2013 Volume 20 Issue 1 Pages 22-30
It is considered that both phytoestrogens and organochlorine pesticides found in pet animal diets are possible sources of interference with bioassays that assess estrogenic activity. In the present study, we investigated the levels of dietary phytoestrogens, organochlorine pesticides, and estrogenic activities in various commercial pet animal diets and discussed the potential contributions of these substances to the estrogenic activity in comparison to those tested in previous studies. Following hydrolysis by β-glucuronidase, genistein and daidzein were detected in all of the tested diets, and these results were comparable to the data from previous investigations. In addition, organochlorine pesticides, such as α-HCH, β-HCH, HCB, p,p'-DDE and dieldrin, were detected in 2 of 15 tested diets. All of these diets exhibited higher levels of activation of the estrogen receptor β(ERβ) than the estrogen receptor α(ERα) in an in vitro yeast-based bioassay. These results indicated that phytoestrogens, such as genistein and daidzein, were the main substances contributing to the estrogenic activity of the diets. Moreover, the levels of phytoestrogen found in 5 of 15 tested diets may have sufficient amounts to produce a significant estrogenic activity in pet animals.
