Acute Toxicity in Zebrafish
What is Zebrafish Acute Toxicity Study?
Acute toxicity testing in zebrafish (Zebrafish, Danio rerio) is conducted to evaluate the adverse effects of a test substance following short-term exposure under controlled laboratory conditions. In this study, groups of healthy fish are exposed to a series of test substance concentrations for a period of 96 hours, without feeding during the exposure period.
The fish are observed at regular intervals for mortality and clinical signs of toxicity, including abnormal swimming behavior, loss of equilibrium, respiratory distress, and other visible adverse effects. The primary objective is to determine the 96-hour median lethal concentration (LC₅₀).
Study period: Following exposure to the test substance, fish are observed continuously for 96 hours. Assessments are performed at regular intervals, including 24, 48, 72, and 96 hours, with additional observations during the initial phase of exposure as required.
OECD Test Guidelines
OECD test guidelines governing subacute toxicity studies across oral, dermal, and inhalation routes of administration.
Fish Acute Toxicity Test
Fish Acute Toxicity Test
Fish, Early-life Stage Toxicity Test
Early-Life Stage
Fish Embryo Acute Toxicity (FET) Test
FET Test
Principles
Controlled Exposure to Test Substance: Fish or fertilized fish eggs are exposed to graded concentrations of the test substance under controlled aquatic conditions for a defined exposure period.
Assessment of Survival, Growth, Development, and Reproduction: Biological endpoints such as mortality, embryonic development, growth, reproductive performance, and secondary sex characteristics are evaluated to identify toxic effects.
Comparison with Control Groups: Responses observed in exposed groups are compared with untreated control groups to determine concentration-dependent adverse effects.
Determination of Toxicity Thresholds: Data are used to establish toxicity endpoints such as LC₅₀, NOEC, LOEC, and ECx values, which characterize the test substance's hazard potential.
Evaluation of Sub-Lethal and Endocrine-Related Effects: Physiological, reproductive, and biochemical parameters (e.g., vitellogenin induction and gonadal changes) are assessed to detect sub-lethal and endocrine-disrupting effects.
Objectives
Each subacute toxicity study is designed to achieve specific scientific and regulatory objectives.
- 1To evaluate the toxic effects of a test substance on zebrafish under controlled laboratory conditions.
- 2To determine the concentration-response relationship and identify toxicity endpoints such as LC₅₀, NOEC, LOEC, or ECx values.
- 3To assess mortality and sub-lethal effects, including changes in growth, development, behavior, and reproduction.
- 4To identify target organ and physiological effects resulting from exposure to the test substance.
- 5To generate safety and hazard data for risk assessment, regulatory evaluation, and environmental protection purposes.
Experimental Animals
Standardized zebrafish models are selected based on regulatory acceptability and biological relevance.
Environmental Conditions
Controlled housing conditions are maintained throughout the study to minimize variability and ensure animal welfare compliance.
Routes of Administration
The route of administration is selected based on the intended use of the test substance and the applicable OECD guideline.
Waterborne Immersion Exposure
The test substance is dissolved or dispersed in the aquatic test medium, allowing uptake through the gills, skin, and gastrointestinal tract during continuous exposure.
Microinjection Exposure
The test substance is directly administered into zebrafish embryos or specific tissues using a micro syringe or microcapillary needle to achieve precise dosing and targeted delivery.
Suitable Product Types
Sub-Acute toxicity studies are essential for determining the safety profile of a wide range of products before clinical use or regulatory approval.
Chemical substances
Industrial chemicals
Plant protection products (pesticides)
Biocidal products and related active substances
Pharmaceutical compounds