Dietary inclusion of colicin e1 is effective in preventing postweaning diarrhea caused by F18-positive Escherichia coli in pigs

Abstract

With worldwide concern over the use of antibiotics in animal agriculture and their contribution to the spread of antibiotic resistance, alternatives to conventional antibiotics are needed. Previous research in our laboratories has shown that colicin E1 is effective against some Escherichia coli strains responsible for postweaning diarrhea (PWD) in vitro. In this study we examined the efficacy of the dietary inclusion of colicin E1 in preventing experimentally induced PWD caused by F18-positive enterotoxigenic E. coli in young pigs. Twenty-four weaned pigs (23 days of age), identified by genotyping to be susceptible to F18-positive E. coli infections, were individually housed and fed diets containing 0, 11, or 16.5 mg colicin E1/kg diet. Two days after the start of the trial, all animals were orally inoculated with 1 x 10(9) CFU of each of two F18-positive E. coli strains isolated from pigs with PWD. The dietary inclusion of colicin E1 decreased the incidence and severity of PWD caused by F18-positive enterotoxigenic E. coli and improved the growth performance of the piglets. Additionally, the reduced incidence of PWD due to dietary colicin E1, lowered the levels of expression of the genes for interleukin 1beta and tumor necrosis factor beta in ileal tissues from these animals. The dietary inclusion of colicin E1 may be an effective alternative to conventional antibiotics in the diets of weaning pigs for the prevention of PWD caused by F18-positive enterotoxigenic E. coli.

FIG. 1.

Effect of dietary inclusion of colicin E1 on incidence of diarrhea in weaning pigs following an F18-positive enteropathogenic E. coli challenge. Asterisks, significant differences (P < 0.05) between the high-dose group and both the low-dose and the control groups.

FIG. 2.

Normalized expression of the genes for TNF-β and IL-1β in ileal tissue samples 4 days after oral F18-positive enteropathogenic E. coli challenge. Gene expression was determined by semiquantitative real-time PCR and was normalized to the cDNA concentration. The values presented are the least-square means, and the error bars represent the standard error of the mean. Values not sharing a common superscript are significantly different (P < 0.06).