Rearing Tenebrio molitor and Alphitobius diaperinus larvae on seed cleaning process byproducts

Abstract

Insects have recently attracted considerable scientific and commercial interest as an alternative nutrient source. Agricultural wastes is a big, often untapped, pool of nutrients which could be used for insect rearing. Insects can actually feed on these byproducts, converting these low-cost materials to insect protein that will be further exploited as food or feed. In this study, we evaluated ten byproducts of the seed cleaning process of cereals and legumes as feed for larvae of two insect species, i.e., the yellow and the lesser mealworm. The larval growth and survival, as well as the time it took the larvae to become pupae and the amount of feed consumed by larvae were monitored throughout the experiments. According to our results, most of the byproducts tested supported the larval growth of both species. However, larvae grew better when fed with lupin and triticale byproducts. These results aim to enhance the sustainability profile of insect production and integrate insect farming with circular economy practices. The exploitation of agricultural byproducts and organic side-streams as insect feeding substrates is advantageous for insect farming both from an economic and a sustainability perspective. In this context, in the present study we evaluated the suitability of ten byproducts of the cereal and legume seed cleaning process for the rearing of larvae of the yellow mealworm, Tenebrio molitor, and the lesser mealworm, Alphitobius diaperinus. Byproducts were offered singly to 20 T. molitor and 50 A. diaperinus larvae with provision of carrots as moisture source. After four weeks of undisturbed development, larval weight and survival was evaluated biweekly until pupation. Feed utilization and economic feasibility parameters were determined for each byproduct at the end of the bioassays. Our results show the suitability of several of the byproducts tested for the rearing of T. molitor and A. diaperinus larvae. The best results though among the byproducts tested in terms of larval growth and survival, development time and feed utilization were obtained with larvae fed with lupin and triticale byproducts, which efficiently supported complete larval development. The results of our study aim to boost the integration of circular economy strategies with insect farming practices. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.