Ovariectomy Enhances Carcass Performance and Meat Quality by Modulating Muscle Development and Lipid Metabolism in...

Estrogen is a key regulator of skeletal muscle growth and metabolism in birds, yet its specific roles in female chickens remain poorly defined. To address this gap, we established an estrogen-deficient model by surgically removing the ovaries of Wuding hens, a Chinese indigenous slow-growing breed. Growth traits, carcass yield, and meat quality were evaluated across different ages, complemented by histological examination, serum biochemical analysis, and multi-omics approaches (transcriptomics, proteomics, and lipidomics). Ovariectomized hens maintained somatic growth for a longer period and reached greater body weight and carcass yield at 330 days compared with intact controls. Thigh muscle tenderness was also enhanced in the absence of estrogen, despite no long-term differences in muscle fiber morphology. Lipidomic analysis revealed a transient increase in intramuscular triglyceride content at mid-growth (240 days), pointing to altered lipid storage and distribution. Integrated omics profiling further demonstrated significant changes in the mitogen-activated protein kinase (MAPK) and mechanistic target of rapamycin (mTOR) signaling pathways, accompanied by differential expression of key metabolic and structural genes, including mitogen-activated protein kinase 8 (MAPK8), fatty acid binding protein 4 (FABP4), ankyrin 1 (ANK1), and coenzyme Q6 monooxygenase (COQ6). These molecular adjustments suggest that estrogen withdrawal triggers broad reprogramming of muscle signaling and lipid metabolism. Overall, this study highlights the multifaceted role of estrogen in coordinating growth, muscle quality, and lipid homeostasis in hens and provides a functional model for studying estrogen deficiency in poultry with implications for meat quality improvement.