Effects of furazolidone on the development of cardiomyopathies in turkey poults

Graded doses of furazolidone were added to feed mixtures given turkey poults the first five weeks post-hatching. Toxicity from as little as 300 ppm was confirmed. Mortality from 500 ppm for five weeks was high (41%). Furazolidone at 100 ppm apparently stimulated growth, since the poults in this group were significantly heavier at 3 to 5 weeks of age than other poults. At toxic levels, the growth rate of unaffected (normal) birds paralleled that of control birds. Incidence of cardiomyopathies increased with furazolidone dose. The cardiomyopathy observed most commonly was a combined right and left ventricular dilatation. To study spontaneous recovery, all birds were monitored for 7 weeks after removal of the drug. Both development of the round heart syndrome and spontaneous recovery were quite variable in rate.