Pathomorphological changes in the liver of broiler chickens caused by adeno-virus infection. Description of a spontaneous case in a private farm of the Lviv region

Abstract

The article covers the results of pathomorphological studies of broiler chickens' liver (Cobb 500 cross) spontaneously damaged by Group I fowl adenovirus. Clinical signs of the disease in broiler chickens appeared on the 15th day of life and were manifested by a sharp decrease in water and feed consumption. The fowl was lethargic for several days, breathing hard, mostly sitting with its head down and eyes closed. During the breeding period, the mortality rate reached 13.2 %, accompanied by significant growth retardation. A peak of mortality was observed within 20–24 days of life. Antibody titers monitored by immunoenzymatic method using BioChek ELISA tests for infectious bursal disease (IBD), infectious bronchitis (IBV), and Newcastle disease (ND) virus were within normal post-vaccination levels. Pathological autopsy of broiler chickens revealed hepatomegaly, diffuse punctate and petechial hemorrhages under the Glisson's capsule, and military necrosis in the liver parenchyma. Hydropericarditis, pulmonary edema, renal dystrophy, and catarrhal enteritis were also detected in some cases. Liver fragments were selected for histological examination, fixed in a 10 % aqueous solution of neutral formalin, washed in water, and dehydrated in an ascending series of alcohols, followed by sealing and embedding in paraffin. Deparaffinized sections were stained with Mayer's hematoxylin and eosin. Optical examination of hepatocytes revealed large, round basophilic intranuclear inclusion bodies, multifocal necrosis of hepatocytes, stasis, and fatty dystrophy. According to the molecular genetic test results of broiler chickens' liver fragments, the DNA of Group I fowl adenovirus, serotype FAdV-11, was isolated.