Embryonic exposure of medaka (Oryzias. latipes) to propylparaben: Effects on early development and post-hatching growth

Here we proposed a battery of non-invasive biomarkers and a histological survey to examine physiological/anatomical features in embryos, eleutheroembryos (13 days post-fertilization, dpf), and larvae (28 -42 dpf) of medaka to investigate the effects of embryonic exposure to propylparaben (PrP). Concentrations <1000 mu g PrP/L didn't exert early or late toxic effects. However, survivorship was affected at 4000 mu g/L in eleutheroembryos and at >= 1000 mu g/L in larvae. Histological alterations were found in 37.5% of eleutheroembryos exposed to 4000 mu g PrP/L. Morphometric analysis of the gallbladder revealed significant dilation at >= 400 mu g/L throughout embryo development. Ethoxyresorufin-O-deethylase (EROD), as indicator of cytochrome P4501A activity, didn't reveal induction/inhibition although its combination with a P4501A agonist (i.e. beta-naphthoflavone) resulted in a synergic EROD response. Results suggest a low toxicity of PrP for fish and support the use of fish embryos and eleutheroembryos as alternatives of in vivo biomarkers indicative of exposure/toxicity. (C) 2013 Elsevier Ltd. All rights reserved.