Rating enrichment items by female group-housed laboratory mice in multiple binary choice tests using an RFID-based...

Area of Science:

• Laboratory animal science
• Animal welfare
• Ethology

Background:

• Laboratory mice welfare is crucial as they spend most of their lives in housing.
• Enrichment strategies are increasingly popular, but animal-centered benefits require further investigation.
• Understanding mouse preferences for different enrichment types is key to effective welfare refinement.

Purpose of the Study:

• To analyze laboratory mice preferences for different housing enrichment categories.
• To develop a novel method for ranking enrichment items based on animal choice.
• To assess individual differences in enrichment preferences among mice.

Main Methods:

• Categorization of enrichment items into structural, housing, and foraging types.
• Homecage-based multiple binary choice tests with 12 female C57BL/6J mice over 46 hours.
• A new analytical method combining binary decisions to calculate worth values and consensus errors for ranking.

Main Results:

• No single enrichment ranking satisfied all individual mice.
• Certain items, like lattice balls and second planes, were consistently preferred.
• High consensus errors indicated significant individual differences in enrichment preferences.

Conclusions:

• Individual variation in enrichment preference necessitates a varied enrichment approach.
• A single enrichment item cannot meet all individual mouse needs.
• Centering enrichment concepts on animal needs refines housing conditions and improves welfare.