[The passage of nitrogenous compounds through the wall of perfused sheep rumen (author's transl)].

Experiments were performed by the method of the extracorporeal perfusion of sheep rumen lasting 150 minutes. After 60 minutes of perfusion, 20 g of enzymatic casein hydrolyzate were applied to the rumen. Ammonia, urea, and total nitrogen were determined in the samples of perfusate, and ammonia and pH were determined in the rumen content. Considerable amounts of ammonia accumulated in the perfusate in the course of the experiment. At the end of perfusion, the concentration of NH3-N reached an average value of up to 12 mg per 100 ml. The level of urea in the perfusate decreased only in the first phase of perfusion (before the application of casein hydrolyzate to the rumen) and remained unchanged in the subsequent phase. It is assumed that part of urea-N from the perfusate after urea hydrolysis, taking place already in the rumen wall, returned to the perfusate in the form of ammonia. In the first phase of perfusion the passage of nitrogen from the blood into the rumen took place, in the second phase its absorption from the rumen into the blood was observed. The urea-N ratio from the passage of total nitrogen into the rumen ranged between 4.63% and 13.84%, but the concentration of total nitrogen in the perfusate decreased by 7-15% and that of urea nitrogen by 37-42%. It follows from the results that a major part of endogenous nitrogen passing from perfusate to the rumen was represented by proteins and/or their peptidic splits.