Water, sodium and potassium movements across the rumen wall of sheep.
Water, sodium and potassium movements across the rumen wall of sheep.
复制标题
水、钠和钾穿过羊的瘤胃壁。
DOI：
--
复制
发表时间：
1972
影响因子：
--
通讯作者：
B. Stacy
中科院分区：
文献类型：
--
作者：
A. Warner;B. Stacy
唾液完全从瘤胃的羊通过食管瘘，通常由已知成分的合成唾液输液代替。利用可溶性标记物测定瘤胃中的水分运动，并计算钠和钾的运动。向瘤胃中加入水和各种溶液，以在180-550 m-osmole/kg范围内改变其渗透压。
当唾液不被取代时，水负荷后正常瘤胃渗透压的恢复确实非常缓慢。当用合成溶液代替唾液时，水穿过瘤胃壁的运动速率（y，[l./l. hr]）与渗透压（x，[m-osmol/kg]）呈线性关系，y = 0·404-0·001206 x（r =-0statist90）。这表明，瘤胃壁的过滤通透性与蛙皮或蟾蜍膀胱相似。
瘤胃壁对钾的吸收也很慢，但与钾浓度呈正相关。钠吸收似乎取决于钾浓度和渗透压以及钠浓度。虽然中等水平的钾增加了钠的吸收率，但高水平的钾足以使水大量进入瘤胃壁，使钠的吸收率降低，有时甚至显着降低。钾和钠的吸收率似乎取决于动物的即时营养状况。
Saliva was entirely diverted from the rumen of sheep via an oesophageal fistula and usually replaced by infusion of a synthetic saliva of known composition. Water movements in the rumen were measured by the use of soluble markers, and sodium and potassium movements were calculated. Water and various solutions were added to the rumen to vary its osmolality over the range 180–550 m-osmole/kg.
When saliva was not replaced, recovery of the normal rumen osmolality following water loading was very slow indeed. When saliva was replaced by a synthetic solution the rate of water movement across the rumen wall (y, [l./hr]) was a linear function of the osmotic pressure (x, [m-osmole/kg]), such that y = 0·404–0·001206x (r = -0·90). This suggests that the filtration permeability of the rumen wall was similar to that of frogskin or toad bladder.
Potassium absorption across the rumen wall was also slow but positively related to the potassium concentration. Sodium absorption appeared to depend on the potassium concentration and the osmotic pressure as well as on the sodium concentration. While moderate levels of potassium increased the rate of sodium absorption, grossly high levels, sufficient to produce a substantial entry of water across the rumen wall, decreased it, sometimes markedly. The rate of potasium and perhaps sodium absorption seemed to depend on the immediate state of nutrition of the animal.