Publication Database

Social enrichment by pair-housing of male C57BL/6JRj mice (2019)

Art

Poster

Autoren

Hohlbaum, Katharina (WE 11)

Frahm-Barske, Silke

Rex, André

Thöne-Reineke, Christa (WE 11)

Ullmann, Kristina

Kongress

19th Annual Congress of EUSAAT

Linz, Österreich, 10. – 13.10.2019

Quelle

ALTEX proceedings

Bandzählung: 8

Heftzählung: 1

Seiten: 79

ISSN: 2194-0479

Sprache

Englisch

Verweise

URL (Volltext): http://www.altex.ch/resources/altex_Linz2019_full.pdf

Kontakt

Institut für Tierschutz, Tierverhalten und Versuchstierkunde

Königsweg 67
14163 Berlin
+49 30 838 61146
tierschutz@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Standard housing in laboratory animal facilities does not reflect social structures of free-living mice [1] and, therefore, comes along with animal welfare issues. A common code of housing practice is to keep mice in single-sex groups. However, in group-housed adult males, aggressive territorial and resource-related behavior is often observed, which in turn can lead to stress due to repeated social defeat and subordination. This may even result in injuries or death [2]. When an unacceptable level of aggression is reached, male mice are separated and housed individually, though the lack of social contact can increase anxiety- and depression-like behaviors as well as stress levels [3].
As a strategy to refine laboratory housing of male mice another housing system called “pair housing” was introduced. To provide social enrichment for individually housed mice, two male mice, separated by a transparent, perforated wall, were kept in a cage together. Pair housing allows olfactory, visual and acoustic contact. Short-term effects of the transition to this housing system were reported for male Hsd:NMRI mice: pair housing increased heart rate, body temperature, and motor activity [4]. However, longterm effects on behavioral, physical and biochemical parameters have not been examined yet. Therefore, we investigated whether long-term pair housing (for eight weeks) fosters well-being of male C57BL/6JRj mice, the most commonly used mouse strain in animal research, when compared to single and group housing (pair: n = 16, single: n = 16, group: n = 16). Besides burrowing and nesting, we assessed anxiety-related behavior in the free exploratory paradigm, the ease of handling by using a rating scale and social behavior in a social interaction test. Moreover, body weight and stress hormone (metabolites) concentrations in feces and fur were measured.
Whereas the housings systems did not affect burrowing performance, pair-housed mice built more complex nests than single-housed mice. The nest position suggested that pair-housed mice preferred the close proximity to their cage mates. Although the free exploratory paradigm did not indicate any effects of the housing systems on trait anxiety, pair-housed mice showed a higher latency to voluntarily interact with the experimenter’s hand than single-housed mice. In contrast, single-housed mice were more difficult to catch. The social interaction test did not reveal any differences between the housing systems, except from the distance moved. Pair-housed mice moved less in the test arena when compared to single- and group-housed mice. Stress-hormone (metabolites) concentrations were not significantly influenced, but a higher body weight gain was found in group-housed
mice.
Overall, our study did not reveal any long-term beneficial effects of pair-housing on stress levels of male mice, though nest complexity may indicate fostered well-being. However, the ventilation in the IVCs can also influence nest complexity. Taking into account that male mice prefer dwelling near other males to staying alone [5], pair housing rather than single housing can meet this need. The decrease in exploratory behavior may suggest higher anxiety-related behavior in pair-housed mice. However, to correctly interpret these findings, state anxiety-related behavior and home cage activity should be further investigated.