Animal User Requirement #7

Title:
Fluid Regulation Policy for Macaques Living at the Wisconsin National Primate Research Center (WNPRC)

Definition:

Macaques offered less than 80 ml/kg of water per day are considered to be "fluid regulated."

Purpose:

This policy provides guidelines for scientists, veterinarians, and IACUC members regarding the use of fluid regulation to motivate nonhuman primates (specifically macaques) to perform behavioral tasks described in IACUC approved experimental protocols. The LSVC and WNPRC have chosen to adopt fluid regulation guidelines based on those already established by the Association of Primate Veterinarians.¹

Guidelines for UW-Madison Scientists Considering Protocols that Utilize Fluid Regulation in Macaques:

1. Fluid regulation can be a powerful behavioral motivator, but it can be physiologically and psychologically distressing to animals if not conducted appropriately.
   1. The use of fluid regulation in macaques must be scientifically justified in each experimental protocol where it is used.
   2. Scientists should strive to utilize the least amount of regulation necessary to achieve their objectives.
   3. It is highly recommended that scientists attempt to utilize alternative methods for motivating an animal to perform a task (e.g., slurries, fruit juice, etc.) early in training to determine if fluid regulation is necessary to achieve desired experimental results.
      1. Attempts to use alternate methods and the result of these attempts should be recorded in the scientist's laboratory notebooks and/or in the WNPRC Electronic Health Records (EHR) system.
2. An individual animal's unrestricted fluid consumption should be evaluated prior to initiating a period of fluid regulation.
   1. Assigning macaques less than 4 years of age to fluid regulation protocols should be avoided as these animals are still growing and fluid regulation could impede their normal growth.
      1. Scientists, in collaboration with veterinary staff, should monitor the growth curve of younger macaques assigned to protocols utilizing fluid regulation.
         
         
3. Transition from unrestricted to regulated fluid access should be accomplished through a measured and systematic limitation of intake over a period of several days - this strategy will allow the physiological changes necessary for an animal to conserve water to occur gradually.
   
   
4. Each animal should be provided with the opportunity to earn fluids to satiety during each work period. Animals failing to consume their calculated daily minimum fluid intake should be provided with supplemental fluids after the training session to ensure the minimal daily fluid intake level and hydration needs have been met.
   
   
5. Ideally, macaques on fluid regulation protocols should receive a minimum of 20 milliliters (ml)/kg of water per day between what they reeive while working at their experimental task, what they receive in their home enclosure, and what they receive through fruit/vegetable supplements. Macaques may be able to receive less than 20 ml/kg of water per day if rationale is approved by the LSVC IACUC, but they should not receive less than 10 ml/kg/day.
   1. Macaque chow should be provided as close as possible to water consumption as this should ensure consumption of the dry food.
   2. Food items with high water content may be given to contribute to the daily fluid intake by calculating fluid equivalents for produce (see the below conversion chart).
      1. Provision of high-water content foodstuffs must be documented and cannot account for >20% of the total daily fluid allowances. Examples:
         1. If minimum water is 20 ml/kg, 16 ml/kg must be from water and 4 ml/kg of fluid can come from produce.
         2. If minimum water is 10 ml/kg, 8 ml/kg must be from water and 2 ml/kg of fluid can come from produce.
      2. The table attached at the end of the policy provides food weight (in grams) to water volume (in milliliters) conversion values for all common fruit and vegetables used to supplement macaque diets at the WNPRC and is based on a widely accepted text.²
      3. Scientists, their staff, and all animal care personnel delivering high-water foodstuffs to meet the minimum daily water requirements should ensure that the foodstuff is consumed and consumption of the items is documented.
         
         
   3. Clinically healthy animals on fluid regulation scheduled for major surgical procedures (e.g., head restraint implant, cylinder implant, craniotomy, extensive cranial implant repair) should be returned to higher fluid levels (for example, an increase from 20 ml/kg to 40-80 ml/kg or ad libitum) at least 48 hours prior to the surgery and should not be returned to fluid regulation until a veterinarian determines that the animals are sufficiently recovered from the procedure.
      
      
6. Once an animal has learned the required experimental task, it is highly recommended that the animal be given opportunities to complete its task with less fluid regulation (i.e., increasing the fluid reward provided for each successfully performed task).
   1. With assistance from veterinarians, scientists should work to discern less motivated animals from acutely dehydrated animals, as stubborn animals may opt to perform simple tasks over more difficult ones, while dehydrated animals will fail on both.
      
      
7. Caution must be used when returning some animals to ad libitum water. A gradual increase of fluid availability to ad libitum access over several days during which the animal is closely monitored initially for food and fluid consumption is recommended.
   
   
8. It is recommended that scientists employ the services of nonhuman primate behaviorists to ensure they and their staff are using appropriate positive reinforcement techniques to train animals assigned to fluid regulation studies.
   
   
9. In collaboration with veterinarians and animal care staff, investigators must document the following information in the WNPRC EHR for each animal undergoing fluid regulation:
   1. Daily water intake while performing experimental task
   2. Daily water intake in home enclosure
   3. Daily produce (i.e., fruits, vegetables) offered by laboratory personnel
   4. Consumption of dry chow
   5. Hydration status
   6. Stool amount and quality
   7. Body weight
      1. Body weight should be collected a minimum of once per week, but investigators should strive to document body weight each time an animal is removed for testing or cleaning of its head apparatus (if one is present).
      2. Animals that lose greater than 15% of their body weight from the day water regulation is initiated should undergo a physical examination by a veterinarian and should receive an increase in their daily water allowance until their body weight increases and a veterinarian deems them healthy enough to resume fluid regulation.
         
