Hepatic immunometabolic signatures associated with the heterophil-to-lymphocyte ratio reveal sex-dependent patterns in yellow-legged ma chickens.

The peripheral blood heterophil-to-lymphocyte ratio (H/L ratio) is widely used as an immunophenotypic indicator in poultry, but its tissue-level molecular basis remains unclear. In this study, individuals with extreme high and low H/L ratios were selected from 113 Yellow-legged Ma chickens, and sex stratification was incorporated. Liver and spleen histology, serum biochemical and oxidative stress indices, transcriptomic data, and metabolomic data were integrated to characterize H/L-associated hepatic immunometabolic features. The results showed no significant differences between the high- and low-H/L groups in liver and spleen histological morphology, serum ALT and AST activities, or oxidative stress indicators, suggesting that H/L variation indicating that H/L variation was not associated with overt histopathological changes, liver injury, or oxidative imbalance under the conditions examined. Multi-omics analyses revealed clear sex-specific molecular patterns. In hens, low-H/L individuals showed higher expression of several immune-related genes, and the differential features mainly involved T cell receptor signaling, cytokine-cytokine receptor interaction, Th cell differentiation, arginine biosynthesis, α-linolenic acid metabolism, and pyrimidine metabolism. In roosters, H/L-associated differences mainly involved nuclease activity, chemokine signaling, JAK-STAT signaling, Toll-like receptor signaling, histidine metabolism, and glutathione metabolism. Integrative analysis identified CCR2 as a potential candidate node that may participate in H/L-related hepatic immunometabolic remodeling. Overall, the H/L ratio is associated with the basal hepatic immunometabolic status of Yellow-legged Ma chickens in a sex-specific manner, providing a molecular basis for further evaluating its application in poultry immune phenotyping and disease-resistance breeding.