4. Proposals involving animal use
- 4.1 Replacement, reduction and refinement of animal experiments
- 4.2 Proposals involving animal use
- 4.3 Experimental design, avoidance of bias and statistical considerations
- 4.4 Peer review
- 4.4.1 Je-S section on ‘Animal research’
- 4.4.2 Je-S section on ‘Animal species’
- 4.4.3 Proposal attachment ‘Case for support - Reproducibility and Statistical design annex ’
- 4.4.4 Je-S section on ‘Resources – Animal costs’
- 4.4.5 Proposal attachment ‘Justification of resources
- 4.4.6 Use of animals overseas
- 4.5 Ethical and welfare standards and review
- 4.6 Home Office licences
- 4.7 Mouse strains
- 4.8 Justification of animal use
The elaboration of a compelling scientific case is an essential prerequisite for justifying the use of animals. Over the past few years there have been a number of important initiatives that have been aimed at raising the sometimes inadequate standard of reporting of animal experiments in the scientific literature. The NC3Rs’ ARRIVE guidelines, for example, lay out criteria that should be met in reporting animal studies in order that their results and conclusions can be properly evaluated by readers. These criteria address a range of issues relating to transparency and validity of experimental design, the avoidance or minimisation of bias and the adequacy of statistical aspects of the study including statistical power and appropriate statistical analysis.
In light of these initiatives MRC has revised and updated its guidelines on what information needs to be provided to allow proper evaluation of the scientific strengths and weaknesses of applications for funding involving animal use. In some cases, adherence to the principles defined in this section will require additional resources eg for animal identification such as ‘microchipping’, increased maintenance charges resulting from the randomisation procedure, or salary costs associated with obtaining statistical support. We recognise this and will support such costs where fully justified in the appropriate sections.
Applicants are expected to have developed their proposals in accordance with the cross-funder guidance for the use of animals in research: Responsibility in the Use of Animals in Bioscience Research and NC3Rs Guidelines: Primate Accommodation, Care and Use.
Experiments using animals funded by the MRC must comply with the Animals (Scientific Procedures) Act 1986 (ASPA), amended 2012 and any further embodiments, in:
- Using the simplest possible, or least sentient, species of animal appropriate
- Ensuring that distress and pain are avoided wherever possible
- Employing an appropriate design and using the minimum number of animals consistent with ensuring that scientific objectives will be met.
Advice on opportunities and techniques for implementing these principles can be found on the NC3Rs website. This includes the Experimental Design Assistant (EDA), a free online tool from the NC3Rs to help optimise experimental design and ensure that the number of animals used is consistent with the scientific objectives.
Researchers are strongly advised to read the following section carefully before preparing a proposal to ensure all the relevant information required is included in the appropriate sections of their application. In particular, applicants should ensure their proposal clearly sets out and justifies the following:
- Research objectives and how the knowledge generated will advance the field
- The need to use animals and lack of realistic alternatives
- Choice of species of animals to be used
- Type of animal(s), for example, strain, pathogen free, genetically modified or mutant
- Planned experimental design and its justification
- Numbers of animals and frequency of measurements/interventions to be used
- Primary outcomes to be assessed
- Planned statistical analyses
There is a wide range of designs and approaches to animal experimentation that are appropriate depending on the objectives of the research proposal. In all cases, the MRC expects that researchers provide well justified information in their applications concerning the experimental design and its suitability to answering the research questions posed.
While we recognise that there are ethical imperatives to reduce the number of animals used, it is also unethical to conduct a study that, because of its limited size, has inadequate statistical power to robustly answer a research question. Applicants should therefore provide adequate justification for their choice of design and numbers of animals and interventions. It is important that adequate information is given concerning methodological issues including (but not restricted to) the following:
- The avoidance of bias (for example blinding of observers assessing outcomes to the group allocation in a randomised design)
- How randomisation will be carried out (if used) or why it is not appropriate if it will not be used
- A clear definition of the experimental unit in the analysis and the implications thereof (that is, there is a difference between N samples from one animal, as distinct from one sample from each of N animals, or combining samples from multiple animals)
- A principled justification of the adequacy of the numbers of animals to be included so as to be able to minimise the likelihood of spurious results due to the play of chance alone
- Where animals are used in multiple types of experimental approaches within a single application (eg for tissue supply, pilot experiments or more defined preclinical studies), exemplars for these types of experiment should be provided
- The number of different time points at which measurements will be made on each animal
- A description of the statistical analysis methods that will be used, explaining how they relate to the experimental design and showing that they are appropriate for the types of data that will be collected
- An indication of the number of independent replications of each experiment to be performed with the objective of minimising the likelihood of spurious nonreplicable results. If there are no plans for studies to be independently replicated within the current proposal then this will need to be justified.
