Comparative transcriptomic analysis reveals beneficial effect of dietary mulberry leaves on the muscle quality of finishing pigs

BACKGROUND: The aim of this study was to investigate the effect of dietary mulberry leaves on the transcriptome profiles of finishing pigs. RNA‐Seq was used to identify differentially expressed genes (DEGs) in the longissimus dorsi of 56 pigs fed either a traditional diet or diets supplemented with 3%, 6% or 9% mulberry leaf powder, and both gene ontology (GO) function and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses were performed. Furthermore, protein–protein interaction (PPI) network and the subnet module analysis were used to identify genes with beneficial potential, and quantitative real‐time polymerase chain reaction (qRT‐PCR) was used to validate the expression patterns revealed by RNA‐Seq. RESULTS: Pigs fed with the 6% mulberry diet exhibited greater average daily gain, lower water loss and lower shear force than the control group and yielded 531 DEGs, including 271 and 260 upregulated and downregulated genes, respectively. Function analysis revealed that the DEGs were significantly enriched in functions related to muscle growth and development. Furthermore, several genes (i.e. ACOT4, ECHS1, HACD1, NPR1, ADCY2, MGLL and IRS1) were enriched in a KEGG pathway that was associated with fatty acid metabolism, and in the PPI subnet module, four of eight node genes, namely TNNC1, MYL3, TCAP and TNNT1, were associated with muscle formation and development. The upregulation of these genes, including TNNC1, TNNT1 and MYL3, was confirmed by qRT‐PCR. CONCLUSIONS: Dietary mulberry leaves (6%) may improve the muscle quality of pigs by modulating the expression of several key genes, such as TNNC1, MYL3 and TNNT1.