Background

As stated in the Guide for the Care and Use of Laboratory Animals, "Animals should have access to potable, uncontaminated drinking water according to their particular requirements," with "ready access to food and water" (the Guide, pages 56, 63, 67). Water restriction protocols, however, are often necessary for physiological, neuroscience, and behavioral research studies. Because these protocols have the potential for causing significant distress to the animal, the Animal Research Committee (ARC) has established the following policy.

Policy

Animals must be provided ad libitum access to water unless scientific justification for water restriction for experimental purposes is provided in the ARC protocol. Every protocol involving water restriction, with the exception of pre-anesthesia restriction, will be individually evaluated to ensure the minimum degree of restriction necessary to achieve scientific goals is utilized, to determine appropriate monitoring to ensure animal welfare throughout the period of restriction, and to identify criteria for removal of animals from restriction.

The following must be addressed in seeking ARC approval for water restriction:

  1. Consideration of Alternatives
    Before water restriction experiments may begin, researchers must consider alternative methods (e.g., addition of citric acid to home-cage water or use of palatable rewards) and provide adequate justification for using water restriction.
  2. Acclimation to Restriction
    Gradual acclimation to the water restriction schedule, wherein the degree of water deprivation is incrementally increased until the study start point, is encouraged to minimize stress.
  3. Level of Restriction

    ARC protocols utilizing water restriction must describe the necessary level of restriction, potential adverse consequences of restriction, and methods for assessing the health and well-being of the animals. The minimum degree of restriction that will achieve the scientific objective must be used.

    No animal may be water-deprived for more than 24 consecutive hours.

    Because there is considerable strain variation in daily water consumption in rodents, the baseline water consumption of the strain to be used must be known before starting experimentation. If not readily available online or in the literature, it must be established by the research lab.

  4. Monitoring

    Water restricted animals—regardless of species—must be monitored daily for continued good health as judged by stability of performance in the experimental protocol, signs of dehydration (e.g., skin turgor, mucous membrane dryness, urine output and specific gravity, blood analysis), and signs of stress (e.g., sleep cycle changes, cage chewing, hair picking, abnormal vocalizations, aggression).

    Records on body weight must be kept for the duration of the restriction protocol, beginning prior to initiation to establish a baseline weight. Weight must be recorded at least weekly, and more often for animals requiring greater restriction or those that have lost >10% from their baseline. Animals must not lose body weight in excess of the limit indicated in the approved protocol. For growing animals, weight loss must be evaluated in the context of normal expected weight gain.

  5. Documentation

    Written records must be maintained for each animal to document daily water consumption, hydration status, and any behavioral and clinical changes used as criteria for temporary or permanent removal of an animal from a protocol.

    Investigators utilizing water restriction protocols must communicate periods of restriction with DLAM staff to prevent animals from receiving improper rations. During periods of water restriction, special treatment cards must be placed on the cage indicating that the investigator’s laboratory will be responsible for watering animals, and identifying the duration (start and end dates) for the special watering schedule. Special treatment cards may be obtained from DLAM.

References

  1. Guide for the Care and Use of Laboratory Animals. National Research Council, pp. 30-31, 2010.
  2. Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research. National Research Council, pp. 49-61, 2003.
  3. Orlans, F.B. Prolonged water deprivation: A case study in decision making by an IACUC. Institute of Laboratory Animal Resources (ILAR) News, Vol. 33, pp 48-52, 1991.
  4. Desimone, R., C. Olson, and R. Erickson. The controlled water access paradigm. ILAR News, Vol. 34, pp 27-29, 1992.
  5. Hughes, J.E., et al. Health effects of water restriction to motivate lever pressing in rats. Laboratory Animal Science, Vol. 44, pp 135-140, 1994.
  6. Vasilev D, Havel D, Liebscher S, Slesiona-Kuenzel S, Logothetis NK, Schenke-Layland K, Totah NK. Three Water Restriction Schedules Used in Rodent Behavioral Tasks Transiently Impair Growth and Differentially Evoke a Stress Hormone Response without Causing Dehydration. eNeuro. 2021 Dec 14;8(6):ENEURO.0424-21.2021. doi: 10.1523/ENEURO.0424-21.2021. PMID: 34815297; PMCID: PMC8672445.
  7. Urai AE, Aguillon-Rodriguez V, Laranjeira IC, Cazettes F; International Brain Laboratory; Mainen ZF, Churchland AK. Citric Acid Water as an Alternative to Water Restriction for High-Yield Mouse Behavior. eNeuro. 2021 Feb 11;8(1):ENEURO.0230-20.2020. doi: 10.1523/ENEURO.0230-20.2020. PMID: 33431508; PMCID: PMC7890523.
  8. Reinagel P. Training Rats Using Water Rewards Without Water Restriction. Front Behav Neurosci. 2018 May 3;12:84. doi: 10.3389/fnbeh.2018.00084. PMID: 29773982; PMCID: PMC5943498.
  9. Bramati G, Stauffer P, Nigri M, Wolfer DP, Amrein I. Environmental enrichment improves hippocampus-dependent spatial learning in female C57BL/6 mice in novel IntelliCage sweet reward-based behavioral tests. Front Behav Neurosci. 2023 Sep 18;17:1256744. doi: 10.3389/fnbeh.2023.1256744. PMID: 37791111; PMCID: PMC10543696.

Approved 11/13/00; Revised 1/28/02, 7/26/04, 7/26/10, 5/18/20, 4/21/25; Updated 1/18/11, 7/26/19