Summary of information submitted by the public to the New Substances program on the environmental and human health risks of four lines of gene-edited pig
The New Substances program provides an opportunity for public engagement in the risk assessment process of vertebrate organisms. These organisms are notified under Schedule 5 of the New Substances Notification Regulations (Organisms) [NSNRO]. This opportunity serves to address the consultation requirements set out in section 108.1 of the Canadian Environmental Protection Act, 1999 (CEPA).
The New Substances program assessed Schedule 5 New Substances Notifications (NSNs) for four notified lines of gene-edited pig:
- A gene-edited Sus scrofa domesticus (Landrace), descendent of Elite Line L02, with deletion of the SRCR5 domain of the CD163 protein conferring resistance to porcine reproductive and respiratory virus (L02-0)
- A gene edited Sus scrofa domesticus (Large White), descendent of Elite Line L03, with deletion of the SRCR5 domain of the CD163 protein conferring resistance to porcine reproductive and respiratory virus (L03-0)
- A gene-edited Sus scrofa domesticus (mix breed of Pietrain, Large White, Hampshire and Duroc), descendent of Elite Line L65, with deletion of the SRCR5 domain of the CD163 protein conferring resistance to porcine reproductive and respiratory virus (L65-0)
- A gene-edited Sus scrofa domesticus (Duroc), descendent of Elite Line L800, with deletion of the SRCR5 domain of the CD163 protein conferring resistance to porcine reproductive and respiratory virus (L800-0)
The New Substances program held a 30-day public engagement regarding the gene-edited pig, which ended on July 20, 2025. Indigenous partner associations, veterinarians, academics, industry associations, and citizens provided comments.
A summary of the comments received, and responses provided, is included below, organized by topic.
Impact of porcine reproductive and respiratory syndrome (PRRS)
Comment Summary 1: The impact of PRSS to the pork industry is devastating. It causes mortality of up to 50% in some herds, slower growth and suffering of the pigs. The virus affects all stages of production from birthing to nursing to fattening and has become increasingly endemic. It also affects pig farm workers at all levels both economically and psychologically. There is currently no effective solution available to definitively control this disease.
Response 1: The New Substances program acknowledges the information provided on the impact of PRSS to the pork industry. Health Canada and Environment and Climate Change Canada officials have also obtained information on the effects of PRRS on the pig farming industry through a review of scientific literature, as well as consultations with external experts and other stakeholders in this field. Socio-economic considerations are not within the scope of the risk assessments under CEPA. However, the New Substances program can consider these if it finds that a substance is toxic under section 64 of CEPA and risk management is required.
Comment Summary 2: PRRS accounts for the loss of $130 million annually to the Canadian Pork industry.
Response 2: The New Substances program acknowledges the information provided on the economic impact of PRRS in Canada. Socio-economic considerations are not within the scope of the risk assessments under CEPA. However, the New Substances program can consider these if it finds that a substance is toxic under section 64 of CEPA and risk management is required.
Gene-edited pigs
Comment Summary 3: By creating healthier pigs, this technology should result in less antibiotic use. This in turn promotes responsible antimicrobial stewardship and reduces antimicrobial resistance concerns.
Response 3: The New Substances program acknowledges the information provided on this technology and its potential contribution to antimicrobial stewardship. The risk assessment under CEPA considers potential risks with the notified animals themselves and its potential to harbor any zoonotic infections. Secondary benefits such as the potential reduction in antibiotic-resistant bacteria were not part of the assessment. However, the New Substances program can consider these benefits if it finds that a substance is toxic under section 64 of CEPA and risk management is required.
Comment Summary 4: These gene-edited pigs can reduce mortality, improve feed efficiency, and lower greenhouse gas emissions. This is because healthier animals lead to less waste, including a reduction in the significant amount of pork wasted due to PRRS.
Response 4: The assessment under CEPA of the notified gene-edited pigs considered potential risks to the environment associated with the use of PRRS-resistant pigs. This includes animal mortality, impacts on other organisms in the environment, and impacts on habitat and biodiversity. The New Substances program acknowledges comments on feed efficiency, greenhouse gas emission and waste reduction. Nonetheless, they are outside the scope of the program’s risk assessment process under CEPA. However, the New Substances program considers these factors if it finds that a substance is toxic under section 64 of CEPA and risk management is required.
