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Auzins A, Leimane I, Reissaar R, Brobakk J, Sakelaite I, Grivins M, Zihare L. Assessing the Socio-Economic Benefits and Costs of Insect Meal as a Fishmeal Substitute in Livestock and Aquaculture. Animals (Basel) 2024; 14:1461. [PMID: 38791677 PMCID: PMC11117214 DOI: 10.3390/ani14101461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 05/08/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Sustainability targets set by the United Nations, such as Zero Hunger by 2030, encourage the search for innovative solutions to enhance food production while preserving the environment. Alternative protein sources for feed, while conventional resources like soymeal and fishmeal become more expensive and scarcer, is one of the possibilities. Studies on substituting fishmeal with insect meal show promising results in terms of animal growth and feed efficiency. This paper aims to assess the socio-economic benefits and costs of insect meal substituting fishmeal in feed and to highlight the factors influencing performance most. The study evaluates the economic value of insect-based products, waste reduction, and reduced greenhouse gas emissions as socio-economic benefits. It combines empirical data derived from laboratory trials and two case studies covering black soldier fly (Hermetia illucens) and yellow mealworm (Tenebrio molitor). Current analyses reveal negative socio-economic balances, emphasizing that reduction of operating and investment costs through upscaling and technological advancements can give a positive move, as well as factors such as current market valuations for nutrients can change significantly. Thus, a negative balance at the moment does not mean that insect rearing, and larva processing are not desirable from a long-term socio-economic perspective.
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Affiliation(s)
- Alberts Auzins
- Institute of Agricultural Resources and Economics, LV-1039 Riga, Latvia; (I.L.); (L.Z.)
| | - Ieva Leimane
- Institute of Agricultural Resources and Economics, LV-1039 Riga, Latvia; (I.L.); (L.Z.)
| | - Rihard Reissaar
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 51006 Tartu, Estonia;
| | - Jostein Brobakk
- Ruralis—Institute for Rural and Regional Research, 7049 Trondheim, Norway;
| | - Ieva Sakelaite
- Institute of International Relations and Political Science, Vilnius University, LT-01130 Vilnius, Lithuania;
| | | | - Lauma Zihare
- Institute of Agricultural Resources and Economics, LV-1039 Riga, Latvia; (I.L.); (L.Z.)
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Salahuddin M, Abdel-Wareth AAA, Hiramatsu K, Tomberlin JK, Luza D, Lohakare J. Flight toward Sustainability in Poultry Nutrition with Black Soldier Fly Larvae. Animals (Basel) 2024; 14:510. [PMID: 38338153 PMCID: PMC10854853 DOI: 10.3390/ani14030510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/27/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
Black soldier fly larvae (BSFL), Hermetia illucens (L.) (Diptera: Stratiomyidae), have emerged as a promising feed ingredient in broiler chicken diets, known for their high protein content, nutritional richness, and environmental sustainability. This review examines the effects of integrating BSFL into broiler feeds, focusing on aspects such as growth performance, nutrient digestibility, physiological responses, and immune health. The ability of BSFL to transform waste into valuable biomass rich in proteins and lipids underscores their efficiency and ecological benefits. Protein levels in BSFL can range from 32% to 53%, varying with growth stage and diet, offering a robust source of amino acids essential for muscle development and growth in broilers. While the chitin in BSFL poses questions regarding digestibility, the overall impact on nutrient utilization is generally favorable. The inclusion of BSFL in diets has been shown to enhance growth rates, feed efficiency, and carcass quality in broilers, with the larvae's balanced amino acid profile being particularly advantageous for muscle development. BSFL may also support gut health and immunity in broilers due to its bioactive components, potentially influencing the gut's microbial composition and enhancing nutrient absorption and overall health. Moreover, the capacity of BSFL to efficiently convert organic waste into protein highlights their role as an environmentally sustainable protein source for broiler nutrition. Nonetheless, further research is necessary to fully understand the long-term effects of BSFL, ideal inclusion rates, and the impact of varying larval diets and rearing conditions. It is crucial for poultry producers to consult nutritionists and comply with local regulations when incorporating new feed ingredients like BSFL into poultry diets.
