Linking Biomarkers to Function in Zebrafish

Research in animal disease models require physiological readouts to translate genetic and molecular changes into a functional context.

Modern analytical methods can identify many potential biomarkers, but it is often unclear which are relevant, as disease markers or targets for treatment. Functional assays are needed to validate findings and focus the downstream work.

Zebrafish models provide a strong platform, combining short development time, well annotated genomes, and multiple physiological assays across life stages.

Swim tunnels as a functional platform

Swim tunnels provide an established platform to measure physiological endpoints in zebrafish. The controlled environment of a swim tunnel enables the exploration and validation of molecular biomarkers and treatment effects.

They provide two primary functions. First, they enable flexible exercise protocols to study physical activity as an intervention, the endpoint being upper critical swimming speed (Ucrit) or swimming endurance. Second, they provide quantitative measurements of oxygen consumption rate as a proxy for aerobic metabolism with endpoints like max MO2, aerobic scope, cost of transport, etc.

Measure of whole-organism physiology

The range of swimming assay measurements provide a system-level view of the physiological state by integrating muscle performance, cardiovascular capacity, and metabolic needs.
Key metrics include swimming endurance, swimming distance, critical swimming speed (Ucrit), and oxygen consumption rate (MO2).

The continuous nature of these metrics supports quantitative analysis and improves biomarker identification through integration with other datasets.

Swimming assays are broadly applied

Zebrafish are established as gold standard model animals due to their regenerative capacity, well mapped genomes, and proven translatability to human biology. Swimming assays provide functional measurements across all these systems.

Swim tunnels are used across a broad range of disease models, including exercise, metabolic disease, cardiology, and muscle disorders. (Heinkele 2021, Buerger 2022, Chen 2025, Wen 2023, Harji 2025) In these studies, swimming assays either provide quantitative measures of recovery or are used directly as controlled exercise interventions

There are several groups working on spinal-cord regeneration in which the swimming endurance assay is a central part of the research. (Lafouasse 2026, Cigliola 2023, Burris 2021) Crucially, they found that early swimming performance at can predict later regeneration outcomes, with measurements at 2 weeks predicting cellular regeneration at 8 weeks. (Jensen 2023)

Conclusion

Swim tunnel assays directly link molecular changes and whole-organism physiology in zebrafish disease models. Through the combination of controlled experimental conditions and quantitative measurements, they enable reproducible assessments of physiological state and treatment effects.

As zebrafish models continue to be used alongside high-throughput analytical methods, swim tunnel assays provide a practical way to connect biological findings to functional outcomes.

How do I get started?

There are excellent published protocols that can walk you through many of the different assays that are discussed in this article.

• Swimming assays in Cardiomyopathy models (Ma 2021)
• Behaviour and swimming endurance in zebrafish models (Burris 2021)
• Spinal cord regeneration (Burris 2024)
• Exercise regiments and oxygen consumption (Castro-Sepulveda 2025)

You are always welcome to reach out to us, and we will guide you on what equipment to get based on the assays that you want to run.

 

Our Performance Swim Tunnel Systems can be found here: Core Performance Swim Tunnels

Our Respirometry Swim Tunnel Systems can be found here: Core Respirometry Swim Tunnels