A number of examples of the level of detail and type of information required can be found here (PDF, 60KB).
In addition, the NC3Rs has developed a free online tool to guide researchers through the design of their experiments, helping to ensure that they use the minimum number of animals consistent with their scientific objectives, methods to reduce subjective bias, and appropriate statistical analysis. The Experimental Design Assistant helps applicants build a machine-readable diagram representing their experimental plan, following capture of their methodology, and allows the applicant to then generate a PDF report which provides a transparent description of the experimental design in a standardised format. The NC3Rs Experimental Design Assistant can be found here
Information relating to the use of animals will be subject to careful scrutiny, and will carry substantial weight when the scientific strength of the proposal is assessed. Guidance on where each aspect should be addressed in Je-S is given below.
This information must be provided for all proposals involving animals, regardless of whether or not the animal costs are requested as part of the proposal.
Within the ‘Animal research’ section, researchers must give details of any procedures categorised as moderate or severe (in accordance with the maximum prospective severity rating in the Home Office licence under which the work will be carried out) in order that the assessment of the proposal can balance the importance of the potential scientific advancement to the welfare of the animals.
Sound scientific reasons for the use of animals and an explanation of why there are no realistic alternatives must be given, with an explanation of how the choice of species complies with ASPA (see section 4.1).
In this section please include the following information:
- Sound scientific rationale for the use of animals
- Explanation of why there are no realistic non-animal alternatives (see also Section 4.1.1)
- How the choice of species complies with the Animals (Scientific procedures) Act (1986). For knockout or transgenic lines briefly include information on the sources these may be obtained from and relevant information to demonstrate the verification of lines selected.
- Relevant information about the animals to be used (eg species, strain, sex, developmental stage, weight)
Applicants are encouraged to provide other ‘supporting information’ regarding experimental design, statistical analyses etc. in the ‘Reproducibility and statistical design’ annex to the case for support (see Section 220.127.116.11) and not in the Je-S application form. Please note that you are not required to duplicate information presented elsewhere in the application.
Section 4.4.3 provides more detail about the information required in the annex for proposals requesting the use of animals. A summary of where to put all required information regarding the use of animals in your proposal is at Section 4.8.
The scientific case underpinning the choice of animal model and the experimental plans should be detailed in the one-page annex to the case for support (entitled ‘Reproducibility and statistical design’ annex) See section 18.104.22.168 for more detail. There is no requirement to duplicate information.
The experimental design should be outlined, including a justification of the total numbers of animals to be used and, where appropriate, the frequency of measurements/interventions required on each animal. Planned procedures to minimise experimental bias (for example, randomisation protocols, blinding) should be outlined or an explanation included as to why such procedures are not appropriate. Each experiment does not need to be described in detail, but sufficient information must be included that reviewers are readily able to understand the experimental plan.
Researchers must provide a properly constructed justification of how the numbers of animals to be used were determined. In general, it would be expected that professional statistical advice will be sought in putting this section together.
In many instances this section will include statistical power calculations based on justifiable and explicit assumptions about the anticipated size of the experimental effects. If statistical power calculations are not given, applicants should provide a principled explanation of the choice of numbers. Power calculations can be used to calculate the minimum sample size required so that one can be reasonably likely to detect an effect of a given size, or to calculate the minimum effect size that is likely to be detected in a study using a given sample size. In general, explanations based solely in terms of ‘usual practice’ will not be considered adequate. An overview of the planned statistical analyses and their relation to the choice of sample size should be included.
