Abstract: The adipose tissue can be categorized into white adipose tissue,which stores energy,and brown adipose tissue,which regulates body temperature and energy balance.Adipose tissue is primarily distributed in four forms in vivo:Subcutaneous fat,visceral fat,intermuscular fat and intramuscular fat.Intramuscular fat,also known as marbling,refers to fat deposited within the muscle and between muscle fibers,it directly influences the juiciness,tenderness and meat flavor,and is an important indicator of meat quality.The intramuscular fat content depends on the size and number of adipocytes,and its development and deposition are regulated by multiple mechanisms.In this complex biological process,the synergistic action of various transcription factors and enzymes is also critical.Increasing the content of intramuscular fat can significantly improve the taste and flavor of meat from livestock and poultry,and enhance the overall quality of meat products,it is one of the key objectives in animal breeding.Therefore,a deeper understanding of the mechanisms and signaling pathways involved in intramuscular fat development and deposition is essential.The authors synthesize relevant literature to describe the process of intramuscular fat deposition,focusing on the structural features and mechanisms of six key genes related to intramuscular fat deposition,and provide recommendations for addressing the existing gaps in current research,offering scientific insights for breeders.

Key words: livestock and poultry; intramuscular fat; fat deposits