Thank you for visiting nature.com. The browser version you are using has limited CSS support. For the best experience, we recommend that you use the latest browser version (or turn off compatibility mode in Internet Explorer). Additionally, to ensure continued support, this site will not include styles or JavaScript.
Insect culture, or ‘entomoculture’, involves using plant waste as a substrate for rearing insects while returning the insect feces to the plants for fertilisation. In this study, strawberry (Fragaria x ananassa) and bean (Phaseolus vulgaris) plant waste was added to a wheat bran-based substrate for rearing mealworms (Tenebrio molitor). The waste was either autoclaved or autoclaved followed by fermentation with Trichoderma reesei and then mixed with wheat bran in a 50:50 ratio. Replacing 50% of the wheat bran with autoclaved bean waste had no significant effect on mealworm yield, but yield was reduced when the bean waste was fermented or untreated. The addition of bean waste, treated or not, increased the calcium, potassium and iron content of mealworms. The addition of strawberry waste to the substrate compensated for the yield regardless of pretreatment, but increased the manganese, zinc and iron content of the resulting wheat. With pretreatment of the waste, the amount of plant flavonoids was reduced and they did not accumulate in the wheat biomass. These results provide a reference for the use of plant waste as a partial supplement to the wheat planting substrate and its potential impact on the growth and nutritional value of wheat biomass.
With the world population expected to reach 9.5 billion by 2050, global demand for nutritionally balanced foods is steadily increasing. 1,2 In 2017, global protein consumption was about 202 million tonnes, with meat and cereals being the main sources. 3 In the case of meat, global demand is also growing and is expected to reach 435 million tonnes by 2050. 4
Given resource limitations and the increasing impacts of climate change, there is a growing need for circularity in food production systems to maximise the use of existing resources and reuse waste5. The transition to a circular economy necessarily requires a shift from traditional linear production to circularity, thereby achieving more sustainable production methods in today’s environmental context5,6,7.
The growth of insect biorefining as a waste management and protein production strategy has attracted worldwide attention8,9. Through this approach, low-value waste can be fed to insects, which can then use it as food and feed. Insect farming has the potential to create value from waste, generate economic benefits, and improve the sustainability of agriculture10,11,12 while reducing the environmental impact of waste disposal13,14. In addition to using insect biomass as food and feed, insect farming also produces a residual substrate “manure” rich in plant-available nutrients that can be used as fertilizer15,16 thereby reducing the use of synthetic fertilizers and promoting environmentally friendly farming practices. A variety of organic wastes can be used as substrate for insect rearing17,18,19,20 including “green waste” of plant leaves generated in crop production systems11,12,21. The integration of plant production with insect production has been studied in the literature and is referred to as ‘entomofarming’11,12. The development and implementation of such systems requires additional knowledge on the use of various plant wastes as insect feed.
The yellow mealworm (Tenebrionidae, Coleoptera: Tenebrionidae) is a common agricultural insect worldwide and is considered safe for human consumption in the EU22, making it a more valuable product than insects raised for feed. Compared with other agricultural insects, mealworms have nutritional advantages such as high protein content and a favourable amino acid profile23,24, as well as abundant unsaturated fatty acids, vitamins and minerals25. From a production perspective, large-scale production of mealworms can certainly be automated more efficiently than many other insect species, as they can be reared in the same ‘box’ system throughout their life cycle and they consume dry substrates, making screening and processing easier26.
This insect is a common pest of stored products27 and can utilize wastes of both plant and animal origin28. In this study, we tested strawberry (Fragaria x ananassa Duch.) and bean (Phaseolus vulgaris L.) crop residues as a partial replacement for high-value wheat bran feed substrates. Both wastes were tested without pretreatment, after autoclaving, or after solid-state fermentation with Trichoderma reesei ‘DSM 768’. T. reesei was chosen as it has been shown to be beneficial for the fermentation of insect substrates, thereby increasing the nutritional value of waste streams29,30. We hypothesized that MW would utilize the crop residues and that solid-state fermentation with T. reesei would increase their nutritional value.
Larval weight (MW) increased in all bins and MANOVA showed a significant effect of substrate on composite production variables (individual larval weight on harvest day, fresh larval yield, dry larval yield, total dry faeces produced, mortality and pupation rate) but no significant effect on feed conversion ratio (FCR) (Pillai’s trace value = 2.86, F = 3.51, p < 0.001), with separate one-way ANOVAs showing similar significant differences. Mean individual larval weight at harvest varied (ANOVA, n = 5, p < 0.05, F = 27.4) from 92 to 124 mg (Figure 1).
