The effects of a dietary or in ovo exposure to the pentabrominated diphenyl ether mixture, DE-71, on retinol and thyroid hormones in captive American kestrels (Falco sparverius)

Polybrominated diphenyl ethers (PBDEs) are one type of brominated flame retardant commonly used in industrial and domestic items. Their lipophilic and persistent properties and global occurrence in wildlife are cause for concern, especially for those at the top of the food chain, such as raptorial birds. This study consisted of dietary or in ovo exposure of captive American kestrels (Falco sparverius) to one of two environmentally relevant levels (high and low exposures) of the pentaBDE mixture, DE-71. Maternal retinol levels were reduced in the low-exposure group after three weeks of exposure and were associated with fewer hatchlings and increasing in ovo BDE-17 concentrations. The in ovo exposure affected the retinol levels of nestling kestrels and altered their thyroid hormones and the functioning of their thyroid system. These parameters were associated with in ovo concentrations of various BDE congeners, body mass, and feather growth. These findings are consistent with the reduced reproductive success of these birds and the altered growth of their young.