How Gene-Edited Animals “Surrogate Sires” Can Boost Food Production
Mon, August 15, 2022

How Gene-Edited Animals “Surrogate Sires” Can Boost Food Production


Animal-based proteins play an important, although not absolutely necessary, part in human nutrition. This is why the global demand for meat, milk, eggs, and another animal-based product is expected to grow. However, animal and plant diseases, climate change, and environmental degradation threaten global agricultural food production. Monitoring and diversification of risk are critical for assuring food security.

Gene-edited animals

A new study conducted by Washington State University researchers shows that gene-editing animals can boost food production. For the first time, scientists have created gene-edited cattle, goats, and pigs that can produce sperm with traits, such as higher meat quality and disease resistance, in what they believe as a step towards genetically improving livestock to improve global food production.

The team shared that they used a genome editing tool called CRISPR-Cas9, which are specialized stretches of DNA. The CRISPR technology itself was adapted from the natural defense of archaea (single-celled microorganisms with the structure the same to bacteria) and bacteria. These organisms utilize Cas proteins, including Cas9, and CRISPR-derived RNA to foil attacks by foreign bodies and viruses. They do so by destroying and chopping up the DNA of a foreign invader.



Spermatogonial stem cell transplantation (SSCT)

The animals could be used as “surrogate sires” or “super dads,” carrying the genetic material of donor animals. The animals were born sterile but they started producing sperm after they were injected with sperm-producing cells from the donor animals. This gene-editing technique will allow surrogate males to sire or parent an offspring that will carry the genetic material of valuable elite animals, including prize bulls.

In the abstract of their study, the team explained that spermatogonial stem cell transplantation (SSCT) is an experimental technique for the transfer of germline between the recipient and donor male that could be used for the preservation of endangered species, dissemination of desirable genetics in food animal populations, and biomedical research. But to fully realize the potential of SSCT, recipient male animals must be devoid of endogenous germline but possess somatic cell function and normal testicular architecture capable of supporting the regeneration of spermatogenesis and allogeneic donor stem cell engraftment.



Precision breeding

The whole process can help farmers rear more productive and healthier animals using only a few resources, such as water, feed, and medicine. Breeders in remote regions are likewise given better access to genetic material if elite animals from other places, thus referred to as precision breeding.”

Reproductive biologist Jon Oatley form the Washington State University said via Science Daily that with such kind of technology, they can improve the efficiency of food production and get better dissemination of desirable traits in animals. This can also have a major impact in addressing global food security. If the countries can tackle it genetically, it means fewer antibiotics, feed, and water to put into the animals.

Meat and dairy production

Meat plays a pivotal role in sustainably feeding the world. It is an important source of nutrition and for more than 50 years already, the global demand for meat is growing. In 2018, the global meat production increases, as detailed in the following regions: Oceania (3.69 million t), Africa (20.17 million t), Central America (8.89 million t), South America (46.12 million t), Northern America (51.73 million t), Europe (63.85 million t), and Asia (143.71). This is according to Our World in Data.

In South Korea alone, the production of meat, which includes cattle, poultry, goat, pig meat, and sheep/mutton in 2018 stood at 2.50 million t from 1.65 million t in 2000. Meanwhile, the global production of cattle (buffalo and beef) meat has more than doubled since 1961, increasing from 28 million tones per year. The United States remains the world’s largest buffalo and beef meat producer, producing 12.22 million tons in 2018. Other major producers are China (6.46 million tons), Brazil (9.9 million t), India (2.61 million t), and Argentina (3.07 million t).



Tampering with nature?

However, while Oatley and team believe that their work could have a major impact in addressing global food insecurity, gene-editing has long been a controversial subject. This means that their work could face resistance from critics opposing the genetic modification of animals. Most critics regard such procedure as dangerous because it means tampering with nature.

The team stressed, though, that the gene-editing process they used was created only to bring changes within the animal species that could happen naturally. They continued it is even a “proof of concept.” Yet, with current regulations, gene-edited surrogate sires may not be used in the food chain although their offspring would not be gene-edited. The team said that they will continue to work out how to best use their work productively to help feed the world’s growing population.

Oatley and colleague’s study is the result of six years of collaborative work among researchers at the Roslin Institute of the University of Edinburgh, University of Maryland, Utah State University, and WSU.

Animal husbandry

Animal husbandry is the branch of agriculture that is concerned with animals that are raised for fiber, meat, eggs, milk, and other products. It is the science of caring and breeding for farm animals. For decades, scientists have been finding a way to create surrogate sires to overcome the limitations of artificial insemination and selective breeding, tools that would require strict control of animals’ movement or animal proximity.

For example, artificial insemination is rarely used in beef cattle because they need to roam freely to feed whereas AI is common in dairy cattle as they are usually confined in one place, which means their reproductive behavior is relatively not difficult to control. For pigs, though, the procedure still needs that the animals are nearby because pig sperm do not survive well in freezing. AI is also quite challenging in goats and it may need a surgical procedure.

However, with surrogate sire technology, the authors believe that it could solve all those concerns because the surrogates will deliver the donor genetic material in a natural way (normal reproduction).  Surrogates and donors do not even have to be near each other because either the surrogate animal or the donor sperm can be shipped to different locations. Female NANOS2, a gene-specific to male fertility, also remains fertile.

The surrogate sire technology introduced by the team may soon open new options not just for the genetic conservation of endangered species but may also help food supply in the developing world.