Reducing the number of animals needed for research

Research looking at the effects of enrichment in the tanks of laboratory zebrafish aims to reduce the number of fish needed in research and refine animal welfare processes.

Research by Carole Lee, an MRes student working in Biosciences, found that around 83 per cent of zebrafish larvae living in tanks enriched with gravel and plants survived to 30 days post-fertilisation compared to 54 per cent of fish raised in plain tanks.

In mature fish, the body condition of females in enriched tanks was higher than females in plain tanks, suggesting that fish benefitted from the plants and gravel.

When mature fish were placed into a novel tank, enriched fish spent more time exploring the new environment than fish from plain tanks, suggesting reduced anxiety in enriched fish.

This study suggests that environmental enrichment can improve survivorship of larval fish and may reduce stress levels in older fish.

Reducing stress in laboratory zebrafish is likely to improve the validity and repeatability of research data and so reduce the number of fish required in any one experiment.