Bacterial flora in the alimentary tract of chickens infected with Eimeria brunetti and in chickens immunized with Eimeria maxima and cross-infected with Eimeria brunetti

Abstract

Differential bacterial counts were made on the intestinal and caecal contents of chickens after inoculation with a standard dose of 320 000 freshly sporulated oocysts of Eimeria brunetti. The numbers of Escherichia coli and Clostridium welchii increased significantly in the small intestine and caeca during the acute phase of the disease. Counts were significantly higher in the intestine of moribund birds killed on Day 5 and 6 than in the survivors examined on Day 7. Counts fell within the normal range of values in survivors on Day 14. The numbers of streptococci, lactobacilli, and bacteroides remained within the normal range. No other organisms were demonstrated by the methods used. In chickens immune to E. maxima examined on the Day 12 after challenge with the same species, E. coli counts were significantly higher in the small intestine, while numbers of C. welchii remained within normal limits. After cross-infection with E. brunetti counts of E. coli and C. welchii were significantly higher in the small intestine and caeca of moribund birds. Serological methods failed to show any qualitative change in E. coli. Strains of C. welchii were isolated which were capable of producing small quantities of alpha and epsilon toxins (Type A and D).