Fig 4. Increased maturity of the small intestinal epithelium of 17 d-old rats, as shown by the portion of adult-type enterocytes, lacking supranuclear vacuoles, appearing on the villi in the distal small intestine after gavage feeding with increasing doses of a microbial-derived protease (P 0.0625, 0.125, 0.25, 0.5 mg per gram body weight) or water (control) during 14–16 days of age.

Statistically significant differences between control and enzyme-treated group (mean ± SD, n = 5–6) is indicated by * P < 0.05, *** P < 0.001.