Response of Digestive Enzymes to Dietary Protein

Abstract

Enzyme activities of the contents of small intestine were determined in rats pair-fed protein-free, 15% casein or 15% whole-egg protein diets during 1-hour intervals spaced 12 hours apart. Casein and whole-egg protein increased the total proteolytic, peptic, tryptic, and chymotryptic activities and the total endogenous nitrogen content of the digesta after 7 days of experimental feeding. Whole-egg protein was shown to increase the synthesis and secretion of trypsin, chymotrypsin and amylase when experimental diets were fed for 1, 7, 15, and 25 feedings. The presence of casein and whole-egg protein appeared to retard the rate of trypsin and chymotrypsin inactivation within the small intestine.