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.

在高产奶牛中，生理和代谢过程是适应分娩前后代谢应激增加的必要条件。为了满足牛奶合成的高能量需求，奶牛动员了大量的身体储备，特别是脂肪和肌肉组织。产后脂肪组织的动员取决于产犊前的脂肪储备量。在身体脂肪动员的过程中，不仅脂肪酸，还有其他亲脂化合物，如类固醇，可以释放到循环中。除了对生殖器官及其激素调节的影响外，这些物质还可能与代谢过程产生显著的相互作用，特别是在分娩前后和哺乳开始时。因此，脂肪组织合成或转化的类固醇的局部作用可能与整个代谢相互作用。除了类固醇及其代谢产物，胆汁酸也是由胆固醇合成的。胆汁酸参与脂质代谢，因此腹膜脂解增加可导致胆汁酸代谢失衡。泌乳早期奶牛体内储备动员的增加对胆汁酸代谢的影响目前尚未研究，但可能会影响葡萄糖、脂质、脂蛋白以及整个能量代谢。在本项目中，我们旨在研究高产奶牛的类固醇激素和胆汁酸代谢。在此过程中，由产犊前较大的身体状况引起的从怀孕到哺乳期脂肪动员增加的影响将与“正常”哺乳期诱导的动员进行比较。除了用于表征代谢的经典动物技术变量和血液参数外，我们的目标是评估血液和脂肪组织中的类固醇激素浓度以及循环胆汁酸（通过“组学”方法）。此外，甾体酶和胆汁酸酶及其受体和转运体在脂肪组织和肝脏中的表达将被研究。关于高产奶牛妊娠晚期到泌乳早期脂肪分解增加，我们旨在阐明类固醇激素（及其代谢物）和胆汁酸的生理相关性，重点是脂肪组织。由此产生的结果可能有助于制定提高奶牛生育能力和健康方面的策略。