Leng L, Bajo M, Várady J, Szányiová M
Vet Med (Praha). 1977 Sep;22(9):529-40.
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.
采用绵羊瘤胃体外灌注法进行实验，灌注持续150分钟。灌注60分钟后，向瘤胃中加入20克酶解酪蛋白水解物。测定灌注液样本中的氨、尿素和总氮含量，并测定瘤胃内容物中的氨和pH值。在实验过程中，灌注液中积累了大量的氨。灌注结束时，NH₃-N的浓度平均达到每100毫升12毫克。灌注液中尿素水平仅在灌注的第一阶段（向瘤胃中加入酪蛋白水解物之前）下降，在随后的阶段保持不变。据推测，瘤胃壁中已经发生尿素水解后，灌注液中一部分尿素氮以氨的形式返回灌注液中。在灌注的第一阶段，氮从血液进入瘤胃，在第二阶段，观察到氮从瘤胃吸收进入血液。总氮进入瘤胃过程中的尿素氮比例在4.63%至13.84%之间，但灌注液中总氮浓度下降了7 - 15%，尿素氮浓度下降了37 - 42%。从结果可以看出，从灌注液进入瘤胃的内源性氮的主要部分是蛋白质和/或其肽类分解产物。
