Department of Animal Science, Michigan State University, East Lansing 48824; Reproductive and Developmental Sciences Program, Michigan State University, East Lansing 48824.
Department of Animal Science, Michigan State University, East Lansing 48824.
J Dairy Sci. 2022 Oct;105(10):8470-8484. doi: 10.3168/jds.2022-21919. Epub 2022 Aug 6.
The objective of this study was to determine the effect of early lactation body condition (BC) loss in multiparous dairy cows on serum lipids and the effect of these changes on oocyte and cumulus cell transcriptomes. Body condition loss in dairy cattle after parturition is associated with reduced fertility and increased pregnancy loss. The complex interplay between BC, nutrition, dry matter intake, milk production, and time of calving has presented a barrier to understanding mechanisms leading to reduced fertility. We identified cows that lost BC (L group; n = 10) or maintained or gained BC (M/G group; n = 8) during the first 27 to 33 d in milk and investigated changes in serum fatty acids and oocyte and cumulus cell transcriptomes at 75 to 81 d in milk. The L group had increased serum levels of nonesterified fatty acids and mead acid, and reduced serum levels of petroselaidic acid and behenic acid. Transcriptome analyses revealed 38 differentially expressed genes (DEG) in oocytes and 71 DEG in cumulus cells of L (n = 3) compared with M/G group (n = 3). Network analysis connected serum fatty acid changes to downstream effects including reduced inflammatory response and mitochondrial membrane depolarization, increased production of reactive oxygen species, and functions related to fatty acid metabolism and cytoplasmic organization in oocytes. These effects were associated with predicted effects on signaling in oocytes through calcium, insulin, O-GlcNAcase (OGA), fibroblast growth factor receptor 4 (FGF4R), peroxisome proliferator activated receptor gamma coactivator 1 α (PPARGC1A), and phospholipase D2 (PLD2) pathways, with a connection to the cumulus cell via calcium signaling. These results connect BC loss following parturition to changes in serum lipid levels, and changes potentially affecting oocyte quality; thus, these results provide new insight into mechanism of reduced fertility.
本研究旨在确定多产奶牛产后早期体况（BC）损失对血清脂质的影响，以及这些变化对卵母细胞和卵丘细胞转录组的影响。产后奶牛的 BC 损失与生育力降低和妊娠损失增加有关。BC 与营养、干物质摄入量、产奶量和产犊时间之间的复杂相互作用，一直是理解导致生育力降低的机制的障碍。我们确定了在产后第 27 至 33 天内失去 BC（L 组；n = 10）或保持或增加 BC（M/G 组；n = 8）的奶牛，并研究了在产后第 75 至 81 天血清脂肪酸以及卵母细胞和卵丘细胞转录组的变化。L 组血清中非酯化脂肪酸和蜂花酸水平升高，而 petroselaidic 酸和正二十二酸水平降低。与 M/G 组（n = 3）相比，L 组（n = 3）卵母细胞中差异表达基因（DEG）有 38 个，卵丘细胞中有 71 个。网络分析将血清脂肪酸变化与下游效应联系起来，包括炎症反应和线粒体膜去极化减少、活性氧产生增加以及与卵母细胞中脂肪酸代谢和细胞质组织相关的功能。这些效应与通过钙、胰岛素、O-连接的 N-乙酰葡萄糖胺酶（OGA）、成纤维细胞生长因子受体 4（FGF4R）、过氧化物酶体增殖物激活受体 γ共激活因子 1α（PPARGC1A）和磷脂酶 D2（PLD2）途径对卵母细胞信号的预测效应有关，并通过钙信号与卵丘细胞相关。这些结果将产后的 BC 损失与血清脂质水平的变化联系起来，这些变化可能影响卵母细胞质量；因此，这些结果为生育力降低的机制提供了新的见解。
