Animal experimentation is the use of non-human animal in scientific research. Around 100 million vertebrate animals worldwide — from zebra-fish to non-human primates — are used annually in scientific experiments. Although much larger number of invertebrates are used and the use of flies and worms as model organism is very important, experiments on invertebrates are largely unregulated and not included in statistics. The earliest reference to animal testing is found in the writings of the Greeks in the second and fourth centuries BC. Aristotle and Erasistratus were among the first to perform experiments on living animals. Galen, a physician in second century Rome, dissected pigs and goats and is known as the ‘father of vivisection’.

Toxicology testing became important in the 20th century. In the 19th century, laws regulating drugs were more relaxed. However, a tragedy in 1937, where a drug labeled ‘Elixir of sulfanilamide’ killed more than 100 people, prompted the US government to pass laws that required safety testing on animals before they could be marketed. In 1960s, in reaction to the Thalidomide tragedy, further laws were passed requiring safety testing on pregnant animals before a drug can be sold. Due to the passing of the laws requiring animal experimentation of drugs before they are marketed, there was indiscriminate use of animals for drug experiments. This wanton destruction of animal life, coupled with the growing concern for animal welfare, gave rise to the controversy of animal testing.

As early as 1822, the first animal protection law was enacted in the British parliament, followed by the Cruelty to Animal Act (1876), the first law specifically aimed at regulating animal testing. The legislation was promoted by Charles Darwin, who wrote: “You ask about my opinion on vivisection. I quite agree that it is justifiable for real investigations on physiology; but not for mere damnable and detestable curiosity. It is a subject which makes me sick with horror, so I will not say another word about it, else I shall not sleep tonight.”

Although attitude towards animal life vary from country to country, from culture to culture, from religion to religion, there exists a single principle when animals must be used for scientific purposes; the need to use them responsibly and ethically. ‘Research’, in reality, involves three facets: acquisition of new knowledge, use of animals in teaching exercises, and testing of compounds, chemicals or devices for safety and effectiveness. There must be the reasonable expectation that research involving animals will contribute significantly to present or future knowledge, which may eventually lead to the protection and improvement of the health and welfare of either human or animals.

Animals should be used only if the scientist’s best effort to find a replacement technique has failed. A basic tenet of any scientific study using animals should be the adherence to the Russel-Burch ‘3Rs’ tenet of replacement, reduction and refinement. Experimental animals must be managed and cared for with necessary facilities for animal holding, provide them comfort and safety in cage. Animal’s social and behavioural needs must be addressed, while avoiding unnecessary pain, stress, and anxiety to them. The ‘animal research team’ commonly includes the animal caretaker, the animal health technician, the research technician, and the investigator, all of whom have received training and developed an understanding of the basic principle of laboratory animal science.

Good laboratory practices for animal facilities are intended to assure quality maintenance and safety of animals used in laboratory studies while conducting biomedical and behavioural research and testing of products. Individual countries must ensure that there is no unnecessary animal use, pain or distress. Legislation must be made to incorporate animal care guidelines. Legislation involves inspectorate which should be staffed with experienced individuals having knowledge of all facets of the use of animals in research, the requirements of physical plants, training of personnel, as well as biological and behavioural needs of the experimental animals. If a country does not have such programme, it is the responsibility of the institute itself to develop a method by which it may ensure that animals are used responsibly and only as required. The WHO/ICCAS guideline for breeding and care of laboratory animals provides valuable source of information.

Animals free of clinically recognizable or latent disease and of appropriate genetic stock or strain should be chosen. They may be obtained from an in-house production system from commercial companies or possibly farmer and other hobbyist having an interest in breeding and raising animals. Animals delivered to animal facility for specific research projects must meet the requirement of the investigation for which they are intended. This often includes socialization. Socialized animals react in a non-aggressive manner, acceptable fashion when handled by the animal care technician, the research technician or the investigator.

Scientist and research technician must be well versed with the choice of appropriate models, in the requirement of good experimental design, and basic understanding of the nutritional needs and biological characteristics of the species to be used. They should possess adequate knowledge of any invasive technique that may be required. It is mandatory that pain should be minimized. The working objective and ethical requirement for use of animals in research dictates the need to use the best method, on the smallest number of appropriate animal required, in order to obtain valid scientific information. Proposed experiment must be justified in terms of the declared objectives. The experimental design must offer very practicable safeguard to the animal. Animal lives should not be wasted because of inadequate knowledge of the requirement of the species being used, incorrect management or handling technique, inappropriate or incorrect experimental design, or a lack of surgical techniques and experience. It must be remembered that animal can and do suffer if knowledge, practices and proper procedures are lacking.

Certain experimental procedures that produce excessive pain are not acceptable e.g. utilization of neuromuscular blockers, like curare, without anesthetics and crushing, burning, striking or beating an unanaesthetized animal. Studies such as toxicological and biological testing, cancer research and infectious disease investigation require ongoing examination so that, when there are distinct clinical signs that such processes are causing irreversible pain or distress, an acceptable endpoint should be sought which would satisfy both the experiment of study and provide humane treatment. Experiment involving withholding of feed or water should entail very short-term deprivation and have no detrimental effect on the health of the animal.

Physical restrain without the use of anaesthetics, analgesics or tranquilizer should only be used after alternative procedures have been fully considered and found inadequate.

Alternative to animal experimentation or in vitro models involve the incubation of biologically derived material in artificial, physical and chemical environments. The term in vitro is equally applicable to enzyme preparations, to isolated organelles, to intact microorganisms and to excised parts of animals and plants. In vitro model has its own limitation. A general criticism of in vitro experimentation is that it is the study of artifacts and extrapolation to situation in vivo may be unjustified.

The establishment of animal research ethics boards or institutional animal care and use committee is very much essential at local level. The objective of these local committees is to ensure that in its own institutional animal facilities are adequate, personnel are trained properly and experiments are conscientiously designed and conducted with adherence to ethical concern. The animal care committee should include scientific personnel experienced in care and use of experimental animals, veterinarians experienced in research and laboratory animal medicine, a representative from departments or faculties where animals are not used in research, e.g. philosophy, religious study, history etc, and a member from the community interested in the welfare of animal.

At the present context, animals are indispensable in testing the potency and safety of biological substances used both in veterinary and human medicine, and in determining the toxicity of the rapidly-growing number of previously non-existent synthetic substances and chemicals which may represent a health hazard. Although man and animals are known beneficiaries of research, it is the animal on experimental table which experience the pain and the result of procedures, and does not know when pain might end or be relieved. If meaningful scientific results are to be obtained through the use of animals in research, teaching and testing, the scientific community, in every country, must ensure humane and ethical treatment of animals is achievable and worthy of consideration before the use of animals is permitted.

Pritom Mohan