The Animal Care and Facilities Committee (ACFC) has modified its position on several methods of euthanasia for rodents. These new recommendations will affect most investigators using rodents and should be studied carefully. The new recommendations are described below, along with a history and explanation of the changes.
Review of animal use protocols ("protocol review") as we know it today, has been in place at Rutgers and other NIH grantee institutions since January 1986. At that same time, the American Veterinary Medical Association revised the Report of the AVMA Panel on Euthanasia. One of the key changes in the 1986 Report was language that discouraged the use of two commonly used procedures for the euthanasia of rodents: cervical dislocation and decapitation. Since that time, the ACFC has discouraged the use of these techniques as a "routine" method of euthanasia, but allowed them when scientifically justified, in writing, in the protocol review form.
Although other methods are approved, one of the most common acceptable methods of euthanasia for rodents is CO2 asphyxiation.
Since 1986 then, the committee’s approach to this issue has been to routinely approve CO2 asphyxiation, or other methods recommended by the AVMA Panel, while discouraging cervical dislocation and decapitation, but approving them for specific projects when justified in writing.
Based on recent reports, including one co-authored by Dr. Buzsaki of Rutgers, Newark, the committee feels that decapitation may in fact be preferred and more humane as compared to CO2. The original concern about decapitation arises from a study which showed electrical activity persisting in the brain for 14 seconds after decapitation. Further analysis of these studies discounts this electrical activity as evidencing consciousness. The effectiveness of decapitation is attributed largely to the rapid loss of blood flow, and since this does not occur following cervical dislocation, one should not extrapolate findings about decapitation to cervical dislocation. Furthermore, the committee is concerned that CO2 asphyxiation may be stressful prior to unconsciousness.
The result of this interpretation, is that the ACFC will no longer discourage decapitation. Investigators are in fact encouraged to consider it as method of euthanasia. However, it’s not that simple!
The result of this interpretation, is that the ACFC will no longer discourage decapitation. |
Decapitation is an acceptable method of euthanasia for small rodents. Decapitation is not without risk to the operator and can be aesthetically unpleasant. It may be stressful for technicians who have to perform it. It should only be performed by properly trained individuals. LAS can provide training for faculty and staff.
To the extent that Rutgers’ Policy has been set by the ACFC, it is not inconsistent with PHS Policy. However, grant applicants should realize that decapitation is still generally discouraged at most institutions and still requires written justification. Its use should be explained and defended in grant applications. A suggested statement to include in the required description of the method of euthanasia would be, "The Rutgers Animal Care and Facilities Committee has determined that decapitation is an acceptable and preferred method of euthanasia for rodents."
Decapitation is not without risk to the operator and can be aesthetically unpleasant. It may be stressful for technicians who have to perform it. |
In order to comply with PHS Policy and the NIH "Guide", investigators should still include a written justification for use of decapitation in the protocol review form. The suggested statement in the previous paragraph should be included in the response to question 25 of the Rutgers protocol request form.
CO2 asphyxia is an acceptable method of euthanasia for small rodents at Rutgers. The Rutgers ACFC has determined that CO2 asphyxia may be stressful to rodents, and that other methods, including decapitation by properly trained individuals, may be preferable. CO2 is probably most appropriate when larger numbers of animals must be euthanized at one time, making decapitation time-consuming and stressful to those performing the procedure.
Cervical dislocation is an acceptable method of euthanasia for mice and rats less than 200 g. However, unless used with prior sedation, it should only be used when it has specific advantages for the research project, and such use must be justified in writing as part of the animal use protocol.
Other approved methods for rodent euthanasia are described in "Care and Use of Laboratory Animals at Rutgers" and include inhalant anesthetics (e.g. metofane used in a hood. Use of ether is discouraged.); injection of barbiturates (e.g. pentobarbital); exsanguination under anesthesia; or microwave irradiation using instruments designed for this purpose. Other methods may be approved on a case by case basis.
The following methods or agents are generally unacceptable for rodent euthanasia: Chloroform, nitrogen, hydrogen cyanide gas, carbon monoxide, T-61, chloral hydrate, strychnine, nicotine, curariform drugs, ketamine/xylazine and air embolism. Ether is flammable and explosive and its use for euthanasia is discouraged. If used, it must be used in a fume hood.
Ether is flammable and explosive and its use for euthanasia is discouraged. If used, it must be used in a fume hood. |