Evaluation of 3-week-old layer chicks intratracheally challenged with Salmonella isolates from serogroup C1 (O:6,7) and Salmonella Enteritidis.

With the exception to Salmonella enterica serotype Typhimurium and S. Enteritidis (serogroups B [O:4] and D [O:9], respectively), there have been very few studies conducted on the respiratory tract as route of infection in chickens with salmonellae from serogroup C1 (O:6,7) . Therefore, the purpose of this present study was to determine the potential organ invasion by Salmonella enterica serotype Potsdam (SP), S. Mbandaka (SM), and S. Infantis (SI) from serogroup C1 (O:6,7) and compare its characteristics from those of S. Enteritidis (SE) on intratracheally (IT) challenged 3-week-old layer chicks. A total of 360 one-day-old White Leghorn layer chicks were acquired from a commercial hatchery and randomly assigned into four treatment groups (SP, SM, SI, and SE, respectively), consisting of three independent trials. Chicks were grown up to 21 days (3-weeks) and IT-challenged thereafter with 106 CFU of respective salmonella organisms per group (n = 30). Chicks (n = 5) were humanely sacrificed every 24 h for 6 days post-IT infection and organs such as lung, heart, liver, spleen, kidney and cecal content were cultured for salmonella. All treatment groups exhibited colonization of lungs and cecal contents at 1 d ( P  = 0.475) and 4 d ( P  = 0.696) post-IT infection, respectively. There is no isolation of SP, SM, and SI in heart, liver, spleen, and kidney. In contrast, SE was obtained from heart, liver, and spleen of IT-infected chicks. The findings of this study contribute to a better understanding of the importance of respiratory route in salmonella infection in poultry.