Effects of endocrine disrupting chemicals (EDCs) on reproductive success and offspring viability in adult zebra finches, phase 1 of a transgenerational study (#339)
Endocrine disrupting chemicals (EDCs), including bisphenol-A (BPA), are found in nearly all plastics and many naturally-occurring plant-derived substances. EDCs often act by mimicking the effects of estrogen or testosterone, and even most plastic containers that are considered food safe release estrogen-like chemicals into their contents. In mammals, fetal exposure to BPA leads to lower birth weight, changes in accessory reproductive gland development, alterations in sexual differentiation in the brain, and altered social behaviors, but many of these studies have used forced administration of selected substances. As the first phase of a transgenerational study, we investigated the effects of EDCs naturally-administered on adult animals and their offspring. We administered drinking water to breeding adult zebra finches via BPA-positive and BPA-negative plastic bottles. Animals in our negative control received drinking water from a glass bottle and animals in our positive control received low-dose estrogen-supplemented (0.5 nmol/g body weight/animal of water soluble beta-estradiol) water from a glass bottle. Preliminary results showed no effect on overall egg production, but decreased egg viability (p < 0.0001), low chick weight at both hatch and fledge (p < 0.0001), and reduced survivability in animals exposed to estrogen and estrogenic compounds through daily water consumption. Offspring in the estrogen and BPA+ treatment groups grew more slowly during the period of nutritional dependence (p = 0.067), and the parents of these offspring had lower plasma prolactin levels (p = 0.042). In avian species, plasma prolactin is associated with parental care. Together, these results suggest that the levels of EDCs that leach from plastic drinking containers may be sufficient to impact parental care and offspring growth and developmental patterns.