title: Testing the efficacy of medium chain fatty acids against rabbit colibacillosis.
abstract: Enteropathogenic Escherichia coli (EPEC) represents a major cause of lethal diarrhea in young mammals. Although the pathogenicity mechanisms of EPEC are now well understood, the intrinsic and environmental factors that control the expression of EPEC virulence remain largely unknown. In the rabbit, suckling reduces pups' sensitivity to EPEC infection. Hence, we have hypothesized that uncharacterized factors present in doe milk may mediate this protection. Medium chain fatty acids (MCFA), known to possess antimicrobial properties, are highly abundant in doe milk. We demonstrate that caprylic acid exhibits a clear bacteriostatic effect in vitro against the rabbit EPEC strain E22 (O103:H2:K-), in a dose-dependent manner. In vivo, the dietary inclusion of triglycerides of MCFA did not however reduce the sensitivity of young rabbits challenged with this EPEC strain. The mortality and fecal excretion of EPEC were not reduced, and the bacterial adhesion to ileum was not inhibited. Amount of MCFA reaching the ileal level might have been too low and/or their association to other milk antimicrobials may have been required to observe a positive effect on disease evolution in a context of a highly virulent challenge.
authors.affiliation: INRA, UMR1289, F-31326 Castanet-Tolosan Cedex, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Gallois
authors.forename: Thierry
authors.initials: T
authors.lastname: Gidenne
authors.forename: Juan
authors.initials: J
authors.lastname: Orengo
authors.forename: Cécile
authors.initials: C
authors.lastname: Caubet
authors.forename: Christian
authors.initials: C
authors.lastname: Tasca
authors.forename: Alain
authors.initials: A
authors.lastname: Milon
authors.forename: Séverine
authors.initials: S
authors.lastname: Boullier
mesh_terms: D000818:Animals; D000833:Animals, Suckling; D001422:Bacterial Adhesion / Q000502:physiology*; D002210:Caprylates / Q000032:analysis / Q000276:immunology* / Q000494:pharmacology; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D004306:Dose-Response Relationship, Immunologic; D054308:Enteropathogenic Escherichia coli / Q000276:immunology / Q000472:pathogenicity* / Q000502:physiology; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D006367:HeLa Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000276:immunology / Q000382:microbiology; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D008892:Milk / Q000276:immunology; D011817:Rabbits; D011897:Random Allocation
chemical_list: D002210:Caprylates; C031492:octanoic acid