Comment Summary 5: Support the approval of these gene-edited pigs. Reasons varied from improved animal health and care to enhanced sustainability and economic benefits to the pork industry.
Response 5: Noted
Comment Summary 6: Opposed the approval of the gene-edited pigs in Canada. Gene-edited animals should not be the solution to the conditions on factory farms that allow for the spread of PRRS.
Response 6: Noted
Risk assessment
Comment Summary 7: Concerns were raised about the potential for impacts to wild species, if the gene-edited pig escapes from the facility with confinement procedures in place.
Response 7: Other than resistance to the infection caused by the porcine reproductive and respiratory syndrome virus (PRRSV), no differences in traits or behavior were observed between the gene-edited and non-gene-edited pigs. The deleted portion of the gene is not known to be the target of viruses other than PRRSV. Pigs lacking the edited-out portion of the gene demonstrate heritable resistance to the PRRSV with no changes in animal performance from birth to maturity. If these gene-edited pigs were to escape into the environment, the impact to wild species is expected to be no different than regular (non-edited) domestic pigs that are currently raised in Canada. Interbreeding of the notified animals with wild animals will not spread resistance because two copies of the gene deletion are required for any resistance. In addition, interbreeding will only generate heterozygous animals with no disease resistance. Since PRRSV only infects pigs, this resistance trait is not expected to be transferred to other animals in the environment.
Comment Summary 8: Concerns were raised regarding whether the disease is a natural way for population control. If the gene-edited pigs were to escape, would they have a greater advantage in succeeding in the wild?
Response 8: The prevalence of PRRSV in the wild is very low and is not expected to control the wild pig population. It is a disease mainly affecting domestic pigs and is rare in the natural environment. Compared to regular (non-edited) domestic pigs, the new Substances program does not expect the PRRS-resistant edited pig lines to have a competitive advantage in the wild. Furthermore, the PRRSV resistance trait is unlikely to persist if the gene-edited pigs escape from farms into the environment. Interbreeding of the notified animals with wild animals will also not spread resistance because two copies of the gene deletion are required for any resistance. Indeed, interbreeding will only generate heterozygous animals with no disease resistance.
Comment Summary 9: Concerns were expressed that there were limitations to the meaningfulness of the consultation. Suggestions were made to make them more meaningful such as providing more details about the risk assessment and examples. These can include consequences of the gene-edit on the pig’s physiology, monitoring of impacts on animal health and the potential for escape and breeding with feral pigs.
Response 9: Noted. The Canadian Environmental Protection Act, 1999 mandates the Minister of the Environment and the Minister of Health to assess information provided under the New Substances Notification Regulations (Organisms) within the prescribed assessment period. To meet these timelines, the public engagement must be held before the risk assessment is complete, thereby limiting the details available to interested parties. In addition, information submitted by notifiers is often confidential. Therefore, only non-confidential details of the notification are generally provided. Key, non-confidential information considered in the risk assessment is presented in the risk assessment summary published at the end of the assessment period.
Comment Summary 10: Concerns were raised that there has been no long-term, independent testing of the gene-edited pigs.
Response 10: New substances risk assessments under the Canadian Environmental Protection Act, 1999 consider the quality and pertinence of all information provided by the notifier. It also uses data and available information from published literature, assessments conducted by other jurisdictions and other external sources of scientific information. The risk assessment conclusion was determined by comparing the gene-edited pigs with non-edited pigs, which have been in commerce in Canada for decades. It also considered how the genetic changes in the notified organisms might alter the risk. Swine experts from Agriculture and Agri-Food Canada and a Canadian academic expert on pig invasiveness peer reviewed the information in the risk assessments of the gene-edited lines of pigs. Their reviews informed the conclusions under the Canadian Environmental Protection Act, 1999.
Gene-editing technology
Comment Summary 11: Strong support was expressed for gene-editing, as a promising tool to improve livestock health. This technology should be made available to pig producers as quickly as possible to find a permanent solution to PRRS.
