Insects raised on food waste : a new source of feed and food?

Abstract: An increasing global population demands an increase in food production, while human impact on the planet necessarily must be decreased to decelerate climate change. Resources currently lost as food waste could potentially be utilized to increase world food production amount and efficiency by feeding it to insects. These insects could be used as feed in animal production. The insects could also serve as food for humans, as evidenced by the fact that two billion people regularly consume insects as part of their diet. The aim of this report is to investigate the nutritional and environmental potential of insects as food and feed. This report will also investigate whether varying the feed source affects the nutritional quality and growth of the insects. Since Europeans still, to a large extent, view the concept of eating insects with neophobia and disgust, alternative ways of using insects are relevant. Aquaculture in Sweden is growing rapidly while fish feed is produced in unsustainable ways. Thus, this report also aims to investigate the potential of using insects as feed for fish. Results show that insects in general are safe to eat for both humans and for fish, good sources of protein, fat, dietary fibre and several minerals and vitamins. Many different types of substrate can be used to raise insects although care must be taken to ensure high enough nutritional quality of the substrate to sustain the insects, and not all substrates fit all insect species. Fatty acid composition of insects is impacted by the fatty acid composition in the substrate while amino acid composition does not seem affected. Fish meal in fish feed can be partially or wholly substituted with insects with good results for several insect species, mainly black soldier fly and mealworm larvae. Insects can improve the immunological health and gut microbiota of fish and results indicate that growth may be improved by including insects in the feed. Results on growth and feed efficiency differ widely between different combinations of insect and fish species. In conclusion, insects can be raised on many different substrates to produce a nutritious food or feed. Further research is required on specific food waste types and their effect on growth and safety, to develop realistically usable insect production systems. More research is also required to determine the most productive combinations of insects and fish.