Isolation, characterization, and effect of administration in vivo, a novel probiotic strain from pig feces.

From porcine rectal swabs or feces, we isolated lactic acid bacteria and used porcine Peyer's patch cells to select them for inducibility of IgA production as an indicator of probiotic effects. The strain selected as a new probiotic was named 'Enterococcus faecium NHRD IHARA'. To verify the probiotic effects of this strain in vivo, 536 piglets at age 25 days were assigned to either the trial group, which administrated the strain, or the control group. An increase in IgA in the feces was observed at age 45 days (P < 0.05 compared with the control group); a significant increase in serum IgA was also observed at the end of the study (P < 0.01) in the trial group. In addition, significant differences between the groups in terms of body weight (P < 0.05) and average daily gain (P < 0.01) were observed. The rate of detection of swine-pathogenic Escherichia coli gene in the feces tended to be lower in the trial group than in the controls. The novel probiotic strain; E. faecium NHRD IHARA may have beneficial effects on swine growth by inducing IgA production and reducing rates of colonization by pathogens in the body.