Preference of laboratory rats for potentially enriching stimulus objects

Area of Science:

• Animal Behavior
• Laboratory Animal Science
• Environmental Enrichment

Background:

• Standard laboratory cages offer limited environmental complexity for rodents.
• Environmental enrichment is crucial for animal welfare and research validity.
• Identifying effective enrichment objects is essential for improving laboratory animal housing.

Purpose of the Study:

• To determine rat preferences for various stimulus objects as environmental enrichment.
• To identify specific object types that promote species-typical behaviors in laboratory rats.
• To evaluate the efficacy of novel enrichment items in standard housing.

Main Methods:

• A free-choice paradigm was used to measure rat preference for 15 diverse objects.
• Object categories included pipes, partitions, manipulanda, and chewable items.
• Time spent near each object was recorded to assess preference levels.

Main Results:

• Rats did not show preferences for objects designed to satisfy wall-hugging tendencies (pipes, partitions).
• Objects intended as manipulanda did not elicit significant interest.
• Rats reliably preferred spending time with some chewable objects over others.
• A predrilled wooden block emerged as the most preferred object.

Conclusions:

• Chewable objects, particularly a predrilled wooden block, are effective for environmental enrichment in laboratory rats.
• Providing opportunities for chewing behavior can enhance welfare and meet species-typical needs.
• Researchers should consider incorporating such objects to improve the housing conditions of laboratory rats.