Effects of a lactation-induced and body condition-dependent mobilization of body reserves on steroid hormone and bile acid metabolism in high-yielding dairy cows

泌乳诱导和身体状况依赖性身体储备动员对高产奶牛类固醇激素和胆汁酸代谢的影响

• 批准号: 451944681
• 负责人: Dr. Susanne Häußler
• 金额: --
• 依托单位: Abteilung Physiologie und Hygiene
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/451944681?language=en
• 关键词: Effects; lactation; induced; body; condition

In high-yielding dairy cows, physiological and metabolical processes are necessary for adapting to the increased metabolic stress around parturition. In order to meet the high-energy requirements for milk synthesis, cows mobilize large amounts of body reserves particularly from adipose and muscle tissue. The mobilization of adipose tissue post partum depends on the amount of fat reserves before calving. In the course of body fat mobilization, not only fatty acids but also other lipophilic compounds such as steroids, can be released into the circulation. Besides effects on reproductive organs and their hormonal regulation, these substances might significantly interact with metabolic processes particularly around parturition and at the onset of lactation. Local effects of synthesized or transformed steroids from adipose tissue might thus interact with the whole metabolism. Besides steroids and their metabolites, bile acids are synthesized from cholesterol. Bile acids are involved in lipid metabolism, therefore an increased peripartal lipolysis can lead to an imbalance of bile acid metabolism. The impact of an increased mobilization of body reserves in early lactating dairy cows on bile acid metabolism has not been investigated so far, however, glucose-, lipid-, lipoprotein- as well as the whole energy metabolism could be affected. In the current project, we aim to investigate the steroid hormone and bile acid metabolism from high-yielding dairy cows. In doing so, the impact of increased fat mobilization from pregnancy to lactation, provoked by a greater body condition before calving, will be compared to a „normal“ lactation-induced mobilization. Besides the classical zootechnical variables and blood parameters for characterizing the metabolism, we aim to assess the steroid hormone concentrations in blood and adipose tissue as well as circulating bile acids (via an „omics“ approach). Furthermore, the expression of steroidogenic and bile acid enzymes as well as their receptors and transporters will be investigated in adipose tissue and liver. Regarding the increased lipolysis during the transition of late pregnancy to early lactation in high-yielding dairy cows, we aim to elucidate the physiological relevance of steroid hormones (and metabolites) and bile acids with focus on adipose tissue. Results generated herein might help to develop strategies to improve cows` fertility and health aspects.

在高产的奶牛中，对于适应分娩周围的代谢压力的增加是必需的。为了满足牛奶合成的高能要求，牛动员了大量的身体储备，尤其是从脂肪和肌肉组织中。脂肪组织的动员在围结和动员取决于产犊前的脂肪储备量。在体内脂肪动员过程中，不仅脂肪酸，而且还可以释放出其他亲脂性化合物，例如类固醇。除了对生殖器官及其马匹调节的影响外，这些物质可能与代谢过程显着相互作用，尤其是在分娩和泌乳开始时。因此，从脂肪组织中合成或转化的类固醇的局部作用可能与整个新陈代谢相互作用。除了类固醇及其代谢产物外，胆汁酸还从胆固醇中合成。胆汁酸参与脂质代谢，因此外周脂解的增加会导致胆汁酸代谢的失衡。到目前为止，尚未研究葡萄糖，脂质，脂蛋白以及整个能量代谢。在当前的项目中，我们旨在研究高产奶牛的立体声恐怖剂和胆汁酸代谢。在此过程中，将与正常的“哺乳化引起的动员”进行比较，从怀孕到泌乳的脂肪动员增加的影响将被比较。除了经典的动态技术变量和血液参数外，我们还旨在评估血液中的酸和脂肪的循环（以及循环的循环），我们旨在评估contere的含量，并循环地评估循环的循环。此外，将在脂肪组织和肝脏中研究类固醇和胆汁酸酶及其受体和转运蛋白的表达。关于在高产奶牛中妊娠晚期过渡到早期泌乳期间的脂解的增加，我们旨在阐明类固醇激素（和代谢产物）和胆汁酸的物理相关性，并侧重于脂肪组织。本文产生的结果可能有助于制定策略以改善牛的生育能力和健康方面。