A Multilayered Farming System for Producing Black Soldier Fly Larvae

Jenn Hoskins
12th July, 2024

A Multilayered Farming System for Producing Black Soldier Fly Larvae

Black soldier fly (Hermetia illucens) prepupae reared on mealworm frass (FR) produced a high-quality biomass with the highest average protein and among the lowest lipid contents, supporting the viability of this multitrophic system for creating valuable animal feed.

Image adapted from: Deguara et al. / CC BY (Source)

Key Findings

  • The University of Malta study explored using mealworm larvae (MWL) and black soldier fly larvae (BSFL) to convert kitchen waste into valuable biomass
  • MWL fed on kitchen waste grew to an average length of 2.4 cm and weight of 0.12 g, with high protein (44.2%) and lipid (16.5%) content
  • BSFL fed on MWL frass and other feeds achieved high growth rates and efficient feed conversion, making them suitable for animal and aquaculture feed
With the world population on the rise and the demand for food increasing, finding sustainable and efficient sources of protein and lipids for animal and aquaculture feed is crucial. The University of Malta has conducted a study exploring a multitrophic system involving mealworm larvae (MWL, Tenebrio molitor) and black soldier fly larvae (BSFL, Hermetia illucens) to transform fruit and vegetable kitchen waste into usable biomass[1]. This innovative approach aligns with the United Nations' 2030 Agenda for sustainable development, particularly goals 2, 11, and 12, which aim to end hunger, create sustainable cities, and encourage responsible consumption and production. The study found that MWL, when fed primarily on kitchen waste, reached an average prepupal length of 2.4 cm and a fresh weight of 0.12 g. The dry matter protein and lipid contents were 44.2% and 16.5% respectively, with an average specific growth rate (SGR) of 2.2%/day and a feed conversion ratio (FCR) of 7.9. Conversely, BSFL, which were fed a variety of feeds including MWL frass, kitchen waste, and oats, achieved an average prepupal length of 1.3 cm and a fresh weight of 0.16 g. Their dry matter protein and lipid contents were 41.4% and 26.3% respectively, with an average SGR of 4.3%/day and an FCR of 8.9. Notably, the BSFL fed MWL frass obtained some of the highest SGR and lowest FCR values, with one group achieving 7.5%/day and 2.9 respectively. This multitrophic system demonstrates the feasibility of using kitchen waste to feed MWL, whose frass (excrement) is then used to feed BSFL, producing protein- and lipid-rich biomass suitable for animal or aquaculture feed. This approach not only provides a sustainable method for protein and lipid production but also addresses waste management by utilizing kitchen waste efficiently. The findings from this study build on previous research that has highlighted the potential of alternative protein sources. For instance, a lifecycle assessment of mealworm production showed that producing one kilogram of edible protein from mealworms results in lower greenhouse gas emissions and requires less land compared to conventional animal protein sources like milk, chicken, pork, or beef[2]. This supports the idea that insects, such as mealworms and BSFL, can serve as more sustainable sources of animal protein. Additionally, another study quantified the production of greenhouse gases and ammonia by various insect species, including Tenebrio molitor and Hermetia illucens. It found that these insects had a higher relative growth rate and emitted comparable or lower amounts of greenhouse gases and ammonia compared to conventional livestock, such as pigs and cattle[3]. This further reinforces the environmental benefits of using insects for protein production. Moreover, research on the suitability of different organic waste substrates for BSFL showed that brewer's waste was the most suitable among the tested wastes, leading to higher larval survival, growth, and nutrient conversion[4]. This aligns with the current study's findings that BSFL can efficiently convert MWL frass and kitchen waste into valuable biomass. The University of Malta's study contributes to the growing body of evidence supporting the use of insects in sustainable food production systems. By leveraging the natural processes of MWL and BSFL to convert kitchen waste into high-quality protein and lipid sources, this multitrophic system offers a promising solution to meet the increasing demand for animal and aquaculture feed while promoting responsible consumption and waste management.

AgricultureSustainabilityAnimal Science

References

Main Study

1) A multitrophic culture system for the production of black soldier fly larvae (Hermetia illucens)

Published 11th July, 2024

https://doi.org/10.1007/s44187-024-00127-2

Related Studies

2) Environmental impact of the production of mealworms as a protein source for humans - a life cycle assessment.

https://doi.org/10.1371/journal.pone.0051145

3) An exploration on greenhouse gas and ammonia production by insect species suitable for animal or human consumption.

https://doi.org/10.1371/journal.pone.0014445

4) Bioconversion of Three Organic Wastes by Black Soldier Fly (Diptera: Stratiomyidae) Larvae.

https://doi.org/10.1093/ee/nvy141


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