PSVI-13 - Identifying Probiotic Bacteria to Reduce Pathogen Colonization in Nursery Pigs

Abstract: Weaning stress and the negative health effects that occur with it cause serious concerns for pork producers. The abrupt environmental and dietary transitions that occur at weaning often take place before the gut microbiome is stabilized in the piglet. This leaves weanling piglets vulnerable to gut dysbiosis and increases susceptibility to enteric pathogens. The infections by opportunistic pathogens can be prevented with antibiotics, but due to growing concerns surrounding antimicrobial resistance in bacterial populations, direct-fed microbial (DFM) formulations have emerged as an alternative prevention method. In the current study, we isolated Lactobacillus spp. and Bifidobacterium spp. from fecal samples collected from neonatal pigs and sows that are capable of inhibiting colonization of Salmonella spp. and Escherichia coli isolated from sick pigs. Diluted fecal samples were plated on Bifidus selective medium (BSM) and deMan, Rogosa Sharpe (MRS) medium to isolate Bifidobacterium and Lactobacillus, respectively. Bacterial isolates were screened against Salmonella and E. coli isolates of porcine origin using a medium consisting of 50% MRS and 50% brain, heart, lung infusion (BHI) using disk diffusion assays. The resulting isolates that demonstrated the highest degree of pathogen inhibition were characterized using 16s rRNA sequencing. Sequence analysis identified the top isolates as L. mucosae, L. reuteri, and B. thermacidophilum subsp. porcinum. Currently, genome sequencing of the selected isolates are underway to identify the mechanisms of inhibition.