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Category: ASAS GRADUATE STUDENT POSTER COMPETITION: MS II

Poster Session III

PSIII-2 - Pediococcus acidilactici demonstrates probiotic properties and inhibits the growth of enterotoxigenic E. coli.

Tuesday, July 18, 2023
9:45 AM – 11:00 AM MT
Location: 140 Aztec/110 Galisteo
Abstract: Lactic acid bacteria are recognized to possess probiotic properties including modulating host physiology. Probiotics are used as direct-fed microbials in the swine industry to optimize pig performance and production efficiency. In the nursery, probiotics have been shown to mitigate post-weaning diarrhea caused by enterotoxigenic Escherichia Coli (ETEC). Studies show beneficial effects of supplementing probiotics and the data are inconsistent. Microbial genome sequencing could help better define the mechanisms of probiotic mode of action and dose required to improve probiotic efficacy. The aim of this study was to determine if Pediococcus Acidilactici PECh3A (PA) that has been genome sequenced for determining gut physiology mechanisms expresses probiotic properties in-vitro. The growth curve of PA was conducted to determine colony forming units (CFU)/mL concentrations in 2-hour intervals until plateau at 15 hours. Based on the results of the growth curve dose response analysis were performed for acid and bile tolerance and antimicrobial activity against ETEC (3030-2: K88ac LT and STb). Doses investigated were 1010, 109, and 108 CFU/mL. For the acid and bile tolerance experiment PA was grown to concentration 1010 CFU/mL and was centrifuged and inoculated in De Mab, Rogosa, and Sharpe broth (MRS Broth) at pH 2, 4, or 6.5 (control) or MRS ± 0.3% oxgall (w/v), respectively, and incubated for 4 h. Following the 4h incubation samples were serially diluted, plated, and incubated at 37°C for 24h to determine percent survival. Antimicrobial inhibition of ETEC was assessed by the agar zone of inhibition (ZOI) methods. PA was grown to previously defined CFU/mL concentrations and 100 µL of the culture and filtered supernatant were plated into wells on Nutrient Agar plates spread with 107 ETEC CFU/mL. ZOI were measured in mm. Data were analyzed according to a factorial design using PROC MIXED procedures in SAS. Survival in acidic media relative to control media was observed in all doses (108,109, and 1010) at pH4 and minimally at pH2 (81.8, 90.6, and 89.5% or 33.8, 28.0, and 0% ±7.7, respectively; P < 0.01). PA survival in 0.3% oxgall increased with increasing dose (74.3, 83.3, and 91.7% ±0.67; P < 0.01). PA culture exhibited antimicrobial activity against ETEC at all doses tested, and the PA filtered supernatant exhibited antimicrobial activity from 109 CFU/mL (4.260mm ± 0.9437, P < 0.01). Taken together the findings indicate that PA PECh3A exhibits functional probiotic properties to potentially improve swine intestinal physiology. Further in vitro and in vivo experiments will access Pediococcus Acidilactici PECh3A function and interaction within the host environment.