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Project to investigate ways to improve welfare of fish in research

A new project, led by the University of Leicester working with scientists from Nottingham Trent University and the Centre for Environment, Fisheries and Aquaculture Science (Cefas), will explore how less-invasive swabbing techniques can be used to collect DNA from fish during scientific research in order to reduce stress and better protect their welfare.

The researchers have developed a swabbing technique to collect DNA from zebrafish and sticklebacks

The project, funded by the National Centre for the Replacement, Refinement and Reduction of Animals in Research, aims to test the hypothesis that swabbing has a significantly lower impact on stress-related behaviour and physiology than fin clipping – and could therefore be used to refine current standard regulated procedures, benefiting fish welfare.

Collecting DNA samples to identify small fish is a common procedure in laboratories throughout the world. It is mostly done to confirm the genetic strain of fish, their population of origin, or whether an individual contains particular versions of genes that are relevant to the research. DNA sequences can be used as markers of other traits, including sex.

DNA sampling is typically performed by fin clipping, an invasive procedure carried out under non-terminal anaesthesia.

A recent survey estimated that of the estimated 3,250 zebrafish labs worldwide, 85% use fin clipping to collect DNA from 100s-1000s of animals per year.

The new technique involves gently stroking a swab – effectively a sterile cotton-bud – along the flank of the fish whilst the fish is held in a net, and can be completed in just a few seconds. The research team have already demonstrated that this collects enough DNA for analysis.

Dr William Norton from the University of Leicester’s Department of Neuroscience, Psychology and Behaviour, who is leading the project, said: “Despite its routine use, fin clipping has the potential to impact fish welfare by causing them pain, altering their physiology and behaviour, and increasing the risk of pathogen infections. Furthermore, anaesthesia treatment could decrease the quality of behavioural and physiological data recorded from fin-clipped fish.

“An alternative approach to sample DNA from fish involves swabbing the surface of the skin. We recently developed a reliable swabbing technique to collect DNA from zebrafish and sticklebacks. However, while swabbing appears to be less invasive than fin clipping, it still requires fish to be netted, held in air and handled; procedures that could potentially cause stress. Therefore, the potential of swabbing as a refinement to standard DNA collection by fin clipping remains untested.

“In this project we will investigate the nature and magnitude of any welfare benefits of swabbing over fin clipping. Such information is essential to validate the swabbing technique and assure its wider adoption by the growing community of researchers that use fish as laboratory models.”

Dr Iain Barber, co-investigator on the project from Nottingham Trent University’s School of Animal, Rural and Environmental Science, added: “Much of today’s biomedical and biological research still relies extensively on the use of laboratory animals, and increasingly on small fishes like zebrafish and sticklebacks, so improving their welfare is really important.

“Scientists are more aware than ever of the need to question traditional research methods and to consider alternative approaches.”

The research will include a series of experimental studies comparing the effects of swabbing and fin clipping on a range of behavioural and physiological indicators of fish stress and wellbeing.

Dr Ioanna Katsiadaki, a principal investigator at Cefas and an expert in the assessment of fish welfare, will collaborate on the project and provide state-of-the-art facilities for the less-invasive measurement of stress hormones released naturally by fish into the water through their gills.

The project, 'Quantifying the potential of skin swabbing as a refinement for DNA sampling of laboratory fish', is funded by the National Centre for the Replacement, Refinement and Reduction of Animals in Research.

More information about the project is available here:

  • Notes for editors

    Press enquiries please contact Dave Rogers, Public Relations Manager, on telephone +44 (0)115 848 8782, or via email.

    Images of the fish ‘skin-swabbing’ technique are available here:

    For more information contact Dr William Norton on (0)116 252 5078 or email or Dr Iain Barber on (0)115 848 5208 or email

    Nottingham Trent University (NTU) is one of the largest UK universities with nearly 28,000 students and more than 3,500 staff across four campuses, contributing £496m to the UK economy every year. It is one of the most environmentally-friendly universities, containing some of the country’s most inspiring and efficient award-winning buildings.

    NTU is home to world-class research, winning The Queen’s Anniversary Prize in 2015 - the highest national honour for a UK university. It recognised the University’s pioneering projects to improve weapons and explosives detection in luggage, enable safer production of powdered infant formula and combat food fraud.

    The university has been awarded the highest, gold, rating in the Government’s Teaching Excellence Framework for its outstanding teaching and learning.

    The Centre for Environment, Fisheries and Aquaculture Science (Cefas) is a world leader in marine science and technology, providing innovative solutions for the aquatic environment, biodiversity and food security. We are the UK’s most diverse centre for applied marine and freshwater science and research, covering an unrivalled breadth of specialist areas to provide a fully integrated, multi-disciplinary approach to all our customers’ needs. For more information about Cefas visit and follow @CefasGovUK

Project to investigate ways to improve welfare of fish in research

Published on 24 July 2017
  • Subject area: Animal, equine and wildlife
  • Category: Press office; School of Animal, Rural and Environmental Sciences

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