Effects of Anaerobic Bacteria on Eimeria tenella Infection in Bacteria-Free, Monofloral, and Conventional Chickens

Abstract

Bacteria-free, monofloral, and conventional chicks were infected with Eimeria tenella. Monofloral chicks were established by inoculating birds in several gnotobiotic isolators with a single species of Escherichia coli or with one of three Bacteroides sp. isolates (#157, #202, or #366). Daily weights of individual birds were recorded for six days post-infection (PI). On Day 6 PI all birds were sacrificed and cecal lesions were scored. Conventional, infected birds lost weight on days 5 and 6 PI and showed severe lesions. Birds maintained as monofloral groups with isolates of Bacteroides sp. #157, #202 or E. coli showed equally severe lesions, but lost weight only on day 6 PI. Conventional, uninfected birds with no lesions, birds infected with Bacteroides sp. isolate #366 with mild lesions, and bacteria-free birds with mild to severe coccidial lesions all continued to gain weight on each day post-infection.