The mechanism of passage of endogenous urea through the rumen wall and the role of ureolytic epithelial bacteria in the urea flux

Abstract

1. The rumen urea concentration in gnotobiotic lambs lacking ureolytic bacteria was equal to that of blood. 2. Bacterial urease ( EC 3.5.1.5.) activity in sheep fed by intraruminal and intra-abomasal infusion was inversely related to rumen ammonia concentration. 3. A model is proposed for the facilitation and control of urea flux by wall-bound ureolytic bacteria.