This guide should serve as an overview of the literature search requirements of Miami University's IACUC (Institutional Animal Care and Use Committee) applications, as well as a tutorial on best practices for completing them.
For more information on Miami's Animal Care and Use Program, please see their website.
Some guidance and suggestions may apply to IACUC applications at other institutions, but please check the specific requirements of your institution as they do vary.
The literature search should not be treated as "just another bureaucratic requirement". It should not be the last thing to do on your application checklist. A good literature search is one that is conducted throughout the planning stages of your research. It should inform your research design.
Federal law requires all researchers working with covered species (basically, all vertebrates, whether in the lab or in the field) to perform and document appropriate literature searches. Specifically, the Animal Welfare Act charges the principal investigator with considering "alternatives to any procedure likely to produce pain to or distress in an experimental animal" and providing a written narrative describing the methods and sources used to determine whether alternatives were available. It also charges PIs with providing "written assurance that the activities do not unnecessarily duplicate previous experiments".
Through literature searches, you can maybe find that there's another laboratory that has already researched what you're interested in, thereby saving you the time and expense of repeating it. You can also potentially find that the procedure you were planning on using is outdated or inefficient, and find a better procedure to use.