Single-cell analysis of differential fat deposition in chicken pectoral muscle and abdominal fat tissues

Excessive abdominal fat (AF) accumulation in poultry impairs laying performance and reduces slaughter rate. As an excellent local breed in China, the mechanisms underlying intramuscular fat (IMF) and abdominal fat deposition in Gushi chickens remain poorly understood. In this study, fat-related indices (including fat content, triglyceride, cholesterol, and phospholipids) in the pectoral muscle and abdominal fat tissues of Gushi chickens aged 2 to 22 weeks were analyzed. Concurrently, single-cell RNA sequencing was performed on the pectoral muscle and abdominal fat tissues of 2-week-old Gushi chickens to identify cell types and molecular characteristics specific to different tissues. The results showed that the AF rate of Gushi chickens presented a gradual increasing trend, while the IMF rate exhibited a "W"-shaped variation pattern throughout the entire process. Single-cell RNA sequencing of tissues from 2-week-old chickens identified cell-type-specific genes: genes such as G0S2 and NEBL were highly expressed in abdominal adipocytes, while genes including PDE3A and NOX4 were predominantly expressed in intramuscular adipocytes. Functional validation revealed that G0S2 upregulated adipogenic genes (e.g., CEBP/α, PPARγ) more significantly in abdominal adipocytes, and specifically increased FASN expression only in abdominal adipocytes (P < 0.01). These findings clarify the tissue-specific characteristics of fat deposition in Gushi chickens and the distinct role of G0S2, providing a reference for understanding the mechanisms of fat deposition in poultry.