The behavioural and adrenocortical effects of differentially housing mice were investigated. 'Isolated' male mice were found to show progressively increased fighting with increased duration of housing. 'Isolated' and grouped (6) mice had similar 'basal' corticosterone titres but the former had elevated 'stress' values of this hormone following longer differential housing. Young mice showed more fighting after short periods of 'isolation' than older animals. The effects of duration of and age at differential housing on behaviour in open field and emergence tests wore investigated. Neither sex seemed particularly 'stressed' when individually housed but 'isolated' males if compared with grouped counterparts did appear more 'reactive' in their behavioural and adrenocortical responses to novelty and stress. Other experiments contrasted 'isolates' with identified dominant and subordinant mice from pairs. 'Isolates' were found to be more like dominants in their intermale fighting; body weight; and adrenal and sox accessory gland weights than subordinates. 'Basal' plasma corticosterone values were similar in all categories. Separation of pairs of mice using three different partitions which allowed passage of different amounts of sensory input did not significantly influence isolation/pairing comparisons. Removal of tactile vibrissae, induction of anosmia and housing with odoriferous (?) substrates all altered the incidence of fighting in 'isolated' mice. 'Total isolation' did not seem quantitatively different from individual-housing. These findings suggest that:- (a) 'Isolation' can not be dismissed as a 'stress' in this species; (b) The adrenals of the 'isolated' males are more 'reactive' to superimposed stress than those of grouped animals. This may account for some claims that 'isolation' is stressful; (c) 'Isolated' males are more similar to dominant than to subordinate mice. It seems likely that group housing reduces the ability of the majority of mice to exhibit aggressive behaviour; (d) Physical contact seems responsible for most of the changes in 'isolation'/grouping comparisons. However, differing amounts of communication between neighbouring cages could account for some variability between studies.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:637068 |
| Date | January 1978 |
| Creators | Goldsmith, J. F. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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