Biotransforming mycotoxin-contaminated raw materials into valuable feed sources by detoxification in insect larvae

Insect farming can play a key role in making feed for farmed fish and domestic animals more sustainable. Proteins and fat of insect larvae are valuable resources, which can replace less environmental-friendly produced materials. Insect farming requires less water, chemicals and space than conventional agricultural production, reducing the carbon and ecological footprint. Especially interesting are the larvae of the Black Soldier Fly (BSF). They can feed on many different types of organic matter, including sewage sludge and mouldy food wastes without apparent effects to their welfare. This ability opens up new opportunities of using otherwise discarded raw materials. However, the robustness of the insect larvae leads to the question of what happens to the toxic compounds in the contaminated feed after uptake. Mouldy materials can contain high levels of certain mycotoxins, which can cause serious diseases or even death in mammals. Therefore, authorities have set maximum allowed values for the most relevant mycotoxins in food and feed. It is thus important to know if novel feed produced from insect protein and fat still contains harmful mycotoxins or if the larvae are able to remove or detoxify these substances. Before this is clarified, and health risks to domestic animals and humans from the consumption of insect-containing products can be excluded, the use of waste materials in insect farming will not be permitted. Currently, the potential detoxification of mycotoxins in BSF larvae is largely unexplored. The DetoxBug project aims to fill this data gap by studying the physiological processes (metabolism) in the larvae that result in specific changes in the mycotoxin molecular structures, decreasing their toxicity. Furthermore, the mycotoxin levels in the larvae, their faeces and rests of the feeding stuffs will be determined. The project is realised in a collaboration between Norwegian BSF producing companies and the Norwegian Veterinary Institute.

Efforts to use insects as ingredient in novel feed and food products are increasing, as they are a valuable source of high-quality protein and fat. At the same time, insects can be reared on low-quality organic matter, and insect farming requires less water, chemicals and space than conventional agricultural production, reducing the environmental footprint. The larvae of the black soldier fly are of special interest: They are able to feed on all kinds of organic matter, increasing the circular use of otherwise discarded by-products, which is of great significance in bioeconomic strategies for sustainable food and feed production. This versatility of the insects rises, however, questions regarding the safety of the derived products. Low-value feed such as spoilt grains and food waste often contain mycotoxins that are produced by different fungi. Black soldier fly larvae and other insects show promising survival rates, when exposed to relatively high levels of mycotoxins, but a notable content of mycotoxins would constitute a threat to consumers of insect-derived products. Considering the risk to human and animal health from mycotoxins, food safety authorities worldwide have implemented maximum levels for frequently occurring and highly toxic mycotoxins. It is thus a requirement for the utilisation of larval resources that the fate of the absorbed mycotoxins is elucidated. However, the detoxification capacity, metabolism pathways and biotransformation products of mycotoxins in insects are largely unknown. This significant knowledge gap prevents the assessment of health risks connected to the use of larval products as nutritional ingredients. The DetoxBug project aims to fill this gap by studying the biotransformation of major mycotoxins in black soldier fly larvae, and determine their distribution in insect larvae, frass and residual feed materials. The project is a collaboration between the Norwegian black soldier fly industry and the Norwegian Veterinary Institute.