Congestive cardiomyopathy induced in ducklings fed graded amounts of furazolidone.

Newly hatched male White Pekin ducklings (n = 119) were allotted to 7 groups of 17 each and fed furazolidone (FZ) at dose levels of 0, 100, 250, 500, 750, 1,000, and 1,250 mg/kg of feed for 4 weeks. The frequency and severity of clinical signs of FZ toxicosis, including growth retardation, ascites, and mortality, were dose related. At necropsy, the affected ducklings had ascites, hydropericardium, and biventricular dilatation. The frequencies of cardiomyopathy, ascites, and mortality, respectively, for the several dose levels of drug were as follows: 0, 100, and 250 mg of FZ/kg of feed--0%, 0%, 0%; for the 500 mg/kg level--35%, 12%, 0%; for the 750 mg/kg level--100%, 53%, 18%; for the 1,000 mg/level--79%, 57%, 57%; and for the 1,250 mg/kg level--33%, 20%, 73%. Ducklings with FZ-induced congestive cardiomyopathy had decreased left ventricular free wall and ventricular septal thickness, increased left ventricular chamber diameter, increased left ventricular dilatation score, decreased absolute heart weight, and increased relative heart weight. Cardiac histopathologic changes were minimal; some ducklings had myocytolysis. Liver and lungs were congested. Furazolidone-induced cardiomyopathy in ducklings offers a model for studies of congestive cardiomyopathy in a species that is free from the hereditary cardiomyopathy ("round heart disease") seen in turkeys.