Diabetes mellitus concurrent with hepatic haemosiderosis in two macaws (Ara severa, Ara militaris)

Abstract

Diabetes mellitus was diagnosed in a 5-year-old male chestnut-fronted macaw (Ara severa) and an 8-year-old female Military macaw (Ara militaris) based on persistent hyperglycaemia and glucosuria. Hepatic biopsies showed marked hepatic haemosiderosis, while pancreatic biopsies showed no inflammatory lesions. Repeatable and titratable responses to bovine or porcine protamine zinc insulin were recorded in both patients, who were followed up for more than 2 years. In addition, iron-elimination therapy was initiated by chelation or phlebotomy, and the birds' diet was changed to low-iron content pellets. Both birds responded favourably to this therapy, showing a decreased demand for extrinsic insulin. Follow-up biopsies demonstrated marked reduction in hepatic haemosiderin. Plasma fructosamine and β-hydroxybutyric acid levels were measured periodically in both birds and compared with euglycaemic psittacines. Both tests appeared useful for monitoring treatment success. The potential association between diabetes mellitus and excessive iron storage in birds should be further investigated. © 2007 Houghton Trust Ltd.