The scope of toxicity testing in the UK
According to Home Office figures for 2003, at least 16 per cent (or 448,000) of all procedures (i.e. experiments) were for toxicological purposes, and it was claimed that five out of every six of these were performed to conform to legal or regulatory requirements (2).
This figure may well be an underestimation. The complete picture is difficult to assess because of the unhelpful way in which the Home Office categorises different classes of experiment. Testing the safety of new pharmaceuticals accounted for 63% of all toxicity tests on animals in the UK during 2003 - or 280,585 animals.
Marmoset, tamarin monkey
Of the above total, not only were mice the most commonly used animals, but it was also they who bore the brunt of the acute lethal toxicity tests. Here, the animals experience a rapid onset of toxicity and a short, but severe, course of symptoms, leading to death. Painkillers are not used as they could interfere with the results. These experiments were used for safety, efficacy and quality control, mainly by the pharmaceutical industry. Rats were generally used in longer-term exposures, for example, reproductive system studies involving pharmaceutical products. Fish were largely used to study the effects of pollution, while rabbits were employed as living test tubes to detect product impurities for the pharmaceutical industry. Guinea pigs as well as mice were used to test products used in agriculture and industry that could cause skin irritation. Fowl were preferred for the safety testing of agricultural and pharmaceutical products.