Furazolidone toxicosis in young broiler chicks: morphometric and pathological observations on heart and testes.

Broiler chicks 1 d and 3 w of age were given 0, 400, 800, or 1000 mg furazolidone (Fz)/kg feed for 4 w. Bi-ventricular heart dilatation (as measured by increases in ventricular diameter and thinning of the ventricular walls) was present in 1-d-old chicks fed 800 mg Fz, whereas in 3-w-old groups these changes occurred at 1000 mg Fz. There was no heart hypertrophy. Microscopic changes in the heart were not discernible in and Fz-fed birds. The liver had congestion and cytoplasmic vacuolation of hepatocytes. About 37-50% of the male birds in the different Fz-fed groups had testicular degeneration varying from mild to cystic enlargement. The degenerated testes had dilatation of seminiferous tubules; in cystic testes the seminiferous tubules were extremely dilated and had flattened epithelium. The interstitial tissue between the dilated tubules was compressed and atrophic.