{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,31]],"date-time":"2026-10-31T02:25:16Z","timestamp":1793413516491,"version":"4.5.0"},"reference-count":40,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,4,1]],"date-time":"2022-04-01T00:00:00Z","timestamp":1648771200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biology"],"abstract":"<jats:p>Euthanasia in zebrafish (Danio rerio) younger than 5 days post fertilization (dpf) is poorly described in the literature, and standardized protocols are lacking, most likely because larvae not capable of independent feeding are often not protected under national legislations. We assessed the euthanasia efficacy in laboratories in different countries of a one hour anesthetic overdose immersion with buffered lidocaine hydrochloride (1 g\/L, with or without 50 mL\/L of ethanol), buffered tricaine (1 g\/L), clove oil (0.1%), benzocaine (1 g\/L), or 2-phenoxyethanol (3 mL\/L), as well as the efficacy of hypothermic shock (one hour immersion) and electrical stunning (for one minute), on zebrafish at &lt;12 h post fertilization (hpf), 24 hpf, and 4 dpf. Based on the survival\/recovery rates 24 h after treatment, the most effective methods were clove oil, lidocaine with ethanol, and electrical stunning. For 4 dpf larvae, signs of aversion during treatment demonstrated that all anesthetics, except lidocaine, induced aversive behavior. Therefore, the most suited euthanasic treatment was lidocaine hydrochloride 1 g\/L, buffered with 2 g\/L of sodium bicarbonate and mixed with 50 mL\/L of ethanol, which euthanized both embryos and larvae in an efficient and stress-free manner. Electrical stunning also euthanized embryos and larvae efficiently and without signs of aversion; this method needs further assessment in other laboratories to draw firm conclusions.<\/jats:p>","DOI":"10.3390\/biology11040546","type":"journal-article","created":{"date-parts":[[2022,4,1]],"date-time":"2022-04-01T21:22:39Z","timestamp":1648848159000},"page":"546","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["A Multi-Site Assessment of Anesthetic Overdose, Hypothermic Shock, and Electrical Stunning as Methods of Euthanasia for Zebrafish (Danio rerio) Embryos and Larvae"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4895-6867","authenticated-orcid":false,"given":"Jean-Philippe","family":"Mocho","sequence":"first","affiliation":[{"name":"Joint Production System Ltd., Potters Bar EN6 3DD, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Florian","family":"Lang","sequence":"additional","affiliation":[{"name":"Center of PhenoGenomics, School of Life Sciences, Ecole Polytechnique F\u00e9d\u00e9rale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4596-6282","authenticated-orcid":false,"given":"Guillaume","family":"Valentin","sequence":"additional","affiliation":[{"name":"Center of PhenoGenomics, School of Life Sciences, Ecole Polytechnique F\u00e9d\u00e9rale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5358-3014","authenticated-orcid":false,"given":"S\u00e9bastien","family":"Bedu","sequence":"additional","affiliation":[{"name":"Zebrafish Neurogenetics Unit, Institut Pasteur, UMR3738, CNRS, 75015 Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robin","family":"McKimm","sequence":"additional","affiliation":[{"name":"Electro Fishing Services Ltd., Donaghadee BT21 0LN, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6279-7268","authenticated-orcid":false,"given":"Juan","family":"Ramos","sequence":"additional","affiliation":[{"name":"Cellular Biology, Physiology and Immunology Department, Universitat Aut\u00f2noma de Barcelona, 08193 Bellaterra, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yolanda","family":"Saavedra Torres","sequence":"additional","affiliation":[{"name":"The Francis Crick Institute, London NW1 1AT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah E.","family":"Wheatley","sequence":"additional","affiliation":[{"name":"The Francis Crick Institute, London NW1 1AT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joseph","family":"Higgins","sequence":"additional","affiliation":[{"name":"The Francis Crick Institute, London NW1 1AT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mollie E.","family":"Millington","sequence":"additional","affiliation":[{"name":"The Francis Crick Institute, London NW1 1AT, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8284-1844","authenticated-orcid":false,"given":"Pia Rengtved","family":"Lundegaard","sequence":"additional","affiliation":[{"name":"Department of Biomedical sciences, Faculty of Health and Medical sciences, University of Copenhagen, 1017 Copenhagen, Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rub\u00e9n","family":"Chamorro Valverde","sequence":"additional","affiliation":[{"name":"Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Cient\u00edficas, 36208 Vigo, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vlasta","family":"Jen\u010di\u010d","sequence":"additional","affiliation":[{"name":"Institute of Pathology, Wild Animals, Fish and Bees, University of Ljubljana-Veterinary Faculty, 1000 Ljubljana, Slovenia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4886-9699","authenticated-orcid":false,"given":"Kristine","family":"von Krogh","sequence":"additional","affiliation":[{"name":"Von Krogh Consult, 1266 Oslo, Norway"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,1]]},"reference":[{"key":"ref_1","unstructured":"European Union (2010). 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