Will you eat lab-grown meat? Your pet will.

In bioreactors around the world, animal cells are proliferating, on their way to becoming meat and seafood that we might someday consume without killing any animals.

Lab-grown shrimp is being developed in Singapore, beef in the United States, and kangaroo in Australia — these and other futuristic proteins are often touted as the solution for the rampant environmental, health, and animal welfare problems caused by industrialized agriculture.

But one scientific obstacle looms over this work: Replicating the musculoskeletal system that underpins a steak or a fish filet is really hard. What many of the companies working toward this goal have made in the meantime is an animal protein in mince form.

This limitation in the texture of lab-grown meat could inhibit its commercial viability, since many people will want more variety. But commercial pet food is a different story — it’s ground up or dried to begin with. And so the first lab-grown meat people buy might end up being for their pets, not themselves.

To make its forthcoming lab-grown chicken treat for dogs, scientists at Bond Pet Foods in Boulder, Colo., started by taking a blood sample from a heritage breed chicken on a Kansas farm. From the sample, they extracted the genetic sequence for the proteins — leaving behind all the other cellular material — and embedded that sequence into microbial hosts, like yeast. The yeast are then left in a bioreactor where they produce more chicken protein, this time without the chicken itself.

That part of the process is called recombinant protein production, and it’s been used for decades to make the key protein in rennet for cheese. It’s also how Impossible Foods makes heme, the protein that gives its veggie burgers their meaty look and taste.

The end result for Bond Pet Foods is a powder that looks and smells a bit like nutritional yeast. It has a long shelf life because it’s dried, and it will be added to batter for dog treats or mixed into a base for wet food. It’s essentially a protein powder — but unlike the ones people add to post-workout shakes, it’s not plant- or milk-based, so it contains more essential amino acids and dogs can digest it more easily, says Pernilla Audibert, chief technology officer at Bond Pet Foods. Her company has sent samples to an external lab for nutritional assessment, and the company is beginning trials with dogs to make sure their bodies can actually absorb the nutrients the treats contain. The product could reach the market in two or three years.

“There’s no reason to think that this couldn’t also be used for human food if people actually wanted to try it,” says Audibert. But the word “if” carries a lot of weight. Health- and safety-wise, it would be fine, but people don’t tend to covet their pets’ food. So it’s possible that associating lab-grown meat with pet food could taint its reputation before it can cross over to human plates.

Chicken is Bond Pet Foods’ first target because it’s one of the meats that both people and pets consume most. The company plans to later produce treats from lab-grown turkey, fish, and cow protein. “Proteins that are already commonly used in pet food are what we’re doing first,” Audibert says.

A company called Because Animals in Toronto is doing the opposite: making unusual lab-grown animal proteins bound for pet food. Scientists at Because Animals began with a tissue biopsy from the ears of two mice, then forced these skin cells back into a stem cell state before redirecting them to become muscle, fat, and organ cells. These cells grow in a nutrient-rich, animal-free serum, and are later transferred to a bioreactor where a fermentation process similar to beer-making turns them into something resembling a “meat slurry.” That slurry can be baked into a dry kibble or blended into a wet food. A mouse treat for cats is slated to launch in a limited batch in 2021. This fall, the company plans to begin working on lab-grown rabbit for dogs.

“The main sources of protein in pet food of course are the remnants of the human food system, and they’re the cheapest and most convenient to give our pets,” says Shannon Falconer, chief executive and co-founder of Because Animals. “We saw this as a real opportunity to grow a meat that is [in] the [animals'] ancestral diet.”

However, Lisa Freeman, a veterinary nutritionist at the Cummings School of Veterinary Medicine at Tufts University, says it’s really not necessary for a lab-grown protein source to recreate what a domesticated animal would eat if it were still wild. Domesticated animals have much longer life spans, different nutritional needs, and different metabolisms.

“What is optimal for a wolf or a tiger in the wild may not be optimal for a long healthy life for a domesticated pet,” she says. “Animals need nutrients, not ingredients — and not just ingredients that are trending or sound appealing to us as owners.”

Instead, the real potential of lab-grown pet food is to address pet owners’ concerns about animal welfare in the food system without depriving their pets of any key nutrients. Some pet food is already brewed in labs, but that’s all vegan; there are no commercially available pet foods containing lab-grown meat yet.

Until then, Freeman says the most sustainable and humane option is to buy pet food containing byproducts — parts that are hard to sell to humans, like kidney, heart, or pancreas, but come from the same animal supply chain that feeds people. Many people falsely believe that seeing the words “contains byproducts” on a pet food label indicates the food is low quality; some brands even specifically advertise that their food only contains meat. But there can be high-quality byproducts and low-quality meat. Freeman also says that organs are often the most nutritious parts of an animal and are a particularly healthful addition to a pet’s diet, and, without commercial pet food complimenting the American human diet this way, these byproducts would just get thrown away.

Julia Sklar is a freelance science journalist in Boston.