Javorský P, Rybosová E, Havassy I, Horský K, Kmet V
Physiol Bohemoslov. 1987;36(1):75-81.
In experiments on six sheep fed on a low nitrogen diet (3.7 g N/day), urease (EC 3.5.1.5) activity (nkat X mg-1 bacterial dry weight) 3 h after feeding was found to be highest in the bacteria adhering to the rumen wall (13.25 +/- 2.10), lower in the rumen fluid bacteria (8.96 +/- 1.35) and lowest in the bacteria adhering to feed particles in the rumen (5.69 +/- 2.13). The urease activity of bacteria adhering to the rumen wall and of the rumen fluid bacteria of six sheep fed on a high nitrogen diet (21 g N/day) was significantly lower than in sheep with a low N intake and in both cases was roughly the same (3.81 +/- 1.37 and 3.76 +/- 1.02 respectively); it was lowest in bacteria adhering to feed particles in the rumen (1.92 +/- 0.90). It is concluded from the results that the urease activity of rumen fluid bacteria and of bacteria adhering to the rumen wall and to feed particles in the rumen is different and that it falls significantly in the presence of a high nitrogen intake. From the relatively high ureolytic activity of bacteria adhering to the rumen wall in the presence of a low nitrogen intake it is assumed that this is one of the partial mechanisms of the hydrolysis of blood urea entering the rumen across the rumen wall and of its reutilization in the rumen-liver nitrogen cycle in ruminants.
在对六只以低氮日粮（3.7克氮/天）饲养的绵羊进行的实验中，发现喂食后3小时，附着于瘤胃壁的细菌中的脲酶（EC 3.5.1.5）活性（纳摩尔每毫克细菌干重）最高（13.25±2.10），瘤胃液细菌中的活性较低（8.96±1.35），而附着于瘤胃中饲料颗粒的细菌中的活性最低（5.69±2.13）。以高氮日粮（21克氮/天）饲养的六只绵羊的瘤胃壁附着细菌和瘤胃液细菌的脲酶活性显著低于低氮摄入的绵羊，且在两种情况下大致相同（分别为3.81±1.37和3.76±1.02）；附着于瘤胃中饲料颗粒的细菌中的活性最低（1.92±0.90）。从结果得出结论，瘤胃液细菌、附着于瘤胃壁的细菌以及附着于瘤胃中饲料颗粒的细菌的脲酶活性不同，并且在高氮摄入情况下其活性显著下降。从低氮摄入时附着于瘤胃壁的细菌具有较高的尿素分解活性推测，这是反刍动物瘤胃壁进入瘤胃的血液尿素水解及其在瘤胃-肝脏氮循环中再利用的部分机制之一。
