Amyloidosis in Laying Hens
Amyloidosis is a well-recognized disorder in birds characterized by deposition of proteinaceous material between cells in various tissues and organs of the body. (1, 2)
No specific clinical signs or gross lesions are associated with systemic amyloidosis. In Brown egg-laying type chickens, locomotor problems due to swollen joints and weight loss can be encountered. But often the birds with amyloidosis are submitted for necropsy after being found dead with no prior clinical signs. The affected joints are enlarged, swollen and contain orange-yellowish matter. Brown egg-laying type chickens are particularly susceptible to amyloid arthropathy associated with Enterococcus faecalis and Mycoplasma synoviae (MS). (1, 2)
Observed Clinical Signs Happenings
Visibly sick birds
- Few visibly sick birds
- Low mortality or increases gradually
- Poor body fleshing condition (weight loss)
Lameness or unusual movement incoordination ataxia
- Locomotor problems, claudication
Body Parts (Neck, wings, breast, abdomen, shanks, legs, hock, feet, joints, vent, and skin)
- Swollen joints / enlarged joints (Brown egg-laying type chickens are particularly susceptible)
- Swollen abdomen
- .The affected joints are enlarged, swollen and contain orange-yellowish matter.
Amyloidosis in Laying Hens DOES NOT exhibit or manifest any of the following clinical signs happenings:
- Egg drop
- High mortality or increases rapidly
- Dead birds: Good body fleshing condition
- Many visibly sick birds
- Flock behaviour activity change
- Droppings abnormalities
- Respiratory abnormalities
- Neurological Nervous
- Eyes abnormalities
- Head: Comb Wattles Face Nostrils Sinuses Mount Beak Earlobes (except eyes)
- Feathers abnormalities
- Feed Consumption Changes
- Diet or Feed Changes
- Shell quality defects
- Internal Egg defects
- Causing Agents
- Bacterial Infection. Caused by a prolonged stimulation of the immune system usually due to chronic bacterial infection such as Enterococcus faecalis but not by all E. faecalis isolates and Mycoplasma synoviae particularly in brown egg-laying type chickens. Other bacteria such as E. coli, Salmonella enteritidis and Staphylococcus aureus Mycoplasma gallisepticum, and hepatitis-splenomegaly syndrome have also associated with amyloidosis.
- Affected Systems/Organs
- Locomotor System. Foot and leg joints
- The disease itself is non-transmissible. It is more prevalent in genetically predisposed hens
- Mainly Affects
- Liveability and cull birds increased
- Adequate management to prevent chronic infections or stress in hens would reduce the incidence of amyloidosis. Control of predisposing infection. Drug therapy (antinflammatory drug). Amyloidosis arthropathy in the joints was enhanced by feeding a high dose of vitamin A.
- Suggested Actions
- Can be confirmed with clinical signs and gross lesions
- Can be dealt with in house
- Technical assistance recommended
- Can be managed with feed additives, off-the-shelf medications
- Diagnosis should be confirmed with rapid assays and/or a certified laboratory
- Veterinary intervention is recommended
Impact on Egg quality
Impact on Liveability
Impact on Production
Overall Economic Impact
- Y.M. Saif. 2008. Disease of Poultry. 12th Edition. page 1152
- David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 1237
- Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.
- Paul McMullin. 2004. A pocket Guide to Poultry Health and Disease. First Edition.
- Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.
- Donald D. Bell, Williams D. Weaver. 2009. Commercial Chicken Meat and Egg Production. Fifth Edition.