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Affiliation(s)
- Md Salahuddin
- Poultry Center, Cooperative Agricultural Research Center, Prairie View A&M University, Prairie View, TX 77446, USA; (M.S.); (D.L.)
| | - Ahmed A. A. Abdel-Wareth
- Poultry Center, Cooperative Agricultural Research Center, Prairie View A&M University, Prairie View, TX 77446, USA; (M.S.); (D.L.)
- Department of Animal and Poultry Production, Faculty of Agriculture, South Valley University, Qena 83523, Egypt
| | - Kohzy Hiramatsu
- Laboratory of Animal Functional Anatomy (LAFA), Faculty of Agriculture, Shinshu University, Kami-ina, Nagano 399-4598, Japan;
| | - Jeffery K. Tomberlin
- Center for Environmental Sustainability through Insect Farming, Texas A&M AgriLife, College Station, TX 77843, USA;
| | - Daylan Luza
- Poultry Center, Cooperative Agricultural Research Center, Prairie View A&M University, Prairie View, TX 77446, USA; (M.S.); (D.L.)
| | - Jayant Lohakare
- Poultry Center, Cooperative Agricultural Research Center, Prairie View A&M University, Prairie View, TX 77446, USA; (M.S.); (D.L.)
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Beesigamukama D, Tanga CM, Sevgan S, Ekesi S, Kelemu S. Waste to value: Global perspective on the impact of entomocomposting on environmental health, greenhouse gas mitigation and soil bioremediation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 902:166067. [PMID: 37544444 PMCID: PMC10594063 DOI: 10.1016/j.scitotenv.2023.166067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 08/08/2023]
Abstract
The innovative use of insects to recycle low-value organic waste into value-added products such as food, feed and other products with a low ecological footprint has attracted rapid attention globally. The insect frass (a combination unconsumed substrate, faeces, and exuviae) contains substantial amounts of nutrients and beneficial microbes that could utilised as fertilizer. We analyse research trends and report on the production, nutrient quality, maturity and hygiene status of insect-composted organic fertilizer (ICOF) generated from different organic wastes, and their influence on soil fertility, pest and pathogen suppression, and crop productivity. Lastly, we discuss the impact of entomocomposting on greenhouse gas mitigation and provide critical analysis on the regulatory aspects of entomocomposting, and utilization and commercialisation ICOF products. This information should be critical to inform research and policy decisions aimed at developing and promoting appropriate standards and guidelines for quality production, sustainable utilization, and successful integration of entomocompost into existing fertilizer supply chains and cropping systems.
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Affiliation(s)
- Dennis Beesigamukama
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya.
| | - Chrysantus M Tanga
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya.
| | - Subramanian Sevgan
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya
| | - Sunday Ekesi
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya
| | - Segenet Kelemu
- International Centre of Insect Physiology and Ecology, P. O. Box 30772-00100, Nairobi, Kenya
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Rossi G, Ojha S, Müller-Belecke A, Schlüter OK. Fresh aquaculture sludge management with black soldier fly (Hermetia illucens L.) larvae: investigation on bioconversion performances. Sci Rep 2023; 13:20982. [PMID: 38017013 PMCID: PMC10684894 DOI: 10.1038/s41598-023-48061-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 11/22/2023] [Indexed: 11/30/2023] Open
Abstract
Aquaculture solid waste (ASW) is a nutrient rich material that can pose a significant environment challenge if not properly managed. This study investigated the potential of black soldier fly (BSF) larvae in converting this waste into biomass. Five substrates comprising chicken feed supplemented with varying proportions of fresh ASW (0%, 25%, 50%, 75%, 100%) were formulated and evaluated for larval growth and waste bioconversion efficiency. High nutrients retention (N: 23.25 ± 1.40%; C: 21.94 ± 0.99%; S: 12.20 ± 1.33%) and feed conversion ratio (1.78 ± 0.08) were detected on substrate 100ASW, although the limited feeding rate (114.54 ± 5.38 mg dry substrate/larvae) and the high amount of indigestible fibres (ADF = 15.87 ± 0.24%; ADL = 6.36 ± 0.17%) were translated to low larval growth (final larval average weight: 66.17 ± 1.81 mg). Decreasing ASW content resulted in reduced fibres and ash, increase in non-fibrous carbohydrates and C/N ratio, and improved larval growth and substrate utilization. However, high larval metabolic activity suggested higher nutrients loss to the environment. Substrate 75ASW demonstrated the best performances in terms of larval production (final larval average weight: 176.30 ± 12.12 mg), waste reduction (substrate reduction corrected by percentage of ASW: 26.76 ± 0.86%) and nutrients assimilation (N: 22.14 ± 1.14%; C: 15.29 ± 0.82%; S: 15.40 ± 0.99%). This substrate closely aligned with optimal BSF rearing substrates reported in literature. Overall, this study highlights the potential of BSF larvae in managing fresh ASW, offering a dual benefit of waste reduction and insect biomass production.
