Diagnosis and Treatment of Gout in Black Swans

Avian gout is a nutritional disease caused by a disorder of nucleoprotein metabolism in birds, characterized by the accumulation of large amounts of urates in various organs (visceral type) and joint tissues (articular type). Clinically, it presents as sluggish movement, swelling of the leg and wing joints, anorexia, and diarrhea. Gout has occurred in many bird species in our park, including mute swans, Indian peafowl, white peafowl, kalij pheasants, and silver pheasants. Here we report a case of gout in a black swan at our park.

I. Case history: In the waterfowl lake of our park, 10 mute swans, 6 black swans, and several dozen wild ducks are kept. On January 10, 2004, a keeper noticed that a female black swan hatched in the first half of the previous year showed poor spirits, loose droppings, and reluctance to move. Upon capture and examination, the bird was found to be emaciated, with an empty crop and a body temperature of 42°C. It was immediately given an intravenous injection of 5% glucose and sodium chloride injection, amikacin, vitamin C, and dexamethasone sodium phosphate injection, but the condition did not improve, and it died the next morning.

II. Clinical signs: The affected bird was listless, lying on the ground or huddling to one side, unwilling to move, and rarely active in the water; the corners of the beak opened and closed weakly, and appetite was reduced; droppings were thin and watery, white in color, with white loose feces adhering to the feathers around the vent.

III. Necropsy findings: Large amounts of white urate deposits were present in the knee and wing joints; the epicardium, liver, and kidney surfaces were all covered with a layer of white, lime-like urate sediment; urates were also deposited in the proventriculus, pancreas, and mesentery; the liver was pale and degenerated, the kidneys were enlarged, pale in color, covered with petechiae, and firm to the touch; the ovaries were atrophied and the ova degenerated. Based on the large amounts of urate deposits, a preliminary diagnosis of avian gout was made.

IV. Experience in prevention and treatment: (1) The water in the waterfowl lake should be clean, preferably flowing water; balance the diet, increase the supply of green fodder, routinely increase the supply of vitamin A and vitamin D, and control the calcium and phosphorus levels in the diet; reduce stress by adding anti-stress drugs to the feed or drinking water; allopurinol 5 g mixed into 10 kg of feed, used continuously for 1 to 2 weeks, can achieve a certain effect; strengthen feeding management, increase exercise, and pay attention to observation and environmental cleanliness and hygiene. (2) In the waterfowl lake of our park, the feed is mainly rice grain supplemented with green vegetables, making it difficult to ensure a balanced diet for each individual animal. Because the animals are on display in the zoo and live in a single environment for a long time, they lack exercise. Moreover, external factors affect their growth and development over the long term, such as water quality problems and disturbance by visitors. As infectious diseases and parasitic diseases become fully understood, the economic losses caused by nutritional and metabolic diseases are increasingly recognized, so it is particularly important to accurately supplement the target nutrients in animal diets or drinking water.