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Conference abstract2007

Assessing the effect of different housing conditions on the welfare of laboratory rats, with focus on physical fitness

Spangenberg Elin, Dahlborn Kristina, Essen-Gustavsson Birgitta, Cvek Katarina


The current housing of laboratory rats provides limited opportunities for physical activity and restricts their behavioural repertoire. The basic problem is that they are kept in too small and too low cages. We have previously shown that laboratory rats increase the amount of active behaviour, such as running and climbing, if kept in a large pen that allows for different activities. The aim of this project was to assess the effect of different housing conditions on the welfare of laboratory rats, with focus on improved physical fitness. A majority of the laboratory rats are inactive and overweight, which we consider an animal welfare problem. Improved physical fitness, through more physical activity, has positive effects on both the physical and mental health of rats. It can reduce their body weight and body fat content and improve cardiovascular functions and insulin responsiveness. Moderate physical activity can positively affect the immune system and also have an anxiolytic-like effect. One way to promote physical fitness, and other welfare parameters, of laboratory rats, is to improve the housing conditions. First and foremost, the cages have to be bigger and higher to allow for a diverse activity pattern. They should also be equipped with structures that can be used by the rats for activities, such as grids for vertical climbing, shelves for resting and jumping up/down and protected areas (huts/houses) for resting/nesting. Housing rats in larger cages also allow keeping them in bigger groups with more social interactions. Rats from different housing conditions have been tested for both physiological and behavioural parameters. In an exercise test on a treadmill, the rats housed both in groups of four or eight performed better compared to rats housed in pairs. Rats kept in groups of eight in large pens had lower body weight and greater muscle glycogen content than rats kept in standard cages. The home cage social interactions increased when the group size went from two to eight rats. In the Elevated Plus Maze, rats housed in groups of eight showed a higher activity and more risk assessment behaviours compared to rats kept in pairs. In handling tests, we found no effect of housing conditions on the rats’ willingness to be handled. This battery of test parameters will now be used to assess commercially available alternative cages and their possibilities to improve physical fitness and animal welfare in different strains of rats

Published in


The 10th FELASA Symposium