Integrating Industry Co-Products and By-Products into Farmed Insect Diets to Build a Circular Economy Framework

The demand for insect meal as a feed ingredient in the pig, poultry and salmon farming sectors in the UK alone could reach 540,000 tonnes a year by 2050. For every tonne of farmed insects produced more than 1 tonne of feed is required, with the exact amount depending on the insect species, diet, life stage and rearing conditions. Insect feeds influence every aspect of insect farming, from productivity, product specification and risk of contamination with microbes or chemicals to compliance with national regulation. Adopting a circular economy approach by utilising co-products and by-products sourced from the food and beverage manufacturing sectors or agriculture as insect feed ingredients can reduce the carbon footprint of production and lower costs. This can make insect farming more sustainable and economically viable. Co-products are valuable secondary materials intentionally produced alongside a primary product during manufacturing, while by-products are unintentional outputs that still retain economic or industrial value and can be repurposed. Here, we consider how to assess the suitability of industry co-products and by-products as ingredients in insect diets. We describe the use of nutritional geometry as a tool to optimise the diets of farmed insects, by maximising desirable traits such as feed conversion ratio and reducing the time to harvest.