Project Objectives

• Test three commercial enrichment items (C‑Saw, CellPad, Mouse Swing) across multiple mouse housing conditions.
• Use an ethogram (a comprehensive, objective catalog of specific behaviors exhibited) and a structured data collection protocol to quantify behaviour.
• Compare behaviour with and without enrichment using repeated observations.
• Assess enrichment effectiveness in wild‑type and genetically modified mice.
• Evaluate usability in single‑housed males, grouped mice, and breeding cages.
• Determine practicality regarding cost, autoclavability, and long‑term feasibility.
• Produce evidence‑based recommendations for implementation.

How This Advances 3Rs Implementation

• Provides science‑based guidance that replaces subjective enrichment choices.
• Enables refinement of housing conditions across diverse research strains.
• Supports regulatory expectations for enrichment in single‑housed animals.
• Reduces welfare‑related variability that can affect research reproducibility.
• Gives technicians practical tools for improving everyday care.

Background

Laboratory mice are commonly housed in individually ventilated cages under specific pathogen-free conditions. Standard environmental enrichments such as tunnels, nesting materials, and crinkle paper are often used, and are thought to reduce stress levels and make mice calmer and easier to handle. However, their impact is not always systematically evaluated, and facility observations suggest that they may not fully meet the behavioural needs of diverse mouse strains, such as immunocompromised or genetically modified animals.

Nonetheless, Cantonal authorities in Ticino now request the addition and rotation of enrichment for single‑housed males, increasing the need for evidence‑based guidance. This project applies a rigorous approach to assess three commercially available enrichment items, using repeated behavioural observations across different genotypes, housing types, and cage formats. The goal is to generate robust, practical recommendations for enrichments that genuinely improve welfare and can be sustainably adopted facility‑wide.