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Endocrine-disrupting chemicals (EDCs) are widespread used and can interfere on hormone regulation with adverse consequences for both biota and human. Vitellogenin (vtg) is a yolk precursor protein synthesized by the liver in response to estrogen. In order to characterize the vtg of tropical fish Rhamdia quelen and establish a molecular biomarker, adult male individuals were exposed to 17-β-estradiol (E) for vtg induction and anti-R. quelen vtg polyclonal antibodies production. Vitellogenic female fish were used as positive control group. E-induced vtg was characterized as a glycolipophosphoprotein of high molecular mass with peptide mass fingerprint very similar in E-exposed male and vitellogenic female fish. A polyclonal serum containing anti-R. quelen vtg antibodies was produced and showed high specificity and sensibility to detect the vtg of three fish species: R. quelen, Piaractus mesopotamicus and Prochilodus lineatus. Wildlife and laboratory studies reported that EDCs released into the environment may alter the levels of plasma vtg in male fish, making this protein a valuable biomarker of xenoestrogens exposure. Then, we propose the use of anti-R. quelen vtg as a tool for biomonitoring studies and water quality assessment in Brazil and South American countries where the three fish species occur.

In the last decades, there has been an increase in demand for new polymers, including flame-retardants compounds, to meet fire prevention by international safety standards. The decabromodiphenyl ether (BDE-209) is a polybrominated diphenyl ether (PBDE) congener still in use worldwide. This compound presents lipophilic properties and so is easily bioaccumulated in the food chain. The 2, 4, 6 - Tribromophenol (TBP) is a PBDE metabolite also used as pesticide and flame-retardant for wood conservation. In the current study, the acute and chronic toxicity of BDE-209 and TBP was evaluated in Oreochromis niloticus through the analyses of redox unbalance, neurotoxicity and histopathological biomarkers after acute (24, 48, 72 and 96 h) and chronic (90 days) exposures to 0.5, 5 and 50 ng/g of the PBDEs. The results showed effects in GST activity and damage to biomolecules in both acute and chronic exposures. Histopathological findings were observed in the acute experiment, while hepatocyte lesions were found in both experiments. Only BDE-209 presented neurotoxic effects. The current study revealed new endpoints related with polybrominated compounds in fish, highlighting the needs to review the risk of exposure to biota and human populations.