The influence of various bacteria on the cecal mucosa of monoflora chickens infected with Eimeria tenella. A scanning electron microscopic study.

Monoflora chickens were established at the age of 2 days by an oral inoculation of one of six species of bacteria (Lactobacillus acidophilus, Bifidobacterium thermophilum, Bacteroides vulgatus, Clostridium perfringens, Escherichia coli, or Streptococcus faecalis). Two days later the chickens were infected with Eimeria tenella (5 X 10(4) oocytes per bird). There were four groups: uninfected birds as controls, the birds infected with either bacteria or E. tenella alone, and the birds infected with bacteria and E. tenella. As observed under the scanning electron microscope (SEM) seven days after E. tenella infection, damage of the cecal mucosa in all groups infected with bacteria + E. tenella was more severe than in that infected with E. tenella alone. Most severe damage to the cecal mucosa was found in the birds infected with either C. perfringens or B. thermophilum combined with E. tenella.