Lessons learned running a Zebrafish Extended One Generation Reproduction Test (ZEOGRT) as part of a validation exercise.

Becky Cahill, Richard Maunder, Matthias Teigeler.

An update to the Classification, Labelling and Packaging (CLP) regulation to include new hazard classes including those relating to Endocrine Disruption (ED) aligns this with the existing regulations for biocides and plant protection products whereby substances require assessment for their ED properties as part of their environmental risk assessment.

In this project a ZEOGRT study was conducted at Scymaris, Brixham Laboratory, UK as part of the validation.

The OECD provides guidance for ED testing under a conceptual framework with tests being assigned a level based on the comprehensiveness of the testing.

The highest level 5 tests include multigeneration testing, such as the Medaka Extended One Generation Reproduction Test (MEOGRT; OECD 240, Ref 1). This test has been reported as difficult to perform, with tests often failing to meet validity criteria, meaning interpretation of results can be difficult. An alternative EOGRT option using zebrafish (Danio rerio; ZEOGRT) was proposed in 2015 and is currently at the ring test stage of validation as part of an OECD workplan.