Pigs in Research
Pigs are highly intelligent and social animals that have been used in research for centuries. The most recent report on pigs used in research in the U.S. revealed that 50,777 pigs were used in research protocols in 2019.
Pigs are used in a wide variety of research areas, including agricultural and biomedical studies. They are used as general surgical models, in dermatological studies involving wound healing and plastic surgery procedures, in toxicology and pharmacology studies, and in transplantation studies, among other areas of research.
Research that would enable the transplantation of pig organs into humans is seen by some in the research community as a solution to the shortage of organs available for transplantation. Pigs are preferred for this research for a number of reasons, including the size of their organs and the fact that genetic modification of this species has been done for years. Despite the fact that many serious scientific challenges stand in the way of transplantation of pig organs into humans as a solution to the organ shortage problem, research on editing the pig genome to overcome some of these hurdles is ongoing.
Miniature pigs were developed in the 1950s and have been selectively bred for their small size and docile nature. They have been used as a non-rodent species in toxicity testing since that time. Their smaller size is considered an advantage to researchers for housing and handling purposes and for chemical and drug testing, as body weight affects dosing and test compounds may not be available in large amounts.
According to the U.S. Department of Health and Human Services Office of Research Integrity, the popularity of pigs used in research is due, in part, to the idea that “most people lack the emotional attachment to swine” and as they are “devalued by society, their use as tools of science is generally more acceptable by the public.” This belief is held, in part, because the pig is viewed as a food animal. As a result of this sentiment, efforts to implement the 3Rs—reduction, refinement and replacement—of animal use may negatively impact pigs. The number of pigs used in research may increase as they are viewed as an alternative to other non-rodent animals, including dogs, which the public identifies as companion animals, and nonhuman primates, who may be given greater consideration because they are more closely related to humans.