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Conference abstract2006

Is treadmill training a good alternative for exercising rats?

Spangenberg, Elin; Pettersson, Karin; Cvek, Katarina

Abstract

The typical running behaviour of a wild rat (Rattus Norvegicus) is short sprint-like movements from one place to another. Laboratory rats display similar running patterns when they are allowed to exercise voluntarily in running wheels. They run for short periods, approximately 1 min, at high speeds, around 40 m/min [1]. We have previously seen that rats do increase their activity if they are kept in a larger space [2]. They also run in a way similar to the wild rats. This type of activity is difficult to quantify and there are individual variations in how much the rats run. Therefore a treadmill is often used for studying effects of physical activity in rats. Exercising rats on a treadmill usually involves running at the same speed for a continuous time period, up to 90 minutes. In addition, running on a treadmill is a forced type of exercise, commonly with some aversive stimuli (e.g. electric shocks) to make the rats run. One advantage with treadmill exercise, contrary to running wheels, is that it is possible to group-house the rats while training them. Another advantage is that the training can be standardised, i.e. the experimenter can set equal options for the exercise for all rats. Voluntary running wheel exercise can never be standardised since daily running distance vary between individuals. We work with the hypothesis that increased physical exercise is beneficial for the welfare of laboratory rats and we aim to incorporate physical fitness into the animal welfare concept. To be able to identify good and reliable physiological and behavioural parameters of exercise in rats, we have trained them in a standardised manner on a treadmill. This study gave a lot of experience regarding the individual differences between rats in motivation to run, the effect of an aversive stimulus, and how a treadmill should be designed to best suite the running behaviour of rats. It is common that there are a couple of rats that have to be excluded from each treadmill study due to unwillingness to run and we experienced that as well. Regarding the design of the treadmill it should be equipped with long lanes to ensure the rats to run in the manner that they prefer. They can sprint to the front and then rest for a few seconds while travelling back with the lane and the sprint to the front again. This resembles their natural sprint-like movements. The treadmill we used did not permit this type of behaviour due to shorter lanes. When performing studies on the effects of exercise, treadmill training can be questioned as the best training alternative for rats. They are forced to run in a manner that is not natural for them, and they cannot choose at what time of the day to run. Alternative exercising methods could be swimming, running wheels or using the rats’ ability to climb on a laddermill [3]. References: 1. Rodnick KJ, Reaven GM, Haskell WL, Sims CR, Mondon CE. Variations in running activity and enzymatic adaptations in voluntary running rats. J Appl Physiol 1989;66:1250-1257. 2. Spangenberg EM, Augustsson H, Dahlborn K, Essen-Gustavsson B, Cvek K. Housing-related activity in rats: effects on body weight, urinary corticosterone levels, muscle properties and performance. Lab Anim 2005;39:45-57. 3. Norton KI, Jones MT, Armstrong RB. Oxygen consumption and distribution of blood flow in rats climbing a laddermill. J Appl Physiol 1990;68:241-247

Published in

Conference

the 36th Scand-LAS Symposium on Laboratory Animal Science