COBALT VITAMIN-B-12 DEFICIENCY CAUSES ACCUMULATION OF ODD-NUMBERED, BRANCHED-CHAIN FATTY-ACIDS IN THE TISSUES OF SHEEP
COBALT VITAMIN-B-12 DEFICIENCY CAUSES ACCUMULATION OF ODD-NUMBERED, BRANCHED-CHAIN FATTY-ACIDS IN THE TISSUES OF SHEEP
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DOI：
10.1079/bjn19940111
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发表时间：
1994-01-01
影响因子：
3.6
通讯作者：
YOUNG, PB
中科院分区：
文献类型：
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作者：
KENNEDY, DG;KENNEDY, S;YOUNG, PB
将9只5月龄羔羊随机分为两组，分别饲喂缺钴全麦日粮(N 5)和添加Co的相同日粮(N 4)。这些羔羊用各自的日粮喂养了28周。6周后血浆维生素B-12浓度降至正常值下限以下，10周后血浆甲基丙二酸(MMA)浓度回升至正常值上限以上。然而，在实验接近结束时，血浆RIMA浓度下降到接近正常水平，这表明根据血浆MMA浓度的测定诊断更严重的钴缺乏症的价值可能有限。屠宰时采集的组织样品分析表明，与对照相比，缺钴绵羊组织中维生素B-12浓度和甲基丙二酰辅酶A变位酶(EC5.4.99.2)活性显著降低。虽然钴缺乏的动物的组织中MMA的浓度与对照组没有显著差异，但我们确实检测到支链脂肪酸的浓度增加。这表明，脂肪酸中出现了MMA的错误结合，而不是丙酸。钴缺乏的羔羊没有出现任何神经症状，这表明支链脂肪酸的积累可能不参与神经损伤的发展。
Nine 5-month-old lambs were randomly allocated to two groups and were fed on either a Co-deficient whole-barley diet (n 5), or the same diet supplemented with Co (n 4). The lambs were fed on their respective diets for 28 weeks. Plasma vitamin B-12 concentrations fell below the lower Limit of normality after 6 weeks, and plasma methylmalonic acid (MMA) concentrations rose above the upper Limit of normality after 10 weeks. However, plasma RIMA concentrations fell to near normal levels towards the end of the experiment suggesting that diagnosis of more severe Co deficiency based on determination of plasma MMA concentrations may be of limited value. Analysis of tissue samples collected at slaughter revealed a marked reduction in the vitamin B-12 concentration and the activity of methylmalonyl-CoA mutase (EC 5.4.99.2) in the tissues takes from the Co-deficient sheep, by comparison with the controls. Although tissue concentrations of MMA in the Co-deficient animals were not significantly different from those of the controls, we did detect increased concentrations of branched-chain fatty acids. This suggested that misincorporation of MMA, but not propionic acid, into fatty acids had occurred. The Co-deficient lambs did not develop any neurological signs, suggesting that accumulation of branched-chain fatty acids may not be involved in the development of neurological lesions.