|Wednesday, November 25|
Reducing spatial footprint and handling in a Black Soldier Fly bio-waste conversion unit using incubator containers
* Bram Dortmans, Eawag, Switzerland
Tina Kusumawardhani, Eawag
Teguh Rahayu, Eawag
Christian Zurbrügg, Eawag
At the FORWARD project pilot site in Sidoarjo, Indonesia, a manually operated Black Soldier Fly (BSF) biowaste conversion system has proven that this approach can offer a solution for urban biowaste treatment close to the source of the generated waste - from households and markets. The city of Surabaya has developed two facilities at waste transfer stations, where biowaste from households and markets is currently processed using BSF larvae. The conversion units are setup as six layers of six plastic crates (each 61x43x15 cm) on a pallet. Each layer of crates is separated from the other by a frame providing a ventilation gap of 8 cm. During setup, each crate is stocked with 10,000 5-Day-Old-Larvae (5-DOL) and 3 kg of shredded biowaste. Additional feeding at day four (5 kg) and day seven (4 kg) amounts to the total of 12 kg treated over a period of 12 days. It was observed that the larvae between the age of five and nine days do not require the full surface area in the crate. Based on this observation a trial was designed to test if the spatial footprint of the conversion units and its handling time can be reduced by reducing the crate size in the early age of the larvae without negatively affecting the performance and low-tech nature of the BSF system developed. For the first part of the 12-day feeding period, smaller incubator containers (30x20x10 cm) were used to each accommodate 10,000 5-DOL and fed either 1 or 1.5 kg as a first feeding. Different setups then tested an emptying of the incubator container into the standard conversion crate after 2, 3 or 4 days. Thereafter a varied amount of waste was fed, in one or two additional feedings. A trial using the standard feeding regime and crate sizes was used as control. All thirteen trials fed a total of 12 kg of waste to 10,000 larvae over a duration of 12 days. Each feeding regime was setup in triplet and larval mass was measured on day 0, 7 and 12. Parameters measured on day 12 were survival rate, waste reduction and Biomass Conversion Rate (BCR). Comparing the results between the thirteen trials, a high larval mass, survival rate and BCR in the setup where larvae were fed 1 and 1.5 kg of biowaste in incubator containers in combination with one feeding of 11 and 10.5 kg in the conversion crates after three days was found. Such a setup for biowaste treatment would reduce the spatial footprint of the conversion system by around 20%. Handling time is also reduced as the conversion units do not need to be dismantled for a third feeding which is the case with the current setup.
Synchronous front-face fluorescence measurement as a method to rapid discrimination of edible insect powders
* Giacomo Rossi, Quality and Safety of Food and Feed, Leibniz Institute for Agricultural Engineering and Bioecono, Germany
Sara Bußler, Quality and Safety of Food and Feed, Leibniz Institute for Agricultural Engineering and Bioecono
Julia Durek, Quality and Safety of Food and Feed, Leibniz Institute for Agricultural Engineering and Bioecono
Shikha Ojha, Quality and Safety of Food and Feed, Leibniz Institute for Agricultural Engineering and Bioecono
Oliver Schlüter, Quality and Safety of Food and Feed, Leibniz Institute for Agricultural Engineering and Bioecono
Edible insects are being suggested as a future food and feed source. To promote their widespread on a large scale, comprehensive research studies are required. Identification and classification of insects in the context of knowing their origin and characterizing the technological treatments during processing could support the consumer acceptance. Rapid and non-destructive methods are therefore needed for quality control purpose. Fluorescence spectroscopy is a powerful tool to perform various analyses on environmental and food matrices and could also play an important role in in the context mentioned above. Total synchronous fluorescence spectroscopy, a technique that measures the emission intensity by moving along excitation and emission wavelengths in sync, was applied at several wavelengths shifts (Δλ) in order to classify edible insect powders. For this purpose, seven different insect species (Acheta domesticus, Gryllus bimaculatus, Gryllus assimilis, Locusta migratoria, Schistocerca gregaria, Tenebrio molitor, Zophobas morio) were freeze-dried and ground to record synchronous fluorescence spectra between 250 and 600nm with Δλ ranged between 10 and 120nm in 10 nm steps. Recorded data revealed clear differences in the emission spectra of powder from different insect species. Linear discriminant analysis (LDA) and partial least-square discriminant analysis (PLS-DA) were applied on the whole set of unfolded data in order to investigate the ability of specific detected fluorescence signals to classify insect powders. Therefore, single Δλs were separately studied. Principal components analysis (PCA) as well as LDA and PLS-DA applied on each set of data allowed to obtain good classification and prediction. Results of the current analysis suggest that synchronous fluorescence coupled with powerful chemometric methods could offer a promising tool to identify the composition of different mixed fractions of intermediate insect powders.
