The action of cellulose on the intestinal mucosa and element absorption by the rat.

The effect of 0, 5, 10 and 20% cellulose on the apparent absorption of P, Ca, Mg, Fe, Zn and Cu were measured in balance trials, and the entire intestinal tracts of the rats were examined histologically after 23 days on the test diets. Growth and food consumption were not significantly different among groups. Mg and Zn absorption were significantly lower (P less than 0.01) in animals consuming 10 and 20% cellulose compared with animals ingesting 0 or 5% cellulose in their diets. No animals was in negative balance for any element. With increasing dietary cellulose levels, higher numbers of neutrophils and more mitotic activity were observed in crypt epithelial cells, especially of the duodenum and jejunum. However, the intestinal tracts of all animals were described as essentially normal. Lower Mg absorption at high cellulose levels was suggestive of decreased mucosal contact due to decreased intestinal transit time. The decrease in Zn utilization may arise from altered crypt and/or villous epithelial cell biochemical activity.