Manure Valorization Using Black Soldier Fly Larvae: A Review of Current Systems, Production Characteristics, Utilized Feed Substrates, and Bioconversion and Nitrogen Conversion Efficiencies

Abstract

The growing demand for animal products leads to mounting environmental impacts from the livestock sector. In light of the desired transition from linear to circular nutrient flows and an increasing number of formal commitments toward reducing environmental impacts from livestock production, manure valorization using insects (particularly black soldier fly larvae; BSFL) gains increasing importance. Based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, this paper identified 75 BSFL production systems utilizing various types of manure as feed substrates. The review highlights considerable differences in system design regarding the different production steps and their specific characteristics. These differences lead to a wide spectrum of rearing performances, which were measured by a suite of indicators, including dry matter reduction (DMR), waste reduction index (WRI), feed conversion efficiency (FCE), bioconversion rate (BCR), and nitrogen reduction. The results further show that, to date, most manure-valorizing BSFL production systems operate at the micro-scale level. However, specific reduction targets for manure-related emissions will likely necessitate large-scale systems at the farm or industrial level, and further research should thus focus on the comprehensive assessment of potential environmental benefits of manure valorization using BSFL.

Evaluation of the decomposition ability and characteristics of pig manure treated with different larval instar stages of black soldier fly (Hermetia illucens L.)

“…This may be explained by differences in the decomposition abilities of different BSF larval instar stages, concerning microbiological degradation of pig manure (Choi 2022). The TN values of BSF larvae-treated manure obtained in this study were hardly comparable to those reported in other published studies using chicken, pig, or cattle manure, owing to the different insect larvae or experimental conditions used (Parodi et al 2021;Choi 2022;Grassauer et al 2023). For the TC content and C:N ratio, significant differences between groups were observed for Days 10 and 25 (p < 0.05) but not for Days 0, 5, 15, 20, and 30 (p > 0.05).…”

Viability of the Black Soldier Fly larvae pilot of Dhaka’s Food System project : Assessment using the roadmap approach

“… To date, most manure-valorizing BSF larvae production systems operate at the microscale level. However, specific reduction targets for manure-related emissions will likely necessitate large-scale systems at the farm or industrial level [6].  The pilot contributed to technical knowledge development, but more research and longterm support is needed for further uptake by the private sector to make it sustainable.…”