Effects of the Physical Form of Diet on the Outcome of an Artificial Salmonella Infection in Broilers

To prove the hypothesis that the physical form of diet affects the outcome of an artificial infection with Salmonella Enteritidis in broilers, 7-day-old birds were allotted to one of four groups and fed botanically, and nearly also chemically identical diets, differing in grinding and further compaction. In total, two birds from each group (age 14 days) were administered on average 1.06 x 10(8) colony-forming units (CFU) of Salmonella Enteritidis directly into the crop by gavage and immediately put back as seeder birds'' into their respective groups. The salmonella status of each bird was analyzed by cloacal swabs, and at postmortem examination, cecal content and liver tissue samples were taken. Shedding (measured by cloacal swabs) was reduced significantly (P < 0.05) in groups offered the coarsely ground and pelleted diet and the diet including whole wheat compared with the groups fed the finely ground and pelleted and the coarsely ground and extruded diet. Nevertheless, only broilers fed the diet containing whole wheat showed a significantly (P < 0.05) lower frequency of Salmonella Enteritidis isolation in the cecal content and liver tissue. This diet was characterized by the highest percentage of particles >2 mm. In this study the physical form of diet affected the outcome of an artificial infection with Salmonella Enteritidis significantly.