Far from a science fiction movie, the Agronutris factory in Rethel, in the Ardennes, raises black soldier flies that transform agricultural waste that nobody wants, into proteins: "gold" to feed pets but especially farmed fish, a booming market around the world under the pressure of demand.

"The growth of aquaculture is gigantic and means that we need raw materials to feed these farms," says Raphaël Smia, the director of the plant that will release its first insect meal this summer, with a target volume of 5,000 tons in 2024.

Confident, the company announced Wednesday the establishment of a second plant in Rethel whose work will begin next year, to transform "more than 280,000 tons" of organic residues into "30,000 tons of flour", without specifying when or the amount of the investment.

Environmental paradox

With the recent evolution of European regulations, more than 5% of fish consumed in the EU could come from farms using insect-based proteins by 2030, estimates the insect meal lobby in Brussels, IPIFF.

Meal for farmed fish is now partly made from wild fish. For years, international NGOs have denounced this paradox, which leads to overfishing with harmful consequences on ecosystems, the marine food chain and the livelihoods of local populations.

An employee shows a black soldier-fly (hermetia illucens) at the factory of the company Agronutris, on June 15, 2023 in Rethel, in the Ardennes © FRANCOIS NASCIMBENI / AFP

Insect meal therefore represents an alternative, developed in France by three players now entering an industrialization phase: Ynsect, Innovafeed and Agronutris, which raised 100 million euros in 2021 and has just signed a contract of "several tens of millions of euros" with BioMar.

This Danish company, the world's leading manufacturer of feed for farmed fish and especially salmon, decided to invest.

"There is no point in feeding fish with fish that can be eaten by humans directly" or "with soy", imported massively and whose intensive cultivation promotes deforestation, justifies Katherine Bryar, marketing director of BioMar.


In Rethel, in a transparent container, swarm what looks like thousands of semolina seeds.

"These are larvae that have just hatched. Today, they weigh 15 micrograms and they will multiply this weight by 10,000 in just fifteen days. So 100 grams of neonates, it will represent a ton of larvae in two weeks, "says Cédric Auriol, the co-founder of Agronutris.

The rapid growth rate of black soldier fly larvae is one of the reasons why society selected this non-invasive species known as the queen of composting.

An employee shows flour produced from the larvae of black soldier flies (hermetia illucens) at the factory of the company Agronutris, on June 15, 2023 in Rethel, in the Ardennes © FRANCOIS NASCIMBENI / AFP

This choice as well as the recipe of the dough or the optimal conditions to industrialize the production were the subject of 12 years of research in a laboratory in Toulouse, according to the company.

After two weeks of growth, 98% of the larvae are crushed to give protein and 2% are preserved to become breeders.

Inside one of the aviaries where adult flies abound, Antoine Raybois, his hat covered with insects, explains that "the main activity here is laying eggs, the goal being to recover as many eggs as possible". A female black soldier can lay between 600 and 1,000 eggs in her short life (two weeks).

Waste waste

Another outlet for fly farming is "frass", a mixture of droppings and moults, considered an excellent fertilizer for agriculture.

The goal is to produce about 16,000 tons at cruising speed.

Larvae of black soldierfly (hermetia illucens) at the factory of the company Agronutris, on June 15, 2023 in Rethel, in the Ardennes © FRANCOIS NASCIMBENI / AFP

As for human food, it is not for tomorrow. "It will take time, but the players of the insect subsidiary will be the best positioned tomorrow on human food," says Raphaël Smia, the director of the plant.

© 2023 AFP