IV.

Animals Used

Worldwide, rodents are used mainly in biomedical research; the use of other mammals, birds, reptiles, amphibians, and fish is small in comparison. The species selected for use in an experiment is dependent on the investigation and the amount of harm the animal may experience. The recognition of adverse effects in different species is subjective. Observations on animal behaviour linked to brain development studies have been used as a form of assessing harm experienced by animals, but exceptions do arise, for example, in the octopus, which is an invertebrate that has been shown to respond to adverse stimuli.

The 1986 European Community Directive states that specific animals should be purpose-bred (specific countries have chosen to be exempt) as they will have a controlled genetic makeup, a known record of disease, and they will be adapted to human contact and the animal husbandry systems. The EC Directive also protects the use of wild-caught animals for animal experimentation because of the adverse effects of entrapment, quarantine, and adaptation to captivity. A conservation status for wild animals exists to prevent population reduction and species extinction.

Purpose-bred strains are the products of many generations of controlled selective breeding; specific strains possess distinctive characteristics, such as animals with nonhereditary abnormalities or pathologies, which makes them useful as models in certain areas of biomedical research. Transgenic animals are bred for a specific use and have an altered genetic makeup that is produced by directly transferring genetic material (DNA) from one animal to another. Transgenic technology can rapidly alter certain desired characteristics in one generation, for example, the “oncomouse”, developed by Harvard University, has been bred to contain human cancer genes and develop tumours after birth. Transgenesis raises several ethical issues, such as gene transfer between species, genetic manipulation of eggs and sperm, and the environmental risk of releasing animals carrying manipulated genetic material.

The use of stray cats and dogs in research is forbidden in most of Europe. In some countries, however, there are so many stray animals that their use in research has been advocated. It has been suggested that stray animals would suffer more than purpose-bred animals, while public opinion has focused on the possibility that lost pets may end up in laboratories.

Since 1976, the number of animals used for biomedical research has been in decline—a trend accelerated by the 1986 Act. This fall may reflect the rise in interest of molecular biology and the use of more in vitro methods and computer models. The increased costs of maintaining animals, the rise in public interest in vivisection issues, and the powerful lobbies against some forms of animal use, such as cosmetics testing, may also have influenced the decline.