Modifications in growth and morphology of ovine jejunal and ruminal epithelia as affected by inert dietary substances.

Thirty-two lambs were used to study the effects of a nondegradable material in the alimentary tract on growth and morphology of ruminal and jejunal epithelia. Lambs were fed isoenergetic rations that differed only by addition of ground polyethylene. Eight of the lambs receiving each diet were given polyurethane cubes orally that were confined to the rumen. Lambs were slaughtered after 30 d; morphological and growth characteristics of the anterior-ventral and posterior-dorsal ruminal epithelia and jejunal epithelia were examined. Weights of the stomach complex were greater (P less than .05; 1.57 vs 1.48 kg) for lambs fed the polyethylene diet. Polyurethane cubes had no effect on weights of the stomach complex and small intestines. Deoxyribonucleic acid levels and both height and width of papillae were greater (P less than .05) in ruminal epithelial from lambs fed the diet with polyethylene than in those from lambs given the control diet. Protein and DNA levels in jejunal epithelia also were affected (P less than .05) by diet, averaging 8.2 mg/cm2 and 510 micrograms/cm2, respectively, for lambs fed the polyethylene diets vs 7.3 mg/cm2 and 417 micrograms/cm2 for lambs fed the control diet, respectively. Average villus height was greater (P less than .05) in jejunal epithelia of lambs fed the control diet than in jejunal epithelia of those given the polyethylene diet (553 vs 466 microns). Polyurethane cubes did not affect growth or morphological characteristics of either ruminal or jejunal epithelia.(ABSTRACT TRUNCATED AT 250 WORDS)