The principles of the 3 Rs are also reflected in the Guide, which says that the following topics should be considered in the development and review of animal protocols (p. 10):
Justification of the species and number of animals requested.
Availability or appropriateness of the use of less-invasive procedures, other species, isolated organ preparation, cell or tissue culture, or computer simulation.
Appropriate sedation, analgesia, and anesthesia.
Unnecessary duplication of experiments.