Publications on the 3Rs (Replacement, Refinement and Reduction)

Cefas conducts applied research using aquatic animals (e.g. fish, bivalve molluscs, crustacea) which aims to: protect wild populations, biodiversity and the environment; and reduce disease and improve welfare in cultured stocks.

Cefas has a strong culture of care, supported by Animal Welfare and Ethical Review Bodies which ensure all animal use is justified. Researchers minimise numbers used via robust experimental designs, and minimise suffering by implementing humane end-points and frequent monitoring. Cefas researchers are active in the implementation and promotion of the 3Rs (Replacement, Refinement & Reduction) of animal use in research. For example, we have recently refined techniques used to attach tags to European bass and spurdog and published papers on:

Paper	Year	Journal	Summary
Opercular shortening in laboratory reared Atlantic salmon	2022	Animal Welfare	Opercular deformity is a common morphological abnormality of laboratory and other cultured fishes, observed in a wide variety of species but with an unclear aetiology. Following observations of short opercula in stocks of Atlantic salmon ( Salmo salar ) reared in our laboratory, we developed a photographic key to score individual fish on a scale of 1 to 5. Among the many potential causal factors, nipping is suggested as the primary cause of short opercula within our culture system, with asymmetry due to the clockwise current. We also present evidence that short opercula are associated with gill damage which supports this deformity being a welfare issue that merits assessment.
The housing, care, and use of a laboratory three-spined stickleback colony - ScienceDirect	2022	Laboratory Fish in Biomedical Research	The three-spined stickleback (Gasterosteous aculeatus) is a common laboratory fish used across many scientific disciplines. However, little guidance is available on its housing and care in the scientific literature. Here we outline the methods to maintain a colony of sticklebacks based upon >20 years of experience at the Cefas Weymouth Laboratory.
Dying for change: A roadmap to refine the fish acute toxicity test after 40 years of applying a lethal endpoint	2021	Ecotoxicology and Environmental Safety	Cefas led this publication, following a Defra-funded workshop, in which a clear roadmap on how to refine the most commonly used regulatory test guideline is presented. Two key opportunities were identified and discussed, namely the application of early humane endpoints in lieu of death and the shortening of the duration of the test to 48hours (instead of 96hours).
Clarification of early end-points for refinement of animal experiments, with specific reference to fish	2021	Laboratory Animals	Ambiguity is hampering the adoption of end-points to refine laboratory animal experiments. We differentiate endpoint (single word, response variable to the treatment) from end-point (hyphenated, time-point when exposure to the treatment and suffering ends), and propose seven distinct types of early end-point.
The application of continuous-time Markov chain models in the analysis of choice flume experiments	2021	Journal of the Royal Statistical Society: Series C (Applied Statistics)	This paper develops an advanced statistical method for choice experiments. It models how the number of fish moving from one chamber to another changes over time in the presence or absence of a chemical signal. This allows effective use of the data, refining the amount and quality of information available from this type of experiment.
Skin swabbing is a refined technique to collect DNA from model fish species	2020	Scientific Reports	The aim of the study was to investigate the potential stress-related effects following skin swabbing in comparison to fin clipping, in two model fish species, stickleback and zebrafish. For this purpose, changes in gene expression, behaviour and physiology such as cortisol levels were analysed. In terms of welfare, skin swabbing proved to be a refined technique.
Key Opportunities to Replace, Reduce, and Refine Regulatory Fish Acute Toxicity Tests	2020	Environmental Toxicology and Chemistry
In-tank underwater cameras can refine monitoring of laboratory fish	2019	Animal Welfare	Using case studies, we illustrate how camera monitoring can aid detection of abnormalities in fish behaviour and appearance, enabling earlier interventions. Additionally, recordings provide a resource for reference and retrospective analysis, and evidence to support severity classification and identify humane end-points.
Application of Passive Sampling to Characterise the Fish Exometabolome	2017	Metabolites	The overall project was to gain an insight into the biochemical trail left by fish experiencing different feelings, using cutting edge technology (NMR metabolomics). To capture these endogenous metabolites, Chemcatcher® passive samplers were trialed and proved to be efficient.
Prozac affects stickleback nest quality without altering androgen, spiggin or aggression levels during a 21-day breeding test	2015	Aquatic Toxicology	The main objective was to investigate the effects of Prozac on the breeding stickleback but we also reported a non-invasive method to collect DNA material. Instead of cutting the spines/fins, potentially harming the fish, the fish body sides were swabbed using cotton buds to collect mucus and epithelial cells.