Identification of key genes for intramuscular fat content in the longissimus dorsi muscles of different pig breeds using RNA sequencing

Abstract

There are significant differences in fat deposition capacity in muscle among different pig breeds, and such differences may be affected by the regulation of gene expression. Comparison of gene expression differences in intramuscular fat (IMF) content in the longissimus dorsi muscle of different pig breeds by RNA sequencing can reveal important genes and pathways related to IMF content and provide theoretical support for meat quality improvement and genetic breeding. In this study, 11 863 expressed genes were identified in six different pig breeds in total, and 2774 differentially expressed genes were identified between high-IMF and low-IMF groups, of which ADAMTS8 was significantly differentially expressed across all six breeds. Based on these data, an enrichment analysis was performed, and the Kyoto Encyclopedia of Genes and Genomes pathways closely related to IMF content were found to be PI3K-Akt signaling pathway, cGMP-PKG signaling pathway, and extracellular matrix–receptor interaction; the PI3K-Akt signaling pathway is especially closely related to muscle development and fat deposition. Analysis of differentially expressed genes in the PI3K-Akt signaling pathway by protein–protein interaction network showed that EGFR, EGF, ITGB3, IGF1, FGF2, and PDGFA are the key genes related to IMF content. These findings can not only contribute to understanding of the genetic regulation of IMF, but also provide scientific basis for future pork quality improvement and breeding strategies.