Ethics of Research involving animals
Basic research (Chapter 5)
10.2 Basic or curiosity-driven research encompasses a wide range of behavioural, physiological, developmental and genetic studies. In Chapter 5 we described a number of experiments to show that animal research in this area extends from mostly observational to highly invasive experiments. Some research, such as the study of birdsong, is undertaken primarily to increase our knowledge of the animal kingdom (see paragraphs 5.2-5.3). Other areas of basic research seek to improve understanding about fundamental biological processes. Some of this knowledge may eventually lead to applications from which humans benefit directly.
Observational research
10.3 Observational research on animals in their natural habitat is undertaken for purposes of conservation and in order to understand, for example, patterns of social interactions between animals. If conducted with care, it may not result in obvious adverse effects to the animals. The effects of behavioural studies undertaken in laboratory environments depend on contingent factors, such as transport, breeding, the standards of handling and husbandry and conditions of housing (see paragraphs 4.36-4.48 and 12.21) as well as on those that are determined by the experiment itself. We included the common example of mazes used to investigate aspects of rodent learning and memory (see paragraph 5.4). The actual experimental setting of these behavioural studies would normally be expected to cause the animals only relatively minor distress or suffering, if any. However, some behavioural studies include manipulations of the environment that make certain tasks more difficult or unpleasant for the animals. The welfare implications of such procedures depend on the degree to which the challenges are experienced as stressful by the animal.
Physiological studies
10.4 Physiological studies involve surgical, dietary or drug treatments that are directed at understanding function at the physiological, cellular or molecular levels. These types of experiments have been undertaken in a wide range of research projects that contributed to current knowledge about human and animal biology, and medicine. Most of our knowledge about the endocrine (hormonal) system, the immune system and the nervous system (paragraphs 5.5-5.11) is based on research involving animals. Studies of the responses underlying graft rejection in immunodeficient rodents eventually facilitated the development of organ transplantation in humans (see paragraph 5.8). Research on immunodeficient rodents is now contributing to the understanding of the complex processes of diseases that affect the immune system, such as HIV/AIDS and other diseases (paragraph 5.9). With regard to welfare implications malaise is a common feature of infection in humans and animals, which both show slowed locomotion, poor appetite and abnormal body temperature. Sub-clinical infections may become clinical in immunocompromised animals.
Neurobiology
10.5 Animal studies have also contributed to our knowledge of the human nervous system (see paragraph 5.11). Primates have been used in research aimed at understanding how complex brains work, as their neurological development and higher cognitive functions are very similar to humans. Members of the Working Party observed research being undertaken on macaque monkeys which sought to investigate how activity in groups of brain cells in the motor cortex controlled specific hand and finger movements. The purpose of this research was to increase understanding of how stroke can impair use of the human hand. Similar research has led to the development of treatment to reduce the symptoms of Parkinson’s disease (see Box 5.4). With regard to welfare implications arising from the experimental procedure itself, the introduction of very fine microelectrodes into the brain is not painful for the animal, because the brain itself has no pain receptors.
Animal development
10.6 The study of animal development has contributed to our knowledge of basic processess in human embryonic development. Chick, zebrafish, rodent and frog embryos are often used to gain a better understanding of the roles of single genes or groups of genes in developmental processes (paragraph 5.12). GM mammalian embryos have also been created for this purpose (paragraph 5.13). Research on juvenile and adult animals has also been important, especially in mammals, where major development occurs after birth (paragraph 5.15).
Genetic research
10.7 Genetic studies constitute a significant part of animal research and are likely to increase dramatically in future, with experts in the field estimating that over the next two decades 300,000 new transgenic mouse lines could be created (paragraph 5.22). Spontaneous mutants, deliberate random mutations and targeted mutations have all provided useful information on gene function (paragraphs 5.16-5.22). Large programmes of mutagenesis in mice have been initiated, which aim to characterise the functions of both individual and combinations of mouse genes (see paragraph 7.5). With regard to the welfare of animals used in such research, the defects that may result from a genetic manipulation cannot usually be predicted in advance. In many cases gene knock-outs produce no obvious abnormality, although in others, they may lead to serious effects. Studies vary considerably in design and conduct and the likelihood of negative welfare effects including minor or severe discomfort and increases in mortality and susceptibility to disease varies accordingly (paragraph 4.57). Methods of producing GM animals also have the potential to be painful and distressing. In mice, this usually involves hormone injections, surgical embryo transfer (which may be undertaken without pain relief) or surgery to produce vasectomised males, tail biopsy or ear notching. Where possible, the use of pain relieving medicines can help to reduce the effects for the animals (see paragraphs 4.12 and 4.58). The methods used to produce GM animals are relatively inefficient (3-5%), and substantial numbers of animals do not have the desired genetic traits and are usually euthanised (see Box 5.6).
Animal cloning
10.8 The process of cloning animals, which aims to create genetically near-identical offspring (paragraph 5.26), has a range of potential uses. These include medical applications such as facilitating the provision of organs for xenotransplantation, or pharming (paragraph 5.31). In principle, the technology can also be used for other purposes, for example to produce ‘copies’ of farm or sport animals with desirable traits, or to replace deceased pets. The technology is still very inefficient and there is a high probability of malformations. The longterm implications for welfare are not yet known for most animals (see paragraphs 3.41–3.43).
Production of research tools
10.9 Animals are widely used for the production of antibodies, which can be employed to identify, localise, quantify or purify a substance. To produce antibodies against an antigen of interest, an animal is repeatedly immunised with the antigen together with an immunostimulant (an adjuvant), and the antibodies are then harvested from the blood. The use of adjuvants in animals (which are not always required) can lead to the development of sterile abscesses or lameness after intramuscular injections into the leg. Immunisation can sometimes cause anaphylaxis which can be lethal. The use of mice, primed with an irritant, to produce large amounts of a monoclonal antibody in ascitic fluid in the peritoneal cavity is now rarely used in the UK; it has been replaced by an in vitro method.