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Conference abstract2003Peer reviewed

Housing-related activity and its effects on physical fitness in rats – implications for animal welfare

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

Abstract

The standard housing currently used for laboratory rats provides little opportunities for the rats to engage in most forms of physical activity, resulting in sedentary and overweight animals. The question is if other housing systems can offer increased physical activity thus increasing physical fitness and animal welfare. Fortyeight male Sprague Dawley rats (180 g) were randomised into four groups for seven weeks. Sixteen rats were housed in pairs in Makrolon type IV cages (59x38x20 cm) (ST). This system allows only restricted physical activity and social contact with one cage mate. Eight rats were housed individually in small steel cages fitted with running wheels and grid floor (25x33x23 cm) (RW). This system allows physical activity but no social contact. Furthermore, 16 rats were kept in two groups in rebuilt rabbit cages (60x72x51 cm) with a shelf at 30 cm height (RC), and eight rats were housed in a pen (150x210 cm) on the floor furnished with two Makrolon cages turned upside down (PH). These two housing systems allow both physical activity and social contact. Data were statistically analysed with ANOVA on Ranks (SigmaStat for Windows, version 2.03) and are presented as means  SEM (table 1). Physical activity was measured directly in RW-rats. The mean distance run was 5108  1551 m during 24 hours, with a running time of 9717 minutes. Physical fitness of the rats was measured using an inclined plane test where the maximum angle at which the rats could stay on the plane (strength test) and the time, in seconds, that they could stay on the plane (endurance test) were recorded. The RC-rats were the superior group in this test, closely followed by PH-rats. Table 1. Body weight and results from an inclined plane test in rats kept for seven weeks in four different housing systems. Parameter/Housing type Standard Rabbit cage Pen-housed Running wheel Body weight at end of study (g) 48916a 4677a,b 44232a,b 42011b Strength test () 59.70.9a,b 62.50.5a 61.90.8a 55.01.1b Endurance test (seconds) 8211b 1319a 12014a,b 6618b Different superscripts letters (a, b) on the same line indicate significant differences (p<0.05). The extensive running in RW-rats was not reflected as strength or endurance in the inclined plane test. However, this activity did create a lasting difference in body weight compared to the most sedentary group, the ST-rats. The RC- and PH-rats were housed in the environments that allowed the most varying forms of activity, such as jumping, climbing and running. In addition, these housing systems provided the animals with several cage mates. This study confirms earlier findings, which show that rats improve their physical fitness if they, in their home cage, have the opportunity to increase their physical activity with a more diverse activity pattern. We suggest that such housing systems imply increased animal welfare

Published in

Conference

The 15th Nordic Symposium of the International Society for Applied Ethology