Effects of Probiotic and/or Prebiotic Supplementations on Immune Response, Haematology, Oxidant-antioxidant Biomarkers, and Cytokine mRNA Expression Levels in the Caeca of Broilers Infected with Salmonella

The present study was conducted to evaluate the effects of incorporation of the probiotic mix, prebiotic, and synbiotic supplements on immune response, interleukin-6, interleukin-10, and inducible nitric oxide synthase (iNOS) gene expression, hematology, and oxidant-antioxidant biomarkers of broilers infected with Salmonella Enteritidis and Salmonella Typhimurium mixed infection. A total of 273 commercial Cobb 500 chicks were randomly allocated into seven experimental groups, including NC group: fed only a basal diet (negative control), PC group; fed a basal diet and infected with Salmonellae on 3 rd life day (positive control), ProSa group: administrated probiotic mix in drinking water and then infected with Salmonellae, Presa group: fed prebiotic with basal diet and then infected with Salmonellae, SynSa: received probiotic mix and prebiotic (synbiotic) and then infected with Salmonellae, Pro group: given probiotic mix in feed, and Pre group: basal diet supplemented with prebiotic. The probiotic mix, prebiotic, and synbiotic supplementation significantly increased total IgY levels in the sera of infected birds in comparison to those of positive control. Also, the additives significantly downregulated IL-6 and iNOS gene expressions while they significantly upregulated IL-10 gene expression in the caeca of infected birds, in comparison to those of positive control. Also, the supplementary treatments significantly improved Salmonella-induced changes in hematology and oxidant-antioxidant biomarkers of infected groups. Compared with different supplementary treatments, the synbiotic significantly robust immune response of Salmonellainfected birds when compared with single supplementation of probiotic mix or prebiotic. In conclusion, probiotics, prebiotic, and in particular synbiotic supplements improved immune response, hematological and antioxidative biomarkers of birds experimentally infected with mixed Salmonellae.