High Abdominal Fat Deposition was Regulated by Abdominal Fatty Acid Synthesis Related Genes and Reduced Reproduction in Late Stage of Chinese Indigenous Wannan Yellow Chicken

Objective: Compared with commercial laying hens, indigenous chicken breeds generally exhibit lower reproductive performance. This study aims to elucidate the impact of abdominal fat deposition on the reproductive performance of indigenous chickens, providing a theoretical basis for the breeding of high-yielding chickens. Methods: A pure-bred dam line selected from Wannan yellow chickens at their 60 wks of age (1200 hens at their F8 generation) was used for abdominal fat thickness measurement by colored ultrasound and divided the hens into two groups (HF for high abdominal fat thickness, and LF for low abdominal fat thickness). Egg production was recorded individually and compared in two connective generations. Blood lipid concentration, hatchability, and lipid synthesis related genes in each tissue were determined. Results: The abdominal fat and skin thickness was significantly higher in the HF group than that of the LF group. Egg production showed no significant difference before 40 wks of age, while significantly lower in HF than that of the LF in the two generations at 60 wks of age. Abdominal fat thickness between 0.4 to 1.0 cm showed highest egg production. The embryo healthy rate was significantly reduced in the HF group. Serum VLDL was significantly higher in HF than that of the LF at all detecting stages. The expression of fatty acid synthesis related genes showed no significant difference in liver and ovary in the two groups, while the expression of ACACB, ITGAV and ZC3H12A was significantly lower in HF group than that of the LF group. Conclusion: The increased abdominal fat thickness of Wannan yellow chickens decreased the egg production and hatchability in the late laying period (60 wks). Fatty acid synthesis related genes expressed in abdominal fat, but not liver, responsible for fat deposition in abdomen at the late 60 wks of age in chicken.