Transcriptome-based analysis of key genes and pathways affecting the linoleic acid content in chickens

Linoleic acid is an essential polyunsaturated fatty acid that cannot be synthesized by humans or animals themselves and can only be obtained externally. The amount of linoleic acid present has an impact on the quality and flavour of meat and indirectly affects consumer preference. However, the molecular mechanisms influencing the deposition of linoleic acid in organisms are not clear. As the molecular mechanisms of linoleic acid deposition are not well understood, to investigate the main effector genes affecting the linoleic acid content, this study aimed to screen for hub genes in slow-type yellow-feathered chickens by transcriptome sequencing (RNA-Seq) and weighted gene coexpression network analysis (WGCNA). We screened for candidate genes associated with the linoleic acid content in slow-type yellow-feathered broilers. A total of 399 Tiannong partridge chickens were slaughtered at 126 days of age, fatty acid levels were measured in pectoral muscle, and pectoral muscle tissue was collected for transcriptome sequencing. Transcriptome sequencing results were combined with phenotypes for WGCNA to screen for candidate genes. KEGG enrichment analysis was also performed on the genes that were significantly enriched in the modules with the highest correlation. A total of 13 310 genes were identified after quality control of transcriptomic data from 399 pectoral muscle tissues. WGCNA was performed, and a total of 26 modules were obtained, eight of which were highly correlated with the linoleic acid content. Four key genes, namely, MDH2, ATP5B, RPL7A and PDGFRA, were screened according to the criteria |GS|>0.2 and |MM|>0.8. The functional enrichment results showed that the genes within the target modules were mainly enriched in metabolic pathways. In this study, a large-sample-size transcriptome analysis revealed that metabolic pathways play an important role in the regulation of the linoleic acid content in Tiannong partridge chickens, and MDH2, ATP5B, RPL7A and PDGFRA were screened as important candidate genes affecting the linoleic acid content. The results of this study provide a theoretical basis for selecting molecular markers and comprehensively understanding the molecular mechanism affecting the linoleic acid content in muscle, providing an important reference for the breeding of slow-type yellow-feathered broiler chickens.