         
10. If husbandry (i.e., enclosure wash down) needs to be modified for water regulated animals, details should be included in the non-standard husbandry section of the protocol. Most commonly, spot cleaning of the enclosure with careful spraying of water under enclosures to minimize access to supplemental water can be arranged instead of normal wash down procedures. Given the proximity of enclosures, animals with less strict water regulation (i.e., 40 ml/kg or more daily water) will also be cared for similarly. Enclosures may have normal wash down 1-2 days per week when water is less restricted (i.e., Saturdays), and as needed.

Guidelines for WNPRC Veterinarians Providing Care for Macaques on Fluid Regulation Protocols:

1. Prior to placing an animal on fluid regulation, the animal should be given a complete physical examination by a veterinarian.
   1. The veterinarian should carefully note an animal’s body condition at the beginning of any fluid regulation paradigm and monitor and document body condition throughout the fluid regulation period.
      1. A Body Condition Score (BCS) should be calculated as described in accepted texts.^3,4
      2. Animals with a BSC of less than 2.0 should not be utilized in studies involving fluid regulation.
   2. Baseline clinical chemistry panels, serum/plasma osmolality, urinalysis, urine osmolality, and other tests should be conducted as needed to establish baseline data and determine the animal's renal function and readiness for study.
      
      
2. A physical examination by a clinical veterinarian with attention to the animal’s body condition and assessment of bloodwork (serum chemistry and osmolality and complete blood count and differential) should be performed at least every 6 to 12 months. Urinalysis may also be performed as needed.
   
   
3. As noted above, and in collaboration with scientist(s) and animal care staff, the veterinarians should closely monitor the hydration status, fluid consumption, appetite, weight, body condition, stool consistency and activity level of each animal assigned to protocols employing fluid regulation and all of these parameters should be documented in the WNPRC EHR and can also be documented in the scientists’ laboratory notebooks.
   1. Animals exhibiting signs of dehydration (e.g., reduced skin turgor, decreased or no urine output, scant or hard feces, lethargy, incoordination, etc.) should have immediate evaluation of blood work parameters and reduction or elimination of fluid regulation in a safe, gradual manner.
      
      
4. If an animal loses 15% or more of optimal body weight while on fluid regulation, the clinical veterinarian should assess the animal’s body condition and physical well-being and compare it to the records of the animal at the start of the regulation period.
   1. a. If the veterinarian determines the animal’s condition warrants medical intervention, the investigator should be notified, and the animal’s diet adjusted (increasing chow or water) or supplemented with high calorie treats and/or fluid-soaked monkey biscuits.
   2. Clinical diagnostics such as serum sodium concentration and osmolality may also be used in determining animal well-being.
   3. Animals should be gradually returned to unrestricted fluid access if there is > 15% body weight loss from baseline, the BCS is < 2.5/5, considerable abnormal behaviors have developed, or clinical chemistry parameters are significantly out of normal range.
   4. The animal may be returned to study when improvements in body weight, BCS, and/or behavior have been made.

Guidelines for LSVC IACUC Members Reviewing Protocols that Utilize Fluid Regulation in Macaques:

Each member of the LSVC IACUC should carefully evaluate each protocol proposing the use of fluid regulation and consider (at minimum) the following issues before voting for Designated Member Review:

1. Is fluid regulation essential to address the scientific objectives stated in the protocol and can the regulation be limited to the minimum required to meet the scientific objective?
   
   
2. Have alternatives to fluid regulation been considered (i.e., the use of preferred fluid such as juice for reward or the use of novel food reward)?
   
   
3. What are the limits of the regulation and how were these limits determined?
   
   
4. Will animals have the opportunity to earn additional fluids once they have learned the task(s)?
   
   
5. What physiological and behavioral parameters will be monitored (e.g., appetite, body weight, BCS, activity level, renal values checked via serum chemistry, and blood/urine osmolality) to ensure each regulated animal remains healthy?
   
   
6. What is the intervention plan for animals with compromised health parameters and what are humane endpoints for fluid regulated animals?
   
   
7. How will normal fluid balance be re-established when animals are not undergoing experimental testing and when/if they are removed from the protocol?

References:

1. Association of Primate Veterinarians Guidelines for Fluid Regulation of Nonhuman Primates in Biomedical Research. 2022. J Am Assoc Lab Anim Sci 61(5):397–402.
   
   
2. Bowes and Church’s Food Value of Portions Commonly Used, 18th edition. 2005. Pennington JAT and Douglass JS, ed., Lippincott, Williams and Wilkins: Philadelphia.
   
   
3. Clingerman KJ, Summers L. 2005. Development of a body condition scoring system for nonhuman primates using Macaca mulatta as a model. Lab Anim 34(5):31-37.
   
   
4. Clingerman KJ, Summers L. 2012. Validation of a body condition scoring system in rhesus macaques (Macaca mulatta): inter- and intra-rater variability. J Am Assoc Lab Anim Sci 51(1):31-36.

Author: S. Capuano

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