Effect of Enteral Feeding on Intestinal Epithelial Proliferation and Fecal Bile Acid Profiles in the Rat

Abstract

The preservation of colonic mucosal mass requires the presence of feces; thus, colonic hypoplasia develops with enteral feeding. Fermentable soy fiber may maintain fecal bulk and prevent mucosal atrophy. We therefore compared the effects of Enrich (containing soy fiber) with Ensure (fiber-free) on mucosal mass, fecal bile acids, and cell proliferation in the rat. Sprague-Dawley rats (n = 20) were randomized into groups receiving either standard rat food, Enrich, or Ensure. After 4 weeks, rats were weighed and killed at intervals after administration of vincristine sulfate (1 mg/kg intraperitoneally), which was given to induce metaphase arrest within the intestinal crypts and to allow calculation of crypt cell production rate. Fecal free bile acids and neutral steroids were analyzed using gas-liquid chromatography and gas-liquid chromatography mass spectrometry. Nucleic acid concentrations in the small and large intestine and crypt cell production rate in the small bowel were unaffected by diet. In the proximal large bowel, both enteral diets produced a marked reduction in crypt cell production rate to values only 5% to 7.5% of control values (p < .001). In the midcolon of rats fed Ensure, there was a similar reduction, but this hypoplastic effect was completely prevented by Enrich. Without an elevation in the lithocolic acid to deoxycholic acid ratio, secondary bile acid concentrations were increased in rats receiving Enrich (p < .05 to .01) but not in those receiving Ensure. Thus, fermentable soy fiber diets may prevent the midcolonic mucosal hypoplasia induced by enteral feeding.