This website provides information to assist research workers develop their skills in the administration of substances to laboratory animals. Initially we have provided material dealing with rats and mice, since they are the animals most widely used in research.
This site focuses particularly on the manual skills needed to carry out the different procedures humanely and efficiently, and on the need to handle animals carefully to reduce any distress caused by the procedure.
Administering substances to animals, for whatever reason, can have a significant impact on their welfare. If carried out incorrectly, not only can animal welfare be compromised, but the scientific goals of the study can be affected. If the administration is for a therapeutic purpose, then incorrect administration can lead to a failure of the treatment.
The selection of a particular route of administration must balance a number of factors – for example the volume and physicochemical properties of the substance, the required speed of onset, and other factors such as the degree of tissue irritation that could be caused. These topics are discussed in more detail in a number of different guidelines.
If a study requires repeated injection of substances the use of Osmotic minipumps may represent a significant refinement.
If you have not carried out an injection procedure before, you should first ensure you are familiar with the relevant anatomy of the species (by examining an animal euthanased for another purpose), and also develop basic skills in handling a hypodermic syringe correctly. A separate tutorial will be available soon to demonstrate correct use of a syringe. It is usually helpful to first practice injection on an inanimate object (e.g. an orange or a specially designed simulator). Before carrying out an injection technique yourself, you should observe and assist more experienced colleagues, then practice the technique on a dead animal (euthanased for another purpose). Only then should you carry out the procedure on a live animal.
Administration of some substances could result in adverse affects on the animal so it is important you know how to recognise these. Further guidance can be found at www.ahwla.org.uk and www.nc3rs.org.uk.
Remember that in the UK both your personal licence, and the relevant project licence, must authorise the procedure you are carrying out, and that it is not permissible to practice procedures on living animals.
All of the animals filmed or photographed were required to undergo the particular procedure as a necessary part of various research projects being undertaken in the UK.
Handling and restraint of the animal
Almost all laboratory animals can be restrained safely and humanely provided they are handled correctly. All animals benefit from being first accustomed to being handled, and this can be done during the period of acclimatization needed before they are used on a research procedure.
It has been shown that picking up mice by the tail induces aversion and high levels of anxiety. (Hurst & West 2010*) Using tunnels or cupping the mice in open hands leads to more rapid acceptance of physical restraint. Habituation to this type of initial restraint persists even when mice are subsequently restrained more securely, for example by the scruff to allow injections to be carried out.
If injections are to be repeated on a regular basis, then familiarization with restraint assumes even greater importance, and training of the animal to co-operate with the procedure may also be helpful.
Restraint will be stressful, even in animals that have become accustomed to handling, so the duration of restraint should be minimized.
If you are relatively inexperienced in the technique that you plan to use, you should ensure you have an experienced assistant who can restrain the animal safely and humanely, and assist and supervise the procedure.
When carrying out procedures, make sure you are wearing appropriate protective clothing, both to protect yourself from hazards such as allergens, and to protect the animal from inadvertent transfer of potential infectious agents.