Comparative effect of water-soluble and -insoluble dietary fiber on bowel function in rats fed a liquid elemental diet

The effect of dietary fibers on the digestive tract mass, diamine oxidase (DAO) activities in the small intestine and plasma and pool of ammonia and organic acids such as acetic, propionic, butyric, lactic and succinic acid in the cecum in rats fed a liquid formula diet was compared. Rats were fed an elemental liquid diet (ED) or ED containing 3g/100 mi of dietary fiber either a mixture of crystal cellulose and carboxymethyl cellulose sodium salt (CC), sugar-beet pectin (BP) or hydrolyzed xyloglucan (HXG) for 14 days. The mass of colon plus rectum was higher in rats fed CC, but not in rats fed BP and HXG than in rats fed ED. Cecal tissue mass was higher in rats fed BP and HXG, but not in rats fed CC, than in rats fed ED. Cecal contents and cecal pH were higher and lower in rats fed CC, BP and HXG than in rats fed ED. DAO activities in the small intestine and plasma were higher in CC than in rats fed ED. Cecal ammonia were lower in rats fed CC, BP and HXG than in rats fed ED. Production of organic acids was similar between rats fed ED and CC except for acetic acid that was much lower in rats fed CC. Diarrhea and loose feces were also improved in rats fed CC. The results suggest that the addition of a combination of water -soluble and -insoluble dietary fiber to a liquid formula diet would have more beneficial effects on the bowel function than water-soluble dietary fiber alone. (C) 1998 Elsevier Science Inc.