Evolution of pig fecal microbial diversity following enterotoxigenic Escherichia coli infection and colistin oral treatment in a post-weaning diarrhea model

The intestinal microbiota plays several important roles in pigs health and growth. The aim of the current study was to characterize the changes in the fecal microbiota diversity and composition of weaned piglets following an oral challenge with an ETECF4 strain and/or a treatment with colistin sulfate. Twenty-eight piglets were used in this experiment and were divided into four groups challenged treated, challenged untreated, unchallenged treated, and unchallenged untreated. Fresh fecal samples were collected during five sampling times along the study. Total genomic DNA was used to assess the fecal microbiota diversity and composition using the V4 region of the 16S rRNA gene. The relative abundances of piglets fecal microbiota were highly affected by the ETEC F4 challenge along the experiment, while CS treatment resulted to a significant decrease of E. coli Shigella population, but only during the treatment period. Moreover, our study is among the first to identified some gut microbiota subgroups, like Streptococcus and Lachnospiraceae, that are associated with healthy piglets as compared to ETEC F4 challenged animals, and this finding could initiate research for the development of alternative strategies to the use of antimicrobials for the control of post-weaning diarrhea in pigs.