Pathology of experimental Salmonella gallinarum infection in turkeys (Meleagris gallopavo)

Abstract

The present study investigated the pathology of a local Nigerian Salmonella gallinarum strain in turkeys. Fifty white Nicholas day-old poults were randomly assigned into two groups of 25 each: A/SGI – Salmonella gallinarum infected and B/SGU – Salmonella gallinarum uninfected. At fourteen-week-old, each bird in group A/SGI turkeys was inoculated with 0.2mL of 1×10⁸ cfu of the Salmonella gallinarum orally into the crop by oral gavage, while each bird in group B/SGU received 0.2 mL of phosphate buffered saline through the same route as placebo. They were examined at different days post-challenge. A/SGI turkeys showed inappetence, depression, and yellow-green diarrhoea. The body weights were significantly (P <0.05) lower than those of B/SGU turkeys. Mortality in A/SGI was 60%. A/SGI turkeys initially had swollen and congested visceral organs with mahogany and bronze sheen liver and spleen, followed by atrophy of the pancreas and heart with thickened pericardium. The histopathological changes were fibrinoheterophilic exudate in the hepatic parenchyma with necrosis of the hepatocytes and epithelium of the bile duct, followed at the later stage by fibrosis and vacuolar degeneration. Severe lymphoid depletion was observed in the spleen. There was marked necrosis followed by pancreatic fibrosis. The heart showed marked congestion, inflammatory oedema with fibrinoheterophilic exudate, myocardial necrosis and myocardial fibrosis. These findings suggest that initial swelling, congestion of visceral organs and distinctive coppery bronze sheen of the liver and spleen, atrophy of the heart and pancreas, and fibrinoheterophilic exudates in the liver, spleen, heart and pancreas, hepatic and pancreatic fibrosis and hepatocellular vacuolar degeneration were lesions of Fowl typhoid in turkeys observed in this study.