Response 11:
The New Substances program assesses new living organisms to Canada based on their traits and the potential risks they may pose. The process used to develop the organism, including a tool like gene-editing, is considered as a part of the full assessment of the organism.
Comment Summary 12: Gene-editing using CRISPR-Cas9 is a safe technique both for the animals and humans that eat them. It mimics a DNA modification that could arise randomly in a conventional breeding program. No new genetic material is introduced, and in the case of these PRRS-resistant pigs only specific DNA fragments that permit the virus to infect the pigs are removed.
Response 12: The risk assessments of new living organisms under the Canadian Environmental Protection Act, 1999 are based on the characteristics of the entire new living organism. They are not based on the technology used to create the organism. When new genetic material is introduced into an organism, the New Substances program assesses the products of the genetic addition for potential impacts to human health and the environment. For gene-edited organisms, in which no new genetic material is introduced, the assessment focuses on the impacts of the resulting phenotypic and genotypic changes to the environment and health of people in Canada.
Comment summary 13: There is significant public confusion over the different types of technologies for genetic modifications.
Response 13: The New Substances program has used the term “gene-editing” to describe a method that precisely modifies an animal’s existing DNA. This method does not add any new DNA and targets specific DNA sequences. In the case of the notified GE pig lines, gene-editing using CRISPR-Cas9, resulted in a targeted removal of a gene fragment coding for the binding site for porcine reproductive and respiratory syndrome virus (PRRSV).
Regulation
Comment Summary 14: Science-based regulatory approaches should focus the review on the specific traits of an organism rather than the technology used to create it.
Response 14: The New Substances program assesses the potential risks of new living organisms to the environment and human health. This applies regardless of the technology used to develop the organism. In its assessment, the program ensures that it submits the inherent characteristics of these new organisms to a robust science-based process.
Comment Summary 15: The New Substances program should exempt novel organisms with traits that do not introduce foreign DNA from the regulations. Especially, if the process introduces a trait which could have been achieved through conventional breeding techniques. Such an exemption is already in place in Canada when regulating plants with novel traits. This precedent should also be applied to gene-edited livestock to remove regulatory barriers.
Response 15: The New Substances program acknowledges the information provided on novel organisms with traits that do not introduce foreign DNA. Currently, all new living organisms to Canada, including genetically modified organisms and genetically edited organisms, require notification under the New Substances Notification Regulations (Organisms) of the Canadian Environmental Protection Act, 1999. This applies to any new gene-edited livestock.
Comment Summary 16: The federal government should only focus on the safety of the product. It is the role of industry to educate the public, and not the role of the government.
Response 16: The Government of Canada is committed to the protection of the environment and to the health and safety of people in Canada. The New Substances program used a robust science-based process to assess the effect of genetically modified animals on the environment and on human health. Decisions are communicated to the public through reports, fact sheets and other appropriate means. This approach is used to increase transparency and better communication on the risk assessment process and regulatory decisions for living organisms.
Comments outside the scope of this assessment
Comment Summary 17: Concerns were expressed about the potential risk of the gene-edited pigs to the $5-billion Canadian pork export market. The Government of Canada should take action to ensure that this technology, if approved, is not used as a technical barrier to trade. The Government of Canada should further consult with global trading partners (especially in key Canadian export markets) to ensure their acceptance of this technology.
Response 17: Noted.
Comment Summary 18: This innovation aligns with global sustainability frameworks. It positions the Canadian pork sector to meet the evolving supply chain and market expectations.
Response 18: Noted.
Comment Summary 19: The Canadian government should enforce mandatory labelling of all genetically engineered or edited food products. It should also hold open public consultations before permitting such products on the market.
Response 19: The risk assessments of new living organisms conducted under the Canadian Environmental Protection Act, 1999 do not include an assessment of an organism for food or feed use. These specific uses fall under the purview of the Food and Nutrition Directorate of Health Canada (HC), under the Food and Drugs Act. They also fall under the Canadian Food Inspection Agency (CFIA) under the Feeds Act.