Use of black soldier fly and house fly in feed to promote sustainable poultry production

The growing human population, changing dietary habits and intensifying competition between food and feed production underline the urgent need to explore novel sustainable production chains. In the past, the poultry sector has gained popularity due to its superior environmental and economic benefits compared to other livestock production systems. Therefore, it is of special interest to focus on refinement and innovation along the value chain to further improve the sector's sustainability. One major issue is the transition towards sustainable protein sources in poultry feed. In this regard, insects are the secret rising stars. Insect species such as the black soldier fly (Hermetia illucens) and house fly (Musca domestica) have been proposed for farming as multifunctional mini-livestock for feed. One major property of these flies is that larvae can convert low-quality organic waste streams into valuable body mass containing high levels of high-quality protein and fat. Furthermore, the larvae are reported to have health- and welfare-promoting effects due to bioactive compounds and poultry having a natural interest in them. The aim of the current paper is to discuss the state-of-the-art of using black soldier fly and house fly larvae as components of poultry feed and to highlight knowledge gaps, future opportunities and challenges. Some first studies have focussed on the successful partial replacement of soybean meal or fishmeal by these insects on poultry performance. However, since the sector is still in its infancy several uncertainties remain to be addressed. More research is required on identifying optimal inclusion levels, clearly differentiating between insect products based on their nutritional value and health-stimulating effects, and comparing the potential of insect products across species