Serum biochemical changes associated with cystic ovarian degeneration in pigs after atrazine treatment.

Biochemical and histopathological parameters of the ovarian function were observed to assess the toxic effect of low dose of atrazine, an s-triazine herbicide, in female pigs (gilts) undergoing intensive breeding. Female pigs (cross-bred between Swedish and German landrace) received 2 mg atrazine kg-1 body wt. in feed daily during 19 days of the oestrous cycle. The last treatment day corresponded to day -3 of the onset of the next expected oestrus. Blood samples were collected 3 times daily at 3-h intervals on the first 5 post-treatment days. Serum 17 beta-oestradiol (17 beta-E) and progesterone (P) concentrations were determined. A significantly higher (P < 0.05 and P < 0.001, respectively) serum 17 beta-E concentration was recorded 48 and 24 h before the onset of the next expected oestrus in atrazine-treated pigs, as compared to intact pigs. The onset of the next expected oestrus failed to occur, but no other adverse clinical reactions associated with the treatment were recorded. Histopathological examination of the ovaries of treated pigs indicated multiple ovarian follicular cysts and persistence of corpus luteum. Biochemical and histopathological findings showed that subacute exposure of female pigs to low dose of atrazine prolonged their oestrous cycle.