Effects of Lactobacillus salivarius on immunity and intestinal commensal microbiota of heat-stressed broiler chickens infected with Salmonella Enteritidis

Abstract

Stress is a reality in the world poultry production. Environmental stressors impair both welfare, performance parameters and immunity in broiler chickens. Heat stress decreases macrophage activity in broiler chickens and many environmental stressors that impact animal production increases animal's susceptibility to diseases. The neuroimmunomodulation is defined as the interrelationships between the Central Nervous System and the Immune System. 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 levels. Furthermore, mild acute multifocal lymphoplasmacytic enteritis, characterized by foci of heterophil infiltration in the duodenum, jejunum and ileum, was observed in the heat stressed chickens. When chickens were experimetly infected with Salmonella Enteritidis, we observed an increase in Salmonella counts in the spleens of the 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. There is increasing evidence that Lactobacillus 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 on the immune system, intestinal morphology and commensal microbiota population in heat stressed broiler chickens experimentally infected with Salmonella Enteritidis. (AU)