The challenges and potential of insects as sustainable protein for animal feed
Agriculture contributes roughly 35% of anthropogenic greenhouse gas emissions – more than any other sector. This is largely due to a surge in meat consumption, which has driven the allocation of land and resources to producing feed ingredients for livestock. Modern approaches to sourcing protein are particularly damaging, as most animal feeds are formulated with soybeans and/or fishmeal - soy agriculture is a leading driver of tropical deforestation and commercial fishing has already overexploited most wild forage fish populations. Insects are an emerging alternative, particularly the black soldier fly (Hermetia illucens, BSF). BSF larvae are very efficient at converting organic matter into concentrated protein, and their preferred feedstock is food waste. Thus, BSFs provide a potential mechanism to ‘up cycle’ food waste – currently 35% of food is wasted – into a valuable, sustainable and alternative protein for animal feed. Here we examine environmental controls on insect production, specifically, reproduction and waste conversion rate and efficiency. These elements of the BSF lifecycle represent key bottlenecks in the mass rearing of insects, which are critical to the ultimate economic competitiveness of insects against soy and fishmeal.
Prior research has shown that BSF fecundity is dependent on light availability and relative humidity. Using a climate-controlled hatchery equipped with four separate artificial lighting systems, we discovered that mating success and egg viability were greatest under the light treatment that most closely mimicked sunlight. Humidity however had no significant effect on mating or egg eclosion. In a separate facility, larvae were fed various forms of pre-consumer waste from Whole Foods Market and other food businesses. Early results show the BSF can convert greater than 20 kg/m2/day into roughly 4 kg of larvae, 4 kg of nutrient-rich excreta and 12 kg of metabolites. Across a range of food waste treatments, BSF protein balance and abundance (45%) was similar to fish and superior to soy. Overall, these results suggest that BSF may be a viable alternative feed ingredient on a nutritional basis. At such rates and quality, we calculate that BSFs could replace the fishmeal market if 40% of current food waste was bioconverted at the globe scale. The success of BSF protein however depends in part on its effectiveness as an integrated feed ingredient for animals, which we are currently testing in several feeding trial to chickens and fish.