| 1. |
- Van Loo, PLP, et al.
(författare)
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Long-term effects of husbandry procedures on stress-related parameters in male mice of two strains
- 2004
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Ingår i: Laboratory animals. - : SAGE Publications. - 0023-6772 .- 1758-1117. ; 38:2, s. 169-177
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Tidskriftsartikel (refereegranskat)abstract
- In socially unstable groups of male laboratory mice, individuals may experience a chronic stress situation. Previous experiments have shown that the transfer of specific olfactory cues during cage cleaning, and the provision of nesting material decrease aggression and stress in group-housed male mice. In this study, the combined effect of these husbandry procedures were tested for their long-term effect on stress in groups of moderately aggressive (BALB/c) and severely aggressive (CD-1) male mice. The physiological and behavioural stress-related parameters used were body weight, food and water intake, spleen and thymus weight, adrenal tyrosine hydroxylase activity, urine corticosterone levels and behaviour in a cage emergence test. Long-term provision of nesting material and its transfer during cage cleaning was found to influence several stress-related physiological parameters. Mice housed in cages enriched with nesting material had lower urine corticosterone levels and heavier thymuses, and they consumed less food and water than standard-housed mice. Furthermore, marked differences were found between strains. CD-1 mice were less anxious in the cage emergence test, weighed more, ate and drank more, and had heavier thymuses but lighter spleens and lower corticosterone levels than BALB/c mice. We conclude that the long-term provision of nesting material, including the transfer of nesting material during cage cleaning, reduces stress and thereby enhances the welfare of laboratory mice.
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| 2. |
- Van Loo, PLP, et al.
(författare)
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Male management: Coping with aggression problems in male laboratory mice
- 2003
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Ingår i: Laboratory animals. - : SAGE Publications. - 0023-6772 .- 1758-1117. ; 37:4, s. 300-313
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Tidskriftsartikel (refereegranskat)abstract
- In a laboratory environment, aggressive interactions between male mice may exceed normal levels leading to negative effects both on the well-being of the animals and on the validity of experimental results. In this paper we review results from the literature and our own research with regard to coping with excessive aggressive behaviour in male laboratory mice. Based on this review practical recommendations concerning the housing and care of male laboratory mice are formulated. In short, it is recommended to avoid individual housing, to transfer odour cues from the nesting area during cage cleaning and to apply nesting material as environmental enrichment. Furthermore, group size should be optimized to three animals per cage. Further research, in particular into the effects of frequency, duration, type and severity of disturbances during an experiment on the degree of aggression, is recommended.
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| 3. |
- Van Loo, PLP, et al.
(författare)
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Preference for social contact versus environmental enrichment in male laboratory mice
- 2004
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Ingår i: Laboratory animals. - : SAGE Publications. - 0023-6772 .- 1758-1117. ; 38:2, s. 178-188
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Tidskriftsartikel (refereegranskat)abstract
- Due to their aggressive nature, male mice are less frequently used than female mice in biomedical research. When aggressive males are being used, individual housing is common practice. The question arises whether this is an acceptable housing for a social species. The present study was designed to gain more insight into the nature of inter-male social contact and into the potential of a form of environmental enrichment (nesting material) to compensate for the lack of social contact. In a series of tests, we analysed whether male mice of different ages preferred to spend time (1) near a familiar cage mate versus an empty cage, or (2) near to a familiar cage mate versus direct contact with nesting material (tissues). Dwelling time in each of the test cages and sleeping sites was recorded, as was the behaviour of the test mice. Results indicated that when other conditions were similar, male mice preferred to sleep in close proximity to their familiar cage mate. Furthermore, the need to engage in active social behaviour increased with age. Tissues were used to a large extent for sleeping and sleep-related behaviour. It is concluded that single housing in order to avoid aggression between male mice is a solution with evident negative consequences for the animals. When individual housing is inevitable due to excessive aggressive behaviour, the presence of nesting material could partly compensate for the deprivation of social contact.
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| 4. |
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| 5. |
- Meijer, MK, et al.
(författare)
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Effect of restraint and injection methods on heart rate and body temperature in mice
- 2006
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Ingår i: Laboratory animals. - : SAGE Publications. - 0023-6772 .- 1758-1117. ; 40:4, s. 382-391
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Tidskriftsartikel (refereegranskat)abstract
- Routine procedures in the laboratory, inducing acute stress, will have an impact on the animals and might thereby influence scientific results. In an attempt to gain more insight into quantifying this acute stress by means of the parameters heart rate (HR) and body temperature (BT), we subjected mice to different restraint and injection methods. We first compared the treatment response of HR and BT, measured by means of radiotelemetry, with the treatment response of plasma corticosterone (pCORT), a common and well-validated parameter for measuring acute stress responses. It was found that HR, and to a lesser extent also BT, parallels pCORT values after subjecting the animals to different methods of restraint. Secondly, the acute stress response caused by different injection methods was evaluated. Again, HR was found to be a more sensitive parameter than BT. We found that, in case of sham injections, the acute stress response after an intraperitoneal (i.p.) injection was more pronounced than after intramuscular (i.m.) or subcutaneous (s.c.) injections, but this difference was found to be inconsistent when saline was used as injection fluid. In a third experiment we investigated if the level of experience of the animal technician influenced the stress response after s.c. injections, but no differences were found. Overall, the results have indicated that HR might be considered as a useful parameter for measuring acute stress responses to routine procedures, but the value of BT seems to be of limited value in this respect.
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| 6. |
- Meijer, MK, et al.
(författare)
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Influence of environmental enrichment and handling on the acute stress response in individually housed mice
- 2007
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Ingår i: Laboratory animals. - : SAGE Publications. - 0023-6772 .- 1758-1117. ; 41:2, s. 161-173
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Tidskriftsartikel (refereegranskat)abstract
- In this study we investigated the effect of environmental enrichment and handling on the acute physiological stress response caused by short periods of restraint in individually housed female mice. Heart rate (HR) and body temperature (BT) were measured by radiotelemetry and compared with plasma corticosterone (pCORT) levels. Also, postmortem thymus weight and tyrosine hydroxylase (TH) activity were assessed. The acute stress response was seen in both HR and BT. Enrichment and handling were found to increase rather than decrease this stress response, but pCORT values, measured 90 min after restraint, suggested a lower stress response in the enriched groups. No effect was found with thymus weight or TH as parameters.
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