Brewery Waste as a Sustainable Protein Source for the Banded Cricket (Gryllodes sigillatus)

Abstract

Crickets, like other edible insects, can convert organic by-products of the food and agricultural industries into high-value protein. Waste products high in protein like brewers spent grain and brewers spent yeast are particularly attractive replacements for unsustainable protein sources in cricket feed like fishmeal or soy. Such replacement will only be advantageous, however, if feeding on these waste products does not impact, or only minimally impacts, cricket survival, growth, and body composition. In this study, a farmed cricket species, Gryllodes sigillatus, was reared in isolation on experimental diets in which fishmeal was wholly or partially replaced with either brewers spent grain or brewers spent yeast. Cricket survival, development and macromolecular composition were not different across diets. However, wholly replacing fishmeal with brewers spent yeast or brewers spent grain reduced cricket adult body mass by approximately 16%. To extend these findings toward a farm environment, a second cohort of crickets were reared communally on diets in which fishmeal, and fishmeal and soy (a secondary protein source), were replaced by brewers spent grain. We found that in a communal environment, crickets reared on both diets performed equally as well as the control. Therefore, brewing waste products are promising candidates for use as a primary protein source in the feed of G. sigillatus. In addition to contributing towards the goals of a circular bioeconomy through the repurposing of waste, the use of brewing waste in cricket feed may have a positive impact of the cricket farming industry as a cost-effective and sustainable alternative to traditional feed. Conflict of InterestThe authors have an ongoing research agreement with Aspire Food Group and Entomo Farms, who produce crickets as food and feed. Funding StatementThis research was funded by Discovery Grants awarded by the Natural Sciences and Engineering Research Council of Canada (NSERC) to H.A.M. (RGPIN-2018-05322) and S.M.B. (RGPIN-2017-06263). Additional support was provided by an NSERC Alliance Grant (568647-21) and a Deep Space Food Challenge grant (22IUCCAR22) from the Canadian Space Agency awarded to both H.A.M. and S.M.B. Equipment used in this study was purchased with support to H.A.M. from the Canadian Foundation for Innovation (project number 37721).