Growth of mealworm larvae (MW). MW were reared on wheat bran (Bran). 50% of the wheat bran was replaced with autoclaved strawberry waste (SB-A), strawberry waste fermented with T. reesei (SB-F), untreated strawberry waste (SB), autoclaved legume waste (Bean-A), legume waste fermented with T. reesei (Bean-F), or untreated autoclaved legume waste (Bean). The mean weight of individual larvae and their standard deviation are shown. One-way ANOVA (n = 5, p < 0.05) and Tukey’s test showed significant differences in individual larval weights on the day of harvest (week 5). Different letters next to the legend indicate significant differences.
The wheat bran treatment had the highest individual larval weight. Replacing 50% of the wheat bran with autoclaved, unfermented, or fermented bean waste significantly reduced the mean larval weight. Unfermented bean waste treated with an autoclaved bean had higher individual larval weights than fermented T. reesei bean waste. The strawberry waste treatment had the lowest growth rate, with no differences between the three treatments (autoclaved, fermented, or untreated) (Figure 1).
Fresh yield of MW varied between treatments (ANOVA, n = 5, p < 0.05, F = 44.8), with the highest yield in MW receiving 100% wheat bran and the lowest when 50% of the wheat bran was replaced with autoclaved strawberry leaves (Fig. 2). A similar trend was observed for total dry yield, with significant differences between treatments (ANOVA, n = 5, p < 0.05, F = 10). Replacing 50% of the wheat bran with autoclaved legume waste did not reduce total dry yield, but yield was reduced when the legume waste was fermented or untreated (Fig. 2). Addition of strawberry leaves resulted in a significant reduction in dry yield compared with the bran treatment. Treatments also differed in terms of substrate intake, resulting in significant differences in residual fecal output (ANOVA, n = 5, p < 0.05, F = 36.6). The wheat bran-fed group had the lowest fecal output (Fig. 2), which increased significantly after partial replacement of wheat bran. However, neither ANOVA nor MANOVA revealed significant differences in feed conversion ratio among treatment groups.
Mealworm total yield (MW) fresh weight, dry weight, total faecal residual, and feed conversion ratio (FCR). MW is cultured wheat bran. 50% of the wheat bran was replaced with autoclaved strawberry waste (SB-A), strawberry waste fermented with T. reesei (SB-F), untreated strawberry waste (SB), autoclaved legume waste (Bean-A), legume waste fermented with T. reesei (Bean-F), or untreated autoclaved legume waste (Bean). Means and standard deviations of total dry weight, total faecal residual, and feed conversion ratio (FCR) are shown. Significant differences detected by ANOVA and Tukey’s test (n = 5, p < 0.05) are indicated by different letters above the bars.
The highest mortality was observed in MW with the addition of wheat bran (control) and when 50% of the wheat bran was replaced by bean waste, with no significant differences between these treatments. However, the addition of untreated or autoclaved strawberries significantly reduced mortality compared to the control, untreated bean waste, and autoclaved bean waste (Kruskal-Wallis test, n = 5, p > 0.05, H = 22.1) (Fig. 3). There were also significant differences in the pupation rate of MW between the different treatments (ANOVA, n = 5, p > 0.05, F = 34.4), with the highest pupation rate in MW observed when 50% of the wheat bran in the MW matrix was replaced by untreated bean waste. The inclusion of strawberry leaves in the matrix resulted in the lowest pupation rate (Fig. 3).
Mortality and pupation rate of mealworms. MW were reared on wheat bran (Bran). 50% of the wheat bran was replaced with autoclaved strawberry waste (SB-A), strawberry waste fermented with Trichoderma reesei (SB-F), untreated strawberry waste (SB), autoclaved legume waste (Bean-A), legume waste fermented with Trichoderma reesei (Bean-F), or untreated autoclaved legume waste (Bean). Means and standard deviations are shown. Significant differences in pupation rate were shown by ANOVA and Tukey’s test (n = 5, p < 0.05), and significant differences in mortality were shown by Kruskal-Wallis and Dunn’s tests (n = 5, p < 0.05). Significant differences are indicated by different letters above the bars.