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Affiliation(s)
- Giacomo Rossi
- Department of Systems Process Engineering, Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Max-Eyth-Allee 100, 14469, Potsdam, Germany
| | - Shikha Ojha
- Department of Systems Process Engineering, Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Max-Eyth-Allee 100, 14469, Potsdam, Germany
- Department of Land Sciences, School of Science and Computing, South East Technological University, Cork Road, Waterford, X91 K0EK, Ireland
| | | | - Oliver K Schlüter
- Department of Systems Process Engineering, Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB), Max-Eyth-Allee 100, 14469, Potsdam, Germany.
- Department of Agricultural and Food Sciences, University of Bologna, Piazza Goidanich 60, 47521, Cesena, Italy.
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Gebiola M, Rodriguez MV, Garcia A, Garnica A, Tomberlin JK, Hopkins FM, Mauck KE. Bokashi fermentation of brewery's spent grains positively affects larval performance of the black soldier fly Hermetia illucens while reducing gaseous nitrogen losses. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 171:411-420. [PMID: 37783136 DOI: 10.1016/j.wasman.2023.09.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/21/2023] [Accepted: 09/24/2023] [Indexed: 10/04/2023]
Abstract
Digestion of waste feedstocks by larvae of the black soldier fly Hermetia illucens (Diptera: Stratiomyidae) (BSF) results in proteins for animal feed and organic fertilizer with a reduced environmental footprint, but it can still have negative environmental effects through greenhouse gas (GHG) and ammonia (NH3) emissions. Both biomass conversion by BSF larvae and associated GHG and NH3 emissions can depend on substrate properties that may be optimized through microbial inoculation pre-treatments, such as bokashi fermentation. Here, we quantified the effects of bokashi fermentation of brewery's spent grains on BSF rearing metrics and associated GHG and NH3 emissions at benchtop scale. We found that bokashi fermentation increased larval biomass by 40% and shortened development time by over two days on average, compared with unfermented spent grains. In line with increased larval growth, CO2 emissions in BSF larvae treatments were 31.0 and 79.0% higher in the bokashi fermented spent grains and Gainesville substrates, respectively, compared to the unfermented spent grains. Adding BSF larvae to the spent grains increased cumulative N2O emissions up to 64.0 mg N2O kg substratedry-1 but there were essentially no N2O emissions when larvae were added to fermented spent grains. Bokashi fermentation also reduced NH3 fluxes from the volatilization of substrate nitrogen in the BSF larvae treatment by 83.7-85.8% during days 7 and 9, possibly by increasing N assimilation by larvae or by reducing the transformation of substrate NH4+ to NH3. Therefore, bokashi fermentation may be applied to improve performance of BSF larvae on a common industrial waste stream and reduce associated emissions.
