Effects of housing on rodent behavior: Wire vs. solid plastic caging

Abstract

Housing of laboratory animals has changed dramatically in the last 20 years; however, the effect of modern rodent housing on behavior has not been extensively evaluated and published findings are conflicting. In the present study, aged (19 mo) Sprague-Dawley rats were single-housed in either suspended wire-mesh cages or suspended plastic cages for two months. Thereafter, rats completed a battery of balance, coordination, and strength tests, including walking on a horizontal rod, planks of varying widths, and rotarod as well as clinging to an inclined screen and horizontal wire. Rats also completed a working memory task in the water maze. Following introduction to the rodent housing, plastic cage-housed rats initially lost body weight but returned to baseline when water was made available through an additional route. Although no pathologies were observed in the rats’ extremities, analysis of behavioral data showed that plastic-housed rats balanced significantly longer on medium and wide planks and were able to cling longer to an inclined screen. No housing effects were observed in results from the water maze. These findings support concerns that modernization of rodent housing may impact measures of both motor and ingestive behavior.