Intestinal structural changes in African green monkeys after long term psyllium or cellulose feeding

Intestinal structure of male adult African Green monkeys (Cercopithecus aethiops ssp vervets) was studied after 3 1/2 yr of consuming diets containing 10% psyllium husk or cellulose. Scanning electron microscopy (SEM) identified mild damage (cellular swelling and disarray, and microvillar denudation and disarray) at villous tips throughout the small intestine in the psyllium-fed monkeys. The cellulose group had similar duodenal damage. Differences were not found in colons by SEM. By light microscopy, jejunum had shorter villi with psyllium feeding, based upon villous height (P less than 0.05), and length around a sectioned villus (P less than 0.1), but not based upon the number of enterocytes per villus. Jejunal and ileal circular and longitudinal muscle layer thicknesses were increased in psyllium-fed monkeys. Colonic mucosal height was significantly (P less than 0.05) reduced and muscle layer thickness was mildly reduced in the psyllium-fed monkeys. Group differences were not found in intestinal weight or length or in the weight of small intestinal mucosal scrapings. Psyllium husk may cause epithelial cell loss and muscle layer hypertrophy in the jejunum and ileum and thinning of the colonic wall after prolonged feeding.