A three‐generational study of In ovo exposure to PBDE‐99 in the zebra finch

Abstract

Abstract-Based on a literature review of avian data for polybrominated diphenyl ethers (PBDEs), ecologically relevant doses, low (10 ng/egg), medium (100 ng/egg), and high (1,000 ng/egg) of the 2,2 0 ,4,4 0 ,5-pentabromodiphenyl ether (BDE-99) congener along with dimethylsulfoxide (DMSO) control were injected into the yolk sac of un-incubated eggs of zebra finch, Taeniopygia guttata. Offspring development and adult phenotype were followed over three generations. No effects of in ovo PBDE exposure on hatching success, chick growth, thyroid hormone levels, or hematological traits were measured at sexual maturity (90 d posthatching). However, the authors did detect significant effects of BDE-99 treatment on adult phenotype of in ovo-exposed birds by breeding observations, in which clutch size was significantly smaller in all PBDE-dosed birds (low, medium, and high) compared with controls. A trend was also seen for longer laying intervals in PBDE-dosed birds (13-14 d) compared with control birds (8 d). In addition, a significant effect of PBDE was found on growth of the second-generation offspring of in ovo-treated females; body mass was significantly lower in the high-PBDE dosed birds compared with controls from hatch through to fledging (day 30). The authors found no evidence of effects over the longer term and in successive generations, whether in adult, reproductive phenotype of the second-generation offspring of in ovo-treated birds, or in the growth of their (third-generation) offspring. Their results suggest that egg levels as low as 10 ng/g BDE-99 may affect reproduction in small passerines by reducing clutch size. Environ. Toxicol. Chem. 2013;32:562-568. # 2012 SETAC

Effects of the Bioaccumulative Polybrominated Diphenyl Ether Flame Retardant Congener BDE-47 on Growth, Development, and Reproductive Success in Zebra Finches

“…This suggests that these levels were acquired via background contamination or maternal transfer, and may be why we observed higher than expected levels of BDE-47 in all dose groups. Similar background levels were also observed in the eggs and chicks of zebra finches by Winter et al (2013) under the same experimental conditions. Projected cumulative input of BDE-47 was expected to be approximately 0, 105, 1,050, 10,500 ng/g, based on a 20 day dosing regime; however, we observed 515, 516, 1,987, 23,223 ng/g in adipose tissues.…”

“…Growth hormones, insulin-like growth factors, T4 and T3 are the main hormones responsible for growth in birds post hatch, and it has been suggested that PBDEs can directly impact thyroid hormones through competitively binding with thyroid transport proteins. No effects on growth were observed in the present study, and previous research in our laboratory had shown that a similar compound, BDE-99, also had no effect on thyroid hormone homeostasis or growth in zebra finch offspring (Winter et al 2013;Eng et al 2013). Furthermore, while Fernie et al (2006) did report some marginal effects on growth in kestrels dosed with a mixture of PBDEs, including BDE-99, Winter et al (2013), Eng et al (2013) did not in zebra finches, suggesting interspecies variation in sensitivity to PBDEs as reported by McKernan et al 2009.…”

“…We chose the zebra finch as an animal model given our experience with other brominated FRs in our laboratory (Winter et al 2013;Eng et al 2012), and the widespread environmental exposure of birds, including passerine species to those chemicals (Eens et al 2013). Zebra finches were housed in a controlled environment in the Animal Care Facility, Simon Fraser University, and birds were bred using the same methods as described previously (Eng et al 2012).…”

Dissection and Downstream Analysis of Zebra Finch Embryos at Early Stages of Development

“…This protocol opens the way for a plethora of cellular-molecular assays that will allow investigators to determine the developmental origins of adult phenotypes. For example, it will be possible to examine gene expression implicated in vocal learning under various environmental conditions or following pharmacological treatments at the earliest stages of development 28,29,30,31 . Although not demonstrated in this paper, this method potentially allows for other procedures such as radioactive in situ hybridization on zebra finch tissue sections and electroporation/in ovosurgery 32,33,34 .…”

Polybrominated diphenyl ethers (PBDEs) in eggshells of the Southern Ground-Hornbill (Bucorvus leadbeateri) and Wattled Crane (Bugeranus carunculatus) in South Africa

“…This may not be entirely true because different avian species are known exhibit different responsiveness to PBDE exposure. (Winter et al, 2013) observed that in ovo PBDE levels as low as 10 ng g -1 PBDE-99 may affect reproduction in small passerines with reduction in clutch size noted as the most important indicator of exposure to PBDEs. (Fernie et al, 2009) were probably the first researchers to demonstrate cause-and-effects of PBDE exposure on avian reproduction.…”