Long-term Carcinogenicity and Toxicity Study of Zearalenone in the Rat

The effects of lifetime dietary administration of zearalenone, a fungal estrogen produced by Fusarium spp., were studied in FDRL Wistar rats. Animals were fed a control diet or a diet supplemented with zearalenone at levels of 0.1, 1.0 or 3.0 mg per kg body weight per day. The afiimals used were derived from F-0 parents fed equivalent levels of zearalenone for 5 weeks before mating, and throughout mating and gestation, but not during lactation. Feeding of zearalenone at 1.0 and 3.0 mg kg(-1) to male rats caused a significant decrease in body weight gain compared with controls. During the study, sporadic depressions in body weights occurred in females fed 1.0 and 3.0 mg per kg. However, no differences were noted at the end of the study. No significant differences among groups were found in the hematology, clinical chemistry or urine analysis data measured during or at the termination of the study. At the end of the study, significantly increased liver weights at the 3.0 mg kg(-1) dose level and uterine weights at 1.0 and 3.0 mg kg(-1) were noted in female rats. These weight differences did not correlate with any clinical or morphological finding. In rats receiving the high dose level of zearalenone, a greater incidence of increased medullary trabeculation of the femur was noted. The degree of medullary trabeculation was scored on a scale from 0 to 4; statistically significant increased scores were found in male and female rats at the high dose level compared to control rats. Other microscopic findings were unremarkable; no tumorigenic effect of zearalenone was noted.