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Published on: January 20, 2015
Environmental enrichment, immunocompetence, and resistance to Babesia microti in male mice
C J Barnard1, J M Behnke, J Sewell
1Behaviour and Ecology Research Group, University of Nottingham, University Park, UK. plzcjb@pln1.nott.ac.uk
Abstract:
Groups of male CFLP mice housed in cages furnished with shelves and nestboxes showed increased aggression and reduced resistance to an experimental infection of Babesia microti when compared with groups in unfurnished cages. Both a bystander measure of immunocompetence (serum total IgG concentration) and resistance to B. microti decreased as the number of attacks received by mice increased, but increased with the number of times individuals were recorded on shelves or in nestboxes. Serum concentrations of testosterone and corticosterone were generally downregulated in furnished cages; the absence of hormone-related reduction in resistance may have been due partly to this, but partly also to the apparent modulation of hormone concentrations in relation to concurrent immunocompetence. Some welfare implications of the results are considered.
Insights
Environmental enrichment in mouse housing increased aggression and decreased resistance to Babesia microti infection. These changes were linked to social stress and altered hormone levels, impacting immunocompetence.
Area of Science:
- Animal behavior
- Immunology
- Animal welfare
Background:
- Environmental complexity can influence animal health and behavior.
- Social stress is known to impact the immune system.
Purpose of the Study:
- To investigate the effects of environmental enrichment on mouse aggression, immunocompetence, and resistance to Babesia microti.
- To explore the relationship between social interactions, hormone levels, and immune function in mice.
Main Methods:
- Male CFLP mice were housed in furnished (shelves, nestboxes) or unfurnished cages.
- Aggression, resistance to Babesia microti infection, serum total IgG concentration, and hormone levels (testosterone, corticosterone) were measured.
- Behavioral observations recorded attacks, shelf use, and nestbox use.
Main Results:
- Mice in furnished cages exhibited increased aggression and reduced resistance to Babesia microti.
- Higher numbers of attacks correlated with decreased immunocompetence and B. microti resistance.
- Increased use of shelves and nestboxes was associated with improved immunocompetence and B. microti resistance.
- Testosterone and corticosterone levels were generally lower in furnished cages.
Conclusions:
- Environmental enrichment, while potentially beneficial, can increase social stress and negatively impact immune function and disease resistance in mice.
- The interplay between social stress, hormone regulation, and immunocompetence is complex and influenced by environmental factors.
- Findings have implications for laboratory animal welfare and experimental design, highlighting the need to consider environmental complexity and social dynamics.
