Combination of vaccination and competitive exclusion to prevent Salmonella colonization in chickens: experimental studies.

Vaccination and competitive exclusion (CE) represent accepted prophylactic measures to control Salmonella infections in chickens. To use the advantages of both the CE technique and vaccination with live Salmonella vaccines the combination of these methods was studied. In three experiments, SPF chickens were pre-treated using combined or unique administration of CE and vaccination with a live Salmonella typhimurium strain on days 1 and 2 of life and challenged with the antibiotic resistant, but otherwise isogenic mutant of this Salmonella typhimurium strain on days 3, 15 or 40 of life.