APOA1 and obesity due to melanocortin 4 receptor deficiency: Intriguingly, as metabolic disorders such as obesity and liver steatosis often stem from the dysregulation of lipid homeostasis and immune pathways (Steinberg, 2007; Gurzov et al., 2016), our study also revealed that differentially acetylated peaks were involved in the regulation of a number of genes enriched in lipid metabolism, glucose homeostasis, and immune biological processes, including PCK1, APOA1, ANGPTL4, FABP1, NTRK2, FGF7, PDGFRA, and KIT. To the best of our knowledge, this is the first study to investigate the variation of H3K27ac marks in FLHS in chickens.