An explanation should be provided of how and why the animal species and model being used can address the scientific objectives and the relevance to human biology. For knockout or transgenic lines this should include information on the sources these may be obtained from and relevant information to demonstrate the verification of lines selected.
It is essential that the case is clearly made as to how the chosen design (with reference to the information regarding the numbers of animals and planned statistical analyses provided) will enable the stated objectives of the study to be achieved. In addition to the usual background and specification of the primary and secondary objectives of the study, or specific hypotheses being tested, the primary and secondary experimental outcomes to be assessed should be clearly defined (eg cell death, molecular markers, behavioural changes). Each experiment does not need to be described in detail, but sufficient information must be included that reviewers are readily able to understand the design rationale and make robust judgements on the scientific case.
The costs of both the animals themselves and their maintenance may be requested and should be listed in the ‘Resources – Animal Costs’ section of the Je-S form. See section 22.214.171.124 for additional information. Where experiments involve genetically altered animals, examples of the breeding strategies may be included in the justification of resources section to support total number of animals requested.
Applicants contemplating the use of animals purchased from commercial suppliers should, wherever possible, use UK suppliers, to minimise the risk of suffering during transport. For cats, dogs and primates, Home Office-approved suppliers must be used.
If applicants are contracting out animal research or proposing to undertake any animal experiments as part of collaborative programmes outside the UK, please see section 4.5.
Applicants planning research using rhesus macaques should obtain animals from the MRC Centre for Macaques, who will advise on costs.
4.4.5 Proposal attachment ‘Justification of resources'
A detailed justification of the costs incurred should be given in the justification of resources attachment (see section 2.2 for further information). This should detail the animal costs requested, and may outline breeding programmes if appropriate to support the number of animals required. No experimental or statistical details should be included in this section; these details must be included in the ‘Animal species’ section of the Je-S form and case for support.
4.4.6 Use of animals overseas
From 1 September 2017, if your project involves the use of animals overseas you must submit a signed statement (uploaded as a Letter of Support to the Je-S application) from both UK and overseas PIs that:
- they will adhere to all relevant national and local regulatory systems in the UK and overseas
- they will follow the guidelines laid out in the NC3Rs ‘Responsibility in the use of animals in bioscience research’ document (www.nc3rs.org.uk/responsibility-use-animals-bioscience-research) and ensure that work is carried out to UK standards
- before initiation of the proposed research work, appropriate approvals from Institutional and/or central animal ethics committees will be obtained for experimental protocols to be adopted in their projects. Successful proposals may be expected to provide copies of these permissions before funding is released.
- Details on where the animal research will take place (UK or overseas) and through which funder the resources are being sought.
If the research involves the use of rodents overseas, rather than in the UK, please also complete the ‘Additional questions on the use of rodents overseas’ (DOCX, 117KB) form, and attach as a letter of support in Je-S.
Applicants must ensure that best practice in relation to animal husbandry and welfare is followed. Where the work proposed is not covered by an existing project licence under ASPA, applicants should put their proposals to the local Animal Welfare and Ethical Review Body for review prior to submission and ensure that ethical and welfare issues raised are addressed. Applicants should be aware that the NC3Rs will be involved in the review of any MRC applications proposing to use non-human primates, cats, dogs or equines, providing advice specifically on the 3Rs and animal welfare.
If applicants are contracting out animal research or proposing to undertake any animal experiments as part of collaborative programmes outside the UK, these experiments must be conducted in a way that conforms to the legal and ethical practices in that country, as well as conforming to the standards (including animal welfare) required in the UK. Where standards are different, the more rigorous guidelines will apply. Such applicants are strongly advised to view the ‘Choosing contractors for animal research: expectations of the major UK public funders’ presentation produced by the NC3Rs, which sets out the requirements of the MRC, and other major funding bodies, with regard to standards of animal welfare and study design, including for preclinical studies at contract research organisations. The presentation can be found on the NC3Rs website.
From 1 September 2017, if the research involves the use of rodents overseas, rather than in the UK, please also complete the “Additional questions on the use of rodents overseas“ (DOCX, 117KB) form, and attach as a letter of support in Je-S.
It is the responsibility of all applicants to ensure that the appropriate Home Office licences are obtained. This will include the requirement that the research proposals are approved by the local ethical review process.
