Genomic insights into the contribution of de novo lipogenesis to intramuscular fat deposition in chicken

The proportion of animal based foods in daily diet of consumers is constantly increasing, with chicken being highly favored due to its high protein and low fat characteristics. The consumption of chicken around the world is steadily increasing. Intramuscular fat (IMF) is a key indicator affecting meat quality. High IMF content can contribute to improve the quality of chicken meat. The regulatory mechanism of IMF deposition in chicken is poorly understood, so its complete elucidation is essential to improve chicken meat quality. Here, we performed whole genome resequencing on 516 yellow feather chickens and single-cell RNA sequencing on 3 63-day-old female JXY chickens. In addition, transcriptome sequencing techniques were also performed on breast muscle tissue of JXY chickens at different developmental stages. And 13C isotope tracing technique was applied. In this study, a large-scale genetic analysis of an IMF-selected population and a control population identified fatty acid synthase (FASN) as a key gene for improving IMF content. Also, contrary to conventional view, de novo lipogenesis (DNL) was deemed to be an important contributor to IMF deposition. As expected, further analyses by isotope tracing and other techniques, confirmed that DNL mainly occurs in myocytes, contributing about 40% of the total fatty acids through the regulation of FASN, using the available FAs as substrates. Additionally, we also identified a relevant causal mutation in the FASN gene with effects on FA composition. These findings contribute to the understanding of fat metabolism in muscle tissue of poultry, and provide the feasible strategy for the production of high-quality chicken meat.