Abstract
Mancozeb manganese ethylenebis dithiocarbamate polymeric complex – with zinc salts is a very important protective non-systemicfungicide, classified as an ethylenebisdithiocarbamate fungicide. It is used to control fungal diseases for a wide variety of crops because its broad-spectrum fungicidal effects and high compatibility with agrochemicals. The objective of this study was to investigate the effects of the fungicide mancozeb at different doses on some biochemical parameters, reproductive performance and histological changes in testes and thyroid gland. The low dose equal 1/7 of LD50 manc-d1 and high dose equal 1/3.5 of LD50 manc-d1. Doses of mancozeb (manc-d1 and manc-d2) adjusted according to rat's body weights. The results showed that mancozeb significantly (P<0.05) decreased plasma testosterone level, sperm count, viability, motility, and significantly (P<0.05) increased abnormal sperms, altered acrosome and abnormal DNA. Treatment of rats with manc-d1 and manc-d2 significantly (P<0.05) decreased T3. Also, T4 significantly (P<0.05) decreased in the group treated with manc-d2. Treatment of rats with manc-d1 and manc-d2 significantly (P<0.05) increased TSH. Furthermore, the histological investigation revealed that exposure to mancozeb reduced number of mature spermatozoa, necrosis and basal vacuoles observed in some tubules. On the other hand, mancozeb reduce colloid in most follicles resulting in desquamation of the follicular epithelium into the lumen of the thyroid follicles. In conclusion, despite mancozeb exhibit low acute toxicity, it has been shown to cause detrimental effects on reproduction, thyroid gland and its secretion. For this reason, it should be necessary to be careful when using mancozeb in agricultural areas and should take precautions.

Key words: Mancozeb, rats, thyroid glands, testes, histology, fungicidal -pesticide and Reproductive bioindicies