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

摘要： 为研究剩余采食量（Residual Feed Intake，RFI）对黄羽肉鸡肝脏能量及脂质代谢的 调控机制，该研究选取经RFI选择的高（HRFI）、低（LRFI）两个品系。从两个品系中各选取20 只1日龄的健康黄羽肉鸡（公母各半），在相同条件下饲养至70日龄。屠宰采样，使用qRT? PCR检测线粒体呼吸链及脂质代谢关键基因的mRNA表达，同时使用酶标仪测定复合体Ⅰ－ Ⅳ活性及ATP 产量。结果显示：与HRFI 组相比，LRFI 组鸡肝脏中线粒体呼吸链关键基因 （MTND1、MTND4、CYTB、COX1）的mRNA表达水平显著上调（P<0.05）；同时，脂质代谢关键基 因（ACACA、FADS1、ACSL1）的表达也显著升高（P<0.05）。进一步功能验证结果表明，LRFI组肝 脏线粒体呼吸链复合体I、II、III、IV的活性及ATP产量均显著高于HRFI组（P<0.05）。综上所 述，低RFI黄羽肉鸡通过协同上调肝脏线粒体氧化磷酸化及脂肪酸合成相关基因的表达，显著 增强线粒体功能，从而提升能量与脂质的代谢周转效率，这可能是其实现更高饲料利用效率 的关键分子机制。该研究为黄羽肉鸡饲料效率的遗传改良提供了一定的理论依据。

关键词: RFI；脂肪酸代谢；黄羽肉鸡；线粒体功能; 氧化磷酸化