LAUSR

The aim of this study was to analyse the microscopic and ultrastructural lesions of the livers of broiler chickens during fattening. Three genetic lines of broiler chickens (Ross 308, Cobb 500, Hubbard F15) were investigated. The liver samples were taken on the 3 rd , 10 th , 17 th , 24 th , 31 st , and 38 th day of life from six healthy broiler chickens from each commercial broiler flock. The dominant microscopic lesions were associated with prolonged hypoxia and bile ductules, including: fatty, vacuolar and parenchymatous degeneration, necrosis of epithelial cells of bile ductules, necrosis of hepatocytes around the proliferating bile ductules, lymphoid cell infiltration around the bile ductules and blood vessels, proliferation of the bile ductules, proliferation of the connective tissue around bile ductules and stimulation of the lymph nodules. Ultrastructural evaluation revealed abnormalities involving mitochondria and rough endoplasmic reticulum. The mitochondria underwent swelling, polymorphism, prolifera- tion and damage. The rough endoplasmic reticulum underwent defragmentation and acinar transformation. The cytoplasm of most hepatocytes showed vacuoles of varying size or lipid droplets and the presence of cytoplasmic myelin-like structures. This study shows that the livers of br