STUDY ON THE HISTOPATHOLOGICALAND ENZYMATIC RELATIONSHIP IN CHICKENS AFFECTED BYMAREK'S DISEASE

The aim of the present study was to determine the relationship between histopathological lesions and tissue enzymes in chickens affected by Marek's disease.Five apparently healthy chickens(as control group)and 25 chickens affected by Marek's disease were selected. After consideration of history and gross lesions, tissue samples were collected from kidney, liver, heart, ovary, pectoral muscle, spleen, crop, proventriculus and bursa of fabricius for histopathological and tissue enzyme studies. In tissue samples, the activity of aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatine kinase (CK), superoxide dismutase (SOD)and glutathione peroxidase (GPX)was measured. Histopathologically, lymphomatous lesions in visceral organs were included in local or diffuse ple omorphic small to medium lymphocytes, lymphoblasts,marek cells and rarely plasma cells. The results indicated that the activities of AST, LDH, CK, SOD and GPX were decreased in the crop of affected chickens. The activities of CK, LDH and AST in the liver tumors and the activities of LDH, AST, ALP, SOD, CK and GPX in pectoral muscles were increased. In proventriculus, the activities of AST, ALP, LDH and SOD were shown to be increased,but the activity of CK was decreased. The activities of AST and SOD in the ovary lesions and the activities of SOD, AST, CK and LDH in the heart lesions showed an increase. Fluctuations in the activity of enzymes in different tissues showed that measurement of these enzymes can not be used as a tumor marker in the diagnosis of Marek's disease.