The results of partial elemental analysis of the obtained mealworms showed significant differences in the contents of calcium, phosphorus, magnesium, potassium, sulfur, copper, zinc, manganese and iron, while there were no significant differences in the crude protein content of wheat flour (Table 1). The addition of legume waste increased the calcium, zinc and iron contents of wheat flour biomass, while decreasing the copper content, regardless of the pretreatment. In addition, replacing 50% of wheat bran with strawberry waste increased the contents of phosphorus, iron and zinc. The addition of strawberry leaves increased the potassium content of wheat flour biomass, regardless of the pretreatment.
Three flavonoids were identified in the strawberry waste used in the MW feeding experiments (SB, autoclaved SB, and fermented SB; Table 2), but none were detected in the MW fed with these substrates. However, one kaempferol derivative that was not detected in the substrate was detected in the MW fed with fermented strawberry waste (SB-F). Similar results were obtained for the bean waste, with a higher diversity of flavonoids in the untreated bean waste (six species), and novel quercetin derivatives formed in the MW produced from both untreated bean waste and autoclaved bean waste (Bean and Bean-A, respectively). Autoclaved and fermented strawberry waste differed significantly in total flavonoid content (t-test, n = 3, p < 0.05, F = 281.3) and had lower values compared to untreated strawberry waste. For bean waste, a decrease in total flavonoid content was observed between autoclavation and fermentation (t-test, n = 3, p < 0.05, F = 14) (Table 2). However, the flavonoid content of the resulting MW biomass was lower than that of the corresponding fed substrates. Flavonoids were not detected in MW fed with fermented strawberry waste (SB-A), untreated strawberry waste (SB), or fermented bean waste (Bean-F) (Table 2). Flavonoids were not detected in the wheat bran material used as a control in the feeding experiments. Consequently, flavonoids were not detected in larvae fed with this substrate.
Legumes are widely considered to be one of the best plant sources of high-quality protein, with protein contents ranging from 16% to 33% depending on the species31, and beans account for over 80% of global legume production32. The post-harvest residues of broad beans (Phaseolus vulgaris L.), including leaves and stems (straw), are abundant and easily accessible and are usually discarded on farms after the pods are harvested. These residues offer economic opportunities as livestock feed. Legume residues contain more protein and energy than barley and wheat straw33. The effect of adding legume leaves to the diet of animals was studied in male Wistar rats fed a high-fat/high-saccharide diet and showed that legume leaves reduced weight gain and fat accumulation, most likely due to the presence of bioactive compounds34. However, due to the high fibre content of legume leaves and the potential antinutritional effects of their metabolites, tannins and phenolic compounds, only small amounts of legume leaves can be included in animal diets and pre-treatment is recommended for optimal inclusion35,36,37. Another common plant residue is strawberry leaves and stems, which have limited research on their use as animal feed. Strawberry plant residues are suitable as a partial replacement for clover hay in rabbit diets to improve growth performance and economic benefits38. Strawberry leaves also contain bioactive secondary metabolites such as tannins, flavonoids and ascorbic acid39, which may enhance its biological activity.
Previously, strawberry waste has only been reported as a wet supplement to MW40 in production systems, but its nutritional value has not been emphasized. To our knowledge, this study is the first to test dry legumes and strawberry waste as an additive to MW feeding substrates.
The elemental composition of vegetative plant biomass depends on many factors including the mode of plant nutrient acquisition in the growing system (e.g. hydroponics vs. soil culture)41, seasonal variations42 or stress43. The elemental composition of potassium, calcium and zinc in the strawberry plant waste used in this study was within the range of elemental composition observed in strawberry leaves by Dominguez et al.42, while the contents of other elements such as nitrogen, magnesium and iron were above or below the range studied by Dominguez et al.42. The bean plant waste used in our study had relatively high levels of nitrogen, potassium, sulfur and calcium, with concentrations of all elements exceeding the values reported by Oyelude et al.44. Tuma et al.45 reported differences in the contents of potassium, magnesium and calcium in different parts of bean plants and under different nutritional conditions. In this study, whole plant shoots (including stems and leaves, excluding fruits/pods) were pooled and homogenized for bean and strawberry waste streams. This approach recognizes that in addition to the various factors that influence the elemental composition of the waste, its composition may differ from that reported in the literature for a particular plant material. It is therefore critical to assess the composition of plant waste (and waste streams in general) on a case-by-case basis.
