关键词: RFI；脂肪酸代谢；黄羽肉鸡；线粒体功能; 氧化磷酸化

Abstract: To investigate the regulatory mechanism of residual feed intake（RFI）in hepatic energy and lipid metabolism in yellow?feathered broilers，two lines divergently selected for high RFI（HRFI）and low RFI（LRFI）were used in this study. Twenty 1?day?old healthy yellow?feathered broilers（half male and half female）from each line were reared under identical conditions until 70 days of age. The mRNA expression of key genes related to the mitochondrial respiratory chain and lipid metabolism was examined by qRT?PCR，and the activities of complexes I－IV as well as ATP production were determined using a microplate reader.Results showed that compared with the HRFI group，the LRFI group exhibited significantly upregulated mRNA expression levels of key mitochondrial respiratory chain genes （MTND1，MTND4，CYTB，COX1）in the liver（P<0.05）. Similarly，the expression of key lipid metabolism genes （ACACA，FADS1，ACSL1） was significantly increased（P<0.05）. Further functional validation revealed that the activities of mitochondrial respiratory chain complexes I，II，III，and IV，as well as ATP production，were significantly higher in the LRFI group than in the HRFI group（P<0.05）. In conclusion，low?RFI yellow?feathered broilers enhance mitochondrial function through the coordinated upregulation of genes involved in mitochondrial oxidative phosphorylation and fatty acid synthesis，thereby improving the efficiency of energy and lipid metabolic turnover. This likely represents a key molecular mechanism underlying their superior feed efficiency. These findings provide a new theoretical basis for the genetic improvement of feed efficiency in yellow?feathered broilers.

Key words: Residual feed intake；Fatty ? acid metabolism；Yellow ? feather broiler；Mitochondrial function；Oxidative phosphorylation