Consensus module analysis of abdominal fat deposition across multiple broiler lines

Despite several RNA-Seq and microarray studies on differentially expressed genes (DEGs) between high- and low-abdominal fat deposition in different broiler lines, to our knowledge, gene coexpression analysis across multiple broiler lines has rarely been reported. Here, we constructed a consensus gene coexpression network focused on identifying consensus gene coexpression modules associated with abdominal fat deposition across multiple broiler lines using two public RNA-Seq datasets (GSE42980 and GSE49121).

In the consensus gene coexpression network, we identified eight consensus modules significantly correlated with abdominal fat deposition across four broiler lines using the consensus module analysis function in the weighted gene coexpression network analysis (WGCNA) package. The eight consensus modules were moderately to strongly preserved in the abdominal fat RNA-Seq dataset of another broiler line (SRP058295). Furthermore, we identified 5462 DEGs between high- and low-abdominal fat lines (FL and LL) (GSE42980) and 6904 DEGs between high- and low-growth (HG and LG) (GSE49121), including 1828 overlapping DEGs with similar expression profiles in both datasets, which were clustered into eight consensus modules. Pyruvate metabolism, fatty acid metabolism, and steroid biosynthesis were significantly enriched in the green, yellow, and medium purple 3 consensus modules. The PPAR signaling pathway and adipocytokine signaling pathway were significantly enriched in the green and purple consensus modules. Autophagy, mitophagy, and lysosome were significantly enriched in the medium purple 3 and yellow consensus modules.

Based on lipid metabolism pathways enriched in eight consensus modules and the overexpression of numerous lipogenic genes in both FL vs. LL and HG vs. LG, we hypothesize that more fatty acids, triacylglycerols (TAGs), and cholesterol might be synthesized in broilers with high abdominal fat than in broilers with low abdominal fat. According to autophagy, mitophagy, and lysosome enrichment in eight consensus modules, we inferred that autophagy might participate in broiler abdominal fat deposition. Altogether, these studies suggest eight consensus modules associated with abdominal fat deposition in broilers. Our study also provides an idea for investigating the molecular mechanism of abdominal fat deposition across multiple broiler lines.