Laying performance is an important economic trait in hens, and this physiological process is largely influenced by the liver function. The livers of hens at 20- and 30-week-old stages were investigated using the next generation sequencing to identify the differences of microRNA expression profiles. Compared with the 20-week-old hens, 67 down- and 13 up-regulated microRNAs were verified to be significant differentially expressed (false discovery rate, FDR ≤ 0.05) (SDE) in the 30-week-old. We also identified 13 down- and 6 up-regulated novel differentially expressed (DE) microRNAs. miR-22-3p and miR-146b-5p, which exhibit critical roles in mammalian lipid metabolism, showed the most abundant expression and the highest fold-change, respectively. A total of 648 potential target genes of the SDE microRNAs were identified through an integrated analysis of microRNAs and the DE genes obtained in previous RNA-sequencing, including FADS1, FADS2, ELOVL6 and ACSL5, which are critical lipid metabolism-related regulators. Bioinformatic analyses revealed that target genes were mainly enriched in lipid-related metabolism processes. This work provides the first study of the expression patterns of hepatic microRNAs between 20- and 30-week old hens. The findings may serve as a fundamental resource for understanding the detailed functions of microRNAs in the molecular regulatory systems of lipid metabolism.

中文翻译：

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系统分析的microRNA在鸡肝脂质代谢中的调节功能。

产蛋性能是母鸡的一项重要经济特征，这种生理过程在很大程度上受肝脏功能的影响。使用下一代测序研究了20周龄和30周龄母鸡的肝脏，以鉴定microRNA表达谱的差异。与20周龄的母鸡相比，在30周龄的母鸡中，有67个下调的microRNA和13个上调的microRNA被证实具有显着差异表达（错误发现率，FDR≤0.05）。我们还确定了13个下调和6个上调的新型差异表达（DE）microRNA。在哺乳动物脂质代谢中发挥关键作用的miR-22-3p和miR-146b-5p分别显示了最丰富的表达和最高的倍数变化。通过对microRNA和以前的RNA测序中获得的DE基因进行综合分析，共鉴定出648个SDE microRNA的潜在靶基因，包括FADS1，FADS2，ELOVL6和ACSL5，它们是与脂质代谢相关的关键调控因子。生物信息学分析表明，靶基因主要富集在脂质相关的代谢过程中。这项工作提供了对20到30周龄母鸡中肝microRNA表达模式的首次研究。这些发现可以作为了解微小RNA在脂质代谢分子调控系统中的详细功能的基础资源。生物信息学分析表明，靶基因主要富集在脂质相关的代谢过程中。这项工作提供了对20到30周龄母鸡中肝microRNA表达模式的首次研究。这些发现可以作为了解微小RNA在脂质代谢分子调控系统中的详细功能的基础资源。生物信息学分析表明，靶基因主要富集在脂质相关的代谢过程中。这项工作提供了对20到30周龄母鸡中肝microRNA表达模式的首次研究。这些发现可以作为了解微小RNA在脂质代谢分子调控系统中的详细功能的基础资源。