Impact of some local organic by-products on Acheta domesticus growth and meal production

The house cricket Acheta domesticus is one of the species of major interest as alternative protein source for humans in the recent research of sustainable and nutritious sources of food. However, grain feeds, feed for poultry and soybean still represent common source of feeds for the insect industry. The aim of this study was to evaluate the influence of some agro-food by-products on the growth parameters of the crickets and the nutritional composition of the final cricket meal. Our study included five by-products (maize grain distiller, fruits and vegetables, grape marc, and two brewery’s wastes), while hen feed was used as a control diet. Substrates were analysed for their microbiological contamination prior to be provided to crickets. No Listeria and Salmonella were detected, but high microbial counts were observed. Crickets grown on the given by-products showed significant differences on the insect’s weight starting from the third week. High mortality was observed on all substrates, except on maize distiller and the control diet. The final cricket meal showed a similar protein content (66-68% as is), while the lipid content was higher in the meal from cricket reared on maize distiller (22% as is). Finally, microbiological and chemical analyses on the cricket meals did not show safety concerns for the consumers. The by-products studied, except maize grain distiller, did not support an optimal cricket rearing, but more studies are necessary to identify a mix-formulation meeting the cricket nutritional requirements.