Pancreatic Enzymes in Germfree and Conventional Rats Fed Chemically Defined, Water-soluble Diet Free from Natural Substrates

Abstract

The effects of intestinal microflora and chemically defined, liquid diet free from natural substrates (for pancreatic enzymes), on pancreatic function and on fate of pancreatic enzymes, were studied using germfree and conventional rats fed liquid and semipurified solid diets. Histopathological examination of pancreatic sections of rats fed either diet showed that pancreatic acinar cells in all sections were normal. Serum lipase and amylase levels were normal in germfree and conventional rats fed either diet. Lipase and amylase levels in the pancreas were not affected either by germfree status or by diets. Germfree status had no effect on trypsinogen and chymotrypsinogen in the pancreas, whereas feeding of liquid diet resulted in lower activities of these enzymes in both germfree and conventional rats as compared with those fed a semipurified diet. Feeding of liquid diet and presence of microflora were associated with a lower activity of lipase in the contents of cecum and large intestine, and with a decrease in activities of amylase, trypsin and chymotrypsin in small intestine, large intestine and cecum. These results indicate that the pancreatic enzymes undergo a progressive inactivation on entering the small intestine, and subsequently, passing through the entire intestinal tract. Diets without natural substrates and microflora played an important role in inactivation of these enzymes in the intestinal tract. It is concluded that the chemically defined, liquid diet used in this study was nutritionally adequate for germfree and conventional rats as far as normalcy and function of pancreas were concerned.