Long‐term effects of binary mixtures of 17α‐ethinyl estradiol and dibutyl phthalate in a partial life‐cycle test with zebrafish (Danio rerio)

Abstract

Using 17α-ethinyl estradiol (EE2) and dibutyl phthalate (DBP) as a typical estrogen and phthalate ester, respectively, their combined in vivo effects on zebrafish (Danio rerio) were investigated from the juvenile state to the adult stage. The authors spiked EE2 (5 ng/L and 20 ng/L) and DBP (0.1 mg/L and 0.5 mg/L) either individually or in mixture. At 45 d postfertilization (dpf), the survival rate of zebrafish was comparable in all treatments. Dibutyl phthalate did not induce vitellogenin (VTG) synthesis, and no interaction was found between EE2 and DBP on VTG induction. At 90 dpf, both liver and gill were subject to more severe damage (lipid vacuoles of hepatocytes, amalgamation of gill lamellae, and clubbing at the tips of the secondary lamellae) when coexposed to these 2 chemicals, compared with single exposure. At 115 dpf, generally none of the binary mixture groups showed significantly different growth and sex ratios compared with the corresponding EE2 alone groups. In conclusion, no obvious interactions were detected between EE2 and DBP on the growth, VTG induction, or sex ratio of zebrafish, and they may act independently. However, the influence on morphology of gonad, liver, and gill induced by exposure to the mixture of EE2 and DBP was generally more potent than that by single exposure to EE2 or DBP, indicating the combined long-term harmful effects of EE2 and DBP on the development of zebrafish. Environ Toxicol Chem 2015;34:518-526. © 2014 SETAC.

Impact of sublethal di-n-butyl phthalate on the aquaculture fish species Nile tilapia (Oreochromis niloticus ): histopathology and oxidative stress assessment

“…duration effect. Similar results were reported by Chen et al (2015) in a study with sublethal concentrations of the DBP (0.1 and 0.5 mg L À1 ) on zebrafish after 90 days post fertilization. Fish gills are generally considered good indicators of toxicant exposure due to the direct interaction with the surrounding medium and their vulnerable structure (Mallatt 1985;Poulino, Souza & Fernandes 2012).…”

“…Xu et al (2014) reported cloudy swelling, pyknosis, vacuolization and accumulation of lipid droplets in adult male zebrafish exposed to 100 and 500 lg L À1 DBP after 45 days supporting results of this study. However, Chen et al (2015) did not find any significant alterations in the liver of zebrafish exposed to sublethal DBP after 90 days post fertilization. They reported that exposure to 20 ng L À1 EE2 in combination with DBP (0.1 mg L À1 or 0.5 mg L À1 ) resulted in vacuolization of the liver.…”

“…1) observed only after 96 h of exposure to DBP. In this study, most of the alterations observed in gills are common in several fish species exposed to different kinds of contaminants ( Xu et al (2014) and Chen et al (2015), DBP is likely strongly absorbed by the gills due to its high lipophilicity. duration effect.…”

“…Fish gills are generally considered good indicators of toxicant exposure due to the direct interaction with the surrounding medium and their vulnerable structure (Mallatt 1985;Poulino, Souza & Fernandes 2012). In this study, most of the alterations observed in gills are common in several fish species exposed to different kinds of contaminants ( Xu et al (2014) and Chen et al (2015), DBP is likely strongly absorbed by the gills due to its high lipophilicity. Xu et al 2014 reported epithelial hyperplasia, lamellar fusion and oedema in adult male zebrafish after 45 days exposure to 100 and 500 lg L À1 DBP.…”

“…DBP; Weir, Wooten, Smith & Salice 2014), that may affect thyroid function (Mathieu-Denoncourt et al, 2015), neurodevelopment, reduced steroidogenesis, genotoxic and antioxidant status effects (Qu, Feng, Sun & Wang 2014;Wang, Jiang, Ge, Chen, Yang, Ji, Zhong, Guan & Liu 2015), autism spectrum disorders, and development/ reproductive physiology in animals (Aoki, Harris, Katsiadaki & Sumpter 2011;Bello, Madekurozwa, Groenewald, Aire & Arukwe 2014;Bhatia, Kumar, Ogino, Gregg, Chapman, McLaughlin & Iguchi 2014;Chopra, Harley, Lahiff & Eskenazi 2014); furthermore, they are thought to be carcinogenic (Ahuactzin-Perez, Torres, Rodriguez-Pastrana, Soriano-Santos, Diaz-Godinez, Diaz, Tlecuitl-Beristain & Sanchez 2014). Antiandrogenic activity have been shown in adult male three-spined sticklebacks (Gasterosteus aculetaus) exposed to 15, and 35 mg DBP L À1 for 22 days by Aoki et al (2011); however it is unclear if they have any oestrogenic induction effect in fish (Ortiz-Zarragoitia, Trant & Cajaravillet 2006;Bhatia et al 2014;Chen, Li, Liu & Xu 2015).…”