BACKGROUND Fertility is the most important economic trait in sows, as it is critical for profitability. Considerable phenotypic variation in litter size exists in Large White sows. However, relatively little is known about the underlying molecular and genetic bases. OBJECTIVE An experiment was conducted to screen key genes that affect the fecundity of pigs during the luteal (L) and follicular phases (F) of the estrous cycle. METHODS Eight sows (n = 4 for high fertility sows and n = 4 for low fertility sows) were sacrificed on day 14 (day 1 = first day of estrus) after estrus in the L phase. Another eight sows were slaughtered on day 20 of the estrous cycle in the F phase. Sixteen ovarian tissue samples were collected at the different sacrifice time points. Total RNA extracted was used to construct the library and then sequence on an Illumina HiSeq X10 system. Differentially expressed genes (DEGs) between high and low fertility in Large White sows were identified, and their potential biological functions were analyzed using bioinformatics analysis. RESULTS In total, 457 DEGs (161 up-regulated and 296 down-regulated genes) were detected in the ovarian tissues of the high and low fertility groups in the L phase of the estrous cycle. Furthermore, 475 DEGs (253 up-regulated and 222 down-regulated genes) were identified in the F phase. Twenty-nine DEGs were common to both comparisons. Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that the DEGs were mainly associated with steroid biosynthesis, the Hippo signaling pathway, and lysosomes. Others, such as MSMO1, CYP27B1, and CTSB, were related to reproduction. CONCLUSION These results will contribute to a better understanding of the individual differences in fertility at the transcriptome level, which may provide useful information to explore new ways to improve fertility in pigs.

中文翻译：

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卵巢转录组的比较分析揭示了大白母猪繁殖力差异的新颖见解。

背景技术生育是母猪最重要的经济特征，因为它对获利至关重要。大白母猪的产仔数存在明显的表型差异。但是，对潜在的分子和遗传基础知之甚少。目的进行了一项实验，以筛选在发情周期的黄体期（L）和卵泡期（F）影响猪繁殖力的关键基因。方法在L期发情后的第14天（第1天=发情的第一天）处死八只母猪（高生育力母猪n = 4，低生育力母猪n = 4）。在F期的发情周期的第20天，宰杀了另外8头母猪。在不同的牺牲时间点收集了十六个卵巢组织样品。提取的总RNA用于构建文库，然后在Illumina HiSeq X10系统上测序。确定了大白母猪高低繁殖力之间的差异表达基因（DEG），并使用生物信息学分析法分析了它们的潜在生物学功能。结果在发情周期的L期，在高和低生育力组的卵巢组织中共检测到457个DEG（161个上调基因和296个下调基因）。此外，在F期鉴定出475个DEG（253个上调基因和222个下调基因）。两个比较共有29个DEG。京都基因与基因组百科全书中的富集分析表明，DEGs主要与类固醇的生物合成，河马信号通路和溶酶体有关。其他，例如MSMO1，CYP27B1和CTSB，与生殖有关。结论这些结果将有助于更好地理解转录组水平上个体的育性差异，这可能为探索改善猪育性的新方法提供有用的信息。