In the wild, insects are natural parts of poultry species’ omnivorous diet. Commercially, however, only birds kept in free-range systems would normally come into contact with them. Insects, though, are a protein-rich food source and have been traditionally used to supplement both the diets of animals and humans. 

If the agricultural industry is to meet the challenge of feeding the world’s increasing population, the issue of protein needs to be addressed. Whilst the developing world and the burgeoning middle classes are increasing their demand for animal protein; less-developed nations remain protein deficient. Therefore, the requirement for protein to feed livestock will increase, along with the waste produced. 

So, what if these insects could be widely used to produce a cost-effective, widely available protein source to feed poultry?  

Insect production

Black soldier fly (BSF) (Hermetica illucens) and the common housefly (Musca domestica) are two insect species mainly being investigated. 

The flies are bred, eggs laid and larvae hatch – all under controlled conditions at around 30 degrees Celsius. The larvae are then fed until they reach a suitable size (e.g. in the case of BSF, they reach two centimeters in two weeks). BSF can be reared on variety of food or animal waste; the housefly is usually fed on manure or abattoir waste. 

Insects have impressive life cycles: a female housefly lays 750 eggs a week and the larvae increase in weight over 400 times in just a few days; and BSF can develop from egg to adult in 38 days.

In large-scale facilities the larvae are harvested, then cooked and/or dried before being turned into a meal. In terms of food conversion, insects are highly efficient. 

Commercialization of insects for feed

Innovation in mass-rearing systems is taking place in many countries. China already produces insects for use in aquaculture. In Western Europe, insects are reared for pets and zoo animals as well as for fishing bait. In developing countries, small-scale businesses already produce insects to be sold as poultry feed. A company in the United States is using DDGS as a food source for BSF and is already selling its high-protein larval meal for use in aquaculture.

Large-scale insect production is not just blue-sky thinking, but the subject of discussion for the Food and Agriculture Organization (FAO) and research institutes internationally. PROteINSECT, for example, aims to create a pro-insect platform to share experience and expertise in rearing, processing and using insects as a component of animal feed. With partners in Europe, Asia and Africa, the group is focused on optimizing rearing systems for insects; ensuring the quality and safety of insect meal; and demonstrating its efficacy in monogastric nutrition.

Life-cycle analysis will also be a focus as a way of assessing the environmental impact of insect protein production processes.

Nutritional value

Insect meal is rich in protein (40 to 50 percent) with a greater concentration of essential amino acids than soybean meal (Table 1).

Relative to lysine, BSF meal contains higher levels of threonine, valine, isoleucine and leucine when compared to fishmeal. Insects are also relatively high in fat, supplying energy at levels comparable to, if not higher than, that of cereals or legumes. 

The metabolizable energy value of housefly maggots was evaluated in two trials (14.2 MJ/kg DM; 17.9 MJ/kg). Total tract amino acid digestibility is high, between 91 and 95 percent, but individual amino-acid digestibilites for poultry have yet to be determined. 

Waste benefits

In nature, insects play a vital role in waste biodegradation, breaking down organic matter so that nutrients are available in the soil for plant growth. Commercial production could collectively convert 1.3 billion tons of waste per year - significantly reducing the disposal and transportation costs as well as the environmental footprint.

By utilizing nutrients in waste, they also reduce the risk of organic pollution. It was found that BSF reduced the levels of nitrogen, phosphorus and potassium in pig manure by 50 to 60 percent. 

Safety and legislation

As insects feed on waste, there may be concern over hygiene and the spread of disease. However, initial research suggests that insects pose less risk of transmitting zoonotic diseases than livestock species. 

Before harvesting larvae are removed from waste, they void their guts pre-pupation – clearly presenting the need for a Hazard analysis and critical control points (HACCP) system to be in place. Key elements are the drying step to prevent bacterial growth and oxidation. Nutrient sources would also have to be tested regularly to control the risk of bacterial or heavy metal contamination.

Internationally, a specific regulatory framework for the use of insects as feed has yet to be developed and legislation intended for livestock is challenging its development. In the EU, regulation on feeding processed animal proteins may prevent the use of insects, along with rules governing the use of wastes.

Future potential

Insects could offer part of the answer to how to feed the 9 billion people living on earth in 2050. Increased food production means pressure on land, water and energy resources. Insects offer a means of locally producing protein for poultry that doesn’t compete with human food production. Insects have the potential to yield 200 times the amount of protein per hectare per year as soy and don’t require fertile land. In addition, they reduce the nutrient content and biomass of waste as they convert it into a quality protein source.

“Nutritionally, there are few obstacles,” says Angela Booth from AB Agri, a technology strategy board co-funded project on insect protein. “Insects are an attractive source of protein for poultry.” 

However, there are technical, economic and legislative challenges for insect meal producers. “These are not insurmountable and the benefits of being able to utilize material considered to be waste to produce protein make this innovation worthwhile,” she explains. 

In the short- to medium-term, Booth sees insect meal replacing fishmeal; however, in the long term, there is potential for wider inclusion. The aim of those involved in insect technology is to support the livestock supply chain whilst improving its sustainability.