Oral Exposure of PBDE-47 in Fish:  Toxicokinetics and Reproductive Effects in Japanese Medaka (Oryzias latipes) and Fathead Minnows (Pimephales promelas)

Abstract

The toxicokinetics of 2,2,4,4-tetrabromodiphenyl ether (PBDE-47) was studied in the Japanese Medaka (Oryzias latipes) after a single oral exposure followed by termination at specific time points. The effects of repeated oral exposure to PBDE-47 on reproductive performance was assessed using a pair breeding experimental design with fathead minnows (Pimephales promelas) given daily PBDE-47 exposures for 25 days, during which fecundity was measured as an indicator of reproductive performance. Medaka and fathead minnows were orally exposed to PBDE-47 by bioencapsulation in brine shrimp, Artemia sp. In the medaka studies, measurable levels of PBDE-47 were detected in the carcass within 0.25 h with peak levels occurring at 8 h. The body levels of PBDE-47 slowly declined and were still 25% of peak levels at 624 h after dosing. Assimilation of the bioencapsulated dose was at least 80% and may well approach 100%. The PBDE-47 concentration-time profile was fitted to a one-compartment clearance-volume toxicokinetic model and the model-predicted value for elimination half-life was determined to be 281 h and the first-order absorption rate constant was Ka = 0.26 hr(-1). In the fathead minnow study, egg laying in the PBDE-treated breeding pairs stopped after 10 days. The condition factor of PBDE-treated males was significantly reduced (P <0.011) compared with control males, whereas no significant difference was observed in females. Histological examination revealed a greater than 50% reduction in mature sperm in PBDE-47 exposed minnows compared to controls. Collectively, these results suggest PBDE-47 is selectively toxic to sexually mature male fathead minnows.

Chronic exposure to environmental levels of tribromophenol impairs zebrafish reproduction

“…Indeed, very limited information is available on reproductive toxicity of bromophenols, while several studies have been conducted on other brominated flame retardants (BFRs). For example, oral exposure to the PBDE congener 2,2′,4,4′-tetrabromodiphenyl ether (PBDE-47) impaired reproductive activity in fathead minnow (Muirhead et al 2006). Exposure to low doses of 2,2′,4,4′,5-pentabromodiphenyl ether (PBDE-99) during critical periods of development permanently impairs spermatogenesis in adult rat offspring (Kuriyama et al, 2005) and PBDE-99 have also been shown to interfere with sexual development and sexually dimorphic behaviors, both of which are mediated by hormones produced in endocrine glands (Lilienthal et al, 2006).…”

Assessing reproductive and endocrine parameters in male largescale suckers (Catostomus macrocheilus) along a contaminant gradient in the lower Columbia River, USA

“…Fish condition factor (Torres et al, 2014-in this issue), often used to assess the overall condition and stoutness of a fish, was not different for LSS among sites (P = 0.3095), likely because sites were differentially influenced by nutrients, chemical mixtures, and hydrology. In an experiment in which adult fathead minnows (Pimephales promelas) were fed daily for 25d with BDE-47, the condition factor of only the males was significantly reduced (P b 0.011) compared with controls (Muirhead et al, 2006). Contrary to that finding, longterm continuous exposure to BDE-209 was related to an increase in the condition factor in adult male zebrafish (Danio rerio), suggesting a potential link with obesity-related genes (He et al, 2011).…”

“…In contrast, chlorpyrifos (an organophosphate insecticide) and current-use pesticides were positively correlated with GSI in this study with LSS (Table 3). Male medaka (Oryzias latipes) GSI was not different between BDE-47-treated fish and controls, although this congener was reproductively toxic in males as noted by a cessation of spawning and a lower percentage of mature spermatozoa (Muirhead et al, 2006). Similarly, BDE-47 was not related to GSI, yet it was negatively correlated with sperm motility in LSS (Table 3).…”

“…In fathead minnows, histological analyses of testes from individuals treated with BDE-47 revealed a more than 50% reduction in mature sperm, and egg-laying in treated breeding pairs stopped after 10 days (Muirhead et al, 2006). Male minnows exposed to BDE-47 had fewer mature spermatozoa and more primary spermatocytes and spermatids compared with control males (Lema et al, 2008).…”

Effect of parental exposure to trenbolone and the brominated flame retardant BDE-47 on fertility in rainbow trout (Oncorhynchus mykiss)

“…The BDE-47 was incorporated into the pelleted trout feed and assayed by GC-ECD using methods described in Muirhead et al (2006) to verify the concentration and stored at −20°C until day of feeding. Each morning of the exposure, a known mass of BDE-47 feed was provided to individual trout.…”