Tiny larvae - huge potential

Eww larvae - that's certainly the first thing many of you might have thought when looking at the cover picture. And disgust is a good thing. It triggers a biological protective function, originally intended to prevent us from eating spoiled food. The fear of insects, on the other hand, is usually instilled. If our parents have a problem with them, we also develop a strong aversion. But actually, insects are a miracle of nature - really fascinating creatures. I was able to learn this during my doctorate at ETH, where we successfully used insect larvae as an alternative feed in poultry nutrition. Larvae suddenly became an essential part of my life and led me to my current job – and somehow my own aversion has turned into a passion!

Why should we consider insects as feed?

Not only are insects enormously important for our ecosystem but also most of them are full of valuable nutrients - they are true "superfoods". In many regions of the world, insects are already part of the regular diet. Worldwide, more than two billion people eat insects every day. But in most industrialised countries, this sounds more like a dare than a healthy snack. In these countries, meat is and will probably remain the more popular source of protein. A single citizen of a developed country consumes on average 68.6 kg of meat a year, which adds up to a total of 320 million tonnes worldwide every year. With the increase to nearly 10 billion people by 2050 and our current dietary habits, the supply with adequate amounts of protein will become a challenge. To ensure food security, the demand for feed with a correspondingly high protein content will also increase. Such high-value feeds, especially soy or fish meal, have environmental disadvantages. The production of fishmeal contributes to overfishing of the oceans and is also expensive. Regarding soy, the demand in Switzerland is greater than the local production, which means that large quantities must be imported - from overseas or other European countries. This in turn goes hand in hand with deforestation of rainforests, cultivation of monocultures, pollution of groundwater, and a generally long import path.

However, a crucial problem is that most animal feed, regardless of where and how it is produced, can also be used directly in human diets and thus is in direct competition with human food security. For this reason, alternative feeds are needed, which compete less or not at all with human nutrition. As it is culturally less common in the Western world to include insects in the daily human diet, they would be an ideal sustainable alternative in animal nutrition.

The larvae of the black soldier fly - a promising solution

Black soldier flies on the net of their "love cage" where they are brought to breed (Photo: NutriFly).

Among insect species that are particularly suitable as feed, the larvae of the black soldier fly (BSFL, Hermetia illucens L.) stand out. They show a distinctly advantageous nutrient composition - especially in terms of their amino acid, fatty acid and mineral composition. They also grow quite fast and can be harvested after only 10 to 15 days. Thereby, they need significantly less land and water than the cultivation of an equivalent amount of soy.

They are also not very demanding when it comes to their own feed and grow excellent on all kinds of side streams of the food and agricultural industry. Therefore, they are ideal for a local, sustainable circular economy. Everything that is no longer usable, such as fruit, vegetables, by-products from milling or dairy products, and would otherwise end up in a biogas plant, is suitable for upcycling by the BSFL into a high-protein feed. 

When the BSFL are large enough, they are separated from the substrate and can then be further processed. Basically, they can be integrated whole (foraged or dried) into animal feed or ground and then used as a meal (full fat or partially defatted). The fat separated during grinding can be used as a substitute for fish or vegetable oil. The remaining substrate, which consists mainly of the excreta of the BSFL, can also be used – as a fertiliser in agriculture or private gardens. It is considered a real growth accelerator.

Our studies with BSFL in poultry nutrition have shown that their use is particularly suitable as a sustainable, alternative substitute for soy. But the larvae are not only suitable for feeding farm animals. Our pets, such as dogs, cats or reptiles, also love the little protein bombs and they are suitable for wild animals, such as hedgehogs or birds.

Weight control of a laying hen in a feeding trial with insect-based feeds (Photo: Maike Heuel).

Black soldier fly larvae are a natural and healthy protein source for hens – they love to eat them (Photo: NutriFly).

So - now what?

One might think that the interest in insects as feed for our animals should be huge - and it is! Even during my doctorate, the interest in our research was huge. I was allowed to give presentations, newspaper articles were written, and we introduced school classes and students to the topic. Now, as the interest is still very high and the industry is growing, I joined a start-up that produces BSFL as animal feed. But, if there is so much interest, why is insect-based feed not yet available for the livestock sector? For Switzerland, the explanation is quite simple: unlike in the EU, it is not (yet) permitted to use processed insects as a feed for poultry or pigs. There are various reasons for this. First and primarily, it is to ensure that new feedstuffs must not pose a risk to animals, humans or the environment - there must, for example, be no risk of disease transmission from the larvae to the livestock. For pets and in the aquaculture, however, the larvae and especially their meal can already be used in Switzerland, and there are even a few dog feeds based on BSFL protein meal. Approval in Switzerland for insect-based livestock feed should follow in the foreseeable future. Then, something more can be done to secure our food system in this country too - and I firmly believe in the potential of these tiny larvae!

ABOUT THE AUTHOR

Maike Heuel did her doctorate in the animal nutrition group at ETH. Her work with the project title "Hen and Fly", which has resulted in several publications, was carried out within the framework of the Mercator Research Program. She successfully used the meal and fat of black soldier fly larvae as an alternative to soybean meal and oil in the feeding of laying hens and broilers. After her doctoral studies, she is now working in a start-up (NutriFly AG) that produces the larvae to make animal feed, among other things. What drives her and all the employees of NutriFly is the goal to help nature recover by revolutionising the way they feed animals.