What types of enrichment are appropriate for laboratory mice and what must be ensured?

• A. Enrichment is unnecessary if times studied.
• B. Only nesting material.
• C. Nesting material, shelter, tunnels, and chewable items; ensure enrichment is safe, clean, and does not interfere with procedures.
• D. Enrichment should be expensive.

Answer: (C)

Providing enrichment helps mice express natural behaviors and reduces stress, which is important for their welfare and for the reliability of experimental results. The best choice recognizes that a combination of enrichment items supports comfort, security, exploration, and dental health. Nesting material lets mice build a comfortable nest and helps with temperature regulation. Shelters give a safe retreat where they can hide and feel secure. Tunnels encourage movement and exploration, adding complexity to their environment. Chewable items satisfy the natural gnawing instinct and help maintain dental wear.

The crucial requirement is safety and practicality: enrichment must be non-toxic, free of small parts that could be ingested or cause choking, easy to inspect and clean, and not capable of contaminating or interfering with procedures or data. It should be kept clean and replaced as needed to prevent mold or harboring pathogens, and it should be compatible with the housing system and experimental protocols to avoid introducing bias or affecting results.