Conversion of organic material by black soldier fly larvae: establishing optimal feeding rates

TLDR

Larvae of the black soldier fly are voracious feeders that can be used in simple engineered systems to reduce organic waste in low‑ and middle‑income countries. The study aimed to determine the optimal feeding rate of organic waste for the CORS system and to evaluate the resulting prepupae as a fishmeal substitute. The authors performed controlled feeding trials using standard fodder to identify the optimal waste addition rate for the CORS system and to assess prepupae protein content. A daily feeding rate of 100 mg chicken feed per larva achieved a 41.8 % waste reduction and 48 mg prepupal dry weight, yielding 3–5 kg m⁻² of market waste or 6.5 kg m⁻² of human faeces processed, with prepupae containing 28.2–42.5 % protein and producing 145 g dry biomass m⁻², demonstrating that black‑soldier‑fly larvae can convert substantial organic waste into fishmeal‑suitable protein.

Abstract

Larvae of the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae), are voracious feeders of organic material and may thus be used in simple engineered systems to reduce organic waste in low- and middle-income countries. Controlled feeding experiments with standard fodder were conducted to assess the optimum amount of organic waste to be added to a CORS system (Conversion of Organic Refuse by Saprophages). A daily feeding rate of 100 mg chicken feed (60% moisture content) per larva resulted in an optimum trade-off between material reduction efficiency (41.8%, SE 0.61) and biomass production (prepupal dry weight: 48.0 mg, SE 2.0). Applied to market waste and human faeces, this corresponds to a potential daily feeding capacity of 3—5 kg/m 2 and 6.5 kg/m 2 , respectively. In addition, H. illucens prepupae quality was assessed to determine their suitability to substitute fishmeal in animal feed production. The chitin-corrected crude protein content ranged from 28.2 to 42.5%, depending on the amount of food provided to the larvae. Based on our study, a waste processing unit could yield a daily prepupal biomass of 145 g (dry mass) per m 2 . We conclude that larvae of the black soldier fly are potentially capable of converting large amounts of organic waste into protein-rich biomass to substitute fishmeal, thereby contributing to sustainable aquaculture.