Experimental colonization of broiler chicks withCampylobacter jejuni

Abstract

SUMMARYMinimal colonization inocula for two broiler strains ofCampylobacter jejuniwere determined in broiler chicks aged 2–3 days and 2 weeks. Individually housed chicks were exposed to a single oral or cloacal challenge. Diarrhoeal symptoms were absent in all 380 chicks included in the study. Chick susceptibility to the twoC. jejunistrains varied. Colonization was effected by < 102−104colony forming units (c.f.u.) via cloacal challenge and 104–106c.f.u. via the oral route. Colonization inocula for 2-to 3-day and 2-week-old chicks were similar. Treatment of 1-day-old chicks with fresh adult caecal flora or an anaerobic broth culture of adult caecal flora did not inhibit colonization after challenge with low-doseC. jejuni. Susceptible chicks were colonized rapidly.C. jejuniwas detected in 167 of 189 (88%) colonized chicks within 3 days of challenge and persisted during the 2-week monitoring period. Our data suggest that colonization of broiler chicks withC. jejuniis effected more easily by the cloacal than the oral route and is independent of age.