The testing of new pharmaceutical compounds on animals will always be an emotive subject. The use of animals is generally accepted as an unpalatable but necessary stage in drug development, but the level of acceptance varies widely according to the species: companion animals such as dogs, and primates that are closely related to man understandably evoke a more powerful negative emotional response than rodents.
But where on the scale will the minipig sit, if the recommendations put forward in the RETHINK report are adopted?
The report makes a good case for using minipigs in pharma testing, not least because they closely resemble man in many features of their anatomy, physiology and biochemistry. In particular, the cardiovascular system, skin and digestive tract are considered to be very good models for man.
They also present fewer welfare issues as they are largely sedentary, not active like dogs nor arboreal like primates, while their compact size makes them easy to look after and to handle in a laboratory environment.
But the report rejected any suggestion that minipigs would suffer less harm than other non-rodent species, and found their use as a replacement for dogs and primates on these grounds alone was not ethically justifiable, even though as food animals their use in testing may cause less offence to the general public.
But in the UK, at least, the minipig is finding a place as a pet in some households. It may just be a passing fad, but there is no denying that minipigs are intelligent, playful and companionable, with a high ‘cuteness’ factor.
Leaving emotion aside, there are a couple of other benefits from using minipigs for testing. First, they are no more expensive to use than dogs, and by inference considerably less costly than primates. And second, unlike the dog, the pig is well positioned to take advantage of genomics and gene manipulation technologies. The minipig is the only non-rodent toxicology model where transgenic animals can be readily generated.
Further research is needed but if the initial promise is realised, the result could be a reduction not only in the number of primates and dogs used, but also in the total number of animals sacrificed.