Spleen transcriptomics reveals breed-specific mechanisms of Salmonella resistance under heat stress in chickens.

Heat stress and Salmonella infection are two major challenges threatening poultry health and productivity. Native breeds generally show stronger resistance than commercial lines, but the molecular mechanisms underlying this advantage remain unclear. This study aimed to evaluate the resistance of two genetically distinct chicken breeds, Beijing You (BY) and Guang Ming (GM2), to Salmonella infection under heat stress to identify key hub and candidate genes involved in this response. A total of 90 birds each from the BY and GM2 breeds, 22 days old, were randomly assigned to three groups: control (CTL), Salmonella infection (SE), and combined heat stress and Salmonella infection (HS+SE, 33°C for 8 hours/day). Results showed that BY chickens exhibited greater resistance to both SE and HS+SE treatments compared to GM2 chickens, with zero mortality versus 13.3% mortality in GM2 under HS+SE conditions. Further analysis revealed that BY chickens activated the calcium signaling pathway under heat stress, effectively resisting Salmonella infection. RNF141, CNOT7, and HMGN1 were identified as key driving factors for BY chickens' ability to resist Salmonella infection under heat stress. HIST1H46 and MMP7 were identified as candidate genes shared by both BY and GM2 breeds, sensitive to both Salmonella infection and heat stress. In conclusion, this finding preliminarily reveals the key genes and molecular pathways underlying the superior heat tolerance and resistance to Salmonella infection in BY chickens, providing new genetic and pathway clues for breeding chickens that resist Salmonella infection under heat stress conditions.