DEVELOPMENT OF LARGE INTESTINAL ATTACHING AND EFFACING LESIONS IN PIGS IN ASSOCIATION WITH THE FEEDING OF A PARTICULAR DIET

Hysterotomy-derived piglets were kept in gnotobiotic isolators and art ificially colonized at 7 days of age with an adult bovine enteric micr oflora, At 3 weeks of age, the pigs were transferred to conventional e xperimental accommodation and weaned, either onto a solid diet that ha d been associated with field cases of typhlocolitis in pigs or onto a solid control diet. At necropsy at 5 weeks of age, groups of pigs fed the diet associated with field eases of typhlocolitis were found to ha ve developed typhlocolitis. This was absent from the groups fed the co ntrol diet. The typhlocolitis was characterized by attaching and effac ing lesions typical of those described following experimental inoculat ion of various species with enteropathogenic Escherichia coli. A nonve rocytotoxic, eae probe positive E. coli serotype O116 was isolated fro m pigs on the colitis-associated diet but not fi om any of the pigs on the control diet. Coliform bacteria attached to the colonic lesions r eacted with polyclonal antiserum to E. coli O116 in an immunoperoxidas e assay of histological sections of affected tissue. No reaction with this antiserum was observed in corresponding tissue sections taken fro m pigs on the control diet. No colon lesions were observed in germfree pigs fed either of the diets. It is postulated that proliferation and possibly expression of pathogenicity of the attaching and effacing E. coli responsible for the lesions are strongly influenced by diet.