Ultrasonic Vocalization Analysis as a Novel Metric to Assess Cage Enrichment in Rats
Laboratory rodent housing conditions vary significantly across laboratories and facilities. Variation in housing can be associated with animal stress leading to study variability and the subsequent inability to replicate experimental findings. Optimization and standardization of animal housing are n...
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Published in | Journal of the American Association for Laboratory Animal Science Vol. 61; no. 2; pp. 140 - 148 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
American Association for Laboratory Animal Science
01.03.2022
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Online Access | Get full text |
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Summary: | Laboratory rodent housing conditions vary significantly across laboratories and facilities. Variation in housing can be associated with animal stress leading to study variability and the subsequent inability to replicate experimental findings. Optimization and standardization of animal
housing are necessary to promote animal welfare and data consistency, thereby reducing the number of animals necessary to detect treatment effects. While interest in environmental enrichment is increasing, many studies do not examine the behavior of animals in the home cage, neglecting important
aspects of enrichment. To determine how increased vertical home cage area affects animal welfare, double-decker cages (enriched), which allow rats to upright stand, were compared with standard single-level cages, which impede the ability to upright stand. Home cage welfare was assessed by
analyzing ultrasonic vocalizations, fecal corticosterone, upright standing, and fighting. Ultrasonic vocalization was further explored by analyses of call type as defined by a 14 call-type schematic. Rats housed in enriched cages spent more time fighting, produced fewer 50 kHz calls, and had
higher levels of fecal corticosterone. Rats in standard cages attempted to upright stand more often but remained upright for a shorter amount of time due to the height limitation imposed by standard cages. In addition, standard cages restrict some naturalistic behaviors such as upright standing
and reduce fighting, which may be attributable to their single-tier organization and floor space. Enriched cages permit rats to engage in normal ethological behavior but also increase fighting. This study demonstrates that housing conditions have a meaningful impact on multiple measures of
animal affect. When considering study design, researchers should be aware of how housing conditions affect animal subjects. |
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Bibliography: | 1559-6109(20220301)61:2L.140;1- |
ISSN: | 1559-6109 2769-6677 |
DOI: | 10.30802/AALAS-JAALAS-21-000024 |