The difference in muscle fiber types is very important to the muscle development and meat quality of broilers. At present, the molecular regulation mechanisms of skeletal muscle fiber-type transformation in broilers are still unclear. In this study, differentially expressed genes between breast and leg muscles in broilers were analyzed using RNA-seq. A total of 767 DEGs were identified. Compared with leg muscle, there were 429 upregulated genes and 338 downregulated genes in breast muscle. Gene Ontology (GO) enrichment indicated that these DEGs were mainly involved in cellular processes, single organism processes, cells, and cellular components, as well as binding and catalytic activity. KEGG analysis shows that a total of 230 DEGs were mapped to 126 KEGG pathways and significantly enriched in the four pathways of glycolysis/gluconeogenesis, starch and sucrose metabolism, insulin signalling pathways, and the biosynthesis of amino acids. Quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to verify the differential expression of 7 selected DEGs, and the results were consistent with RNA-seq data. In addition, the expression profile of MyHC isoforms in chicken skeletal muscle cells showed that with the extension of differentiation time, the expression of fast fiber subunits (types IIA and IIB) gradually increased, while slow muscle fiber subunits (type I) showed a downward trend after 4 days of differentiation. The differential genes screened in this study will provide some new ideas for further understanding the molecular mechanism of skeletal muscle fiber transformation in broilers.

中文翻译：

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使用RNA-seq技术鉴定不同类型肉鸡骨骼肌纤维中差异表达的基因。

肌肉纤维类型的差异对于肉鸡的肌肉发育和肉质非常重要。目前，肉鸡骨骼肌纤维类型转化的分子调控机制尚不清楚。在这项研究中，使用RNA-seq分析了肉鸡乳房和腿部肌肉之间差异表达的基因。总共鉴定出767个DEG。与腿部肌肉相比，胸肌中有429个上调基因和338个下调基因。基因本体论（GO）富集表明，这些DEG主要涉及细胞过程，单生物过程，细胞和细胞成分，以及结合和催化活性。KEGG分析表明，总共有230个DEGs定位于126条KEGG途径，并显着丰富了糖酵解/糖异生的四个途径，淀粉和蔗糖的代谢，胰岛素的信号传导途径以及氨基酸的生物合成。实时定量逆转录聚合酶链反应（qRT-PCR）用于验证7种选定DEGs的差异表达，结果与RNA-seq数据一致。另外，表达谱鸡骨骼肌细胞中的MyHC亚型显示，随着分化时间的延长，分化4天后快纤维亚基（IIA和IIB型）的表达逐渐增加，而慢肌纤维亚基（I型）的表达则呈下降趋势。本研究筛选的差异基因将为进一步理解肉鸡骨骼肌纤维转化的分子机制提供一些新思路。