Conversion of organic resources by black soldier fly larvae: Legislation, efficiency and environmental impact

Samenvatting

To meet the projected substantial growth in the global demand for meat, we are challenged to develop additional protein-rich feed ingredients while minimizing the use of natural resources. The larvae of the black soldier fly (BSF) have the capacity to convert low-value organic resources into a high quality protein source for pigs, chickens and fish and as such may increase both the productivity and the efficiency of the food chain. The aim of this study was to assess the environmental opportunities of BSF larvae reared on different sources using up to date literature data on the efficiency of BSF larvae in converting such resources into biomass. The current EU legislative framework was used to classify the various resources for rearing insects. Data of forty articles published until 1 September 2017 were used, reporting on in total 78 (mixtures of) resources used for growing BSF larvae. Data on the resource conversion efficiency on dry matter (DM) and N basis was presented in 11 and 5 studies, evaluating 21 and 13 resources, respectively. Resources studied included food and feed materials (A, n = 8 resources), foods not intended (anymore) for human consumption (B1, n = 4), and residual streams such as food waste (D, n = 2), and animal manure (E, n = 7). Conversion efficiency varied from 1.3 to 32.8% for DM and from 7.4 to 74.8% for N. Using life cycle assessment, our environmental results showed that resources within the legal groups (i.e. A and B1) that are, at the moment, not allowed in EU as animal feed have in general a lower impact in terms of global warming potential, energy use, and land use. On a per kg protein basis, BSF larvae reared on a resource that contains food (e.g. sorghum) and feed (e.g. dried distillers grains with solubles) products generally have higher environmental impacts than conventional feed protein sources (fishmeal and soybean meal). Using insects as feed, therefore, has potential to lower the environmental impact of food production but a careful examination of the resource is needed in terms of environmental impact, safety and economics.