EDUARDO CESARAt 8 months they weigh 16 kilos, whilst the conventional pig weighs 70 kilos after 4 monthsEDUARDO CESAR
At 8 months of age, the mini pigs are approximately 47 centimeters in height, 88 centimeters in length and weigh 16 kilos, whilst a member of the same species reared in piggeries for slaughter already weighs 70 kilos after 4 months of life. This size difference was conquered almost two years ago by the São Paulo company Minipig Pesquisa e Desenvolvimento [Minipig Research and Development]. It has gone on to produce the first Brazilian pig, with the name of Minipig Br1, which is especially selected to have dimensions suitable for use in scientific experiments in research institutions.
Due to physiological, morphological and biochemical similarities between the pig and the human being, the use of pigs in scientific research, for medicine testing for example, is nothing new. In the study by the Belgian doctor Andreas Versalius, De humani corporis fabrica, of 1540, an illustration of the pig being used in experimentation is already present, a practice also carried out around one thousand years previously by the Greek doctor Galeano. Closer to man that some primates, they have digestive tract, lungs and eyes very similar to those of humans. The heart also has morphological characteristics identical to man, as well as its skin. Indeed, the pig is the only animal that, outside of man, has pink skin after having been exposed to intense sunlight. Nevertheless, the use of the pig in scientific research is just as difficult as manipulating the animal within the piggery, where when it reaches one year of age it weighs 250 kilos.
Thus some experiments become unviable. The first attempt to produce smaller pigs by way of selection and crossbreeding took place in 1949, at the Homel Institute of the University of Minnesota, in the United States. Since then, various lineages of minipigs have been developed, among them the Minnesota, the Yucatan, coming from the south of Mexico, the Kangaroo Island, from south Australia, the Goettingen from Denmark and the other American lineage named Sinclair. Between 1960 and 2004 nothing less than 3,640 scientific studies were published using minipigs as the experimental model within the United States, Europe and Asia.
Family society
During the decade of the 1960’s, by way of the magazine Scientific American, the medical veterinarian Mário Mariano, then a professor at the Pathology Department of the Veterinary Medicine and Zootechnology School of the University of São Paulo (USP), got to know about the work of the Minnesota researchers, who had reduced the size of the pig for use as an experimental model. He tells that his interest in carrying out a similar experience in Brazil started there, but, after some frustrating attempts to carry out a project in the academic world, the idea went cold. It was only in 1999, when he brought together his scientific experience and brother José Roberto Mariano knowledge in company administration and project development, and with the collaboration of the employee Maria Benedita de Albuquerque Pereira, responsible for the maintenance and progression of crossbreeding, is it that he managed to bring the idea of the minipig to fruition. Then he began the selection of pigs of small stature for procreation on his property located in the municipality of Campina do Monte Alegre, in the western region of the State of São Paulo. Before opening the company, the brothers carried out market research to verify the economic viability of the project.
“It was a huge uphill battle, an experience of trial and error until we reached the stabilization of the adequate size of the animals”, recalls Mário, currently a professor affiliated to the Microbiology, Immunology and Parasitology Department of the Federal University of São Paulo (UNIFESP). After five years of trying to obtain positive results, he thought about giving up. This was when he managed to produce an animal on his farm that when 9 months of age was only approximately 50 centimeters in height. Four years later, the brothers had produced the minipig Br1 ready for commercialization. The current price of each animal is R$ 800.00, freight exempt. In the United States similar animals cost between US$ 900.00 to US$ 1,200.00.
The Brazilian minipig has measurements comparable with those developed in the mini piggeries of other countries. At 11 months of age the male animals reach their maximum weight of 35 kilos and the females some 30 kilos. Since the minipig has been produced in Brazil some two years ago, 110 animals have been used for scientific research and 144 are already sold to laboratories. One of the first experiments using the minipig in Brazil was carried out at the Dental School at USP’s unit in the town of Bauru, which resulted in publications in international magazines and a master’s thesis. These animals were also used in various master’s and doctoral studies at UNIFESP. Just the Digestive Endoscopy group of that university has carried out four studies in their area using the minipigs. All of them were supervised by professor Angelo Paulo Ferrari Júnior. One was the theme of a master’s degree study from Rodrigo Azevedo, with the title, Experimental model of manometry and the effect of midazolam and propofol on the sphincter of Oddi of the Minipig Br1. “The practicality of the small animal and the similarity with the anatomy of the digestive tract of the human being are major advantages when using this model in experimental studies”, says Azevedo.
Researchers from other centers, such as the Heart Institute (InCor) of the Hospital das Clinicas, of USP’s Medical Faculty, the Advanced Sciences in Otolaryngology Institute (Icao) and USP’s Veterinary Faculty have already acquired or solicited the acquisition of animals.
Small mothers
During the selection that resulted in the minipig, the Mariano brothers selected the mothers with characteristics of being ‘good mothers’, small and with low body fat index. All of the mothers and reproducers did not reach 40 kilos. Professor Mário emphasized that the rearing of these animals does not follow the industrial production techniques for pigs, which is accustomed to maintaining them in cages, but followed the criteria of the animal’s well being set by the World Health Organization (WHO). The mothers are kept in bays with a covering of grass and the weaned-off piglets are transferred to areas with an 80 centimeter floor covering of wood shavings that helps in the hygiene of the environment. When adult, they go into open bays with grassy pickets for pasturage.
The animals are vaccinated against six types of illness and given a vermifuge to control parasites. The feces, after treatment, are used for fertilizing the pasturage. The animal’s maintenance, transportation to the laboratories and all medical assistance in the areas of anesthesiology, X-rays, ultra-sonography and general surgery were also facilitated due to an agreement of the company with veterinary hospitals. The company produces and offers the appropriate animal feed for the pigs and even assists in the elaboration of research projects.
“It’s good to remember that we only make the pigs available for scientific projects approved by an ethics committee”, emphasizes José Roberto. The use of the pig for research is directed towards investigation areas such organ transplants, toxicology, pre-clinical tests and others. “The minipig is also an ideal model for the realization of pre-clinical tests with new medicines and to substitute dogs in experiments.”
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