Effects of Lactobacillus spp. on cytokine, avian defensins e toll-like receptors gene expression of heat-stressed broiler chickens infected with Salmonella Typhimurium

Abstract

Environmental stressors, i.e heat stress, impair welfare, performance parameters and immunity in broiler chickens. The neuroimmunomodulation is defined as the interrelationships between the Central Nervous System and the Immune System, acting in the HPA axis releasing corticosterone and in Sympathetic nervous system releasing noradrenaline. Moreover, stressful events have been associated with disruption of intestinal commensal microbiota. We observed that the heat stress decreased performance parameters, relative weight of lymphoid organs, the macrophage activity and increased corticosterone serum level and intestinal inflammation. When chickens were experimentally infected with Salmonella Enteritidis or Samonella Typhimurium, we observed an increase of Salmonella counts in the spleens, liver and caecum of the heat-stressed chickens. The probiotics have been used as an alternative to antimicrobial growth promoters for control food-borne pathogens (ie Salmonella). The Lactobacillus is one of the most important representatives of probiotics and it is capable of modulating immune responses in humans and birds. In this way, the objective of the current study is to examine the effects of Lactobacillus salivarius, Lactobacillus acidophilus and Lactobacillus reuteri on cytokine, AVBD and TLR expression in heat stressed broiler chickens experimentally infected with Salmonella Typhimurium. We also propose analyze the role of in vitro noradrenaline on chicken macrophage activity treated with Lactobacillus. (AU)