title: Oxygen requirements of zebrafish (Danio rerio) embryos in embryo toxicity tests with environmental samples.
abstract: The zebrafish embryo test is a widely used bioassay for the testing of chemicals, effluents and other types of environmental samples. Oxygen depletion in the testing of sediments and effluents is especially important and may be a confounding factor in the interpretation of apparent toxicity. In order to identify oxygen levels critical to early developmental stages of zebrafish, oxygen consumption of zebrafish embryos between 0 and 96h post-fertilization, minimum oxygen levels required by the embryos for survival as well as the effects of oxygen depletion following exposure to model sediments were determined. No significant effects on zebrafish embryo development were observed for oxygen concentrations between 7.15 and 3.33mg/L, whereas at concentrations between 3.0and 2.0mg/L minor developmental retardations were observed, yet without any pathological consequences. Oxygen concentrations lower than 0.88mg/L were 100% lethal. In the sediment contact tests with zebrafish embryos, native sediments rich in organic materials rapidly developed strongly hypoxic conditions, particularly at the sediment-water interface (0 to 500μm distance to the sediment).
authors.affiliation: Aquatic Ecology and Toxicology Section, Department of Zoology, University of Heidelberg, Im Neuenheimer Feld 230; D-69120 Heidelberg, Germany. Ruben.Strecker@zoo.uni-heidelberg.de
authors.forename: Ruben
authors.initials: R
authors.lastname: Strecker
authors.forename: Thomas-Benjamin
authors.initials: TB
authors.lastname: Seiler
authors.forename: Henner
authors.initials: H
authors.lastname: Hollert
authors.forename: Thomas
authors.initials: T
authors.lastname: Braunbeck
mesh_terms: D000826:Animal Testing Alternatives; D000818:Animals; D020964:Embryo Loss / Q000139:chemically induced; D004625:Embryo, Nonmammalian / Q000002:abnormalities / Q000187:drug effects* / Q000378:metabolism*; D047108:Embryonic Development / Q000187:drug effects / Q000502:physiology; D004784:Environmental Monitoring / Q000379:methods; D019015:Geologic Sediments / Q000737:chemistry; D000860:Hypoxia; D008136:Longevity / Q000187:drug effects; D010100:Oxygen / Q000032:analysis; D010101:Oxygen Consumption; D013997:Time Factors; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000196:embryology* / Q000502:physiology
chemical_list: D014874:Water Pollutants, Chemical; D010100:Oxygen