​Food and Water Restriction in Non-Rodent USDA Species

Policy

Food or water regulation/restriction, other than that designed to maintain animals in a healthy and non-obese state and directed by the clinical veterinary staff, must be scientifically justified and approved by the IACUC. This scientific justification must contain a harm benefit analysis which addresses the following questions⁷:

1. What is the benefit of this research?
2. Are there potential ways to motivate the animals that will be less likely to have adverse effects yet allow successful completion of the research goal?
3. Can the level of motivation (i.e., degree of restriction) be different during different stages of the research project?
4. Are there procedures in place to monitor and report adverse outcomes?

If food or water regulation/restriction is to be used for behavioral research, it must be of minimum severity to achieve the desired behavioral outcome⁶. Positive reinforcement methods, such as the use of desirable food or fluid ‘treats’ to motivate behavior, must be considered thoroughly when proposing a food or fluid regulation/restriction paradigm. Scientific justification must be included in IACUC protocols to explain why positive reinforcement, without food or fluid restriction, is not sufficient alone. Less severe dietary or fluid regulation/restriction may be needed after a period of initial training, and adjustments in degree of regulation/restriction should be made accordingly. Whenever an animal obtains any portion of its diet through food or water reward, the sum of the food or water earned through reward and that of ad libitum must be sufficient to maintain the animal in a healthy state without a significant loss of weight.

Transitions from ad libitum access to food or water regulation/restriction should be gradual, over the course of one or more days to minimize animal stress unless otherwise explained in the IACUC protocol. When access to food or water is time-limited, it should be made available at consistent times during the animals’ light/dark cycle to allow behavioral accommodation to the study schedule.

When used as a behavioral motivator, the type and concentration, if applicable, of the food and fluid reward must be specified in the IACUC protocol. Food and fluid rewards that are nutritionally balanced for the species involved should be selected if the majority of the animals’ daily food intake occurs during motivated behavioral testing. Fluid-rich treats, such as watermelon, jello or grapes, can be used to provide some of the daily fluid intake between free-fluid sessions.

All IACUC protocols with food or water regulation/restriction must clearly state how the animals’ health is monitored and include criteria for intervention, such as weight loss, decreases in body condition, and/or clinical signs of dehydration. If intervention procedures are unsuccessful in stabilizing animal health or there are other adverse outcomes due to water/food regulation/restriction, a veterinarian must be promptly contacted. All animals must be weighed at least once weekly and weight charts maintained for examination by the Veterinary Staff and the IACUC. Investigators working with young animals must specifically address the need for dietary requirements for normal growth and comparison to normal growth curves must be described. Physical examinations, including body condition scoring, must be performed at least once every six months. Additional body condition scoring may be needed in growing animals. For protocols which include general anesthesia, intake before and after the procedure must be addressed in the protocol. For protocols which include fluid control, intake should be increased prior to surgery.

Fluid or food deprivation (complete withholding of food or fluid) beyond 24 hours or food restriction to less than 85% of baseline body weight would need strong IACUC-approved scientific justification, and such protocols would be considered a USDA-category E.