Department of Animal Science, University of Tennessee, Knoxville, TN 37996, USA.
Department of Chemistry, University of Tennessee, Knoxville, TN 37996, USA.
J Anim Sci. 2022 Jul 1;100(7). doi: 10.1093/jas/skac152.
Extremes in body condition reduce fertility and overall productivity in beef cattle herds, due in part to altered systemic metabolic conditions that influence the intrafollicular and uterine environment. Follicular fluid and serum metabolome profiles are influenced by body composition in women and dairy cattle; however, such information is lacking in beef cattle. We hypothesized that body condition score (BCS)-related alterations in the metabolome of preovulatory follicular fluid and serum may influence oocyte maturation while impacting the oviductal or uterine environment. Therefore, we performed a study with the objective to determine the relationship between BCS and the metabolome of follicular fluid and serum in lactating beef cattle. We synchronized the development of a preovulatory follicle in 130 cows of varying BCS. We collected blood and performed transvaginal follicle aspirations to collect follicular fluid from the preovulatory follicle ~18 h after gonadotropin-releasing hormone administration to stimulate the preovulatory gonadotropin surge. We then selected follicular fluid and serum samples from cows with BCS 4 (Thin; n = 14), BCS 6 (Moderate; n = 18), or BCS >8 (Obese; n = 14) for ultra-high performance liquid chromatography-high resolution mass spectrometry. We identified differences in the follicular fluid or serum of thin, moderate, and obese animals based on multiple linear regression. MetaboAnalyst 5.0 was used for enrichment analysis of significant metabolites. We identified 38 metabolites in follicular fluid and 49 metabolites in serum. There were no significant differences in follicular fluid metabolite content among BCS classifications. There were 5, 22, and 1 serum metabolites differentially abundant between thin-obese, moderate-thin, and moderate-obese classifications, respectively (false discovery rate [FDR] < 0.10). These metabolites were enriched in multiple processes including "arginine biosynthesis," "arginine/proline metabolism," and "D-glutamine/D-glutamate metabolism" (FDR < 0.04). Pathways enriched with serum metabolites associated with BCS indicate potentially increased reactive oxygen species (ROS) in serum of thin cows. ROS crossing the blood follicular barrier may negatively impact the oocyte during oocyte maturation and contribute to the reduced pregnancy rates observed in thin beef cows.
体况极端会降低肉牛群的繁殖力和整体生产力，部分原因是改变了系统代谢状况，从而影响了卵泡内和子宫内的环境。卵泡液和血清代谢组谱受女性和奶牛的体组成影响；然而，在肉牛中缺乏此类信息。我们假设与体况评分（BCS）相关的促黄体激素释放激素（GnRH）预处理后卵母细胞成熟过程中，卵泡液和血清代谢组的变化可能会影响卵母细胞的成熟，并影响输卵管或子宫环境。因此，我们进行了一项研究，目的是确定 BC 与泌乳肉牛中卵泡液和血清代谢组的关系。我们对不同 BC 的 130 头母牛同步了一个促黄体激素释放激素（GnRH）预处理后卵泡的发育。我们在 GnRH 注射后约 18 小时采集血液并进行阴道超声卵泡抽吸术，以从促黄体激素释放激素预处理后卵泡中采集卵泡液。然后，我们从 BC4（消瘦；n = 14）、BC6（适中；n = 18）或 BC > 8（肥胖；n = 14）的牛中选择卵泡液和血清样本进行超高效液相色谱-高分辨率质谱分析。我们根据多元线性回归确定了瘦、中、肥胖动物卵泡液和血清中差异代谢物。使用 MetaboAnalyst 5.0 对显著代谢物进行富集分析。我们在卵泡液中鉴定出 38 种代谢物，在血清中鉴定出 49 种代谢物。BC 分类之间卵泡液代谢物含量没有差异。瘦-肥胖、中-瘦和中-肥胖分类之间的血清代谢物分别有 5、22 和 1 个差异丰度（错误发现率[FDR] < 0.10）。这些代谢物富集在多个过程中，包括“精氨酸生物合成”、“精氨酸/脯氨酸代谢”和“D-谷氨酰胺/D-谷氨酸代谢”（FDR < 0.04）。与 BC 相关的与血清代谢物相关的途径表明，瘦牛的血清中可能存在增加的活性氧（ROS）。ROS 穿过血液卵泡屏障可能会在卵母细胞成熟过程中对卵母细胞产生负面影响，并导致瘦肉牛妊娠率降低。
