[Effect of the ruminal amino nitrogen level on the nitrogen passage into the isolated rumen of sheep].

Eight trials were performed with two sheep to study the passage of ammonia nitrogen, urea nitrogen, and amino nitrogen into an isolated rumen at different amino nitrogen levels in rumen after a single intraruminal application of enzymatic casein hydrolyzate. After casein hydrolyzate application the level of amino nitrogen in rumen increased; consequently, the passage of ammonia to the isolated rumen rapidly decreased. The passage of nitrogen as urea and amino nitrogen to the isolated rumen is the same, both at a higher and a lower level of amino nitrogen in the rumen. The total quantity of urea and ammonia nitrogen (N-NH3 + N-urea) and amino nitrogen (N-NH3 + N-urea + amino-N) present in the isolated rumen shows a highly significant correlation with ammonia passage. This quantity reaches its maximum before the application of casein hydrolyzate to the rumen. An intensive drop occurs within one and two hours after application. The results of our study testify to the fact that the chemical composition of rumen content plays an important role in the ruminohepatic circulation of nitrogen, particularly when endogenic nitrogen passes into the rumen through rumen wall, and that the passage of nitrogen compounds from blood to the rumen is influenced not only by the concentration ratio between blood and rumen content but also by neurohumoral effects.