Skip to main content

Strain-Specific Effects of Cage Enrichment in Male Laboratory Mice (Mus Musculus)

Buy Article:

$25.00 plus tax (Refund Policy)

Abstract:

'Environmental enrichment' is often considered to improve captive animal welfare. However, some studies using male mice, Mus musculus, indicate that increasing cage complexity increases aggression. Limited evidence suggests that enrichment differs in its effects on behaviour and physiology between strains; but behaviour also differs between strains in non-enriched environments. Differences in enrichment type, evaluation methods, and strains used, have caused difficulty in interpreting the efficacy of environmental enrichment in improving welfare. Using enrichment suitable for commercial laboratories (nesting material and a Perspex tunnel), we compared within-cage behavioural and physiological responses among males of six strains housed in non-enriched standard polypropylene cages with those housed in 'enriched' cages. Outbred ICR(CD-1) and TO mice, and inbred BALB/c mice were more aggressive than C57BL/6, CBA/Ca and DBA/2 mice, which exhibited low levels of aggression typical of most inbred strains. Enrichment did not significantly affect aggression levels. Animals in enriched cages spent more time investigating the internal cage environment, eating and drinking, and in stereotypic behaviour patterns, although levels differed between strains. The greatest increase in stereotypy levels (bar-related stereotypies) with enrichment was found in DBAI2 mice. Higher testosterone levels were maintained over the study period in mice housed in enriched cages, and in more aggressive strains. IgG levels were also higher in mice housed in enriched cages, and in the outbred strains ICR(CD-1) and TO compared with inbred strains. The relationship between aggression, testosterone and 'enrichment' suggests that increasing complexity in laboratory cages may increase a naturally selected territorial response in some strains. The implications for strain-specific welfare are discussed.

Keywords: ANIMAL WELFARE; BEHAVIOUR; ENRICHMENT; MICE; PHYSIOLOGY; STRAIN DIFFERENCES

Document Type: Research Article

Publication date: 1999-11-01

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more