Gout is a sign and not a disease. In poultry, renal diseases lead to gout, which can further damage the kidneys or other body systems. It is a metabolic disorder resulting in hyperuricemia and the deposition of uric acid or urates in tissues. In broilers, it is usually found in the first 3 weeks of life than being later on.

The nutritional or metabolic causes of gout include- excessive dietary calcium, high protein diet, excess salt, low phosphorus, imbalance between Ca–P levels, adulteration of feed with urea, deficiencies of vitamin A and D, high altitude farming, water deprivation followed by over dosages of certain drugs like sulphas and the antibiotic aminoglycosides often causes kidney damage, managemental stress like, high brooding temperature and higher level of ammonia concentration in the shed can also cause high mortality due to gout, mycotoxins and phytotoxins, poisoning with phenolic disinfectants or insecticides, and infectious causes viz. bacteria (Salmonella, E.coli) and viruses (Infectious bronchitis virus (IBV), avian nephritis virus (ANV) .

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In birds, Uric acid is the end- product of protein and is normally excreted through Kidneys. Uric acid is insoluble in water and since birds lack enzyme Uricase, there is no further conversion of Uric acid in to water soluble Allantoin, as in mammals. However, in birds, Uric acid is solubilised by binding with specific protein in the proximal tubules of kidneys so that its crystallization in kidneys is prevented. If there is renal failure or excessive formation of Uric acid in the body or both, due to various predisposing causes, Uric acid accumulates in the blood resulting in hyper Uricemia. Normal levels of Blood Uric acid in Birds is 4.5 to 5 mg/dl and when it rises to 10 -20mg/ dl, clinical symptoms of gout appear and when it rises to 25.5 – 42.2 mg/dl, there is severe gout mortality. High level of Uric acid in blood lead to precipitation of monosodium/ calcium urate crystals in various tissues and organs. These crystals, being insoluble in tissue fluids and having sharp ends, cause physical damage to the tissues leading to a cascading inflammatory reaction.

Gout is of 2 types- articular (random cases) and visceral (most common and of economic importance):

1. Articular Gout: The accumulation of urates within the synovial capsules and tendon sheaths of the joints and ligaments, including the toes of the feet and wings. This is a chronic form and occurs sporadically. Mostly, roosters are affected. In articular gout, birds go lame; Urate deposits (Tophi) are found around periarticular tissue and also within joints of feet and legs. Joints of wings, spine and mandibles may also be similarly affected. Microscopically, granulomatous inflammation of soft tissue in these locations is marked.

1. Visceral Gout: The precipitation of uric acid crystals along the surface of internal visceral organs and other sites within the body. This is more acute- form and common form than articular gout and can affect the whole flock. It occurs in both sexes.Visceral gout presents no significant clinical signs and sudden onset and rise in mortality draws farmers› attention to the flock. Dead birds are dehydrated. In mild form ureters are thick, white and prominently seen. Kidneys appear pale with prominently visible uriniferous tubules. In severe form, in addition to these changes, white chalky deposits are found covering heart, liver, intestines, peritoneum, spleen lungs air sacs, muscles and inner lining of proventriculus. In few birds, such deposits may also be found in synovial sheaths of tendons, joints and subcutaneously on legs. Microscopically, inflammatory.

Economic Impact of Gout-

Gout has a direct effect on the productivity by lowering the weight gain of the birds, higher Feed Conversion Ratio (FCR) and mortality, which may go up to 11- 30%.

Prevention and Control:

 1-   At hatchery level, minimize dehydration at all stages including chick holding and transport etc. Try to start chick life during daytime in cold weather when temperature is ideal.

2-    Maintain correct temperature at litter level during arrival of chicks and first 10 days at-least. Try to maintain 60- 70% humidity during first 3 days of chick life. Allow chicks to drink water for 1 or 2 hours and then only offer pre-starter feed.

3-    Ensure correct level of Calcium and Phosphorus levels in feed. Use toxin binders and liver tonics to keep minimum levels of fungal toxins in feed. Avoid excessive protein levels in diet.

   4- Use recommended levels of aluminum-free Sodium bicarbonate in feed during high temperatures. Use electrolytes at recommended doses in water.

    5- Review Infectious Bronchitis vaccine programme in Breeders and broiler farms. Even vaccine spray at hatchery level found to be effective in field condition.

    6 -High level of Methionine in feed also found helpful to some extent.

    7- When gout is noticed, reduce the load on kidney by reducing the daily intake of protein either by reducing the quantity of feed or use grinded maize fortified with vitamins and minerals at correct level for 24 to 48 hours along with uses of Ammonium sulphate or Ammonium chloride at correct levels.