Probiotics mediated gut microbiota diversity shift are associated with reduction in histopathology and shedding of Lawsonia intracellularis

Clinical intervention during bacterial infections in farm animals such as pigs commonly consists of antimicrobial use. With the rise of antimicrobial resistance and the attempts to reduce the use of antibiotics in food animals, effective alternatives are urgently needed to reduce or even remove pathogens and disease risk. Improving clinical outcomes and overall pig health by using probiotics appears attractive. However, reliable data sets on the efficacy of probiotics are scarce. The obligate intracellular bacterium Lawsonia intracellularis is widespread in pigs and associated with severe enteropathy, mainly in the ileum, commonly resulting in substantial reduction in weight gain. The impact of three in-feed probiotics and a commercial live L. intracellularis vaccine were compared in a pig challenge model. Probiotic treatment was associated with reduced L. intracellularis fecal shedding and reduced gut lesions. Here, the bacterial microbiome of the ileum of these pigs was characterized with 16S rRNA gene sequencing and was subsequently analyzed with bioinformatics tools.