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Affiliation(s)
- Marco Gebiola
- Department of Entomology, University of California Riverside, Riverside, CA, USA.
| | - Michael V Rodriguez
- Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA.
| | - Alexandro Garcia
- Department of Entomology, University of California Riverside, Riverside, CA, USA
| | - Andrea Garnica
- Department of Entomology, University of California Riverside, Riverside, CA, USA
| | | | - Francesca M Hopkins
- Department of Environmental Sciences, University of California Riverside, Riverside, CA, USA
| | - Kerry E Mauck
- Department of Entomology, University of California Riverside, Riverside, CA, USA
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Avila-Arias H, Turco RF, Scharf ME, Groves RL, Richmond DS. Larvae of an invasive scarab increase greenhouse gas emissions from soils and recruit gut mycobiota involved in C and N transformations. Front Microbiol 2023; 14:1102523. [PMID: 37025631 PMCID: PMC10072269 DOI: 10.3389/fmicb.2023.1102523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 03/01/2023] [Indexed: 04/08/2023] Open
Abstract
Background Soil-derived prokaryotic gut communities of the Japanese beetle Popillia japonica Newman (JB) larval gut include heterotrophic, ammonia-oxidizing, and methanogenic microbes potentially capable of promoting greenhouse gas (GHG) emissions. However, no research has directly explored GHG emissions or the eukaryotic microbiota associated with the larval gut of this invasive species. In particular, fungi are frequently associated with the insect gut where they produce digestive enzymes and aid in nutrient acquisition. Using a series of laboratory and field experiments, this study aimed to (1) assess the impact of JB larvae on soil GHG emissions; (2) characterize gut mycobiota associated with these larvae; and (3) examine how soil biological and physicochemical characteristics influence variation in both GHG emissions and the composition of larval gut mycobiota. Methods Manipulative laboratory experiments consisted of microcosms containing increasing densities of JB larvae alone or in clean (uninfested) soil. Field experiments included 10 locations across Indiana and Wisconsin where gas samples from soils, as well as JB and their associated soil were collected to analyze soil GHG emissions, and mycobiota (ITS survey), respectively. Results In laboratory trials, emission rates of CO2, CH4, and N2O from infested soil were ≥ 6.3× higher per larva than emissions from JB larvae alone whereas CO2 emission rates from soils previously infested by JB larvae were 1.3× higher than emissions from JB larvae alone. In the field, JB larval density was a significant predictor of CO2 emissions from infested soils, and both CO2 and CH4 emissions were higher in previously infested soils. We found that geographic location had the greatest influence on variation in larval gut mycobiota, although the effects of compartment (i.e., soil, midgut and hindgut) were also significant. There was substantial overlap in the composition and prevalence of the core fungal mycobiota across compartments with prominent fungal taxa being associated with cellulose degradation and prokaryotic methane production/consumption. Soil physicochemical characteristics such as organic matter, cation exchange capacity, sand, and water holding capacity, were also correlated with both soil GHG emission, and fungal a-diversity within the JB larval gut. Conclusions: Results indicate JB larvae promote GHG emissions from the soil directly through metabolic activities, and indirectly by creating soil conditions that favor GHG-associated microbial activity. Fungal communities associated with the JB larval gut are primarily influenced by adaptation to local soils, with many prominent members of that consortium potentially contributing to C and N transformations capable of influencing GHG emissions from infested soil.
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Affiliation(s)
- Helena Avila-Arias
- Department of Entomology, Purdue University, West Lafayette, IN, United States
- *Correspondence: Helena Avila-Arias,
| | - Ronald F. Turco
- Department of Agronomy, Purdue University, West Lafayette, IN, United States
| | - Michael E. Scharf
- Entomology and Nematology Department, University of Florida, Gainesville, FL, United States
| | - Russell L. Groves
- Department of Entomology, University of Wisconsin-Madison, Madison, WI, United States
| | - Douglas S. Richmond
- Department of Entomology, Purdue University, West Lafayette, IN, United States
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Fuhrmann A, Wilde B, Conz RF, Kantengwa S, Konlambigue M, Masengesho B, Kintche K, Kassa K, Musazura W, Späth L, Gold M, Mathys A, Six J, Hartmann M. Residues from black soldier fly (Hermetia illucens) larvae rearing influence the plant-associated soil microbiome in the short term. Front Microbiol 2022; 13:994091. [PMID: 36225364 PMCID: PMC9550165 DOI: 10.3389/fmicb.2022.994091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/06/2022] [Indexed: 11/13/2022] Open
Abstract
