The effects of experimental administration of low doses of zearalenone on the histology of ovaries in pre-pubertal bitches.

The experiment involved 30 clinically healthy Beagle bitches aged approximately 70 days with an initial body weight of approximately 8 kg. The animals were randomly divided into two experimental groups (EI and EII) and a control group of 10 animals each. Group EI was administered 50 microg of body weight zearalenone/kg per os for 42 days, group EII received 75 microg of body weight zearalenone/kg per os for 42 days, and the control group was administered placeboper os for 42 days. The bitches were ovariectomized at the end of the treatment period for anatomopathological examination. At the same time, peripheral blood samples were collected for endocrinological analyses (17beta-estradiol and progesterone). Administartion of zearalenone particularly higher doses, resulted in the hyperestrogenism degeneration and atrophy of ovarian cells and tissues with accompanying edema and blood extravasation, leading to increased 17beta-estradiol concentrations and an insignificant decrease in progesterone levels.