Salmonella enterica serovar Typhimurium-induced alterations in inflammatory chemokine mRNA expressions and hemato-biochemical variations in three different strains of chicken

This study aimed to understand the differential and tissue-specific immune responses of three different chicken strains [Vanraja, Kashmir Commercial Layer (KCL), and broiler] by assessing the CXCLi1 chemokine mRNA expression in different tissues (liver, spleen, and cecum) in <i>Salmonella Typhimurium-</i>challenged birds. In addition, hematological and biochemical parameters were also assessed. <i>Salmonella enterica serovar Typhimurium</i> culture was used for induction of infection. Differential expression of the <i>CXCLi1</i> gene following induced infection was studied on different days post-infection (0, 1, 3, 5, 7, 9, 11, 13, and 15). An infection dose of 2 × 10⁸ CFU/mL produced the symptoms characteristics of salmonellosis. An immune response gene expression study revealed enhanced expression until the 5th-7th day post-infection, followed by a steady decrease until the 15th day post-infection. The overall gene expression was higher in broiler chicks than in KCL and Vanraja chicks. The tissue-specific response showed higher expression in the cecum followed by the spleen and liver. The real-time mRNA gene expression results indicated that commercial broilers are more susceptible than backyard chicks. Differential cellular responses revealed heterophilia and initial lymphopenia followed by lymphocytosis. Pronounced hemato-biochemical alterations were observed as the clinical indicators of <i>Salmonella</i> infection. These findings imply that the integration of disease-resistant alleles from indigenous or backyard poultry into high-performance exotic germplasm could improve <i>Salmonella</i> resistance in commercial poultry populations.