RESUMO
The effects of treatment with anaerobic cecal microflora (ACM) and/or lactose and/or acetic acid on systemic and digestive tract of broiler chicks infection with "Salmonella" Typhimurium and "S." Enteritidis were studied. ACM was used without previous bacterial identification. Treatment with ACM contributed to the resistance of broiler chicks to infection with "Salmonella" spp. The infections were more persistent in the cecum, rectum and crops in decreasing order of intensity. The infections were also self-limiting since treated and control lots presented similar infection rates at the end of the experiments. Alone or in combination with lactose, ACM reduced the colonization of the digestive tract of broiler chicks by "S." Typhimurium and "S." Enteritidis. The effect of the combination of ACM with lactose or acetic acid was not potentiated in terms of reduction of fecal excretion of "Salmonella" spp. Treatment with ACM reduced the amount of "S." Typhimurium and "S." Enteritidis in feces. Alone or in combination with lactose, ACM reduced the cecal pH in treated birds. "S." Enteritidis was much more invasive than "S." Typhimurium and the use of ACM alone was more effective on the reduction of systemic infection. An explanation for the process of prevention of intestinal colonization with "Salmonella" spp. probably resides in the interrelationship of physiological, microbiological and immunological phenomena, as well as the variation in cecal pH.