As the world’s population grows, so does the challenge of feeding everyone. Current projections indicate that by 2050, global food demand could increase by 59% to 98% above current levels. In particular, there will be an increased demand for high quality protein foods, such as meat and dairy products.
Livestock producers in the United States and other exporting countries are looking for ways to increase production while being sensitive to the environmental impacts of agricultural production. An important leverage point is finding animal feed ingredients that can replace grains, freeing up more farmland to grow crops for human consumption.
The cattle is natural upcyclers: Their specialized digestive system allows them to convert poor quality nutrient sources that humans cannot digest, such as grass and hay, into high-quality protein foods like meat and milk that meet human nutritional needs. But when the protein content of grass and hay becomes too low, usually in winter, producers give their animals an additional source of protein, often soybean meal. This strategy helps livestock grow, but it also drives up the cost of meat and leaves less farmland to grow crops for human consumption.
Cereal cultivation also has environmental impacts: for example, large-scale soybean production is a driver of deforestation in the Amazon. For all these reasons, our laboratory works to identify new alternative sources of protein for livestock.
Black soldier fly larvae
A insect breeding industry is rapidly emerging across the world. Growers cultivate insects for animal feed because of their nutritional profile and ability to grow rapidly. The data also suggests that feeding livestock with insects has a smaller environmental footprint than conventional forage crops such as soybean meal.
Among thousands of species of edible insects, the one that catches the eye is the black soldier fly (Hermetia illucens). In their larval form, black soldier flies contain 45% protein and 35% fat. They can be efficiently feeds on waste many industries, such as pre-consumer food waste. The larvae can be reared on a large scale in factory-sized facilities and are shelf stable after drying.
Most adults in the United States are not ready to put black soldier fly larvae on their plates but are much more willing to consume meat from cattle fed black soldier fly larvae. This sparked research into using black soldier fly larvae as livestock feed.
Already approved for other farm animals
Extensive research has shown that black soldier fly larvae can be fed chickens, pigs and fish as a replacement for conventional protein foods such as soy meal and fish meal. The American Association of Food Control Officialswhose members regulate the sale and distribution of pet food in the United States, has approved the larvae as food for poultry, pigs and some fish.
Until now, however, there has been little research on feeding black soldier fly larvae to livestock. This is important for several reasons. First, more than 14 million cattle and calves are fed grain or animal feed Second, the specialized digestive system of cattle may allow them to use black soldier fly larvae as food more efficiently than other livestock.
Promising results in cattle
At the beginning of 2022, our laboratory published the results of the first trial of feeding cattle with black soldier fly larvae. We used cattle that had been surgically fitted with small porthole-like devices called cannulas, which allowed us to study and analyze the animals’ rumen – the part of their stomach that is primarily responsible for converting dietary fiber, such as grass and hay, into energy they can use.
The cannulation is widely used to study digestion in cattle, sheep and goats, including the amount of methane they release, which contributes to climate change. The procedure is performed by veterinary professionals under strict protocols to protect animal welfare.
In our study, cattle were fed a staple diet of hay and a protein supplement made from black soldier fly larvae or conventional protein feed from the beef industry. We know that giving cows a protein supplement with grass or hay increases the amount of grass and hay they consumeso we hoped that the insect-based supplement would have the same effect.
This is exactly what we observed: the insect-based protein supplement increased hay consumption and animal digestion in the same way as the conventional protein supplement. This indicates that black soldier fly larvae have potential as an alternative protein supplement for livestock.
Costs and by-products
We have since conducted three additional trials evaluating black soldier fly larvae in cattle, including two funded by the United States Department of Agriculture. We are particularly interested in feeding defatted cattle larvae. Data suggests that fat can be converted to biodieselproducing two sustainable black soldier fly products.
We are also studying how eating the larvae will affect the methane-producing microbes that live in the stomachs of cattle. If our current research on this issue, slated for publication in the spring of 2023, indicates that eating black soldier fly larvae can reduce the amount of methane produced by cows, we hope this will motivate regulators to approve the larvae as feed for livestock.
The economy matters too. How much will beef and dairy cattle producers pay for insect feed, and can insects be bred at that price? To begin to answer these questions, we conducted a economic analysis of black soldier fly larvae for the U.S. beef industry, also released in early 2022.
We found that the price of larvae would be slightly higher than current protein sources normally used for livestock feed, including soybean meal. This higher price reflects the superior nutritional profile of black soldier fly larvae. However, it is not yet known if the insect farming industry can grow black soldier fly larvae at this price, or if cattle ranchers would pay for it.
The global market for edible insects is grow fastand advocates argue that using insects as ingredients can make more sustainable food and feed. In my view, the livestock feed industry is an ideal market, and I hope to see further research that engages both insect and cattle producers.