In this study, two waste streams were pre-treated (autoclaved and fermented) and used to replace 50% of the wheat bran in a wheat bran (WB) feed matrix. The highest individual larval weights were observed in the 100% wheat bran treatment, while the addition of plant waste compensated for its growth deficit (Figure 1). In addition, differences in WB growth parameters were observed, with WB performing better with autoclaved legume waste than Trichoderma reesei fermented waste and also better than strawberry waste (Figures 1 and 2).
Although there is extensive literature on the use of food waste and high quality substrates in wheat feed matrices46, only a few studies have investigated the addition of dry plant waste to wheat feed matrices, possibly due to its high fibre content, relatively low macronutrient content and possible antinutrient content. A study by Harsanyi et al.47 investigated the addition of yard waste to wheat feed, which contains various components such as grasses, leaves and drupes, providing sufficient macronutrients and resulting in better wheat growth compared to regular vegetable waste. The study found that the addition of moringa leaves to wheat diet improved its nutritional quality without reducing the growth rate, in addition to increasing the levels of crude protein and vitamins. This was observed even at a 50% inclusion rate48. In a study by Bai-wen et al.49, the addition of walnut leaves to a wheat bran-based feed matrix resulted in decreased wheat growth unless the leaves were fermented. Studies have shown that adding leaves such as pomegranate, chestnut and acacia to wheat feed matrices at 10% can enhance the biomass production of wheat. 50 In this study, the nitrogen content of legume waste was higher than that of wheat bran and strawberry leaves (Table 3), and the reason for its slow growth may be its lower energy content than the control bran. However, when 50% of the wheat bran was replaced by autoclaved legume waste, the final yield was not compensated (Figure 2).
Autoclaving or heat treatment of plant material can significantly alter its nutritional value, particularly affecting fibre properties and composition, as well as a range of other nutritious and anti-nutritional factors. For example, autoclaving beans reduces the activity of trypsin and α-amylase inhibitors, thereby increasing the bioavailability of proteins and carbohydrates.51 Autoclaving legume waste produces similar effects. The results of thermal pretreatment of substrates depend on temperature, duration, pressure and possibly the target insect species. For example, in a study by Isibiki et al.30, heat treatment of banana peels at 120 °C and 2 bar for 60 min resulted in reduced growth and metamorphosis of black soldier fly larvae (BSFL), an effect attributed to the release of toxic tannins. A study of sewage sludge showed that heat treatment at 90 °C for 16 hours promoted BSFL growth and maximized the protein and fat content of BSFL biomass.52 In addition to altering nutrient bioavailability and removing antinutrients, heat treatment can also reduce or eliminate microbial activity, which may have a positive or negative effect on insect growth.53
We hypothesized that solid-state fermentation (SSF) using T. reesei could improve the nutritional value of the plant wastes tested in this study. The development of SSF technologies aimed at improving nutrient availability to insects has the potential to enhance insect performance on high-fiber, low-value wastes and modulate the secondary metabolite profile of substrates, thereby increasing insect biomass yields54. The enzyme repertoire of T. reesei, especially the enzymes involved in cellulolytic activity, plays a vital role in the conversion of lignocellulosic biomass into valuable feed ingredients29,55. T. reesei has been used to ferment banana peels30 and Brassica trimmings56, resulting in improved nutrient availability and thus improved bioconversion of black soldier fly larvae (BSFL). However, in this study, fermentation with T. reesei did not promote the growth of MW on the two plant materials tested (Figures 1 and 2), resulting in negative results compared to autoclaved legume waste. This may be partly due to the formation of fungal antinutritional secondary metabolites such as trichocellin AI and B-II57, which have potential insecticidal activity. However, this did not result in higher mortality of MW in the fermentation treatment, but may have hampered the growth of MW in this experiment. In the present study (Table 2), the flavonoid contents of strawberry (autoclaved and fermented) and bean (fermented) substrates decreased dramatically, indicating that substrate pretreatment had a great impact on the flavonoid profile of the substrate.
