the AID of threonine was greater (P