Developing and Evaluating a Weaned Piglet Model of Enterotoxigenic Escherichia Coli Infection

Abstract

Enterotoxigenic Escherichia Coli (ETEC) remains the main pathogen associated with post-weaning diarrhea in piglets. Here, we introduce a reliable method to develop an ETEC-infected weaned piglet model. For the first 24 h post-birth, neonatal piglets were separated from dams so that they did not receive colostrum. Afterwards, piglets were returned to the care of their mothers, until weaning (21-day-old). On days 25, 26 and 27 post-birth, piglets were orally challenged with 1011 Colony-Forming Units (CFU) of virulent ETEC strain incubated in colony-forming antigen medium and delivered in chitosan-coated capsules. In all infected piglets, severe diarrhea and typical body weight loss were observed post-infection. To simplify the work, for the newly developed method, the number of challenging ETEC cells was lowered to 1010 CFU/head and the incubation medium was changed to tryptic soy. These modifications influenced neither the diarrheal defecation ratio nor the body weight loss in piglets. To induce experimentally ETEC infection in future work, we recommend that 1010 CFU/head of ETEC cell grown in tryptic soy broth be delivered in chitosan-coated capsules to colostrum restricted piglets, because this methodology stably caused 100% diarrheal defecation and growth reduction.