Fig. 4

Identification and validation of co-expression networks associated with IMF content by WGCNA. A The 19 modules correlated to IMF content were identified by WGCNA. Values in each module represented the correlation coefficient between the module and the IMF content in the LL muscle of 270 and 370-day-old pigs. Red and green color noted the positive and negative correlation, respectively. The P values in parentheses represented the significance of the correlation between modules and IMF content. The six modules marked by asterisks were selected for further analysis. B Enrichment of the KEGG pathways positively or negatively associated with IMF content in the six selected modules from A. The number ahead of the items indicated the enriched gene number in each pathway. The marked asterisks represented the most enriched pathways. C Analysis of the interaction network of differentially expressed genes (DEGs) positively regulating IMF using Cytoscape software. The larger the node, the greater number of connections it has. Nodes come from each module in B shared the same color with the module. D Expression level of hub genes in the interaction network as measured by fragments per kilobase per million (FPKM). E Western blot analyzed the protein levels of AKT, AKT-S473, AMPKα, AMPKα-T172 and SREBP1. n = 3–4 per group. All data were presented as mean ± SEM. ^*P < 0.05, ^**P < 0.01, student's t-test