COMPARISON OF THE EFFECTS OF FEEDING VARIOUS DIETARY FIBERS TO HUMANS, PIGS, AND CHICKEN

Scope of Study. Effects of feeding four dietary fiber sources--oat bran, corn bran, wheat bran, and citrus flour, at various levels to humans, chickens, and pigs were examined in five trials. In the first trial, breath hydrogen concentration, fecal fiber, and bowel function in human subjects consuming 20 gm neutral detergent fiber from corn bran for three weeks were measured. In the second study, subjects consumed a single breakfast containing 40 gm of dietary fiber from oat bran, wheat bran, corn bran, or citrus flour and passage time to the large intestine was estimated from breath hydrogen concentration. In the third study, pigs were fed meals containing corn bran, wheat bran, citrus flour, or milk, and breath hydrogen was measured. In the fourth study, passage time to ileum, digestibility anterior to the ileum and in the total tract, and ileal and fecal composition were measured in pigs consuming oat or corn bran. In the final study, digestibility, passage time, hydrogen concentration, feed intake and intestinal tract size were measured with adult laying hens fed corn bran, oat bran, wheat bran, or citrus flour at 10, 20 or 40 percent of the diet.;Findings and Conclusions. Consumption of corn bran by humans increased breath hydrogen concentration and frequency of bowel movements. In humans, wheat, corn, and oat bran speeded passage to the large intestine. Breath hydrogen increased when pigs consumed corn bran, wheat bran, or milk. Passage to the ileum was slowed when pigs consumed corn bran but was speeded when pigs consumed oat bran. Digestibility of dry matter was depressed by consumption of fiber, but cellulose and hemicellulose both were partially digested prior to entering the large intestine. Hydrogen production was increased when birds consumed oat bran or citrus flour, and passage through the digestive tract was fastest with oat bran and slowest with citrus flour. Since pigs and chickens responded to dietary fiber in a manner similar to humans, information gained from these two species may help explain the various effects of fiber in humans.