The score sheetScore sheet Form for recording clinical signs to determine animal well-being and if appropriate the application of a humane or scientific endpoint. can be an important tool for determining humane endpointsHumane endpoint The moment in the experiment at which pain and/or distress experienced by the investigational animal is ended or alleviated by either killing the animal humanely or by discontinuing the procedure.. It is an (electronic) form on which the clinical statusClinical status An inventory of the health status of a (diseased) animal. This inventory can give an idea of the progression of a disease over time and is therefore essential in determining a humane endpoint. Score sheets can be used to monitor and record the clinical status. of each individual experimental animal is recorded at regular, predetermined intervals. Using a scoring sheet provides insight over time into the development of the animal’s health status.
There is no standardized score sheet for zebrafish. However, increasing attention is being paid to health and welfareWelfare A complex and dynamic internal state that includes: successful biologic functioning, positive experiences, and absence of negative conditions. The animal adapts effectively to internal needs and external stimuli and maintains a good mental state. issues in zebrafish, including genetically engineered mutants.
For each scientific procedure, a separate score sheet can be designed, on which the most relevant clinical signs are recorded during the study. In the case of a new procedure, these signs may not yet be known, and a broad assessment of the animal is required. For well-known procedures, the assessment can be limited to the relevant clinical signs and any unusual findings. The scoring sheet must be logical/consistent, easy to use, and specific, but also sensitive enough to detect subtle changes in the welfare of the laboratory animal.
Analysis of the score sheet will show the pattern of recovery or deterioration of each animal’s health over time, and provides an insight into the effect of the procedure on the animal’s health. A score sheet is an essential instrument in determining humane endpoints.
Example score sheet (source: BfR)
Researchers in Germany have designed a score sheet for the assessment of the health and welfare risks of genetically altered (mutant) zebrafish and Japanese rice fish (medaka). The sheet can be downloaded on the right (see document 1). In the accompanying article, the considerations underlying the score sheet are clearly discussed (document 2). Both documents were written by the Bundesinstitut für Risikobewertung (BfR).
Assessment takes place during the larval stage (at the time when EU regulation starts to apply, which is >120 hours (hpf) or >5 days post-fertilization) and when the fish are sexually mature (between 90–120 days post-fertilization); using the clinical signs described above. In particular, the number of animals displaying the clinical signs is reported (see the final page of the document “Severity assessment of genetically altered fish”). It goes without saying that genetic alterations that lead to serious health problems must be closely monitored and intervention must be considered.
The example score sheet on the right can be used for the assessment of the degree of discomfortDiscomfort A state of pain and distress in laboratory animals. as a result of genetic alteration in zebrafish. Adult fish are observed for the presence of a variety of clinical signs (both in appearance and behaviour) and the number of animals affected is an important metric to be scored. The larva and adult fish risk profile is the basis for final assessment of the severity of sufferingSuffering A negative emotional state which derives from adverse physical, physiological and psychological circumstances, in accordance with the cognitive capacity of the species and of the individual being, and its life experience. resulting from a particular genetic alteration.
Example score sheet (source: UQ)
By scoring clinical signs and their severity in a list, a health record is created over time. The score sheet may record both the number of animals affected and the degree of severity. These data can be the basis for decisions on euthanasiaEuthanasia Killing by applying methods that rapidly lead to unconsciousness and death without pain or discomfort to the animal. Methods for euthanasia can be divided into mechanical and physical.. The score sheet of the University of Queensland in Australia serves as an example; it is used to reach a decision on when to perform euthanasia (see document 3). In this score sheet, several aspects are scored: swimming behaviour, weight, abdominal muscle toneMuscle tone The degree of tension in a muscle., distended abdomen (dropsy, swelling), preferred tank position, and gasping air at the water surface. These aspects are scored as normal or abnormal (mild, moderate or severe), after which they are totalled into a final score. Depending on its value, the final score may or may not require an intervention, and possibly euthanasia.
