Virulence Range and New Pathological Pictures of Salmonella enteridits and Salmonella typhimurium Isolated from Ducklings in Experimental Infected Chicks

Salmonellosis is a major global pathogen in the poultry industry and is a significant public health concern. Ducks are known to be carriers of Salmonella. Therefore, monitoring salmonellosis is the most important strategy for preventing the disease. An experimental design was planned to study the pathogenicity of two Salmonella strains. One hundred and fifty chicks were divided into three groups; group one was inoculated with the Salmonella enteritidis strain, group two was inoculated with the Salmonella typhimurium strain, and group three was UN inoculated. Symptoms, postmortem lesions and mortality rate were recorded. The chick growth performance parameters were also determined. Using ANOVA for statistical analysis, there was a significant difference in body weight, body gain, feed consumption, and feed conversion ratio between the two infected groups and the blank group (uninoculated group). In this study, the prevalence of Salmonella enteritidis was (1.73%) and Salmonella typhimurium (0.43%) in imported ducklings in Egypt. Both Salmonella strains were subjected to an antimicrobial sensitivity test. It showed that Salmonella enteritidis had a 60% antimicrobial resistance profile and Salmonella typhimurium had a 20% antimicrobial resistance profile. Furthermore, genotypic characterization was performed and the seven virulence genes(stn, avrA, sopB, ompF, invA, Mgtc, Ssaq) were found. New pathological lesions of Salmonella infection were discovered, such as skull hemorrhage at 3 days and 6 days of age, and a liver similar to a button shape in necropsied infected chicks with Salmonella typhimurium at 21 days of age. Furthermore, hemorrhagic spots were observed on the duodenum. In the presence of Salmonella, Clostridium perferingens was discovered in a bacteriological investigation of duodenal lesions samples from infected chicks. At 30 days of age, administration of acetic acid (1%) as an alternative tool for controlling Salmonella. In conclusion, salmonellosis is a risk factor for necrotic enteritis, and using acetic acid to eliminate salmonella infection is insufficient.