The larvae of the black soldier fly (BSFL, Hermetia illucens) efficiently close resource cycles. Next to the nutrient-rich insect biomass used as animal feed, the residues from the process are promising plant fertilizers. Besides a high nutrient content, the residues contain a diverse microbial community and application to soil can potentially promote soil fertility and agricultural production through the introduction of beneficial microbes. This research assessed the application of the residues on plant-associated bacterial and fungal communities in the rhizosphere of a grass-clover mix in a 42-day greenhouse pot study. Potted soil was amended with BSFL residues (BR+) or conventional compost (CC+) produced by Rwandan waste management companies in parallel to residues and compost sterilized (BR-, CC-) by high-energy electron beam (HEEB) as abiotic controls. The fertilizers were applied at a rate of 150 kg N ha−1. Soil bacterial and fungal communities in both fertilizer and soil were assessed by high-throughput sequencing of ribosomal markers at different times after fertilizer application. Additionally, indicators for soil fertility such as basal respiration, plant yield and soil physicochemical properties were analyzed. Results showed that the application of BSFL residues influenced the soil microbial communities, and especially fungi, stronger than CC fertilizers. These effects on the microbial community structure could partly be attributed to a potential introduction of microbes to the soil by BSFL residues (e.g., members of genus Bacillus) since untreated and sterilized BSFL residues promoted different microbial communities. With respect to the abiotic effects, we emphasize a potential driving role of particular classes of organic matter like fiber and chitin. Indeed, especially taxa associated with decomposition of organic matter (e.g., members of the fungal genus Mortierella) were promoted by the application of BSFL residues. Soil fertility with respect to plant yield (+17% increase compared to unamended control) and basal respiration (+16% increase compared to unamended control) tended to be improved with the addition of BSFL residues. Findings underline the versatile opportunities for soil fertility arising from the application of BSFL residues in plant production and point to further research on quantification of the described effects.
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Affiliation(s)
- Adrian Fuhrmann
- Sustainable Agroecosystems Group, Institute of Agricultural Sciences, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- Singapore-ETH Centre, Singapore, Singapore
| | - Benjamin Wilde
- Sustainable Agroecosystems Group, Institute of Agricultural Sciences, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Rafaela Feola Conz
- Sustainable Agroecosystems Group, Institute of Agricultural Sciences, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | | | | | | | - Kokou Kintche
- International Institute of Tropical Agriculture, Kigali, Rwanda
| | - Kinfe Kassa
- Faculty of Water Supply and Environmental Engineering, Arba Minch University, Arba Minch, Ethiopia
| | - William Musazura
- School of Agricultural, Earth and Environmental Sciences, University of Kwazulu-Natal, Pietermaritzburg, South Africa
| | - Leonhard Späth
- Sustainable Agroecosystems Group, Institute of Agricultural Sciences, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- Transdisciplinary Lab, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Moritz Gold
- Sustainable Food Processing Laboratory, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zürich, Zürich, Switzerland
- Department of Sanitation, Water and Solid Waste for Development (Sandec), Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Alexander Mathys
- Sustainable Food Processing Laboratory, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zürich, Zürich, Switzerland
| | - Johan Six
- Sustainable Agroecosystems Group, Institute of Agricultural Sciences, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Martin Hartmann
- Sustainable Agroecosystems Group, Institute of Agricultural Sciences, Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
- *Correspondence: Martin Hartmann,
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Lopes IG, Yong JW, Lalander C. Frass derived from black soldier fly larvae treatment of biodegradable wastes. A critical review and future perspectives. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 142:65-76. [PMID: 35176600 DOI: 10.1016/j.wasman.2022.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 01/12/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Inadequately treated biodegradable waste is considered an environmental, social and economic threat worldwide, which call for great attention. Waste treatment with larvae of the black soldier fly (BSF, Hermetia illucens) complies with the concepts of circular economy, as it enables the transformation of these wastes into marketable products, closing loops and promoting circularity. The processing residues of the treatment (frass) is constantly generated in waste management facilities in large volumes, and this product can be used as an organic fertilizer in agriculture, stimulating a transition to a circular economy. However, many aspects related to frass are still unknown, such as its varying composition of nutrients, microorganisms and bioactive compounds, its post-processing requirements for improved biological stabilization, its behavior in the soil and action in the plants' metabolism, among other aspects. In this review article, we highlight the potential of frass from BSF larvae treatment of biodegradable waste in the world market regarding its possible use as a fertilizer, summarize recent results with this novel product and point towards future research perspectives.
