PSV-19 - Trace Amounts of Antibiotic Altered Gut Microbial Profiles of Weaned Pigs Experimentally Infected with A Pathogenic Escherichia coli

Tuesday, March 15, 2022

12:00 PM – 12:45 PM CST

Location: Grand Ballroom Foyer

Presenting Author(s)

Kwangwook Kim

Postdoctoral Scholar
University of California, Davis
Davis, California, United States

Author(s)

Cynthia N. Jinno, M.S.

PhD Candidate
University of California, Davis
Davis, California, United States
Yanhong Liu, PhD

Assistant professor
University of California, Davis
Davis, California, United States

Abstract: Our previous studies demonstrated that trace amounts of antibiotic supplements exacerbated growth performance and systemic inflammation of weaned pigs infected with a pathogenic Escherichia coli (E. coli). The objective of this study was to investigate the influence of in-feed trace amounts of antibiotic on distal colon microbiota of pigs experimentally infected with E. coli F18. Thirty-four weaned pigs (6.88 ± 1.03 kg body weight) were individually and randomly allotted to one of three dietary treatments (9 to 13 pigs/treatment). The three dietary treatments were basal nursery diet (control), and 2 additional diets supplemented with trace amounts (TRA; 0.5 mg/kg) or label-recommended dose (REC; 50 mg/kg) of antibiotic (carbadox), respectively. The experiment lasted 18 days [7 days before and 11 days after the first inoculation (day 0)]. The E. coli F18 inoculum (10¹⁰ cfu/3 mL) was orally provided to all pigs for 3 consecutive days. Distal colon digesta samples were collected on days 5 and 11 post-inoculation (PI), and microbial profiles were analyzed using 16S rRNA gene sequencing at the V4 hypervariable region. All compositional data were statistically analyzed using R software with QIIME2 plugin. Bray-Curtis PCoA analysis displayed those pigs in both control and TRA groups were separately clustered from REC on days 5 and 11 PI. Pigs in TRA group had a lowest (P < 0.05) relative abundance of Lactobacillaceae whereas REC group tended to have increased (P < 0.10) relative abundance of Lachnospiraceae than other treatments on day 5 PI. On day 11 PI, pigs in REC had reduced (P < 0.05) relative abundance of Prevotellaceae than pigs in CON group. In conclusion, in-feed trace amounts of antibiotic could modify gut microbiota of weaned pigs challenged with E. coli F18.