Abstract
In order to study microscopic and macroscopic lesions in chickens infected with low and high doses of Salmonella enteritidis PT 4 (SE), 150 one-day-old White Plymouth Rock chicks were divided into three groups each containing 50 birds. The chickens of the first and second groups were inoculated with 2 x 102 and 2 x 108 cfu of Salmonella, respectively. The chicks of the third group were kept as uninoculated control birds. Five birds from each group were euthanized by cervical dislocation at 6, 12, 18 hours post inoculation (hpi) and then after 1, 3, 7, 10, 14, 21, and 27 days post inoculation (dpi) and were examined for presence of gross and histological lesions. Catarrhal typhlitis and unabsorbed yolk sac were the most prevalent gross lesions in both groups. Histologically, granulomatous nodules in the caecum were found occasionally in some cases in both inoculated groups. The present study demonstrated that the chickens infected with a low dose of SE showed fewer lesions, which were milder in comparison with the birds inoculated with a high dose of SE. It suggests that chickens were able to capture the pathogen in the low dose group