Transfer of zearalenone to the reproductive system of female rainbow trout spawners: A potential risk for aquaculture and fish consumers? Maciej Wo  zny a, * , Kazimierz Obremski b , Tomasz Zalewski c , Maren Mommens d , Alicja Lakomiak a , Pawel Brzuzan a a Department of Environmental Biotechnology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, ul. Sloneczna 45G, 10-709, Olsztyn, Poland b Department of Veterinary Prevention and Feed Hygiene, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, ul. Oczapowskiego 13, 10-950, Olsztyn, Poland c Department of the Salmonid Research in Rutki, Inland Fisheries Institute in Olsztyn, Rutki, 83-330, _ Zukowo, Poland d AquaGen AS, PO Box 1240, N-7462, Trondheim, Norway article info Article history: Received 4 February 2017 Received in revised form 12 June 2017 Accepted 4 July 2017 Available online 5 July 2017 Keywords: Carry over Food safety Glucuronides Metabolism Mycotoxins Tissue distribution abstract To investigate whether ZEN transfers from the alimentary tract of fish to the somatic cells of ovaries or the oocytes, mature females of rainbow trout were orally exposed to ZEN at a dose of 1 mg$kg 1 body mass. At sampling times of 2, 6, 12, 24, 48, and 96 h, tissues of the fish (intestine, liver, ovaries, oocytes, muscles, and plasma) were extracted to determine the concentration of ZEN and its metabolites using immunoaffinity columns and HPLC-FLD. Our results confirm that ZEN is transferred from the alimentary tract to the reproductive system of the fish, and indicate that the mycotoxin concentrates in the somatic cells of the ovaries. Importantly, ZEN transferred to the fishes' oocytes and muscles only to a limited extent. Our additional survey of fish hatcheries and local stores indicated only trace amounts of ZEN residuals in the samples that were collected in Poland and Norway between 2013 and 2015, which probably reflects good hygienic conditions for the feed used in these hatcheries. Furthermore, our results indicate that the health risk from dietary intake of ZEN from fish roe is negligible. However, the potential of ZEN to transfer to the fish ovaries may be of concern for aquaculture. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Zearalenone (ZEN) is a mycotoxin produced by some Fusarium and Gibberella moulds that commonly occur in plant materials. These moulds infect agricultural crops (mainly cereals), resulting in worldwide ZEN contamination of foodstuffs for animals and humans (Zinedine et al., 2007; Rodrigues and Chin, 2012). The most prominent effect of ZEN toxicity is its ability to induce structural disorders or dysfunction in the reproductive system of livestock animals, i.e. pigs, cattle, and poultry (Zinedine et al., 2007; Minervini and Aquila, 2008). ZEN mimics the action of natural hormones (i.e. estrogens), which gives rise to a number of repro- ductive disorders in exposed livestock mammals, including decreased libido, anovulation, and infertility (Kuiper-Goodman et al., 1987; Fink-Gremmels and Malekinejad, 2007; Metzler et al., 2010). The activity of ZEN has also been shown to affect fish repro- duction. For example, water-borne exposure of zebrafish (Danio rerio) to ZEN can reduce spawning frequency (Schwartz et al., 2010) or induce transgenerational changes in fecundity (Schwartz et al., 2013). Although experimental data on the toxicity of ZEN in fish models are constantly increasing, the potential of this mycotoxin to interfere with the reproductive system of economically important fish has been incompletely evaluated (Manning, 2010; Anater et al., 2016; Matejova et al., 2017). In livestock animals (especially pigs), the toxicokinetics of ZEN have been extensively studied. Once ingested, ZEN is rapidly absorbed from the gut. Then, during the I phase of drug meta- bolism, it is primarily metabolized in the intestine and liver to its major metabolites a- and b-zearalenol (a- and b-ZEL) by hydrox- ysteroid dehydrogenases (a- and b-HSD, respectively). In addition, this conversion also takes place in other tissues, e.g. erythrocytes (Chang and Lin, 1984), or ovarian granulosa cells (Malekinejad et al., 2006). In the II phase, the reductive metabolites of ZEN produced in * Corresponding author. E-mail address: maciej.wozny@uwm.edu.pl (M. Wo zny). Contents lists available at ScienceDirect Food and Chemical Toxicology journal homepage: www.elsevier.com/locate/foodchemtox http://dx.doi.org/10.1016/j.fct.2017.07.010 0278-6915/© 2017 Elsevier Ltd. All rights reserved. Food and Chemical Toxicology 107 (2017) 386e394