Go local: Enhancing sustainable production of Tenebrio molitor through valorization of locally available agricultural byproducts.

ABSTRACT

Insects receive increasing attention as an alternative source of protein for animals and humans, and thus, the production of low-cost insects for meeting the dietary demand on sustained basis is an ever-growing concept. This study aims to design dietswith locally available agricultural byproducts from Greece as feed for larvae of the yellow mealworm, Tenebrio molitor L. (Coleoptera Tenebrionidae). This will considerably reduce the cost of insect feed and the environmental impact of insect farming by using locally available agricultural byproducts as economic insect feedstock. More specifically, five agricultural byproducts derived from the production of cereals and legumes were utilized to design twelve different diets at two protein levels, i.e., 17.4 and 22.5% protein content. All diets were evaluated both at laboratory scale, but also at pilot scale. Based on the obtained results, both bioassays revealed that the diets contained one legume and one cereal byproduct (i.e., lupin and triticale as well as lupin and oat) supported more efficiently the growth and performance of the larvae, irrespective of the protein level. Indicatively, individual larval weight of the best performed larvae from both groups ranged from 132 to 142 mg. Moreover, our results highlight the fact that data derived from laboratory scale bioassays are not always easy to be extrapolated to industrial production. For instance, the total harvest of larvae, a parameter assessed in the tray scale bioassay, exhibited a disparity between diet A2 (910 g) and diet A3 (749 g), despite both being deemed optimal in the laboratory-scale experiment. Our study aims to promote a circular approach for the industrial rearing of insects through integration of local agricultural byproducts into specific diets for T. molitor larvae.