Impact of bedding volume on physiological and behavioural parameters in laboratory mice.

The standard housing temperature in animal facilities is substantially below the lower critical temperature of mice. This does not only endanger animal welfare, it can also jeopardize scientific research as cold stress has a major impact on mouse physiology. There is some evidence that deep bedding, comparable to nesting material, can help mice to reduce heat loss. Whenever changes are applied to the cage environment, the potential impact on experimental results, including variation, needs to be assessed. An increased variation can result in a conflict between reduction and refinement, when more animals are needed for significance due to the housing design. The aim of this study was to assess the impact of different bedding volumes (0.5 L, 1.5 L and 6 L per type III cage) on mean values and coefficient of variation (CV) of physiological (pentobarbital sleeping time, blood and anatomical parameters) and behavioural parameters (open-field and novel object recognition tests) of group-housed female and male BALB/c and C57BL/6 mice. A larger bedding volume did not interfere with the CVs, but influenced mean values of organ weights and tail lengths. Mice housed on deeper bedding showed a significant reduction in adrenal, liver, kidney and heart weights as well as an increase in tail lengths; these anatomical changes are akin to warm adaptation, and were previously observed for mice housed under warmer environments. A larger bedding volume appears to be a sensible way to reduce cold stress for laboratory mice without increasing variation in experimental results.

The amount of cage bedding preferred by female BALB/c and C57BL/6 mice.

In order to improve the welfare of laboratory mice, a number of different environmental enrichment strategies have been developed to provide opportunities for mice to engage in naturalistic behaviors. Providing sufficient cage bedding for mice to use as a burrowing substrate could be considered an environmental enrichment strategy, but few studies have considered the welfare aspects of cage bedding amount. The authors compared the preferences of group-housed female BALB/c and C57BL/6 mice for three different volumes of cage bedding (0.5 l, 1.5 l and 6 l). Mice of both strains but especially C57BL/6 mice showed strong preferences for cages with more bedding. The results highlight the importance of providing a sufficient amount of cage bedding to laboratory mice.

Effects of different blood collection methods on indicators of welfare in mice.

Blood collection is a common experimental procedure for which there are many different methods, each with its own advantages and disadvantages. Researchers should use methods that minimize pain, suffering, distress and lasting harm to animals while meeting study requirements. The authors evaluated stress, activity and tissue damage in BALB/cO1aHsd mice after collecting blood using one of six methods: retrobulbar bleeding with thin or thick capillaries, tail vein bleeding, saphenous vein bleeding, facial vein bleeding or jugular vein bleeding. The authors compared in-cage activity, corticosterone concentration and performance in open-field tests between treatment groups and collected histologic samples at 1 h, 3 d and 14 d after bleeding. Mice that underwent retrobulbar bleeding with a thick capillary had a smaller change in corticosterone concentration and higher in-cage activity immediately after blood collection, whereas mice that underwent jugular vein bleeding had a greater change in corticosterone concentration and lower in-cage activity and open-field activity. Mice that underwent saphenous vein bleeding had a high incidence of histological change at 1 h, 3 d and 14 d after blood collection, but few indicators of histological change were present in other groups at 14 d after blood collection. These results suggest that, when collecting a small volume of blood, retrobulbar bleeding with a thick capillary and without anesthesia causes the least stress in mice, whereas jugular vein bleeding and facial vein bleeding cause the most stress and saphenous vein bleeding causes the most lasting damage in mice.

Monitoring perspiration from palms of hypohidrosis patients with a stopped-flow conductometric mini-system.

BACKGROUND: Sensitive and real-time methods are required to characterize the symptoms and resolve the complicated pathology of hypohidrosis. METHOD: We constructed a conductometric humidity sensor and a stopped-flow manifold with suitable dynamic range for monitoring impaired perspiration. The mini-sensor was coated with a water-absorbing polymer of poly-(2-acrylamido-2-methylpropane sulfonate). RESULTS: Perspiration from palms of normal individuals and hypohidrosis patients were monitored and compared. Tangent slopes of the sensorograms were capable of discriminating hypohidrosis patients from normal individuals. CONCLUSION: The conductometric min-sensor and the stopped-flow manifold were proven to be useful as a diagnostic tool for hypohidrosis.