Home Office licences (or amendments to existing licences) do not have to be obtained before the application is submitted to the MRC, but if a grant is awarded, researchers must have the necessary licences in place before any animal experimentation begins.
The MRC encourages the archiving and sharing of genetically altered mouse strains as a means of both reducing and refining animal use3. The MRC supports a central repository of mouse strains, the MRC Mouse Frozen Embryo and Sperm Archive (FESA) at MRC Harwell. FESA aims to ensure that valuable mouse strains are safeguarded, that the need to maintain colonies of live mice for long periods of time is reduced, and that the significant investment in engineering strains is capitalised upon fully.
Where there may be a need for the repeated creation of pre-existing genetically modified mouse strains, this must be fully justified. Applicants planning to produce genetically modified mouse strain(s) should investigate whether suitable strains are available via FESA or elsewhere before requesting resources for creating new strains.
Applicants planning on creating new genetically altered mouse strains as part of their work should actively consider archiving and sharing these strains via FESA. When archiving and sharing of genetically modified mice is not possible please clearly state in your application the reasons for this.
Where a proposal involves multiple experiments (for example a pilot study, tissue supply or treatment comparison) the level of detail shown below should be included for each type of experiment.
|Information||Details||Location and guidance section|
|Procedure severity||Confirmation of the use of animals (this should be ticked as yes even if the animal costs are not requested as part of the proposal) and details of any procedures categorised as moderate or severe in accordance with the maximum prospective severity rating in the Home Office licence under which the work will be carried out.||Animal research section of the Je-S form (section 4.4.1)|
|The need to use animals and the choice of species||
A sound scientific reason for the use of animals and an explanation why there are no realistic non-animal alternatives. An explanation of how the choice of species complies with ASPA.
Relevant information about the animals to be used (eg species, strain, sex, developmental stage, weight)
|Animals species section of the Je-S form under 'Supporting Information' for each species (sections 4.1 and 4.4.2)|
|Experimental approach||The number of experimental and control groups, the total number of animals used in each experiment and the number of animals in each experimental group, and the number of times each animal will be measured; the number of independent replications of each experiment indicated; any steps taken to minimise the effects of bias when allocating animals to treatment (eg randomisation procedure) and when assessing results (eg blinding)||Reproducibility and statistical design annex (Sections 126.96.36.199 and 4.4.3)|
|Sample size||An explanation of how the number of animals was arrived at, including power calculations if appropriate or other supporting information to demonstrate that the findings will be robust. Details of any statistical advice sought/available.||Reproducibility and statistical design annex (Sections 188.8.131.52 and 4.4.3)|
|Planned statistical analyses||An overview of the planned statistical analyses in relation to the choice of sample size, along with details of any statistical advice available.||Reproducibility and statistical design annex (Sections 184.108.40.206 and 4.4.3)|
|Objectives and experimental outcomes||The primary and any secondary objectives of the study, or specific hypotheses being tested. The primary and secondary experimental outcomes to be assessed (eg cell death, molecular markers, behavioural changes)||Reproducibility and statistical design annex (Sections 220.127.116.11 and 4.4.3)|
|Justification of the choice of species/model||An explanation of how and why the animal species and model being used can address the scientific objectives and the relevance to human biology. Relevant information about the animals to be used (eg species, strain, sex, developmental stage, weight)||Reproducibility and statistical design annex (Sections 18.104.22.168 and 4.4.3)|
|Justification of the experimental design and statistical framework||A scientific justification of why the numbers of animals to be used, the experimental design chosen, and planned statistical analyses are appropriate to enable the objectives of the study to be met.||Reproducibility and statistical design annex (Sections 22.214.171.124 and 4.4.3)|
|Funding requested||The total number of animals requested and the associated purchase and upkeep costs listed.|
|Explanation of funding requested||Overview of how the figure for funding requested was reached. No experimental or statistical details should be included in this section, however a breeding plan may be included to demonstrate how the total number of animals requested was determined.||Animal costs section of the Je-S form (sections 3.1.2 and 4.4.4) and Justification of Resources attachment (Section 4.4.5 and 2.2.4)|