Evaluation of Ambient Sound, Vibration, and Light in Rodent Housing Rooms

Abstract

Excessive sound, vibration, and light are detrimental to rodent welfare, yet these parameters are rarely recorded in vivaria. Whether housing environments exceed the suggested thresholds and which specific factors may alter these parameters is generally unknown. The goal of this study was to determine how environmental factors may alter sound, vibration, and light at the room and cage levels. Measurements were made using an ultrasonic microphone, accelerometer, and light sensor. Measurement sites were 1) in open air at a central location in 64 rooms located in 9 buildings, and 2) inside an empty mouse or rat cage containing chow, water, and bedding and located on an animal transfer station (n = 51) or housing rack (n = 102). Information collected for each transfer station and rack measurement included the year of manufacture, the species on the rack, and the number of cages on the rack. For each location, a baseline measurement was taken with the transfer station turned off, followed by another measurement after the transfer station was turned on. In general, many factors influenced ambient sound, vibration, and light, indicating that values are not uniform across rodent rooms in the same institution or across cages in a single room. Sound peaks capable of startling rodents were measured in association with hallway ultrasonic motion sensors and during cage change. Vibration and light intensity were generally low when cages were located on the rack. In contrast, active transfer stations had more vibration and light intensity, reaching levels that were potentially stressful for rodents. These data reflect the ambient sound, vibration, and light that rodents experience during normal facility operations. These patterns may extend to other locations, but given the variability in all parameters, the data highlight the need for institutions to conduct their own monitoring.

Recommendations for measuring and standardizing light for laboratory mammals to improve welfare and reproducibility in animal research

“…Many factors were considered in determining these, including circadian biology, light preference and aversion, human health and safety, and the animal’s species-specific experience. The guidance we provide is for light as experienced by the animal, and it is important to note that this will be determined not just by the nature of room lighting, but also by rack orientation, cage location within the rack, and cage color [ 52 – 54 ]. For this reason, the figures we give relate to in-cage light measurements, with the detector pointing towards the major light source (and the cage in its position in the rack if appropriate).…”

In the Eye of the Beholder: Measuring and Standardising Light for Laboratory Mammals

“…Many factors were considered in determining these, including circadian biology, light preference and aversion, human health and safety, and the animal's species-specific experience. The guidance we provide is for light as experienced by the animal, and it is important to note that this will be determined not just by the nature of room lighting, but also by rack orientation, cage location within the rack, and cage colour [44][45][46]. For this reason, the figures we give relate to in cage light measures, with the detector pointing towards the major light source (and the cage in its position in the rack if appropriate).…”