Transcriptomic Analysis of the Spleen of Different Chicken Breeds Revealed the Differential Resistance of Salmonella Typhimurium

Salmonella Typhimurium (ST) is a foodborne pathogen that adversely affects the health of both animals and humans. Since poultry is a common source and carrier of the disease, controlling ST infection in chickens will have a protective impact on human health. In the current study, Beijing-You (BY) and Cobb chicks (5-day-old specific-pathogen-free) were orally challenged by 2.4 x 10(12) CFU ST, spleen transcriptome was conducted 1 day post-infection (DPI) to identify gene markers and pathways related to the immune system. A total of 775 significant differentially expressed genes (DEGs) in comparisons between BY and Cobb were identified, including 498 upregulated and 277 downregulated genes (fold change >= 2.0, p < 0.05). Several immune response pathways against Salmonella were enriched, including natural killer-cell-mediated-cytotoxicity, cytokine-cytokine receptor interaction, antigen processing and presentation, phagosomes, and intestinal immune network for IgA production, for both BY and Cobb chickens. The BY chicks showed a robust response for clearance of bacterial load, immune response, and robust activation of phagosomes, resulting in ST resistance. These results confirmed that BY breed more resistance to ST challenge and will provide a better understanding of BY and Cobb chickens' susceptibility and resistance to ST infection at the early stages of host immune response, which could expand the known intricacies of molecular mechanisms in chicken immunological responses against ST. Pathways induced by Salmonella infection may provide a novel approach to developing preventive and curative strategies for ST, and increase inherent resistance in animals through genetic selection.