Decreased Absorption of Orally Administered Ammonia by Clinoptilolite in Rats

Abstract

Abstract

Sprague-Dawley growing rats were used in four experiments to determine the effect of a natural zeolite mineral, clinoptilolite, on portal blood ammonia concentration following oral administration of (NH₄), CO₄. Stomach tubing rats with 315, 472.5, 630, or 945 mg clinoptilolite/100 g body wt reduced portal vein blood ammonia concentrations of rats orally administered, simultaneously, 45 or 90 mg (NH₄)₂CO₃/100 g body wt. The reduction was greater at the higher clinoptilolite concentration at each level of (NH₄)CO₃ administration (i.e., 472.5 mg clinoptilolite was more effective than 315 mg at a dosage of 45 mg (NH₄)₂C0₃/100 mg body wt, and 945 mg clinoptilolite was more effective than 630 mg at a dosage of 90 mg (NH₄)₂CO₃/100 mg body wt). Inclusion of 5% clinoptilolite in a diet containing 4% (NH₄)₂CO₃ did not decrease portal blood ammonia after a 30-min meal, but it did reduce portal blood ammonia concentration compared with that of rats fed the basal diet not containing clinoptilolite. It is concluded that clinoptilolite has the capacity to bind free ammonia in the gastrointestinal tract and that the degree of binding is predictable from its known ion-exchange capacity. The ammonia binding may be related to the improved efficiency of feed utilization reported in animals fed diets containing clinoptilolite.