Integrated analysis of mRNA and miRNA expression profiles in livers of Yimeng black pigs with extreme phenotypes for backfat thickness

Fat deposition is an important economic trait in farm animals as well as obesity related diseases in humans, and the liver is a central organ involved in regulating lipid synthesis and metabolism in mammals. In this study, the pig liver transcriptome of two groups (H and L) showing differences in backfat thickness were profiled using RNA-Seq and miRNA-Seq to further explore the molecular mechanism of fat deposition. A total of 238 differentially expressed genes (DEGs) and 58 differentially expressed miRNAs were identified between the H and L group. These genes and miRNAs were functionally related to lipid metabolism, including CYP1A1/2, HMGCS2, ACSS2, UBE2L6, miR-27a, and miR-31. Functional enrichment analysis revealed that genes associated with oxidative stress might be responsible for fat deposition in pigs. Two miRNA-mRNA interaction networks involved in lipid metabolism were identified, and these provided new insights into the molecular regulation that determines fat content in these pigs. Overall, our study furthers our understanding of the molecular mechanisms involved in fat deposition, and these results may help in the design of selection strategies to improve the quality of pork meat and to combat obesity in humans.