Developing of low-impact diets for the mass rearing of Acheta domesticus
* Costanza Jucker, Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan, Italy
Simone Belluco, Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell'Università, Legnaro (PD)
Daniela Lupi, Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan
Sara Savoldelli, Department of Food, Environmental and Nutritional Sciences (DeFENS), University of Milan
Luigi Bonizzi, Department of Biomedical, Surgical and Dental Sciences, University of Milan
Antonia Ricci, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro (PD)
Andrea Mascaretti, Centro per lo Sviluppo sostenibile
Laura Gasco, Dipartimento di Scienze Agrarie, Forestali e Alimentari, University of Turin
The evaluation of different low-cost and sustainable diets, containing by-products and raw-ingredients for the Acheta domesticus rearing will be illustrated.
Lost in the Desert: Influence on wet feed distribution on the density and growth rate of Tenebrio molitor
* David Deruytter, Inagro, Belgium
Carl Coudron, Inagro
Jonas Claeys, Inagro
Stefan Teerlinck, Inagro
The availability of wetfeed is of paramount importance for an efficient growth of Tenebrio molitor. In this research we modelled the changes in density and growth depending on the distance to the wetfeed. It was clear that a heterogeneous distribution, certainly for the small mealworms, results in a heterogeneous distribution of the larvae, a heterogeneous production of frass, a decrease in growth and increase in overall growth variation.
My way or the highway: Transport conditions for Tenebrio molitor
* Jonas Claeys, Inagro, Belgium
Carl Coudron, Inagro
David Deruytter, Inagro
Stefan Teerlinck, Inagro
As insect rearing is becoming more and more specialized, it is to be expected that, analogous to the breeder-broiler distinction in poultry, a homologous distinction will come to be in insect breeding. Companies dedicated to reproducing insects will supply dedicated rearing companies with young livestock. In this regard, transportation of different life stages of the insect is becoming more and more a common practice.
Effect of Prepupae Density in Pupation Crates on Emergence Rate of Black Soldier Flies
* Teguh Rahayu, Eawag, Switzerland
Tina Kusumawardhani, Eawag
Bram Dortmans, Eawag
Christian Zurbrügg, Eawag
Increasing efficiency in a Black Soldier Fly (BSF) rearing unit, entails reducing the required space footprint and labour without compromising the performance. At the BSF rearing unit, as implemented by the FORWARD project in Sidoarjo, Indonesia, the longest retention time in the rearing process is in the pupation unit where prepupae enter the pupation stage, pupate and then emerge as flies. A previous trial, tested the possibility to increase densities of prepupae in 61x43x10 cm pupation crates (using densities of 2,500-7,500 prepupae per crate) and investigated the effect on the emergence rate of the flies. The results revealed that with the densities tested no effect on the emergence rate could be found and it was concluded that densities could be further increased. For the study presented here, 6 different densities between 7,500 and 20,000 prepupae per crate were tested and evaluated. The prepupae used for this trial were fed as larvae on a homogenized and portioned diet of fruit waste and chicken feed (87.5% and 12.5% respectively). Each dark cage (pupation cage) was filled with 16 crates containing prepupae of one density group. Prepupae weight varied between 113±4.7 mg and 164±20.7 mg. Prepupae were added to all crates of each density group over a period of 5 days and crates were added to dark cages after eight days. The emerged flies were harvested daily over a period of two weeks by connecting the pupation cage to one or more oviposition cages for 1 hour per day per cage using a light source to enhance migration of the emerged flies. Total number of flies harvested from each density group was calculated based on the average weight of a triplet sample of 20 flies emerged from each dark cage. The emergence rate is calculated based on the number of prepupae per pupation cage and the number of harvested flies. Further parameters measured include a fly mortality analysis in each dark cage and ambient temperature combined with relative humidity measured in the BSF nursery room every 10 minutes over the complete duration of the trial. Preliminary results show that with the tested range a maximum prepupae density can be determined. Beyond that density, a decrease in emergence rate can be observed. The tested range could increase performance of the rearing unit by nearly threefold per square meter compared to the current prepupae density, impacting significantly on the space footprint and labour requirement.