Trace mineral bioavailability in ruminants
Trace mineral bioavailability in ruminants
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DOI：
10.1093/jn/133.5.1506s
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发表时间：
2003-05-01
影响因子：
4.2
通讯作者：
Spears, JW
中科院分区：
文献类型：
--
作者：
Spears, JW
反刍动物对硒和铜的吸收远低于非反刍动物。反刍动物对这些矿物质的低吸收是由于瘤胃环境发生的变化。硒的生物利用率降低高膳食硫和存在的氰苷在某些豆类。从硒代蛋氨酸或硒化酵母中饲喂有机硒，比用亚硒酸盐获得的组织和牛奶硒浓度高得多。高日粮钼与中到高日粮硫的组合导致硫代钼酸盐在瘤胃中的形成。硫代钼酸盐大大减少铜的吸收，某些硫代钼酸盐物种可以被吸收并全身干扰铜代谢。与钼无关，高饮食硫可能通过形成硫化铜来减少铜的吸收。高膳食铁也降低铜的生物利用度。影响反刍动物锌生物利用率的饮食因素还没有很好的定义。植酸不影响反刍动物锌的吸收，因为瘤胃中的微生物植酸酶降解植酸。反刍动物对锰的吸收非常差，有限的研究表明，高膳食钙和磷可能会减少锰的吸收。
Absorption of selenium and copper is much lower in ruminants than in nonruminants. The low absorption of these minerals in ruminants is due to modifications that occur in the rumen environment. Selenium bioavailability is reduced by high dietary sulfur and the presence of cyanogenetic glycosides in certain legumes. Feeding organic selenium from selenomethionine or selenized yeast results in much higher tissue and milk selenium concentrations than are obtained with selenite. High dietary molybdenum in combination with moderate to high dietary sulfur results in formation of thiomolybdates in the rumen. Thiomolybdates greatly reduce copper absorption, and certain thiomolybdate species can be absorbed and interfere systemically with copper metabolism. Independent of molybdenum, high dietary sulfur reduces copper absorption perhaps via formation of copper sulfide. High dietary iron also reduces copper bioavailability. Dietary factors that affect bioavailability of zinc in ruminants are not well defined. Phytate does not affect zinc absorption in ruminants because microbial phytase in the rumen degrades phytate. Manganese is very poorly absorbed in ruminants, and limited research suggests that high dietary calcium and phosphorus may reduce manganese absorption.