Genetically modified livestock can be sold for food in the United States

Genetically modified livestock can be sold for food in the United States

Cattle whose genome has been modified to have short, smooth hair are the first genetically modified cattle that US authorities will allow to be bred for food.

Food and Drug Administration officials announced March 7 that they found no safety concerns with modified Angus cattle, and meat from the descendants of these cattle may be available in the United States and other countries. country within two years. Although intentional genetic modifications are subject to FDA regulation as drugs, agency officials said the low-risk determination allows them to apply discretion and allow livestock production without drug approval application.

FDA officials have previously applied such risk-based discretion to fish engineered to fluoresce and to animals belonging to food-producing species but intended only to serve as disease models.

The animal on the left is genetically modified to have short, smooth hair that could help it adapt to heat, unlike conventional Angus cattle with longer hair. (Courtesy of the FDA)

In 2015, agency officials granted the first approval for a genetically modified food animal, a strain of Atlantic salmon modified to grow to market size in half the time of conventional salmon. In December 2020, the agency also approved a genetic alteration in pigs that eliminates a sugar molecule known to trigger a rare allergy in humans, and these pigs can be sold for medicinal purposes and for meat.

According to an FDA risk assessment, the modified cattle are products of Acceligen – a subsidiary of Recombinetics – which used CRISPR-Cas9 gene editing in Angus cattle to disrupt a prolactin receptor gene, mimicking thus a mutation that results in the short, smooth coat found on other types of cattle raised for beef in tropical and subtropical environments. The paper notes that traditional breeding methods have produced lines of Holstein cattle with the same smooth coat phenotype.

Agency officials said in the risk assessment that they consider the modification to be equivalent to natural mutations. In the announcement, officials also said the modifications could reduce temperature-related stress in cattle, which could also help beef production.

Modified cattle raised by Acceligen had similar health and growth to conventional cattle, with the exception of one male calf who died of congestive heart failure, according to FDA information. The risk assessment notes that congestive heart failure is known to affect cattle with Angus-influenced genetics, and the calf has inherited genes associated with the disease from its unmodified parents.

Although the risk assessment notes that the company and FDA officials found unintended genetic changes, “none of the unintended alterations identified are expected to result in changes in protein expression based on their location and genomic annotation available”.

“Based on molecular characterization and animal health data, the FDA has determined that these unintended alterations do not pose a safety concern for livestock or for humans consuming food derived from livestock,” the document states.

Sabreena Larson, chief operating officer of Acceligen, said in a message that the company was pleased with the determination of low risk and that the ‘slick’ trait “will be used to transform beef production to be more sustainability and improve animal welfare in warmer climates.” She declined further comment and referred further inquiries to the FDA-released documents.

Dr. Stewart Bauck is a member of the Genomics Committee of the American Association of Bovine Practitioners. He has worked closely with some of Acceligen’s scientists in the past and is the senior director of special projects for Neogen, which performs genomic testing on cattle and other animals around the world. He said the FDA’s decision to clear the modifications to Acceligen was a pleasant surprise and that the terms of that clearance could have implications for other genetic modifications.

He noted that Acceligen had obtained FDA clearance to sell products, including semen, embryos and meat, derived from just two modified cattle and their offspring.

Dr Bauck said this suggests the agency is only applying enforcement discretion to individual genetically modified animals that have undergone genetic sequencing and analysis rather than applying this discretion more broadly to the amendments themselves. If so, Acceligen can use those two modified cattle to create breeding lines, but modifying more cattle to create additional breeding lines with the same or other genetic modifications would require going through the same FDA’s analysis and decision-making process every time.

Dr. Bauck also sees the potential that other modifications could follow a similar path. Polled or polled cattle, for example, can be produced by conventional breeding, but it would require considerable labor to select for this trait while maintaining the high milk production of existing breeds. Genetic modification could speed up this selection process.

FDA spokesperson Juli Putnam responded that Acceligen had asked FDA officials to review two animals and the products of those animals and their offspring, and that agency officials may consider broader risk-based decisions.

Dr Bauck said cattle with heat stress grow more slowly, produce less milk and have more difficulty producing offspring. He said the Acceligen modification could broaden the geographic reach for raising livestock and improving production in tropical environments.

But he also expects that public acceptance of meat or milk from these cattle will depend on how these products are labeled and whether food supply chains separate products from meat or milk from conventional cattle.

the FDA announcement links to risk assessment.