Refining In-Cage Enrichment for Specialized Mouse Scenarios
Environmental enrichment is a critical component of a high-quality animal care and use program to provide opportunities for species-specific behaviors and redirect abnormal repetitive behaviors. We used a scoring system to review our enrichment for singly housed mice to assess usage of supplied items. Following the confirmation of utilization of the selected enrichment, we applied the scoring system to address 2 cases of abnormal behavior. Repetitive food shredding in CD-1 mice was reduced by both manzanita sticks and running wheels; however, manzanita sticks were selected for operational ease. Focal auricular trauma associated with ear tags in BALB/c mice was decreased when gnawing items were provided, thus slowing the deterioration of ear tag condition. Scoring for all 3 studies focused on use of the enrichment, incorporation into the nest, or reduction of abnormal repetitive behavior. The development of a scoring system permits the objective assessment and selection of enrichment for unique scenarios, thus enhancing animal welfare and permitting a standardized way to evaluate enrichment for specialized projects.
Study design for single-housed mouse enrichment utilization.
Study design for feed wastage behavior study.
Study design for auricular trauma with RapID tags study.
(A) Structural enrichment utilization in single-housed mice. The utilization scores of half paper hut and half tunnel are shown. Tests were conducted under the ordinal regression model, with P value adjusted using the Benjamini–Hochberg procedure. *, P ≤ 0.05; †, P ≤ 0.01; ‡, P ≤ 0.001, compared with half-tunnel group. (B) Manzanita stick utilization for single-housed mice. No comparisons or statistics were applied to this group. The use of a manzanita stick shown is for empirical conclusions only.
(A) Enrichment utilization in feed wastage behavior scenario. Scores for each enrichment item are shown. Each line represents an individual cage. Statistics were not performed on these data. (B) Relationship between diamond twist utilization and the presence of enrichment items in feed wastage behavior scenario. Data shown represent how long it takes to reach a score of 5 for diamond twist utilization. Each line represents an individual cage. Statistics were not performed on these data.
Food consumption in feed wastage behavior scenario. Food consumption is represented in grams of presumed ingested and shredded food pellets. Each bar represents an individual cage. Statistics were not performed on these data.
Enrichment utilization for RapID study. Data are shown to convey usage of the in-cage enrichment items, and no statistics were applied.
Duration of normal ear tag condition. A lollipop plot displays the duration of intact ear tags (y-axis) alongside a point indicating the corresponding final ear tag condition. ‡, P 0.001 for both the manzanita stick and running wheel compared with tunnel; +, P 0.005 for wooden block compared with tunnel.
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