Postweaning diarrhoea in pigs: an interaction between change to dry food and colibacillosis

Abstract

Caesarian-derived SPF pigs were maintained on a milk diet until 28 days of age. Two groups were weaned on to a dry diet and one of these orally challenged with enterotoxigenic Escherichia coli bearing the K88 pilus antigen. One of 2 remaining groups on the milk diet was also challenged with K88 bearing ETEC. Infected piglets on the dry diet developed clinical diarrhoea and at necropsy exhibited severe lesions in the small intestine associated with extensive bacterial adherence. Infected piglets on the milk diet had little or no diarrhoea, and focal bacterial adherence in the small intestine was associated with only minor mucosal changes. Control piglets on milk or dry food remained clinically healthy and had normal mucosal morphology. The results suggest that sudden dietary change to dry food at weaning promotes proliferation and colonization of the small intestine by ETEC-bearing K88 which leads to a more severe clinical and pathological syndrome than either event in isolation.