Transcriptomic analysis identifies hub genes involved in age-dependent abdominal fat development in chickens

Excessive accumulation of abdominal fat (AF) reduces feed efficiency and carcass yield, posing a significant challenge to the poultry industry. However, the molecular network underlying age-dependent AF development remains unclear, despite some recent progress. In this study, we quantified the abdominal adipocyte area and sequenced 20 AF transcriptomes from eight 9-week-old (9 W) and twelve 20-week-old (20 W) Wannan chickens. The abdominal adipocyte area increased significantly at 20 W compared with 9 W (p < 0.001). Differentially expressed gene analysis between the two age groups revealed 235 up-regulated and 206 down-regulated genes in the 20 W. Enrichment analysis revealed the cytokine-cytokine receptor interaction, cell adhesion molecules, TGF-beta signaling pathway, and biological processes related to the cell surface receptor signaling pathway and cellular developmental process. We performed weighted gene co-expression network analysis (WGCNA) using a total of 23,225 genes, which identified 32 co-expression modules. The darkgreen, lightcyan1, and royalblue modules were significantly correlated with adipocyte area, abdominal fat percentage (AFP), and age. Genes within these modules were enriched in GO terms such as the catalytic complex, oleate transmembrane transporter activity, and cell cycle process. Notably, 5 up-regulated genes were identified in the darkgreen module, 3 down-regulated genes in the lightcyan1 module, and 23 down-regulated genes in the royalblue module. Among these genes, several genes with the highest connectivity, including JUND, PAPSS2, PAK6, PIEZO2, and BUB1B, were identified as associated with the age-dependent AF development of the Wannan chickens. Overall, our results provide new insights and a valuable resource for understanding gene expression patterns associated with age-dependent AF development in chickens.