Animal Care Practices in Research on Biological Rhythms and Sleep

Twenty years have passed since the Society for Research on Biological Rhythms (SRBR) published its last animal issues statement (Morin, 1993). This publication, which was the report of an ad hoc committee, outlined the regulatory requirements then in force and made recommendations for husbandry and practices to reconcile the well-being of experimental animals with the procedures necessary for the successful completion of experiments on biological rhythms.

In the intervening years, the stringency with which research on vertebrate animals is regulated has increased considerably. The intent of the regulations that govern animal research in the United States and elsewhere is to promote the use of maximally humane procedures, reduce the number of subjects, and replace vertebrates with either less sentient species or nonanimal models to the extent possible. Those of us who use vertebrate animals to study biological rhythms and sleep often encounter particular obstacles. Attending veterinarians and members of institutional review boards may be unfamiliar with the housing conditions and procedures necessary to obtain interpretable results or be unaware of the potential benefits for animal and human well-being in gaining a fuller understanding of biological rhythms.

In 2011, a new edition of the Guide for the Care and Use of Laboratory Animals was published (Institute for Laboratory Animal Research, 2011). In light of these changes, the SRBR and the Sleep Research Society (SRS) have issued a joint statement on animal care practices (Bittman et al., 2013). This publication is the work of the joint animal issues committees of the 2 societies and was assembled with the help of the SRBR executive committee. It also reflects input solicited from members of the SRBR and SRS. We encourage researchers to continue to inform the animal issues committee of concerns and experiences they encounter in dealing with the regulatory environment as they conduct studies of vertebrate biological rhythms.

The Animal Care Practices Statement that appears in the July 2013 issue of the Journal of the American Association for Laboratory Animal Science is intended to help chronobiologists explain to reviewers (and perhaps the general public) the need to subject experimental animals to conditions and procedures that are not typical in other fields. The statement explains the importance of leaving animals undisturbed for sustained intervals, even though this may require a reduction in the frequency of changes of cage bedding or resupply of food and water. We have placed a particular emphasis on the importance of rigorous control of illumination and the light:dark cycle. We document the ways in which noise in the animal colony and even brief exposures to light can introduce artifacts and phase shifts in behavioral records. We address new demands for environmental enrichment of caging environments and expectations that animals be visually checked on a daily basis. We offer suggestions that maximize the experimenters’ control over animal maintenance while remaining in compliance with the Guide for the Care and Use of Laboratory Animals and legal requirements. Within the United States, Institutional Animal Care and Use Committees (IACUCs) can (and often do) permit deviations from standard practices when the scientific justification is provided. While practices in other countries vary, the corresponding regulatory committees require that researchers explain the need for deviations from standard husbandry and maintenance practices.

The statement is intended to improve communication and understanding between researchers, veterinarians, and IACUC members and to help researchers explain and justify experimental procedures commonly used in the study of biological rhythms and sleep. The joint statement has benefitted from input from European chronobiologists, who communicated their experience and concerns, and the committee hopes that the statement will be helpful to researchers both in the United States and internationally. The SRBR wishes to help researchers understand and comply with regulations and to satisfy institutional review panels and veterinarians without compromising their research. We hope that the statement will be useful in achieving these goals.