Diagnostic Methods and Prevention and Control Measures for Gout in Chickens

Gout in chickens is a uric acidemia caused by a disorder of protein metabolism.

I. Analysis of Causes.

1. Nutritional imbalance: When the content of protein and nucleoprotein in the feed is too high, the sharp increase of uric acid in the body exceeds the excretion limit, and thus urate (mainly sodium urate) is deposited on the surface of joints and internal organs and in the subcutaneous connective tissue, causing a series of pathological changes. This disease is especially more likely to occur in flocks with an imbalanced calcium-to-phosphorus ratio in the feed and a deficiency of vitamins A and D.

2. Renal dysfunction in chickens: When excessive sulfonamide drugs are fed and renal dysfunction is caused by other factors, the excretion of uric acid is obstructed and accumulates, which can cause the occurrence of gout.

II. Incidence and Symptoms.

This disease has no seasonality, mostly occurs in flock outbreaks, and generally follows a chronic course. Affected chickens show generalized nutritional deficiency, poor appetite, gradual emaciation, listlessness, ruffled feathers, anemia, pale combs, periodic rises in body temperature, and increased heart rate. They pass white, semi-mucoid, thin droppings from the cloaca, and the droppings contain large amounts of urate. Laying hens show a decline in egg production, or even complete cessation of laying. A few chickens have difficulty breathing and even develop neurological symptoms such as spasms, and most die from exhaustion. Articular gout is characterized by swelling of the joints of the toes and legs, slow movement, lameness, and difficulty standing.

III. Necropsy Lesions.

At necropsy, the kidneys are visibly enlarged and pale in color, with white spots on the surface formed by urate deposition. In severely affected chickens, this lime-like urate precipitate is also often found covering the surface of other internal organs (liver, heart, spleen) and the mesentery, and in severe cases it can form a white membrane. At necropsy of articular gout, white urate deposits can be seen on the joint surfaces and in the tissues around the joints, and some joint surfaces are eroded. When the precipitate is scraped off and observed under a microscope, many needle-shaped sodium urate crystals can be seen.

IV. Diagnosis.

The incidence and clinical signs of gout in chickens are easily confused with those of other diseases. Diagnosis of gout in chickens should be based on the characteristic pathological changes found at necropsy, combined with feeding investigation and analysis of causes.

V. Prevention and Control.

1. Promote the use of complete-price feed to prevent nutritional imbalance. Feed mixed by farmers themselves must be formulated according to the requirements of different chicken breeds, different developmental stages, and different seasons, so as to prepare feed with reasonable nutrition. Prevent blind addition of animal protein feeds such as fish meal, and especially in winter, attention should be paid to adding appropriate amounts of vitamins A and D.

2. When preventing and treating chicken diseases, drugs such as sulfonamides and sodium bicarbonate should not be used for too long, and overdose should especially be prevented; or when gout is suspected, their use should be stopped.

3. Overcrowding in chicken houses, lack of exercise and insufficient light, damp and cold poultry houses, as well as coccidiosis, pullorum disease, Newcastle disease of chickens and other conditions that can affect the normal function of the kidneys, can all promote the occurrence of this disease. Therefore, controlling the rearing environment, strengthening feeding management, and doing a good job in comprehensive disease prevention and control in ordinary times can reduce the occurrence of this disease.

4. In order to reduce kidney damage, sulfonamide drugs should be used as little as possible or not at all during the prevention and treatment of chicken diseases, and sufficient drinking water should be maintained around the clock to ensure the excretion of harmful toxic substances from the kidneys.