Genomic Insights into Abdominal and Intramuscular Fat Deposition in Chickens and Their Implications for Productivity Traits: A Systematic Review

Abdominal fat deposition in chickens significantly impacts production efficiency and is influenced by complex genetic and molecular mechanisms. This review summarizes current genomic and transcriptomic research on the regulation of adipogenesis and fat accumulation in chickens, highlighting key genes and loci identified through genome-wide association studies as well as other candidates involved in lipogenesis, lipolysis, and transcriptional regulation. Major metabolic pathways, including MAPK, AMPK, PI3K/AKT/mTOR, TGFβ1/Smad3, FoxO, JAK-STAT, Wnt/β-catenin, and Sonic Hedgehog signaling, are examined for their roles in fat deposition. The regulatory functions of non-coding RNAs, including microRNAs, long non-coding RNAs, and circular RNAs, are discussed, focusing on their interactions with target mRNAs and signaling networks that control lipid metabolism, adipocyte differentiation, and energy balance. Integrating insights from both avian and human studies, this review emphasizes the molecular mechanisms underlying adipogenesis and highlights potential strategies for genetic selection aimed at reducing excessive abdominal fat and improving poultry productivity.