Stockholm university

Changes to animal feed could supply food for one billion people

While millions around the world face the threat of famine or malnutrition, the production of feed for livestock and fish is tying up limited natural resources that could be used to produce food for people. New research from Stockholm University, published in Nature Food, shows how adjustment to the feeding of livestock and fish could maintain production while making more food available for people.

Chickens around a pot of grain
Food by-products are already part of animal feed, but their use can be increased, according to the study. Photo: Arisa Chattasa/Unsplash

“These relatively simple changes would increase the global food supply significantly, providing calories for up to 13% more people without requiring any increase in natural resource use or major dietary changes,” says Max Troell, researcher at Stockholm Resilience Centre at Stockholm University and programme director for the Aquaculture and Sustainable Seafood Programme at The Beijer Institute of Ecological Economics.

Currently, roughly a third of cereal crop production is used as animal feed, and about a quarter of captured fish aren’t used to feed people.

grafik med olika cirklar för foder som skulle kunna användas som mat
Peter Lundvik/Azote

“This was the first time anyone has collected the food and feed flows in this detail globally, from both terrestrial and aquatic systems, and combined them together. That let us understand how much of the food by-products and residues is already in use, which was the first step to determining the untapped potential,” says Matti Kummu, associate professor of global water and food issues at Aalto University in Finland, leader of the team investigating the potential of using crop residues and food by-products in livestock and aquaculture production, freeing up the human-usable material to feed people.

The team analysed the flow of food and feed, as well as their by-products and residues, through the global food production system. They then identified ways to shift these flows to produce a better outcome. For example, livestock and farmed fish could be fed food system by-products, such as sugar beet or citrus pulp, fish and livestock by-products or even crop residues, instead of materials that are fit for human use.

With these changes, up to 10-26% of total cereal production and 17 million tons of fish (~11% of the current seafood supply) could be redirected from animal feed to human use. Depending on the precise scenario, the gains in food supply would be 6-13% in terms of caloric content and 9-15% in terms of protein content.

“That may not sound like a lot, but that’s food for up to about one billion people,” says Vilma Sandström, researcher at Aalto and first author of the study.

Find the study: “Food system by-products upcycled in livestock and aquaculture feeds can increase global food supply”

Read more about the study

Read more about Max Troells research


QnA by the author team:

1. Is this transition practically doable or more theoretical?

Our study presents the theoretical maximum potential of the change. Its practical implementation is faced with many challenges, as discussed in the paper. However, as by-products are already widely used feed materials, it is not something that would have to be developed from scratch, but it could just be upscaled.

2. If possible - what time frames are we talking about for making the transition?

Many of these food system by-products are already used in animal feeds. For example, oilseed meals, cereal by-products, sugar processing by-products such as molasses or sugar beet pulp and distiller’s grains from ethanol and alcohol industries are already currently widely used feed materials. In addition, currently according to IFFO, in 2020, 27 percent of the global production of fishmeal and 48 percent of the total production of fish oil were obtained from by-products. This transition is therefore already happening, but there is potential to increase their use even more, as shown by our study.

3. And what would be needed for making the transition?

One of the challenges currently is the difficulty of having the production of the by-products (e.g. from crop production, fish or animal processing) and the use (livestock and aquaculture producers) meet each other. Better management of the feed resources would be needed to make the supply and demand to meet. One practical example of this an initiative in one rural area of Finland, Satakunta, where they have created a web page ( "A by-product stock exchange" for food industries to advertise the by-products that are created in their production, and where possible users can go and find them.

Another challenge is the quality issues related to the by-products, as some can be of lower nutritional quality and can contain antinutritive compounds or high amounts of fibre that can impact animal productivity or the nutritional content (e.g., fatty acids composition) of the commodities produced. Processing them through e.g., fermentation or other chemical treatments or additives can be a viable option to improve their nutritional quality. So providing incentives for feed industries could help them to develop and innovate solutions for increased use of the materials most unused as feed, as highlighted by our study. Yet, as shown in the different feed experiment studies reviewed in our study, particularly crop processing and animal by-products are of valuable nutritional quality, and they can replace food-grade feed use while maintaining productivity. Especially in cattle nutrition, it is possible to formulate diets entirely based on non-food-competing feedstuffs even at very high animal production levels.

Consumer preferences such as cultural and taste aspects can hinder the transition if people don't want to eat the food-grade material from previous feed use. For example most of these captured fish going to fishmeal and fish oil production are small, bony, pelagic fish species or other low-value by-catch or juvenile individuals which are not often preferred for direct human consumption. Processing and preserving for example in canned, cured or dried form these low-cost and highly nutritious fish can serve as valuable dietary additions, especially in regions where more expensive fish are not accessible for many people.

4. Are the numbers presented per year?
The numbers are presented for one year, we used a three-year average of 2016-2018 in our study.