REVERSIBILITY OF FURAZOLIDONE-INDUCED CHANGES IN TESTES AND SECONDARYSEX CHARACTERS OF WHITE LEGHORN COCKERELS

Furazolidone (Fz) was fed to 4 groups of cockerels 15 w of age at 0, 4 00, 800 and 1200 mg/kg feed for 3 w and then was withdrawn for another 3 w. In a second experiment conducted simultaneously cockerels were f ed these same Fz levels for 6 w and then were withdrawn from Fz feed f or 4 w. In both experiments, 800 and 1200 mg Fz/kg feed resulted in de creases in comb and wattle size and in the weight of testes. The teste s had smaller seminiferous tubule diameters and increased relative and decreased absolute volumes of interstitium. Spermatogenesis was not o bserved in cockerels fed 800 and 1200 mg Fz/kg feed. Withdrawal of Fz resulted in increased comb and wattle size, weight of testes and diame ter of the seminiferous tubules. There was also an increase in absolut e volume of interstitium along with decreased relative interstitium vo lume. Spermatogenesis was restored.