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Affiliation(s)
| | - Jean Wh Yong
- Department of Energy and Technology, Swedish University of Agricultural Sciences, Box 7032, 75007 Uppsala, Sweden
| | - Cecilia Lalander
- Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden.
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Gebremikael MT, Wickeren NV, Hosseini PS, De Neve S. The Impacts of Black Soldier Fly Frass on Nitrogen Availability, Microbial Activities, C Sequestration, and Plant Growth. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2022. [DOI: 10.3389/fsufs.2022.795950] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Using insects, notably black soldier fly (BSF), is becoming one of the emerging technologies to valorize agrifood waste into high-value products, such as proteins for animal feed. Its market is expected to grow more rapidly following the new European legislation extending larvae protein use in poultry farming. The anticipated increase in larvae protein also results in a parallel increase in frass, a residue leftover after rearing the larvae and selling as a biofertilizer. Little is known about the impacts of frass made from different feedstocks used for raising the larvae on plant growth and soil quality. We set up an incubation and pot experiment to understand their effect on plant growth and soil quality and tested seven frass fertilizers made from various types of food waste and anaerobic digestate and potato pulp as reference materials using maize as a test plant. We found that the effect of frass on N availability and soil microbial quality significantly (p < 0.05) varied depending on the feedstock used for rearing the BSF larvae. N immobilization occurred up to more than 70 days, and 4–20% net N was released at the end of the 103-day-long experiment. In line with N availability dynamics, most of the frass treatments did not significantly increase the plant growth. All frasses significantly increased the microbial biomass C and enzyme activities. About 56–70% of the applied C in frass is estimated to be stable in the soil. Our data confirm that frass is a valuable product to improve soil quality but need to be applied with N sources that are readily available to avoid nutrient shortage during plant growth.
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Watson C, Preißing T, Wichern F. Plant Nitrogen Uptake From Insect Frass Is Affected by the Nitrification Rate as Revealed by Urease and Nitrification Inhibitors. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021. [DOI: 10.3389/fsufs.2021.721840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Insect protein production is considered a sustainable alternative to livestock protein which furthermore utilizes waste streams. Its production can have positive but also potentially negative environmental effects, which require evaluation. Frass, the byproduct of insect production, is regarded an efficient organic fertilizer or soil amendment. However, several studies report negative frass effects on plant growth and nitrogen (N) cycling. Therefore, a pot trial was carried out which sought to understand N release from frass and subsequent growth and nutrient uptake of Italian ryegrass. Mealworm frass (MWF) or buffalo worm frass (BFW) was applied at two rates (1.5 and 3% w/w) to a soil-sand mix. To evaluate N release processes, frass was applied alone, with a nitrification inhibitor (NI), a urease inhibitor (UI), or both (NI+UI). Plant N, nutrient uptake and soil inorganic N were measured at the experiment's end. To gauge whether altered N fluxes induced changes in the microbial community, soil microbial biomass, bacterial/archaeal abundances and ergosterol content as a fungal biomarker, were determined. Both frass types and application rates stimulated microbial growth and N mineralization. The 3% rate inhibited seed germination, possibly due to salinity or ammonia toxicity. At the 1.5% rate, both frass types were effective fertilizers. MWF led to higher biomass and nutrient uptake, owing to its higher extractable nutrient concentrations. The 3% rate caused nitrite accumulation in the absence of NI. NI improved plant biomass, nutrient uptake, stimulated archaeal and bacterial abundances and prevented nitrite accumulation. UI reduced N mineralization, showing that a substantial fraction of frass organic N is ureic. UI enhanced fungal contribution to the microbial biomass, revealing the importance of bacteria in frass N mineralization processes when UI is not applied. NI and UI combined, induced greater N release from frass than UI or NI alone. Our study demonstrated the usefulness of NI and UI in studying N release from frass. NI can improve plant N uptake and minimize N losses following frass application, reducing its potentially negative effects. UI can retard N release from frass, allowing its application as a slow-release fertilizer, but should not be used concurrently with NI.
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