Avian amyloidosis

Abstract

Although amyloid deposits have been described for more than a century and a half, its proteinaceous and fibrillar nature was not revealed until after 1950. Biochemical characterization of amyloids has brought to light that several non-related proteins can re-organize into amyloid fibrils. In some domestic and caged wild birds, and especially waterfowl, amyloidosis is a well recognized pathological disorder and is an important cause of death in Anseriformes. Its regular occurrence in Galliformes has been recognized more recently, where amyloid deposits occur mainly in the joints in contrast to other species studied so far. Avian amyloidosis is systemic in nature, being classified by amino acid sequencing and, monoclonal and polyclonal antibodies as of the AA-type amyloid, also named reactive or secondary amyloid. The pathogenesis of both AA and other types of amyloidosis is a complex phenomenon that is not well understood. It has been shown that the occurrence of certain predisposing conditions and chronic infections, inflammations or tumours increase strongly the serum levels of the hepatic acute phase reactant serum amyloid A (SAA), the precursor protein of amyloid protein A (AA). Although an increased pool of precursor protein is necessary for amyloid to develop and while certain amino acid substitutions may favour amyloidogenicity giving rise to unstable intermediate protein conformations that easily re-organize into fibrils, the action of other factors which are discussed in this review, seems of vital importance at the initiation of fibrillogenesis. As the clinical symptoms of amyloidosis generally are non-specific, diagnosis requires histopathology following biopsy or necropsy. AA-amyloidosis is a fatal progressive disease in birds and other species. Currently no curative treatment is available, therefore special attention should be paid to prevention focusing on hygiene and avoidance of stress.

Mycobacteriosis in naturally infected ring-neck doves (Streptopelia risoria): investigation of the association between feather colour and susceptibility to infection, disease and lesions type

“…Amyloid deposits have been reported previously in birds with chronic inflammatory diseases such as mycobacteriosis and aspergillosis. Several forms of amyloid have been described in mammals, but only amyloid AA (amyloid associate) has been found in birds (Landman et al, 1998;Cotran et al, 1999;Schmidt et al, 2003). Amyloid AA is a product of the proteolytic cleavage of serum AA (SAA), an acute phase-protein produced by hepatocytes (Landman et al, 1998).…”

“…Several forms of amyloid have been described in mammals, but only amyloid AA (amyloid associate) has been found in birds (Landman et al, 1998;Cotran et al, 1999;Schmidt et al, 2003). Amyloid AA is a product of the proteolytic cleavage of serum AA (SAA), an acute phase-protein produced by hepatocytes (Landman et al, 1998). The concentration of SAA in the blood increases within a several hours of the onset of injury, infection, or inflammation.…”

Amyloidogenic potential of foie gras

“…AA amyloid deposits are commonly found in waterfowl, particularly Pekin ducks, in which the liver is predominately involved (8)(9)(10). This pathological alteration is noticeably increased in birds subjected to stressful environmental conditions as well as to the forced feeding that is used to produce foie gras (8).…”

“…However, by injection into 8-wk-old transgenic mice of a single 100-g i.v. dose of an exogenous source of AA fibrils, amyloid deposits are formed within 3 wk, and severe systemic disease (akin to that found in 8-mo-old animals) occurs within 2 mo, at which time the resultant pathology is lethal (7).AA amyloid deposits are commonly found in waterfowl, particularly Pekin ducks, in which the liver is predominately involved (8)(9)(10). This pathological alteration is noticeably increased in birds subjected to stressful environmental conditions as well as to the forced feeding that is used to produce foie gras (8).…”

Hepatic Myelolipoma and Amyloidosis with Osseous Metaplasia in a Swan Goose (Anser cygnoides)

“…Caged wild waterfowl, especially the Anatidae, to which Swan Goose belongs, are prone to systemic amyloidosis (Landman et al, 1998). The predilection organs of amyloid deposition are the liver, spleen, kidneys and small intestine.…”