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Yeasts to control infectious enteritis in swine

To avoid the preventive use of antibiotics in young animals, scientists in the Animal Infectious Diseases and Veterinary Public Health Unit (IASP) have been studying alternative control strategies against E. coli enterotoxinogenic strains (ETEC). They have demonstrated in vitro that some strains of S. cerevisiae secrete biological factors that can control intestinal inflammation in young animals. The addition of these selected yeasts to animal feed could be an effective strategy for the control of ETEC.

Updated on 02/12/2013
Published on 04/05/2012

Piglets: targets of choice for ETEC

The post-weaning period in piglets is a difficult transition phase during which the animals are subject to the stress of a change of diet while having an immature immune system that is susceptible to bacterial infections of all types. Enteritis, mainly caused by enterotoxinogenic E. coli, are commonplace. These bacteria can adhere to the epithelial cells of the intestine (enterocytes) and colonise the intestinal mucous membranes. Once installed, these unwelcome guests secrete enterotoxins that trigger pro-inflammatory signals, disturbing the balance of enterocyte ion exchanges and causing severe diarrhoea. An increase in the incidence of diarrhoea due to ETEC strains is currently being seen throughout the world.

Research on alternatives to antibiotics is necessary

The use of antibiotics is the solution most frequently employed to prevent these infections. But since 2006, European regulations have banned the preventive use of antibiotics (antibiotics used as growth promoters) and antibiotic-resistant bacterial strains have appeared on farms. New preventive and therapeutic strategies have thus become necessary.

The addition of live or probiotic micro-organisms to animal feed in order to prevent the onset of enteric diseases is a path that has seen renewed interest in recent years. Yeasts, in particular, seem to have a protective effect versus some pathogens. To determine the potentially beneficial action of a Saccharomyces cerevisiae strain in preventing enteritis, INRA scientists sought to assess the effect of a selected yeast strain on the inflammatory process triggered by an ETEC strain in piglets. This work was carried out in the context of a research partnership with Lesaffre (thesis project under a CIFRE contract).

Saccharomyces cerevisiae: a clear effect on inflammation

The researchers worked on pig intestinal cells in culture. They compared the expression of inflammation mediating genes in these cells co-cultured with ETEC, in the presence or not of S. cerevisiae yeasts. They were thus able to demonstrate that the presence of these specific yeasts caused a reduction in the transcripts (messenger RNA) of several genes coding for pro-inflammatory proteins (TNF-a, Interleukin-1 a, interleukin-6, interleukin-8, CCL-20, CXCL2). The team then confirmed the immunomodulating effect of S. cerevisiae by observing a reduction in the release of interleukins 6 and 8 into the culture medium. When intestinal cells co-cultured with ETEC were placed in the presence of dead (inactivated) yeasts, interleukin synthesis did not diminish, thus underlining the action of the biological factors secreted by the yeast.

This work has enabled demonstration of one of the modes of action of S. cerevisiae in preventing pro-inflammatory reactions by pig intestinal cells in a context of enteritis. Further studies are now necessary to gain a clearer understanding of the beneficial effects of this S. cerevisiae strain in controlling infections due to E. coli. Nevertheless, these positive findings are highly encouraging and promising with respect to the use of selected strains in alternative control strategies versus pathogens such as ETEC.

Scientific contact(s):

  • Henri SALMON (+33(0)2 47 42 73 31) UR1282 IASP Infectiologie Animale et Santé Publique
  • François MEURENS (+33(0)2 47 42 78 65) UR1282 IASP Infectiologie Animale et Santé Publique

Find out more

  • Zanello, G. ; Meurens, F. ; Berri, M. ; Chevaleyre, C. ; Melo, S.; Auclair, E. ; Salmon, H. Saccharomyces cerevisiae decreases inflammatory responses induced by F4+ enterotoxigenic Escherichia coli in porcine intestinal epithelial cells. Veterinary Immunology and Immunopathology. 2011, 141 (1-2) : 133-138
  • Zanello, G. ; Berri, M. ; Dupont, J. ; Sizaret, P.Y. ; D'Inca, R. ; Salmon, H. ; Meurens, F. Saccharomyces cerevisiae modulates immune gene expressions and inhibits ETEC-mediated ERK1/2 and p38 signaling pathways in intestinal epithelial cells. Plos One. 2011, 6 (4) : e18573
  • Zanello, G ; Berri M. ; Dupont J. ; Sizaret P.Y. ; Chevaleyre C. ; Melo S. ; D’Inca R. ; Auclair E. ; Meurens F. ; Salmon, H - Saccharomyces cerevisiae modulates gut responses to Escherichia coli. Communication to symposium “E.Coli and the mucosal immune system”, 2-5 July 2011, Gent, Belgium.