Skip to main content
SLU publication database (SLUpub)

Conference abstract2006

Does housing in larger cages affect blood pressure and behaviour in laboratory rats? A pilot stu

Cvek, Katarina; Spangenberg, Elin


Background Today most rats are still housed in standard Makrolon type IV (M IV) cages. These cages are not high enough to allow the rats to rear and not large enough to allow much physical activity. We developed a cage prototype, the “Rat Flat” that is a raised top that can be fitted with the cage bottom from a M IV. The raised top has two shelves and can be folded flat for easy storage when not in use. A larger, higher cage should increase the welfare of the rats since they can perform more of their natural behaviours such as rearing, climbing and thereby reach a higher level of physical activity. To get the full picture of the animals well being it is crucial to combine ethological and physiological parameters. When doing so, it is important to use methods that do not disturb the animals while collecting the data. One way of achieving this is to combine studies of animal behaviour with telemetric data of, for example, blood pressure. To do a first preliminary evaluation of whether a higher cage offers a refined environment for the animals, we did a pilot study of behaviour in the home cages and in behavioural tests and telemetrically registered blood pressure. Materials and Methods 10 male rats were used for this pilot study. They were placed in makrolon type IV cages and allowed to acclimatize for a week. Telemetrical transmitters for registration of blood pressure, were surgically placed in the abdomen of 5 of the rats. After full recovery, all rats were randomly placed in makrolon type IV cages in groups of two or in the Rat Flat in groups of three. Three rats with telemetrical transmitters were placed in MIV and two in Rat Flats. The body weight, food and water intake was measured every week. Blood pressure was measured regularly throughout the study. The behaviour of the rats in their home cages was studied and the rats were subjected to a modified open field test with a known and an unknown person. Furthermore the rats were subjected to two tests of muscle strength; the grip strength and the inclined plane tests. Also the willingness of the rats to be handled by an unknown animal technician was tested. Results and discussion The two rats fitted with telemetrical transmitters housed in the two Rat Flats consistently had lower mean arterial blood pressure than the three rats in the M IV cages, which could indicate a higher stress level in the rats housed in the M IV cages. The rats in the Rat Flats had a more diverse behaviour repertoire. The rats housed in standard cages took longer to visit the unknown person than known person in the open field test. This was not the case with the rats housed in the Rat Flats who also tended to spend more time with the unknown person. Since these rats more readily took to a new person, it could suggest that they might better cope with new people in experimental situations. No differences in body weight, food consumption, muscle strength or willingness of the rats to be handled could be detected. The results from this pilot study indicate that a larger cage with climbing possibilities is beneficial for the animals and that telemetry can be useful when evaluating different cage types

Published in


36th Scand-LAS Symposium on Laboratory Animal Science