Salmonella Typhimurium oral challenge model in mature broilers: Bacteriological, immunological, and growth performance aspects

Abstract

In this study, Salmonella enterica serovar Typhimurium challenge models were tested to identify the best conditions under which to perform the experimental infection of 3-wk-old broilers. Such a model would be useful to study the efficiency of therapeutic treatments that could take place at the end of the grow-out period. Salmonella-free chicks were obtained from a breeder flock vaccinated with Salmonella. Intestinal maternal immunity was monitored by ELISA analyses at 2, 9, and 16 d of age. Data indicated that protection of maternal origin was not maintained over time and was drastically reduced at 9 d of age (P < 0.01). At 21 d of age, chickens were orally inoculated with Salmonella Typhimurium. The effects of the oral challenge dose (0, 3 × 10(3), 3 × 10(6), and 3 × 10(9) cfu/bird) and vancomycin pretreatment (no administration or 25 mg/bird) on intestinal immune responses, growth performance, and Salmonella colonization of chickens were investigated. After infection, the mucosal immune response was rapid, with increased (P < 0.01) anti-Salmonella Typhimurium IgA titers measured at 8 d postinfection in intestinal contents. A linear relationship (P < 0.05) existed between specific IgA levels in intestinal and cecal contents and the challenge dose inoculated. None of the challenge protocols caused mortality or clinical symptoms after infection. Nevertheless, the experimental infection induced a significant deterioration of growth performance. The pretreatment with 25 mg of vancomycin at 3 h before Salmonella inoculation was able to establish stable infection rates among the population of 3-wk-old infected chickens. Nevertheless, Salmonella shedding was not stable over the rearing period, and the bacteria seemed to be naturally eliminated from most birds at 22 d postinfection. This natural clearance of the gut, which was related, at least in part, to the intestinal immune response, should limit the usability of the created mature challenge model within 1 to 2 wk after inoculation.

Effect of zinc on growth performance, gut morphometry, and cecal microbial community in broilers challenged with Salmonella enterica serovar typhimurium

“…Infection with Salmonellas leads to a significant negative effect on growth performance of poultry (Vandeplas et al, 2009;Marcq et al, 2011;Wang et al, 2012), which was confirmed in this study. In the present study, there was a significant reduction in BWG after S. typhimurium challenge.…”

Effect of Dietary <i>Bacillus Subtilis </i>C14 and RX7 Strains on Growth Performance, Blood Parameter, and Intestinal Microbiota in Broiler Chickens Challenged with <i>Salmonella Gallinarum</i>

“…The decrease in weight gain might be mainly due to decreased feed intake. Our results was in consistent with previous reports on reduced weight gain and feed intake in poultry challenged with S. gallinarum (Gupta et al, 2005;Vandeplas et al, 2009;Marcq et al, 2011). Our results also demonstrated that the addition of B. subtilis into diets could enhance the growth performance of broilers challenged with S. gallinarum.…”

“…We then performed in vivo broiler experiment followed by experimental challenge/infection. Salmonellosis can lead to depression, diarrhea, severe body weight loss, and mortality of poultry (Vandeplas et al, Journal of Poultry Science, 54 (3) Marcq et al, 2011). Infection with S. gallinarum decreased the weight gain compared to unchallenged broilers in this study.…”

Induction of immune response in broiler chickens immunized with recombinant FliC and challenged by Salmonella Typhimurium

“…These results corroborate Marcq et al (2011) who demonstrated that after challenge with Salmonella Typhimurium, the birds showed higher titers of secretory IgA.…”