Also known as Right ventricular failure, Water belly
Ascites (water belly, right ventricular failure) occurs worldwide where fast growing broilers are produced. More common at high altitude. It affects fast growing broilers and turkeys. It is not contagious. However it is influenced by genetics, breeding, nutrition, growth rate, ambient temperature and oxygen content of the air.
A chronic or acute disease prominent in young, fast growing broilers, ascites is no longer a disease confined to areas of high altitude.
Hypoxia (lack of oxygen) is caused by many agents and leads to constriction of arteries, inducing increased pulmonary arterial pressure which results in right ventricle hypertrophy. The right ventricular valve becomes weak (flabby), which causes back flow of blood and fluid (ascites) in tissues.
It occurs more in males. Hypoxia caused by altitude or gas fumes, carbon monoxide from brooders, worse in winter (tight house), stress of mycotoxins, toxic fat, increased salt in the diet and/or coal tar disinfectants, causes ascites. Respiratory disease can aggravate the problem. It is an important cause of broiler mortality at 5-7 weeks of age, in any area with fast growing broilers, but more so on high altitude. Lighting programmes (reduced photoperiod) to reduce growth rate during the first 2 weeks of age can reduce mortality due to ascites, flip over syndrome and leg problems.
Feeding mash feed instead of pellets also helps to reduce the problem.
Mode of transmission
It is non-contagious and influenced by genetics, breeding, nutrition, growth rate, ambient temperature and amount of oxygen in the air.
Water belly, abdominal distension, reluctant to move, dyspneic and cyanotic lesions are seen. Affected birds are smaller than normal and listless with ruffled feathers. Mortality ranges from 0.5-20% of the flock.
Water belly (straw-coloured fluid in abdominal cavity), blood clots in lungs, enlargement of right side of the heart, liver scarred, congested or mottled with a greyish capsule and irregular surface and shrunken and the lungs are congested, oedematous and haemorrhagic.
Clinical signs and postmortem lesions (water belly with enlarged right heart valve) are diagnostic. Microscopically, cartilaginous and osseous nodules occur in the lung, congestion of kidney, oedema, congestion and haemorrhages in the heart, It simulates salt, crotalaria and furazolidone toxicity.
Adequate temperature control of the house, good air and litter management, reduced sodium and furazolidone content of diet, and water, feed and/or light restriction with reduce the mortality.
If the altitude cannot be changed, the feed ration should be. A less dense (lower energy) feed practise, mash feeding instead of pellets or use a restrictive lighting programme to reduce growth rate during the first 2 weeks of age. More aeration of the house during the cooler months when gas broilers are in longer use will also help. Keep temperature at recommended level. Too high a temperature can also cause ascites. Control of respiratory disease (MG, IB, TRT, etc) which induce ascites should be carried out.