Scott D, McLean A F, Buchan W
Q J Exp Physiol. 1984 Jul;69(3):439-52. doi: 10.1113/expphysiol.1984.sp002830.
Mature sheep fitted with rumen and duodenal cannulae and fed either pelleted hay or grass diets were given supplements of Na2HPO4 by continuous infusion into the rumen and the effects on salivary phosphorus secretion, intestinal phosphorus absorption and pathway of excretion were studied. Little phosphorus was excreted in the urine in control periods and little increase was seen in response to phosphorus supplementation, most of the extra phosphorus given being recovered in the faeces. Infusion of phosphorus into the rumen led to an increase in the flow of phosphorus to the intestine, an increase in absorption, a rise in plasma phosphate level and an increase in salivary phosphorus secretion while withdrawal of supplementary phosphorus was seen to have the opposite effects. In separate studies short sections of the upper small intestine temporarily isolated from the normal flow of digesta were perfused with solutions containing NaH2PO4 (5-50 mmol.l-1). Phosphorus absorption increased with increasing concentration though the relationship was curvilinear such that absorptive efficiency fell from around 0.7 at 5 mmol.l-1 to around 0.35 at a concentration of 50 mmol.l-1. The significance of these results in relation to the control of phosphorus balance in ruminants is discussed.
给装有瘤胃和十二指肠套管且分别饲喂颗粒干草或青草日粮的成年绵羊，通过向瘤胃持续输注补充Na2HPO4，并研究其对唾液磷分泌、肠道磷吸收及排泄途径的影响。在对照期，尿液中排出的磷很少，补充磷后增加也不明显，补充的大部分额外磷都在粪便中回收。向瘤胃输注磷导致进入肠道的磷流量增加、吸收增加、血浆磷酸盐水平升高以及唾液磷分泌增加，而停止补充磷则产生相反的效果。在单独的研究中，将从小肠上部暂时分离出的短节段与正常消化物流动隔离开来，用含有NaH2PO4（5 - 50 mmol·l-1）的溶液进行灌注。磷吸收随着浓度增加而增加，尽管这种关系是曲线关系，即吸收效率从5 mmol·l-1时的约0.7降至50 mmol·l-1浓度时的约0.35。讨论了这些结果与反刍动物磷平衡控制的相关性。
