Fig. 1.

A schematic presentation of the role of urease and ureolytic bacteria in urea metabolism. Urea in gastrointestinal tracts (GIT) is hydrolyzed to ammonia by urease enzymes produced by ureolytic bacteria residing in the GIT. Urease activity in the GIT, especially in the rumen, is highly expressed; their suppression may aid to decrease ammonia toxicity and to improve utilization of protein in ruminants, and to lower ammonia concentration in GIT content in non-ruminants for improved GI health and production performance.