EFFECT OF ENTERAL FEEDING ON INTESTINAL EPITHELIAL PROLIFERATION AND FECAL BILE-ACID PROFILES IN THE RAT

The preservation of colonic mucosal mass requires the presence of fece s; thus, colonic hypoplasia develops with enteral feeding. Fermentable soy fiber may maintain fecal bulk and prevent mucosal atrophy. We the refore compared the effects of Enrich (containing soy fiber) with Ensu re (fiber-free) on mucosal mass, fecal bile acids, and cell proliferat ion in the rat. Sprague-Dawley rats (n = 20) were randomized into grou ps receiving either standard rat food, Enrich, or Ensure. After 4 week s, rats were weighed and killed at intervals after administration of v incristine sulfate (1 mg/kg intraperitoneally), which was given to ind uce metaphase arrest within the intestinal crypts and to allow calcula tion 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 s mall and large intestine and crypt cell production rate in the small b owel were unaffected by diet. In the proximal large bowel, both entera l diets produced a marked reduction in crypt cell production rate to v alues 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 e ffect was completely prevented by Enrich. Without an elevation in the lithocolic acid to deoxycholic acid ratio, secondary bile acid concent rations were increased in rats receiving Enrich (p < .05 to .01) but n ot in those receiving Ensure. Thus, fermentable soy fiber diets may pr event the midcolonic mucosal hypoplasia induced by enteral feeding.