Ki. Kim et al., FEEDING DIETS CONTAINING HIGH-LEVELS OF MILK-PRODUCTS OR CELLULOSE DECREASE UREASE ACTIVITY AND AMMONIA PRODUCTION IN RAT INTESTINE, The Journal of nutrition, 128(7), 1998, pp. 1186-1191
Three studies were done to determine the effect of feeding diets conta
ining high levels of a readily fermentable carbohydrate (lactose in mi
lk or yogurt, or pure lactose) or an undigestible, unfermentable dilue
nt (alpha-cellulose) on urease (EC 3.5.1.5) activity and net ammonia p
roduction in the rat gastrointestinal (GI) contents. Rats (170-200 g)
were fed a control diet or diets containing 55% dried milk or 55% drie
d yogurt, 25% lactose or 10% alpha-cellulose. Feeding diets containing
milk or yogurt decreased urease activity to similar to 11% of the con
trol value in the small intestine (on the basis of grams of collected
contents or total contents), and to 50% in the large intestine (only o
n the basis of grams of collected contents). Feeding the diet containi
ng 25% lactose also decreased urease activity (on the basis of grams o
f collected contents or total contents) to about 20% of the control va
lue in the small intestine, but not (P > 0.05) in the large intestine.
Net ammonia production rate was correlated (r(2) = 0.98) with urease
activity in the large intestinal contents, and the rate of ammonia pro
duction from ureolysis represented about two thirds of the total. Feed
ing the cellulose diet decreased (P < 0.05) both urease activity and n
et ammonia production in the large intestine to similar to 30% of the
control value. Weights of tissue and contents of the large intestine w
ere much higher (P < 0.01) in rats fed diets containing milk products
or lactose than in the control rats, but were not affected by consumpt
ion of the cellulose diet. Results of our studies indicate that feedin
g diets containing high levels of milk products (lactose) or cellulose
reduces urease activity and net ammonia production in the rat intesti
ne, and thus may be beneficial for improving animal and human health.