Consequently, infections with enteric pathogens in broilers have been demonstrated in many studies to result in the minimizing the expression of Muc-2 gene (1, 63), which is consistent with our findings, where S. Typhimurium infection compromises the intestinal barrier functions of challenged broilers via downregulating JAM-2, CLDN-1, occludin, MUC-2, β-defensin-1, and cathelicidins-2 genes, subsequently detrimentally impacting their BWG and FCR. Here, CLDN1 is linked to infection.