This research study investigated the effect of varying trypsin inhibitor activity (TIA), heat-degraded lysine concentration and protein solubility in potassium hydroxide (KOH) on broiler performance and pancreas weight.  Two soybean lots were subject to varying thermal, hydrothermal, pressure, and kilning processing.  This heat treatment resulted in a total of 34 soybean meal lots varying widely in TIA (0.25 to 23.6 mg/g), heat-degraded lysine (1.40 to 8.60 g/kg), and KOH solubilities (65.5-97.6%) levels.  These experimentally-processed soybean were included into a common grower and finisher diet for broiler chicks at fixed amounts (grower: 35%; finisher: 25%) and tested in a 35 day experiment with 1680 broiler chicks.

As expected, excessive levels of TIA significantly depressed broiler gains and feed: gain ratios, and increased pancreas weights.