Lactobacillus johnsonii L531 reduces pathogen load and helps maintain short-chain fatty acid levels in the intestines of pigs challenged with Salmonella enterica Infantis.

•The prevalence of multidrug-resistant Salmonella Infantis in swine is increasing.•SCFAs-promoting probiotic L. johnsonii L531 ameliorates the depletion of SCFAs induced by S. Infantis.•Pretreatment with L. johnsonii L531 enhances growth performance and improves the ability to resist Salmonella.•SCFAs-promoting probiotic is a viable metabolite-based alternative to classical probiotic against Salmonella infection.