Hyde Michelle L, Fraser David R
Faculty of Veterinary Science, University of Sydney,NSW2006,Australia.
Br J Nutr. 2014 Sep 14;112(5):718-24. doi: 10.1017/S0007114514001500. Epub 2014 Jul 7.
In the present study, a method was developed for determining the alimentary tract Ca absorption capacity of ruminant animals by measuring the absorption rate of Sr after the administration of an oral dose of strontium chloride acting as a tracer analogue of Ca. A close correlation between the absorption rates of the two tracers was observed upon simultaneous administration of an oral dose of stable Sr and radioactive calcium (r 0·98). The Ca absorption capacity of the rumen and small intestine was determined separately by either directing the solution into the rumen or by diverting it into the post-ruminal tract by vasopressin-induced closure of the ruminoreticular groove. The animals were treated with 1α-hydroxyvitamin D3 administered via subcutaneously implanted mini-osmotic pumps. The effect of elevated plasma 1,25-dihydroxycholecalciferol concentrations on the Ca absorption capacity of the alimentary tract was then determined. An increased rate of Sr absorption was observed in both the rumen and small intestine of sheep after treatment, although it is unclear whether the rumen possesses the same vitamin D-dependent Ca absorption pathway as the small intestine.
在本研究中，开发了一种通过测量口服作为钙示踪类似物的氯化锶后锶的吸收率来测定反刍动物消化道钙吸收能力的方法。当同时口服稳定锶和放射性钙时，观察到两种示踪剂的吸收率之间存在密切相关性（r = 0·98）。通过将溶液导入瘤胃或将其通过血管加压素诱导的瘤网沟闭合转移到瘤胃后段，分别测定瘤胃和小肠的钙吸收能力。通过皮下植入微型渗透泵给动物注射1α-羟基维生素D3进行治疗。然后测定血浆1,25-二羟胆钙化醇浓度升高对消化道钙吸收能力的影响。治疗后，在绵羊的瘤胃和小肠中均观察到锶吸收速率增加，尽管尚不清楚瘤胃是否具有与小肠相同的维生素D依赖性钙吸收途径。
