基于LCMS技术对牦牛围产后期的血清动态代谢组学分析

旨在应用代谢组学的方法，阐明经产母牦牛围产后期动态代谢情况，探究营养代谢影响生殖激素的机制。本研究随机选取年龄（（7.13±0.78）岁）、体况（2.69±0.35）和胎次（（1.75±0.43）胎）相近的经产母牦牛8头作为试验动物，自分娩日开始每隔7 d收集血清至产后第28天，共5个时间点。应用液相质谱联用技术对5个时间点的血清样本进行检测，并通过生物信息学分析筛选关键代谢物，构建经产母牦牛围产后期动态代谢网络机制。试验在正、负离子模式下分别获得2 841和1 326种代谢物定性分析的结果，通过计算各时间点代谢物表达量的差异倍数、VIP值及每两个时间点T-test检验的P值，共筛选出117种差异代谢物。根据生物信息学分析，分别获得与繁殖性能、脂类代谢和氨基酸代谢相关的3种、7种和8种关键代谢物。基于关键代谢物构建动态代谢网络机制发现，糖代谢在围产后期的起始阶段作用效率较低，末期升高，脂类和氨基酸代谢在起始阶段作用效率较高，末期降低，推测经产母牦牛在产后发生能量负平衡。生殖激素的合成和分泌作用效率在围产后期一直维持较低水平。根据对经产母牦牛动态代谢谱的检测和网络机制的构建发现，经产母牦牛产后发生了能量负平衡，由于过度脂肪动员导致雌激素的合成和分泌受阻，这可能是导致经产母牦牛产后生殖机能不能及时恢复的主要原因，但具体机制还需要进一步验证。

Serum Dynamic Metabonomics Analysis of Yaks in Late Perinatal Period Based on LCMS Technology

The purpose of this study was to elucidate the dynamic metabolism of parous yaks in the late perinatal period and explore the mechanism of nutritional metabolism affecting reproductive hormones by metabolomics. Eight parous female yaks with similar age ((7.13±0.78)years), body condition score (2.69±0.35) and parity (1.75±0.43) were randomly selected. Serum was collected every 7 d from the date of the calving day to the 28th days after calving, in total 5 time points. The serum samples at 5 time points were detected by liquid chromatography mass spectrometry, and the key metabolites were screened by bioinformatics analysis to construct the dynamic metabolic network mechanism of parous yaks in the late perinatal period. The qualitative analysis results of 2 841 and 1 326 metabolites were obtained in the positive and negative ion modes, respectively. A total of 117 differential metabolites were screened by calculating the fold change of metabolite expression at each time point, VIP value and P value of T-test at each two time points. According to bioinformatics analysis, 3, 7 and 8 key metabolites related to reproductive performance, lipid metabolism and amino acid metabolism were obtained. The mechanism of constructing dynamic metabolic network based on key metabolites found that the initial efficiency of glucose metabolism in the late perinatal period was low and increased in the late perinatal period, while the efficiency of lipid metabolism and amino acid metabolism was high at the beginning and decreased in the late, it was speculated that the negative energy balance of parous female yaks occurred. The efficiency of reproductive hormone synthesis and secretion remained at a low level in the late perinatal period. According to the detection of dynamic metabolic spectrum and the construction of network mechanism of parous female yaks, it is found that there is a negative energy balance after calving, and the synthesis and secretion of estradiol are blocked due to excessive fat mobilization, which may be the main reason for the failure of postpartum reproductive function of parous female yaks to recover in time, but the specific mechanism needs to be further verified.