What is gout, a nutritional metabolic disease in ducks?

Gout is an internal medicine disease caused by a disorder of protein metabolism in the duck's body. Its main pathological feature is the accumulation of large amounts of urate in the joints or internal organs and other interstitial tissues. This disease mostly occurs in the cold winter and early spring seasons when green feed is lacking. Ducks of different breeds and ages can all be affected, and clinically it is mostly seen in young laying ducks. It is mostly caused by breeders one-sidedly pursuing weight gain speed while neglecting scientific feed formulation and feeding feed with excessively high protein content. After ducks become ill, it causes emaciation and loss of appetite, and in severe cases often leads to death. It is an important nutritional metabolic disease harming duck production.

1. Causes

The causes of this disease are mainly related to feed and renal dysfunction.

(1) Feeding excessive protein feed, especially feed rich in nucleoprotein and purine bases. Common examples include animal offal, meat, fish meal, etc., as well as plant materials such as soybean meal, spinach, lettuce, and cabbage.

(2) Renal insufficiency or renal dysfunction. Young ducks have insufficient kidney function. Feeding excessive protein feed not only cannot be absorbed by the body, but on the contrary increases the burden on the kidneys, damages kidney function, and leads to the occurrence of this disease. In the clinically seen cases of young ducks and adult ducks, most are related to excessive use of antibacterial drugs that damage kidney function (such as sulfonamides, etc.).

(3) Lack of sufficient vitamins. For example, a lack of VA in the feed can also promote the occurrence of this disease. In addition, damp duck houses, poor ventilation, lack of light, and intestinal inflammation caused by various diseases are all predisposing factors for this disease.

2. Clinical symptoms

According to the different sites of urate deposition, gout can be divided into two disease types, namely visceral gout and articular gout. Visceral gout: mainly seen in young ducks within one week of age. Affected ducks are listless, often completely lose appetite, have weak legs and walk unsteadily, are weak, and often die within 1 to 2 days. When young or adult ducks are affected, they often have poor spirit and appetite, are thirsty at the beginning of the disease, then completely lose appetite, become thin and weak, walk weakly, pass thin white or semi-viscous feces containing large amounts of urate, and gradually become exhausted and die, with a disease course of 3 to 7 days. Sometimes adult ducks may also die suddenly during catching, mostly because large amounts of urate are deposited on the pericardium and myocardium, affecting heart contraction and causing acute heart failure. Articular gout: mainly seen in young or adult ducks. The affected limbs of sick ducks have swollen joints, which feel relatively hard to the touch, often with lameness. Sometimes swelling occurs in the joints of both limbs, and in severe cases paralysis occurs. The other clinical manifestations are the same as those of visceral gout cases, and the disease course is about 7 to 10 days. Sometimes mixed-type cases also appear clinically.

3. Pathological changes

In all dead cases, the skin and webbed feet are dry. In visceral-type cases, necropsy shows large amounts of urate deposited on the surface of internal organs, like a heavy frost, especially with the most severe deposition on the pericardium. The pericardium is thickened, attached to and adhered to the myocardium, and urate is also deposited on the myocardial surface; the kidneys are enlarged and mottled, the renal tubules are filled with urate, the ureters are dilated and thickened, with uric acid crystals inside, and in severe cases uric acid stones may form. In a few cases, a small amount of urate is also deposited in the loose subcutaneous connective tissue. In articular-type cases, the affected joints are enlarged, and large amounts of viscous urate deposits are present in the joint cavity.

4. Prevention and control measures

(1) Improve feeding management, adjust the feed mixing ratio, appropriately reduce protein feed, and at the same time provide sufficient fresh green feed and supplement abundant vitamin A.

(2) Stop using antibacterial drugs in affected duck flocks, especially drugs toxic to the kidneys, and in routine disease prevention, attention should also be paid to preventing excessive medication.