Results from multivariate (MANOVA) and univariate (ANOVA) analyses were consistent, indicating that each production variable responded independently to the substrate factor/treatment and that correlations between production parameters were generally low. In both trials, differences in MW production between treatments did not translate into differences in feed conversion ratio (FCR) (Figure 2). Studies with MW have shown that changing substrates and environmental conditions can influence growth but do not necessarily result in changes in FCR. MW on substrates provided with fresh plant material (e.g. carrots, oranges or red cabbage) showed higher growth and survival rates, while feed conversion ratios remained unchanged58. In this study, FCR values remained unchanged due to lower substrate consumption in the plant waste treatment, which also explains the higher amounts of manure included in the FCR calculation (Figure 2). The higher amounts of manure in these treatments may be due to the high fibre content of the plant waste.
In this experiment, mortality of wheat larvae varied between treatments, with the highest mortality in the 100% wheat bran and 50% untreated bean residue groups (Figure 3). Zim et al.59 found that replacing wheat bran with citrus and tomato crop residues resulted in very high mortality, which may be explained by the presence of insecticidal secondary plant metabolites. Despite the observed differences, mortality values in this study can be considered low (<12%) and comparable to other studies testing non-toxic substrates21,60,61. However, as highlighted in previous studies62,63, protein and carbohydrate levels in the wheat nutritional substrate may have contributed to the differences in mortality. According to Krenke and Benning64, wheat shows a preference for cereal-based diets such as wheat bran, flour, corn hulls, and oat bran, which indirectly affects their development and pupation rates. However, in this study, the addition of untreated bean waste resulted in higher pupation rates than 100% wheat bran substrate. The effects of diet on larval development in wheat have been demonstrated in the literature47,65, and understanding the specific mechanisms that lead to differences in pupation rates is a topic for future research.
Studies have shown that the elemental composition of wheat is dependent on the composition of the substrate it consumes21,66. The contents of Mg, K, Cu, Zn, Mn, and Fe were comparable to values obtained in other studies67,68. In the present study, the calcium and phosphorus concentrations of wheat did not appear to be related to the concentrations of the added substrate components (Table 2). Studies have shown that wheat has lower calcium content than other insects such as black soldier flies21, and Boykin et al.69 reported methods to increase the calcium content of wheat biomass by gut loading. The addition of bean waste increased the calcium content of wheat, which can be considered as an added value. This enrichment effect was also observed when hemp waste was added to wheat feed substrate21. No accumulation of flavonoids was observed in wheat. Trace amounts of flavonoids were detected in wheat biomass regardless of the feed substrate. In some cases, flavonoids were detected in MW that were not detected in the substrate (kaempferol derivatives in SB-F, quercetin derivatives in Bean and Bean-F; Table 2). This suggests the possible formation of degradation products, which can easily occur in complex flavonoids depending on their chemical structure, such as through glycosylation or hydroxylation70. Furthermore, in this experiment, the waste was dried at 60 °C for pre-treatment to simulate the production scenario, which is not optimal and does not contribute to the preservation of the higher flavonoid content of the plant material.
Thermal treatment (autoclaving or cooking) can significantly change the availability of nutrients in food71, which was also observed in this study, as the concentrations of manganese, iron, potassium, magnesium and calcium in microorganisms increased after autoclaving of legume plant waste. Despite the low concentrations of iron, phosphorus and zinc in the original substrate, the combination of plant waste with the substrate resulted in increased iron, phosphorus and zinc content in microorganisms, which can increase the value of microbial biomass and improve its nutritional value72.
In conclusion, the aim of this study was to test the effect of integrating strawberry and legume waste into wheat larval rearing substrates and to test the effect of pre-treatment of this waste (solid-state fermentation with T. reesei and/or autoclaving). Regardless of the pre-treatment, the lowest growth rate of wheat larvae was achieved when wheat bran was partially replaced by strawberry waste. Legume waste enhanced the growth of wheat larvae, since replacing 50% of wheat bran with autoclaved legume waste did not reduce the final yield of dried wheat larvae. Using plant waste as a substrate for wheat larval rearing is a way to reduce substrate-related costs and produce enriched larvae with improved nutrient content. This approach is cost-effective, especially in regions where drying (e.g. solarization) is sustainable and free. However, more research is needed to determine which substrate properties are modified by pre-treatment to enhance larval yield. In addition, the accumulation of plant antinutrients (e.g. phytic acid) in larvae needs to be studied to ensure the safety and suitability of the product.
