EFFECTS OF DIETARY-FIBERS ON GASTROINTESTINAL MUCIN IN RATS

Gastrointestinal mucin is believed to contribute to the intestinal dif fusion barrier for nutrients. This study quantitated the effects of fe eding three dietary fibers on gastrointestinal mucin production. Male Wistar rats (150-175 g) were fed, ad libitum, a diet containing 10 or 20% cellulose, psyllium, or rice bran or a control diet containing no fiber. After 4 weeks, the stomachs, small intestines, and colons were removed, and surface luminal mucin and tissue mucin were collected. Sp ecimens were homogenized, the homogenates were centrifuged, and the su pernatants were assayed for mucin by an enzyme-linked immunosorbent as say (ELISA) technique. The results of the dietary fiber feeding showed that levels of luminal and total (luminal plus tissue) gastric mucin were significantly higher in rats fed 20% psyllium than in rats fed th e control diet. There were no significant differences in the levels of small intestinal mucin among groups. Colonic luminal and total mucin levels, however, were significantly increased in rats fed 10% psyllium compared with those of rats fed the control diet. The increase in col onic mucin levels was later confirmed by periodic acid Schiff(PAS) sta ining. It was observed that large amounts of mucus may have been lost in the feces of rats fed a diet containing 20% psyllium, and smaller a mounts in the feces of those fed 10% psyllium. Reduced absorption of c holesterol and fatty acid was found previously in psyllium-fed rats. T hus, increases in gastric and colonic mucin levels caused by psyllium treatment may protect these organs as well as alter nutrient absorptio n.