Food vs. feed: Upcycling’s untapped potential to minimize resource competition between human and animal nutrition

20 Sep 2022 --- A new study underscores that increasing the volume of upcycled food system byproducts and residues into feed and ingredients remains a critical vehicle to offset competition between livestock and aquaculture fodder production and the F&B industry at large.

This food-feed competition has long reduced the efficiency of the existing food system, as environmental and resource costs are higher when arable land is used for animal feed production instead of directly contributing to human consumption.

The researchers gathered data on global food system material flows for crop, livestock and aquaculture production, focusing on feed use and the availability of byproducts and residues.

Overall, cereals are the largest group of food-competing feedstuff use, in which maize is the most important feed cereal, followed by wheat, rice and barley.They then analyzed the potential of replacing food-competing feedstuff – cereals, whole fish, vegetable oils and pulses that account for 15% of total feed use – with food system byproducts and residues.

“Considering the nutritional requirements of food-producing animals, including farmed aquatic species, this replacement could increase the current global food supply by up to 13% (10-16%) in terms of kcal and 15% (12-19%) in terms of protein content,” they highlight.

“Increasing the use of food system byproducts as feed has considerable potential, particularly when combined with other measures, in the much-needed transition towards circular food systems.”

Overcoming upcycling limitations
The researchers flag that the current structure of the global food system results in shortages in food availability, as a large proportion of the resources used in livestock and aquaculture feeds could be consumed by humans.

Up to 40% of all arable land and more than 30% of cereal crop production is used for animal feeds, and approximately 23% of all captured fish are destined for non-food uses, mainly for fish and livestock feeds, the study highlights.

Upcycling food system byproducts can reduce the environmental pressure on arable land and freshwater ecosystems, as well as reduce greenhouse gas emissions and fertilizer application.

However, some non-food-competing feedstuffs are less suitable for feed use; for example, crop residues are fibrous and of low digestibility and poor protein quality, and others, such as some crop processing byproducts, are protein dense but low on energy.

Yet, some non-food-competing feedstuffs can be improved through processing or additives, the researchers note.

Overall, cereals are the largest group of food-competing feedstuff use, in which maize is the most important feed cereal, followed by wheat, rice and barley. 

Notably, fishmeal and fish oil are important sources of protein and fat, while their byproducts can also be important for the supply of healthy fatty acids like EPA and DHA.

Countries with the most fisheries and aquaculture production (such as China and Indonesia) show the highest availability and the largest potential to increase the production of fishmeal and fish oil from fish byproducts, either for local needs or for export to other countries.

Similarly, oilseed oils can also be converted into human nutrition solutions when looking at the fat content. Oilseed meals are highly valued feed materials, which shows in nearly all oilseed meals being used as feed at the global level.

Fish products, such as fishmeal and fish oil, are important sources of protein and fat.

Filling in critical knowledge gaps
The new study published in Nature offers a systemic view of the “highly interlinked” global food system. Other global datasets including both feed material flows and the availability of food system byproducts and residues at this level of detail do not exist, concede the paper’s authors.

“While different models and reports provide data on livestock or aquaculture feed use, these data are not harmonized throughout the global food system,” they explain.

“Furthermore, while some studies have estimated feed use in both agriculture and aquaculture systems, they do not account for country-level differences in feed use or have only regional focus.”

“Here we combined and harmonized data from various sources including crop, livestock and aquaculture production, as well as wild fisheries, and quantified the dynamics of global feed flows in remarkable detail,” they comment.

According to the data findings, approximately 15% (940 million tons in dry matter) of the total feedstuffs (6,100 million tons) used in livestock and aquaculture production consisted of food-competing feedstuff that could be directly used as human food.

This is in line with existing estimates, the researchers say. At the global level, up to 49% of feed use in aquaculture (total feed use, 67 million metric tons); 68% in poultry (total 421 million metric tons); and 38% in pork meat production (total 1,200 million metric tons) consisted of food-competing feedstuff.

Cattle feed exhibits less competition
Meanwhile, for cattle meat (total 5,200 million metric tons) and dairy (total 1,920 million metric tons), the share of food-competing feedstuff was only 3-4% (in quantities of feed in dry matter).

“The low share of food-competing feedstuff in cattle feed is mainly due to the large share of global cattle production being extensive grazing systems, which have high feed conversion ratios (kg feed per kg output), consuming high amounts of feed consisting mainly of roughages such as grass and hay,” detail the researchers.

“Diets in industrial feedlot cattle systems often include a higher share of food-competing feedstuff,” they explain. “For example, in some North American and European industrial beef cattle systems, the diets in the finishing phase can consist of more than 70% food-competing feedstuff.”

“However, these systems are highly optimized, having lower feed conversion ratios and consequently lower total feed consumption.”

By Benjamin Ferrer