The influence of lactobacilli on the competitive exclusion of paratyphoid salmonellae in chickens.

The competitive exclusion of salmonellae by native gut microflora was investigated by treating chicks with various avian lactobacilli. The evaluation of protection was based on the number of salmonellae adhering to the mucosa of the crop and the cecum, enumeration of salmonellae in fecal droppings, and enrichment of cloacal swabs and fecal droppings using both individual and seeder bird tests. Lactobacilli reduced the number of salmonellae adhering to the crop mucosa by 1 to 2 logs. Treatment with lactobacilli did not lower the number of chickens shedding salmonellae or reduce the number of salmonellae adhering to the mucosa of the cecum. Lactobacilli as a single bacterial treatment played a minor role in protecting the crop, but no protection of the cecum was demonstrated.