Bacteria indicative of good intestinal health in pigs

Mohamed Rhouma, Charlotte Braley, William Thériault, Alexandre Thibodeau (CRIP-FRQNT, GRESA, Université de Montréal), Sylvain Quessy (GRESA, Université de Montréal), Philippe Fravalo (Cnam, France)

The gut microbiota of pigs harbors a large and diverse number of microorganisms that contribute to their health status by stimulating the maturation of their immune systems and by producing nutrients (eg, short-chain fatty acids) to promote their growth. The structure and composition of the pig gut microbiota is largely determined by factors such as diet, age, genetics, environmental conditions, microbial infections as well as the exposure to antimicrobials. Weaning is a critical phase in pig farming being associated with major changes in the composition of the piglet’s intestinal microbiota, predisposing these animals to microbial infections. In fact, during this phase, piglets are subjected to several bacterial infections, in particular those caused by enterotoxigenic E. coli (ETEC, and in particular the ETEC: F4 in pig production in Quebec), which is the most involved bacterial agent in the post-weaning diarrhea (PWD) in pigs. Studies examining the change in the composition and the diversity of the gut microbiota of piglets with clinical PWD remain scarce.

The aim of this study was to characterize the fecal microbiota of piglets following an oral challenge with ETEC: F4 strain. The results revealed that the fecal microbiota of piglets was significantly different between challenged and unchallenged piglets, from the first day after the oral challenge until the end of the experiment (35 days later ).

These results underline that the ETEC: F4 challenge was associated with persistent modification in the fecal microbiota of piglets, characterized by a change in the bacterial composition as well as a decrease in the bacterial diversity within this microbiota. In addition, 16S rRNA gene-based metagenomic analysis identified, for the first time, bacterial populations specifically associated with healthy piglets, such as the genus Streptococcus or the Lachnospiraceae family. In contrast, the fecal microbiota in challenged pigs was significantly associated with the Burkholderiales order.

The significant decrease in the identified microbial markers, such as Streptococcus in the fecal microbiota of the challenged group compared to the control group at the end of the experiment, could explain the growth retardation observed in the challenged piglets.

The results of this study could be a starting point for the development of alternative feeding strategies (e.g., probiotics) to reduce the use of antimicrobials in the control of PWD in pigs, while limiting the deterioration of the zootechnical performance of animals during this critical period.

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From published research: Rhouma, M.; Braley, C.; Thériault, W.; Thibodeau, A.; Quessy, S.; Fravalo, P. Evolution of Pig Fecal Microbiota Composition and Diversity in Response to Enterotoxigenic Escherichia coli Infection and Colistin Treatment in Weaned Piglets. Microorganisms 2021, 9, 1459. https://www.mdpi.com/2076-2607/9/7/1459 Also printed in La Terre de chez nous December 6, 2021. https://www.laterre.ca/actualites/page-conseils/bacteries-cles-identifiant-les-porcelets-sevres-en-pleine-forme