Abstract
The effects of dietary fiber on histological changes in the gastrointestinal tract of rats were studied. A fiber-free diet was supplied for 17 days to a control group and a diet containing 2% rice bran hemicellulose (RBH), high-methoxylated pectin (HMP), or microcrystalline cellulose (MCC) was given to one of three other groups. Weight gain and feed efficiency were greater in the dietary fiber groups than in the control group. Light microscopy (LM) and scanning electron microscopy (SEM) were used to examine the structural changes in the alimentary tract after these dietary manipulations. Mild swelling of the villi was observed by LM in the jejunum of rats fed the 2% RBH and HMP diets. Irregular villi were found by SEM in the jejunum and ileum of rats fed the water-soluble dietary fiber, especially HMP. Swelling at the villus tips was revealed by LM throughout the small intestine of rats fed MCC. The present results suggest that the structural modifications induced by a 2% level of these dietary fibers did not affect the functional characteristics of the gastrointestinal tract because weight gain and feed efficiency were greater in the dietary fiber groups than in the control group.
