Jiang Xingwei, Geng Huijun, Zhang Chenguang, Zhu Yuanyuan, Zhu Miaomiao, Feng Dingping, Wang Dangdang, Yao Junhu, Deng Lu
College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China.
Shenzhen Research Institute, Northwest A&F University, Shenzhen, Guangdong 518000, China.
J Agric Food Chem. 2024 Dec 18;72(50):28178-28193. doi: 10.1021/acs.jafc.4c07488. Epub 2024 Dec 4.
Livestock may respond differently to circadian rhythms, leading to differences in the composition of the animal products. Nevertheless, the circadian effects on rumen microorganisms and animal products are poorly understood. In the study, it was found that dairy cows exhibited increased milk fat levels, decreased acetic acid concentrations in the rumen fluid, and elevated acetic acid levels in the blood during the night compared to those of the day. Correlational analyses suggested a high association between , , , , etc., which were significantly enriched in rumen fluid at night, and milk fat levels. The differential metabolite Vitamin B6, significantly elevated at night, promoted the translocation of acetic acid into the circulation by increasing the level of rumen epithelial MCT1 protein expression. In addition, we found that both acetic acid treatment time and dose modulated the expression of lipid metabolism transcription factors (PPARγ, PPARα, and SREBP1c) and downstream genes (FASN, SCD1, ACCα, and CPT1A). Additionally, the mTORC1 and AMPK pathways were responsible for the effects of acetic acid on transcription factors and genes involved in lipid metabolism. Differences in rumen microbial taxa were observed between the day and night. Microbial metabolite (acetic acid) was found to be absorbed into the bloodstream and entered the mammary gland at night at a significantly elevated level. This regulation impacted the expression of lipid metabolism-related transcription factors (PPARγ, PPARα, and SREBP1c), as well as downstream genes through the mTORC1 and AMPK signaling pathways, ultimately affecting milk fat synthesis. These findings provide a new perspective for the microbial regulation of milk synthesis.
家畜对昼夜节律的反应可能不同，导致动物产品的成分存在差异。然而，昼夜节律对瘤胃微生物和动物产品的影响仍知之甚少。在该研究中，发现与白天相比，奶牛在夜间表现出乳脂水平升高、瘤胃液中乙酸浓度降低以及血液中乙酸水平升高。相关性分析表明，夜间瘤胃液中显著富集的 、 、 、 等与乳脂水平高度相关。夜间显著升高的差异代谢物维生素B6通过增加瘤胃上皮MCT1蛋白表达水平促进乙酸向循环系统的转运。此外，我们发现乙酸处理时间和剂量均能调节脂质代谢转录因子（PPARγ、PPARα和SREBP1c）及下游基因（FASN、SCD1、ACCα和CPT1A）的表达。此外，mTORC1和AMPK信号通路介导了乙酸对脂质代谢相关转录因子和基因的影响。白天和夜间瘤胃微生物类群存在差异。发现微生物代谢物（乙酸）在夜间以显著升高的水平被吸收进入血液并进入乳腺。这种调节通过mTORC1和AMPK信号通路影响脂质代谢相关转录因子（PPARγ、PPARα和SREBP1c）以及下游基因的表达，最终影响乳脂合成。这些发现为乳汁合成的微生物调控提供了新的视角。
