It is unethical to use too many or too few animals in research protocols.
Accordingly, the Animal Ethic Committee (AEC) requires that researchers provide an explanation regarding the numbers of animals requested for use in their proposed experimental protocol. This must include a statistical justification unless the work falls into an exemption category.
Explanation
An explanation of the animal numbers requested should include:
- a list of the planned experiments incorporating treatment groups, time points, group sizes and so on, and the number ('n') of animals required for each protocol
- a justification for 'n' based on a known or expected experimental variance. This number should be the minimum animal number required to achieve statistically valid data with 80 per cent certainty and should be determined by power analysis.
Estimates of experimental variability
In most cases, the variance for a particular experimental protocol will be known because it has been determined previously by the researcher in similar experiments.
Alternatively, estimates of variance established and/or published by other researchers can be used in power calculations. In cases where a researcher is using a protocol for the first time, 'n' should be calculated conservatively to allow for the relative inexperience of the researcher.
Further information can be obtained from a modern statistics textbook or from the Animal Welfare Officer, Animal Welfare Officer.
Exemption categories
- Antibody production: A request for 'n' animals can be based on the past experience of the researcher and his/her need for a particular quantity of antibody product.
- Cell culture preparation: As for antibody production, a request for 'n' animals may be based on the known or expected yield of seeding cells from a digest of intact tissue. Estimates of the yield should be provided as a basis for the request.
- Other: Examples of animal number requests for experimental protocols that may not require formal testing via a power calculation shall be assessed by the AEC on their merits on a case-by-case basis.
University information
CRICOS Code: 00126G