Tenebrio molitor eggs (Coleoptera: Tenebrionidae) were provided by the Belgian Centre for Agricultural Insect Research (Inagro, Roeselare, Lembeck-Bethem). 60 g Tenebrio molitor eggs were placed on 1.2 kg wheat bran with a particle size of <2 mm (LM “Lindenberger mill” GmbH, Brandenburg). Tenebrio molitor (MW) were incubated for 5 weeks at 28 °C, 40–60% relative humidity and continuously supplied with 20% agar as wet food. MW were hand-picked and a pool of larvae with an average weight of 10 mg was used for the experiments.
Bean seeds (Phaseolus vulgaris L. var. modesto) were obtained from Kiepenkerl (Nocken, Rhineland-Palatinate, Germany) and grown in the open field at the Humboldt University of Berlin, Germany (52.467715° N, 13.298407° W). All resulting pods were collected and only the remaining vegetative parts (leaves and stems) were collected for the experiments. Strawberry leaf and stem waste was obtained from Martin Bauer GmbH (Westenbergsgrote, Bavaria, Germany) and consisted of vegetative parts collected at different growth stages and different strawberry cultivars (Fragaria × ananassa). Both waste streams were dried at 60°C and processed into powder using a Bergman ECOLINE food processor (Luchs AG, Bochum, North Rhine-Westphalia, Germany). Table 3 shows the partial elemental composition of the two waste streams, excluding the used bran.
Distilled water was gradually added to the dried strawberry waste and legume waste and the mixture was stirred with a kitchen spatula until a moist porous matrix without any observable free water with a dry matter content of 26.8% was formed. After preparation, 150 g of each matrix was transferred to a 500 ml beaker and covered with aluminum foil on top. The beaker was autoclaved at 121 °C for 20 min and then 5 mycelial plugs (7.5 mm diameter) grown on PDA medium (Carl Roth GmbH + Co. KG, Karlsruhe, Germany) were placed on top of the matrix and inoculated with Trichoderma reesei ‘DSM 768’. In addition, the autoclaved beakers remained uninoculated. Five inoculated and five uninoculated beakers (n = 5) per plant material were incubated at 26 °C for 3 weeks to allow the fungi to colonize and coat the inoculated matrix. After 3 weeks, samples were taken from three beakers, homogenized for flavonoid analysis, and dried at 60 °C. For the microwave feeding experiment, materials in all beakers of the same treatment group were combined, homogenized, and dried at 60 °C to prepare the microwave substrate.
MW feeding experiments were conducted to test how the inclusion of pretreated and untreated strawberry waste and bean waste in mealworm feeding substrates would affect the performance and composition of MW. The experiment included seven treatments with five replicates each (n=5). Wheat bran (LM “Lindenberger mill” GmbH, Brandenburg, Germany) was used as the control substrate “bran”, 50% of which was replaced by: 1. fermented strawberry waste “SB-F”, 2. autoclaved strawberry waste “SB-A”, 3. untreated strawberry waste “SB”, 4. fermented legume waste “Bean-F”, 5. autoclaved legume waste “Bean-A” or 6. untreated legume waste “Bean”. The different dry substrates were prepared and homogenized in batches and 120 g were then placed in 13 × 17 cm plastic containers for five replicates. 500 mealworms (average weight 10 mg, counted manually) were added to the substrate surface and reared at 28°C and 40-60% relative humidity for 5 weeks. Three 20 g/L agar plugs (1 cm diameter, 0.5 cm height) were randomly placed on the substrate surface to ensure that larvae in all boxes had continuous access to agar 73. Any remaining unused agar plugs were regularly removed and new agar plugs were added.
At least 10% of the larvae in each box were hand-collected and weighed each week, larval growth was measured, and larvae were returned to the boxes after data collection. At week 5, all larvae were inspected, quantified, weighed, and the number of pupae and feces were determined. After collection, larvae were freeze-dried to obtain a total dry yield for subsequent analysis. In addition to biomass data, mortality and feed conversion rate (FCR) were calculated using the following formula:
The original substrate composition (wheat bran, strawberry waste and bean waste) and the resulting MW (n = 3) were analyzed for Ca, P, Mg, K, S, Cu, Zn, Mn, Fe and N (to determine crude protein). Samples were ground in a coffee grinder (CLOER 7579, Arnsberg, Germany) and elemental analysis (excluding nitrogen) was performed by microwave digestion on a MARS Xpress instrument (CEM, Matthews, NC) according to the LUFA method, volume III, section 10.8.1.2, described by Yakti et al. 74. Multielement analysis was performed using ICP-OES (DIN EN ISO 11885) and an ICP emission spectrometer (iCAP 6300 Duo MFC, Thermo; Waltham, MA, USA). Crude protein determination: total nitrogen was analyzed according to LUFA Bd. III, 4.1.2 using an elemental analyser (Vario MAX, Elementar Analysensysteme GmbH, Hanau, Germany). The crude protein content in MW was determined using a protein-to-nitrogen conversion factor of 4.7675. Flavonoids were analysed according to the method described by Förster et al. Briefly, insect waste or material was extracted with 70% methanol (v/v; pH = 4, acetic acid). Flavonoids in the different extracts were quantified by HPLC and identified based on their UV and mass spectra (ESI-MS, negative ion mode).
