Collaborative research conducted at the University of Illinois and with a commercial company in Germany studied the effects of excessive heat on digestible energy (DE) and metabolizable (ME) and standardized ileal digestibility (SID) of amino acids (AA) in a heat-treated soybean meal (SBM) fed to growing pigs. Nine treatments were prepared using a conventional SBM that was either not autoclaved or autoclaved following one of 8 treatments: 110°С for 15 or 30 min or 150°С for 3, 6, 9, 12, 15 or 18 min. In the first experiment, 20 barrows weighing about 44 kg were assigned to the 10 treatments. A corn-based basal diet and 9 diets containing corn and one of each SBM treatment were formulated. Urine and feces were collected for 5 day. In the second experiment, 10 ileal-cannulated barrows were allotted to the 10 treatments (one N-free diet and nine SBM treatments). Ileal digesta were collected. Results indicated no effects of autoclaving at 110°С on ME or on SID of AA in SBM, but both ME and SID of AA in SBM were less (P ‹ 0.01) if SBM was autoclaved at 150°С compared with 110°С as shown in the following table. At 150°С, there were linear decreases (P ‹ 0.01) in both ME and SID of AA in SBM as heating time increased.
Table 1. Effect of Heat on Metabolizable energy and Standardized Ileal Digestibility of Amino Acids in Soybean Meal