Effect of Salmonella Typhimurium Colonization on Microbiota Maturation and Blood Leukocyte Populations in Broiler Chickens

Abstract

Reducing Salmonella in commercial chickens is vital to decreasing human salmonellosis infections resulting from contact with contaminated poultry and poultry products. As the intestinal microbiota plays an important role in preventing pathogen colonization, we sought to understand the relationship between Salmonella infection and the cecal microbiota and the host immune system. Day-of-hatch broiler chicks were assigned to three treatments: control, artificial (SA), and natural (SN) Salmonella infection. At seven days of age, control and SA birds were inoculated with PBS or Salmonella Typhimurium, respectively. Five SA birds were transferred to SN cages to facilitate natural infection. Cecal content and blood samples were collected at 0, 8, 14, and 21 days of age for microbiota and leukocyte analysis, respectively. A significant change in microbiota composition was observed in both groups as noted by a decrease in Lactobacillus and Escherichia and an increase in Bacteroides. Leukocyte analysis revealed a decrease in the percentage of circulating monocytes at 7 days post-infection while a decrease in thrombocyte and an increase in heterophil percentages were seen at 14 days post-infection. Taken together, these results demonstrate the ability of Salmonella to modulate the intestinal microbiota to facilitate colonization. Additionally, results indicated an early role of monocytes and thrombocytes during colonization, followed by heterophils.

Animal and In Vitro Models as Powerful Tools to Decipher the Effects of Enteric Pathogens on the Human Gut Microbiota

“…Robinson and colleagues infected broiler chickens with S. ent. Typhimurium ATCC 14028 to evaluate if the subsequent modulation of the cecal microbiota could facilitate Salmonella colonization [44]. The tested pathogenic strain determined an overall reduction in species richness associated with a time-dependent lowering of Bacillaceae, Escherichia, and Lactobacillus, as well as an increase in Bacteroides, thus allowing more effective and stable colonization of chicken cecum by S. ent.…”

“…The tested pathogenic strain determined an overall reduction in species richness associated with a time-dependent lowering of Bacillaceae, Escherichia, and Lactobacillus, as well as an increase in Bacteroides, thus allowing more effective and stable colonization of chicken cecum by S. ent. Typhimurium [44]. Several studies investigated the impact of S. ent.…”

In vitro and in vivo evaluation of tannic acid as an antibacterial agent in broilers infected with Salmonella Typhimurium

“…Whereas colonization of a single strain pathogen in the gut can impair growth performance and gut health of chickens, it is more likely that the pathogen induces imbalance in the entire gut microbiota, which can negative affect growth performance and gut health of chickens ( Robinson et al, 2022 ). In addition to evaluation of antibacterial effects of TA against ST NR in in vitro conditions, whether TA supplementation alters the ileal microbiome in chickens infected with ST NR was investigated.…”

Phenotype Alterations in the Cecal Ecosystem Involved in the Asymptomatic Intestinal Persistence of Paratyphoid Salmonella in Chickens

“…3.1.5. Salmonella Enterica Serovar Typhimurium (ST) and Microbiota ST colonization of the chicken intestinal tract, either after experimental challenge or natural infection, alter microbiota composition with resultant decreases in cecal Enterococcus, Lactobacillus, Escherichia, and Bacillaceae [81]. Further, ST infection significantly reduced α-diversity indexes of ileal microbiota of broiler chickens [54] with a notable increase in Escherichia-Shigella genus levels [82].…”