Effect of Individually Ventilated Bi-Level Caging on Anxiety-Like Behavior and Breeding Performance in Rats
Introduction: Rats housed in complex, environmentally-enriched caging exhibit behavior changes indicative of improved welfare; however,limited studies have been done specifically on bi-level cage design. Objective: To determine if bi-level caging would affect anxiety in rats, three cage types were examined: standard 140 sq in single-levelcages, larger 232 sq in single-level cages, and larger 232 sq in bi-level cages.
Methods: Male Hsd: SD rat offspring born into and housed in each of the three conditions were tested at 45 and 95 days of age using social interaction, locomotion, and center locomotion behavioral analyses. Breeding success and serum corticosterone levels were used as physiological parameters.
Results: No differences in behavior or corticosterone levels were found among groups. Modest non-statistically significant breeding benefits were observed with bi-level caging in the form of shorter time to litters and higher average pup weights at two weeks of age.
Conclusion: Housing in bi-level caging in laboratory rats does not affect anxiety, which is an important finding when employing novel cages in behavioral research. Additionally, increased area for normal bi-pedal posture and species-specific behaviors adds to good welfare.
Lauren E Wimsey, Keely N Wharton, Jareca M Giles, Judith N Nielsen and Darin J Knapp