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首页> 外文学位 >Dry period nutrition and hepatic metabolism of fatty acids and glucose in transition dairy cows.
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Dry period nutrition and hepatic metabolism of fatty acids and glucose in transition dairy cows.

机译：过渡奶牛的干旱期营养和脂肪酸和葡萄糖的肝代谢。

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摘要

In experiment 1, liver slices from multiparous Holstein cows on day -30, -14, 1, 14, and 28 relative to calving were used to determine the effects of far-off and close-up diets on palmitate metabolism in vitro. During the far-off period, d -60 to -25, cows received a low energy control diet fed ad libitum (100NRC) to meet National Research Council (2001) nutrient requirements, a moderate-energy diet fed ad libitum to exceed NRC recommendations for NE L by >50% (150NRC), or the same diet fed at restricted intake to provide 80% NEL of requirements (80 NRC). During the close-up period (day -24 until parturition), cows were fed ad libitum to meet NRC recommendations or in restricted amounts to provide 80% of calculated NEL requirements. The close-up dietary treatments had little effect on palmitate metabolism. Excessive energy intake during the far-off and close-up period promoted decreased hepatic palmitate oxidation and increased esterification of palmitate. In experiment 2, additional liver slices from experiment 1 were used to determine conversion of propionate or alanine into glucose or oxidation. Cows fed restricted amounts of energy in the far-off period had greater hepatic capacity to perform gluconeogenesis both prepartum and postpartum compared with those fed excess amounts of energy relative to requirements. Data from the first two studies indicate that far-off dietary treatment can alter hepatic metabolism. In experiment 3, an in vitro screening system was developed to test the effects of peroxisome proliferator activated receptor-alpha (PPAR-alpha) agonists on oxidation of palmitate by liver slices. The response by liver slices to both natural and synthetic PPAR-alpha agonists was intriguing and led to applications in vivo. In experiment 4, male Holstein calves were treated with both synthetic (clofibrate) and naturally occurring (fish oil) PPAR-alpha agonists to determine if male Holstein calves are a suitable model for studying liver fatty acid metabolism in adult Holstein cows and to determine if PPAR-alpha agonists alter ruminant liver fatty acid metabolism. Increases in hepatic lipid metabolism were much less than those reported in rodents treated with clofibrate or fish oil indicating that ruminants may be weak responders to PPAR-alpha agonists.
机译：在实验1中，相对于产犊，在第-30，-14、1、14和28天从多头荷斯坦奶牛的肝脏切片中测定了远距离饮食和特写饮食对体外棕榈酸酯代谢的影响。在遥远的时期，即-60至-25天，奶牛接受了低能量控制饮食（随意饲喂）以满足国家研究委员会（2001年）的营养要求，中度能量饮食随意饲喂超过了NRC的建议如果NE L大于50％（150NRC），或以限制摄入量进食相同日粮，则可提供80％的NEL需求量（80 NRC）。在封闭期间（分娩前-24天），为满足NRC的建议，随意喂养母牛或以有限的数量喂养母牛，以提供计算得出的NEL要求的80％。特写饮食疗法对棕榈酸酯代谢影响很小。在遥远的和封闭的时期过多的能量摄入促进了肝棕榈酸酯的氧化减少和棕榈酸酯的酯化增加。在实验2中，使用实验1的其他肝脏切片来确定丙酸酯或丙氨酸向葡萄糖或氧化的转化。相对于饲喂过量能量的母牛，在遥远时期饲喂有限能量的母牛具有更高的肝能力，可以进行产前和产后糖异生。前两项研究的数据表明，遥远的饮食疗法可以改变肝脏的代谢。在实验3中，开发了一种体外筛选系统，以测试过氧化物酶体增殖物激活的受体-α（PPAR-alpha）激动剂对肝片对棕榈酸酯氧化的影响。肝脏切片对天然和合成PPAR-α激动剂的反应都很有趣，并导致了其在体内的应用。在实验4中，对雄性荷斯坦犊牛进行了合成（氯贝特）和天然（鱼油）PPAR-α激动剂的处理，以确定雄性荷斯坦犊牛是否是研究成年荷斯坦奶牛肝脏脂肪酸代谢的合适模型，并确定是否PPAR-α激动剂会改变反刍动物的肝脏脂肪酸代谢。肝脂质代谢的增加远少于用氯贝贝特或鱼油处理过的啮齿类动物所报告的增加，表明反刍动物对PPAR-α激动剂的反应较弱。

著录项

  • 作者

    Litherland, Noah B.;

  • 作者单位

    University of Illinois at Urbana-Champaign.;

  • 授予单位 University of Illinois at Urbana-Champaign.;
  • 学科 Agriculture Animal Culture and Nutrition.; Agriculture Animal Pathology.
  • 学位 Ph.D.
  • 年度 2006
  • 页码 173 p.
  • 总页数 173
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 饲料;动物医学（兽医学）;
  • 关键词

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