Abstract

The influence of weaning on day 32 and a simultaneous challenge with a pathogenic strain of Escherichia coli was studied in eight piglets. Another nine weaned but non-infected piglets were used as controls. The distribution of peripheral blood mononuclear cells (PBMC) into subpopulations, as well as their response when stimulated in vitro by pokeweed mitogen, changed in a similar manner during postweaning in both groups. In contrast, superior responses were recorded for PBMC collected from the challenged pigs when stimulated in vitro with concanavalin A and with a heat-inactivated extract of the E. coli strain used for infection, respectively. Despite a successful colonization of the challenge strain, no clinical signs of disease were recorded. Nor did the daily weight gain or the number of E. coli, enterococci, or Clostridium perfringens excreted per gram of faeces differ between the groups. However, the weaning induced a marked decrease in the diversity of coliforms in individual piglets, which announced a reduced colonization resistance of that flora. Also, a decreased homogeneity between coliform floras of different piglets was observed following weaning. The decreased homogeneity indicated that different strains of E. coli were predominant in different animals, which may in turn facilitate the spread of pathogenic strains. The enteric changes were more pronounced and lasted longer in infected animals. Still, the influence of a sole pathogenic strain of E. coli was not enough to induce post-weaning diarrhoea.

Published in

Zoonoses and Public Health
2000, Volume: 47, number: 9, pages: 663-675
Publisher: BLACKWELL WISSENSCHAFTS-VERLAG GMBH

SLU Authors

• Fossum, Caroline

  • Department of Veterinary Microbiology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Clinical Science


Publication identifier

DOI: https://doi.org/10.1046/j.1439-0450.2000.00393.x

Permanent link to this page (URI)

https://res.slu.se/id/publ/106627