Histological and histochemical investigations on hepatic lipidosis in turkeys

This study describes peculiar cases of hepatic lipidosis in turkeys and the results of histochemical and immunohistochemical approaches aimed at better detailing this condition. Hepatic lipidosis of the turkey is a syndrome described in turkey and characterized by enlarged livers mottled by pale yellow areas. Histologically, the main feature is fatty degeneration associated with necrosis and haemorrhage. The cause of hepatic lipidosis is uncertain although nutritional and metabolic factors are suspected. Over a period of 6 years, we observed 8 cases of a hepatopathy with gross and microscopic changes consistent with hepatic lipidosis. Two of these cases affected turkey breeder hens of 12th and 21st week of age. Interestingly, another case was observed at slaughterhouse in 20-week old commercial male turkeys, whereas 5 cases involved commercial poults of 5 to 26 days. Histochemistry revealed the maintenance of the reticulin framework in hepatic lipidosis and excluded a disorder in copper metabolism. Positive adipophilin immunohistochemistry confirmed hepatic lipidosis is characterized by nonphosphorylated lipid accumulations within hepatocytes. Current and alternative pathogenetic hypotheses for hepatic lipidosis are discussed on the basis of these results.