Multi-Laboratory Study Validates Biobide’s Zebrafish DNT Assay as a First-Tier Whole-Organism NAM

A study published in NeuroToxicology supports the zebrafish Light–Dark Transition Test (LDTT) as a reliable early screening tool for developmental neurotoxicity, strengthening its potential role in emerging regulatory testing strategies. 

A new international study provides significant validation for Biobide’s developmental neurotoxicity (DNT) assay, supporting its positioning as a first-tier whole-organism New Approach Methodology (NAM) for identifying chemicals that may disrupt nervous-system development. 

The research evaluated the zebrafish Light–Dark Transition Test (LDTT) across four independent testing laboratories using aligned protocols and 33 compounds, including suspected developmental neurotoxicants and negative controls. By measuring changes in larval zebrafish behaviour following alternating light and dark periods, the assay captures functional effects that depend on the integrated development of the brain, sensory pathways and nervous system. 

The strength of the publication also lies in the calibre and diversity of the institutions involved. The testing consortium includes Oregon State University in the United States, the National Research Council of Canada, the National Institute of Environmental Health Sciences, part of the National Institutes of Health (NIEHS/NIH), and the Netherlands’ National Institute for Public Health and the Environment, among others. This combination of governmental, academic and industry expertise reinforces the independence, international relevance and regulatory value of the findings. 

The results showed reproducible developmental-toxicity and DNT performance across laboratories, with the zebrafish assay detecting 93% of DNT-positive compounds and all putative negatives. The authors propose it as an efficient first-tier whole-organism screen that can bridge mechanistic in vitro assays and more resource-intensive mammalian studies. 

The publication arrives as regulatory organisations work to define tiered DNT testing strategies. For Biobide, it provides strong external support for a scalable assay designed to prioritise substances earlier and improve regulatory decision-making. 

Source: Truong, L.A. et al. “Zebrafish behavioral assessment as a first-tier whole-organism NAM for developmental neurotoxicity: A multi-laboratory evaluation.” Neurotoxicology 116 (2026) 103504.