Share thisThe impact of research animal exposure to noise and vibration in vivariums and animal housing is a frequently overlooked aspect of biomedical research, though there is emerging recognition and study of its significance.
The research animal housing and life sciences laboratory industry in the U.S. is not currently governed by accepted standards for acoustics or vibration. This is probably one of the last sets of environmental influences (along with CO2 and ammonia levels) that have yet to be given serious consideration.
We are playing catch-up to our European colleagues in this regard. Among European standards for individually ventilated cage (IVC) racks are those based on accepted IVC testing parameters developed by the Center for Biomedical Research of the Faculty of Medicine (TierschutzInformationsZentrum für die Biomedizinische Forschung der Medizinischen Fakultät: TIZ-BIFO), at Ludwig-Maximilian University of Munich. TIZ-BIFO testing assesses IVC reliability, safety, and quality through tests of ventilation, climatic and acoustic parameters, as well as factory inspections and field acceptance tests of IVC installations.
In the absence of U.S. standards, Allentown and other IVC manufacturers have achieved TIZ-BIFO standards in the interest of helping shape future U.S. acoustical standards and to provide customers with statistical data which proves the efficiency and safety of our acoustical design parameters as it relates to reliable research outcomes and to animal exposure.
Changing Animal Models
Our industry has seen significant change over the last 20 years. The animal models that we use now are very different. Previously, research involved larger animals that don’t experience noise stress to the level that rodents do.48Until facilities actually began to house large numbers of rodents, and use ultrasonic frequencies and ultrasound-generating equipment in proximity to them, the industry wasn’t as concerned about sound, especially in the frequencies outside the range of human hearing. Now, with the changes that have taken place, concern is growing because of the potential negative impact sound and vibration can have on research paradigms.19, 28, 35, 40, 48, 52
As a foundation, we define our subject matter as:
Sound – mechanical radiant energy that is transmitted by longitudinal pressure waves in a material medium (such as air) and is the objective cause of hearing.
Noise – any sound that is undesirable or interferes with one’s hearing of something.
Vibration – a periodic motion of the particles of an elastic body or medium in alternatively opposite directions from the position of equilibrium when that equilibrium has been disturbed (as when a stretched chord produces musical tones or particles of air transmit sounds to the ear).
From the IVC manufacturer’s standpoint, a customer’s perception of the loudness or quietness of a cage rack is highly subjective. Hard scientific data is needed about threshold frequencies and sound pressure (decibel) levels stressful to rodents that can be taken into account in the design cycle so that these issues are addressed. Aside from individual manufacturers’ internal research, which is largely proprietary in nature, there is very little data involving planned studies over wide frequency ranges and different sound pressures.