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，生理和代谢过程对于适应分娩前后增加的代谢应激是必要的。为了满足牛奶合成的高能量需求，奶牛调动大量的身体储备，特别是来自脂肪和肌肉组织的能量。产后脂肪组织的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，而且其他亲脂性化合物（例如类固醇）也可以释放到循环中。由于对生殖器官及其激素调节的影响，这些物质可能与代谢过程显着相互作用，特别是在分娩前后和哺乳开始时，除了类固醇及其代谢物外，来自脂肪组织的合成或转化的类固醇的局部效应也可能与整个代谢过程相互作用。胆汁酸由胆固醇合成。胆汁酸参与脂质代谢，因此围产期脂肪分解增加会导致早期胆汁酸代谢不平衡。迄今为止，尚未研究泌乳奶牛对胆汁酸代谢的影响，但是，葡萄糖、脂质、脂蛋白以及整个能量代谢可能受到影响。在当前的项目中，我们的目标是研究类固醇激素和胆汁酸。在此过程中，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”泌乳引起的动员进行比较。利用经典的动物技术变量和血液参数来表征代谢，我们的目的是评估血液和脂肪中的类固醇激素浓度以及循环胆汁组织酸（通过“组学”方法）此外，类固醇生成酶和胆汁酸酶的表达为。以及它们的受体和转运蛋白将在脂肪组织和肝脏中进行研究。关于高产奶牛妊娠晚期到泌乳早期过渡期间脂肪分解的增加，我们的目的是阐明其生理相关性。本文产生的结果可能有助于制定改善奶牛生育力和健康方面的策略。