All statistical analyses were performed using SPSS version 28.0.0.0 software (IBM Corp., New York, NY, USA). To examine the overall effect of feed substrate on multiple production variables simultaneously, we performed a multivariate analysis of variance (MANOVA) using individual larval weight on harvest day, fresh yield, dry yield, total fecal residue, feed conversion ratio (FCR), mortality, and pupation rate as dependent variables. Then, a one-way analysis of variance (ANOVA) was performed for all measured parameters (n = 5–3, p > 0.05), and the Tukey test was performed after checking normality and homogeneity of variance. For parameters that did not meet the assumptions of the parametric tests, the Kruskal-Wallis test and Dunn’s multiple comparison test were used.
The datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request.
Kim, S. W., et al. Meeting the global demand for feed protein: challenges, opportunities, and strategies. Annals of Animal Bioscience 7, 221–243 (2019).
Kurzymska, L. and Adamkova, A. Nutritional and sensory qualities of edible insects. NFS J. 4, 22–26 (2016).
Henchion, M., Hayes, M., Mullen, A. M., Fenelon, M. and Tiwari, B. Future supply and demand for protein: strategies and factors influencing a sustainable balance. Food 6, 53 (2017).
Boland, M.J., et al. Future supplies of animal proteins for humans. Trends in Food Science and Technology 29, 62–73 (2013).
Awasthi, M. K., et al. “Agricultural Waste Biorefineries Towards a Circular Bioeconomy.” Renewable and Sustainable Energy Reviews 158, 112-122 (2022).
Stegmann, P., Londono, M. and Junginger, M. Circular bioeconomy: Its elements and their role in the European bioeconomy cluster. Resource Conservation & Waste Recycling X 6, 100029 (2020).
Liu, T. et al. Application of black soldier fly larvae in organic fertilizer recycling and its potential for circular bioeconomy: a review. Science of the Total Environment 155122 (2022).
Van Heijs, A., Dicke, M. and van Loon, J. J. A. Insects feeding the world. Journal of Insect Food and Nutrition 1, 3–5 (2015).
Nijonsaba, H., Höhler, J., Kooistra, J., van der Fels-Klerckx, H. and Meuwissen, M. Profitability of insect farms. Journal of Insects for Food and Feed 7, 923–934 (2021).
Brai, A. et al. Efficient use of agricultural waste for natural enrichment of mealworms and evaluation of their nutritional value. Journal of Insect Food and Forage 9, 599–610 (2023).
Jakti, V., Widjaya, E., Förster, N., Mewis, I., and Ulrichs, K. Evaluation of growth performance of desert locusts (Schistocerca gregaria) fed tomato (Solanum lycopersicum) leaves and wheat (Triticum aestivum) sprouts. J. Insect Food 1, 1–10 (2023).
Coudron, C., Deruytter, D., Craeye, S. and Bleyaert, P. Entomological aquaculture: integrating insect farming into greenhouse vegetable production – the case of mealworms and cucumber production on wires. Journal of Insects and Forages 8, 427–437 (2022).
Nguyen, T. T., Tomberlin, J. C. and Vanlaerhoven, S. Ability of black soldier fly larvae (Diptera: Heterodontidae) to recycle food waste. Ecological Entomology 44, 406–410. https://doi.org/10.1093/ee/nvv002 (2015).
Salomone, R. et al. Environmental impacts of insect bioconversion of food waste: application of life cycle assessment to the black soldier fly (Hermetia illucens) treatment process. Journal of Cleaner Production 140, 890–905 (2017).
Post time: Jun-12-2025