Food and Fluid Regulation
- food/ fluid regulation: Includes food/ fluid scheduling and food/ fluid restriction.
- food/ fluid scheduling: Access to food or fluids is set at intervals. The animal can consume as much as is desired during access to the food or fluid.
- food/ fluid restriction: The total volume of food or fluid consumed/ available to the animal is strictly controlled.
- pre-anesthesia fasting: A fasting period imposed for some hours before surgery to minimize the risk of aspiration of food from the stomach.
- positive reinforcement: The offering of desirable effects or consequences for a behavior with the intention of increasing the change of that behavior being repeated in the future.
If regulation of food and/or fluid intake is required for your study, be clear on appropriate parameters.
Many scientific studies require the use of motivating an animal to "work" for a reward. For example, a rat may be required to press a lever or navigate a maze in order to receive a food treat. Sometimes scientists regulate the normal amount of food or fluid an animal receives in order to motivate it to perform the task. Regulation can take the form of:
- scheduled access to food or fluid in which the animal has unlimited access to food or fluid for a specific time daily or
- restricted access, in which the total amount of food or fluid is strictly monitored or controlled.
Be aware that you will need to scientifically justify your use of food or fluid regulation in your ACUC protocol. In addition, you must consider the following when planning food or fluid regulation studies:
Young animals are especially sensitive
Young and growing animals are especially sensitive to food restriction and placing these classes of animals on food restriction must be evaluated with a concern for their health and minimum growth requirements.
Nutritional needs must be met
Food restriction studies must ensure that the diet is nutritionally adequate so that the animal's metabolic requirements are met and the animal receives the minimum daily requirement of protein, fats, and carbohydrates plus vitamins and minerals to stay healthy. This principle applies unless the study is intended to investigate the minimum nutritional requirement of a certain food component or if the intent of the study is to test hypotheses related to the effects of nutrient deficiency or weight loss.
Regulation is animal and task dependent
Some animals will work for a preferred food without fluid or food restriction. The degree of food or fluid restriction is influenced by the difficulty of the task, the individual animal, and the effectiveness of animal training for the task.
Close monitoring and thorough documentation is required
Animals must be closely monitored to ensure that food and fluid intake meets nutritional needs. Body weight should be measured at predetermined intervals and written records must be maintained for each animal to document daily food and fluid consumption, hydration status, and clinical or behavioral changes. These changes may be used as criteria for temporary or permanent removal from the study.
Note: Veterinary prescribed caloric restriction is a common husbandry technique as a means of weight control in some species. When used for this purpose, calorie restriction is not considered food regulation. Pre-anesthetic fasting or water restriction is also not regulation.
Researchers can consult many resources about food or fluid regulation. First, contact your veterinarian to inquire about acceptable ways to regulate food or fluid while maintaining the welfare of the animals. The following resources may also be helpful:
- NIH's Position Statement 4) Food and Fluid Restriction/Use of Preferred Foods
- NIH's Office of Intramural Research (Office of Animal Care and Use) Guidelines for Diet Control in Laboratory Animals
- Guide for the Care and Use of Laboratory Animals; National Academies Press (2011), pp 30-31
- Guidelines for the care and use of mammals in neuroscience and behavioral research; National Academies Press.