Influence of stressors on normal intestinal microbiota, intestinal morphology, and susceptibility to Salmonella Enteritidis colonization in broilers. Poult. Sci

ABSTRACT In modern poultry production systems, en-vironmental stressors may influence bird performance and susceptibility to pathogens such as Salmonella En-teritidis. Experiments were conducted to determine the influence of 24-h feed withdrawal and 24-h exposure to high temperature (30°C) on intestinal characteristics of broilers. Attachment of Salmonella Enteritidis to il-eal tissue was determined using an in vitro ileal loop assay. Changes in commensal intestinal microbial pop-ulations were determined using denaturing gradient gel electrophoresis, and alterations in ileal morphology were determined histologically. Ex vivo attachment of Salmonella Enteritidis to ileal tissues increased by 1.5 logs (9.05 log10 vs. 7.59 log 10 Salmonella Enteritidis/g of ileal tissue; P = 0.0006) in broilers fasted for 24 h. Simi-larly, ileal tissues from birds subjected to 30°C for 24 h had increased ex vivo attachment of Salmonella Enter-itidis (8.77 log10 vs. 8.50 log10 Salmonella Enteritidis/g of ileum; P = 0.01) compared with birds held at 23°C. Exposure to 30°C for 24 h also altered microbial com-munity structure in the ileum and cecum. Subjecting birds to 30°C for 24 h reduced crypt depth (6.0 vs. 7.8 μm, respectively; P = 0.002), but had no effect on vil-lus height or villus:crypt ratio. This research shows that acute stressors in poultry production systems can cause changes in the normal intestinal microbiota and epithelial structure, which may lead to increased at-tachment of Salmonella Enteritidis