Meeting Abstract
Flame retardants are a diverse group of chemicals, many of which have the capacity to act as endocrine disruptors in birds. Abnormal hormonal signaling can directly influence organismal oxygen consumption rate, but few studies have connected endocrine disrupting compounds with this metabolic endpoint. In turn, metabolic rate has been shown to be closely linked with individual differences in behaviour. Triphenyl phosphate (TPHP), a chemical commonly used as a plasticizer and flame retardant, has been detected in wild birds and is identified as a potentially high-risk chemical. TPHP disrupts the central regulation and hormone synthesis pathways of the thyroid system in fish, which regulates growth and metabolism, but little is known about its effects in birds. Japanese quail (Coturnix japonica) chicks were exposed in ovo and orally for 6 d to safflower oil (control), 5 (level in wild bird eggs in Canada), 50, or 100 ng/g TPHP, or 100 ng/g diphenyl phosphate (DPHP), a major metabolite of TPHP. We measured growth (body weight and tarsus length), O2 consumption using an open-flow gas respirometry system, and assessed thyroid gland histology and circulating thyroid hormone concentrations, all endpoints related to the thyroid system. We observed a dose-dependent suppression of chick growth and O2 consumption. Understanding linkages between hormones and metabolism may help us to predict the population-level consequences of environmental exposure to endocrine disrupting contaminants in birds.
