Protection of Suckling Neonatal Pigs Against Infection with an EnterotoxigenicEscherichia coliExpressing 987P Fimbriae by the Administration of a Bacterial Competitive Exclusion Culture

The objective of these experiments was to evaluate the effects of a porcine-derived CE culture, RPCF, on an enterotoxigenic Escherichia coli infection in suckling neonatal pigs. Litters of piglets from 18 crossbred sows were included in the study. All piglets remained on-sow for the duration of these studies. Piglets in RPCF groups were orally administered 5 ml of the RPCF bacterial competitive exclusion culture within 12 h of birth. Control piglets were given sterile medium orally as a placebo within 12 h of birth. At 48 h of age, piglets in all groups were orally challenged with an enterotoxigenic E. coli expressing the 987P fimbrial adhesin. Daily rectal swabs were taken, mortalities were recorded, and at 5 days post-challenge, piglets in all groups were euthanized and necropsied. Samples were taken from the ileum, jejunum, ileocecal junction, cecum, colon, and ileocecal lymph nodes and cultured for the presence and enumeration of E. coli . Significant reductions (p<0.001) were observed in all samples taken at necropsy from RPCF-treated pigs when compared with control pigs. Both ileal and cecal concentrations of E. coli were reduced by 5 log 10 in those pigs that were administered the RPCF culture. A significant reduction in mortality was observed, decreasing from 23% in the control group to 2.7% in the RPCF group (p<0.001). Clinical colibacillosis is a major economic and animal health concern in the swine industry. The RPCF CE culture may represent a means of possibly reducing the losses and morbidity associated with colibacillosis in pigs and, thus, may help to reduce the economic and animal health strains placed on the swine industry and the animals therein. Keywords: Escherichia coli , suckling pigs, ETEC, competitive exclusion culture.