Lactobacillus and Saccharomyces fermentation products impact performance and the fecal microbiome in weanling pigs inoculated with enterotoxigenic Escherichia coli.

Background: Enterotoxigenic F4 E. coli (F4-ETEC) pose an economic threat to the swine industry through reduced growth, increased mortality and morbidity, and increased costs associated with treatment. Prevention and treatment of F4-ETEC often relies on antimicrobials; however, due to the threat of antimicrobial resistance, antimicrobial use is being minimized, and hence alternative control methods are needed. This study investigated the effects of postbiotics in the form of Lactobacillus acidophilus fermentation products (LFP) and Saccharomyces cerevisiae fermentation products (SFP), on pigs challenged with an F4 ETEC strain. Eighty pigs were selected based on a pre-screening F4-ETEC susceptibility test. The animals were divided into five treatments each with four replicate pens. Pigs were assigned to five different diets: a control diet (CON); CON diet with 3,000 ppm ZnO (ZnO); CON diet with 2,000 ppm LFP (LFP); CON diet with 2,000 ppm SFP (SFP); CON diet with both 2,000 ppm LFP and 2,000 ppm SFP (LAS). Pigs were inoculated per os with F4-ETEC twice, on day 0 and day1 of the experiment.

Results: No significant differences in fecal consistency scores or fecal F4-ETEC concentration in pigs supplemented with LFP and/or SFP were detected. An increased diversity and abundance of Lactobacillaceae in the fecal microbiome of pigs supplemented with LFP were detected, as well as an increased final liveweight of pigs supplemented with LFP and/or SFP.

Conclusion: This study demonstrated that the fecal microbiome is modified in F4-ETEC-challenged pigs supplemented with the combination of LFP and SFP, with these modifications previously associated with increased growth performance and health status in young pigs. Pigs receiving this combination of postbiotics also demonstrated an increased final liveweight, indicating that management of ETEC-associated performance loss may not require the complete removal of ETEC from a production system.