Abstract ALUMOT and Nitsan (1961) reported that intestinal proteolysis was com pletely inhibited in chicks fed unheated soybean meal up to three weeks of age. By four weeks of age proteolysis had increased and approached the normal by six weeks. These workers obtained a correlation between dietary anti-trypsin inhibitors and proteolytic activity in the intestinal contents. Pubols et al. (1964) found higher trypsin activity and lower amylase activity in pancreatic homogenates from fasted birds previously fed unheated soybean meal. These levels of enzymes were maintained fairly constantly during feeding, in contrast to the variations observed when autoclaved soybean meal was fed after a 16-hour fasting period. Applegarth et al. (1964) showed that pancreata from chicks fed unheated soybean meal were completely depleted of zymogen and attributed the decrease in proteolytic activity of the pancreas following feeding of unheated soybean meal to a loss of zymogen granules. Recent work by Salman et . . .