Influence of diet on the occurrence of some bacteria in the intestinal flora of wild and pet birds.

Enterobacteriaceae, E. coli in particular, do not belong to the intestinal flora of granivorous pet birds. This is indicated by the fact that the feces of only 9% of healthy budgerigars and 17% of finches tested were positive for enterobacteria. Stressful situations such as overcrowding in small cages coincident with increased noise and low light levels can enhance the colonization of the gut with E. coli. On the other hand it seems nearly impossible to colonize the intestine of budgerigars with E. coli or Klebsiella spp. even under favourable conditions. The frequent findings of enterobacteria in deceased granivorous birds suggest that E. coli and other enterobacteria are involved in the course of diseases with predisposing factors. Nutritional experiments with young chickens suggest that a diet consisting exclusively of seeds has an inhibitory effect on intestinal colonization with E. coli. Determination of Aeromonas hydrophila in nearly 3500 wild and pet birds provides statistically significant evidence that the composition of the intestinal flora may depend on dietary habits: infection was found in 1.9% of the granivorous and herbivorous species, in 7.1% of the omnivorous and in 12.4% of the carnivorous and insectivorous birds. The occurrence of enterobacteria and Aeromonas hydrophila in the digestive tract is obviously influenced by the composition of the nutrients.