Yellow Mealworm Research Articles

Amino Acid Digestibility of Yellow Mealworm-Based Ingredients using the Precision-Fed Cecectomized Rooster Assay.

Yellow mealworms (Tenebrio molitor) serve as an alternative protein source. Because the amino acid (AA) concentrations, AA digestibility, and protein quality of ingredients may vary depending on their husbandry, harvest and processing procedures, and other factors, each should be evaluated separately. The objective of this study was to measure the AA composition, AA digestibility, and protein quality of yellow mealworm-based ingredients using the precision-fed cecectomized rooster assay. Eighteen cecectomized roosters were randomly allotted to one of three test ingredients (n=6/group): 1) defatted yellow mealworm flour without cuticles (TM); 2) defatted yellow mealworm flour with cuticles (TMc); and 3) whole yellow mealworm pulp (TMp). After 26h of feed withdrawal, roosters were tube-fed test ingredients (15g ingredient + 15g corn). Following crop intubation, excreta (urine+feces) were collected for 48h. Endogenous loss corrections for AA were made using five additional cecectomized roosters. In addition to calculating AA digestibility, digestible indispensable AA score (DIAAS)-like values were determined and limiting AA were identified based on dog and cat nutrient requirements or recommendations from the Association of American Feed Control Officials (AAFCO), European Pet Food Industry Federation (FEDIAF), and National Research Council (NRC). All data were analyzed by the Mixed Models procedure in SAS version 9.4. All ingredients were highly digestible, with all indispensable AA digestibilities being >90%, with the exception of histidine (89.55%) and valine (89.36%) for TMc. Histidine digestibility was higher (P<0.05) for TM and TMp than for TMc. Isoleucine, leucine, lysine, and valine digestibilities were higher (P<0.05) for TMp than TMc. The DIAAS-like values were highest for TM, which scored high enough to be considered a high-quality protein source for most guidelines and life stages, with DIAAS-like values for TMc and TMp being slightly lower. For dogs and growing puppies, methionine or threonine were the limiting AA depending on reference guideline and life stage. For cats and growing kittens, arginine or methionine were the limiting AA. Even though there were slight differences among ingredients differing in composition (with or without cuticles; whole or defatted), our results demonstrate that yellow mealworm-based proteins have high AA digestibilities and protein quality, making them suitable proteins for pet foods.

Seed Fatty Acids Modify Oviposition of Tenebrio molitor (Coleoptera: Tenebrionidae)

Plant–insect interactions mediated by chemical compounds are well documented in roots and above-ground plant parts except seeds. The latter chemoecological interactions remain poorly studied. The chemical composition of seeds, including attractive, repellent, or inhibitory compounds, likely influences oviposition behavior, yet specific studies on this subject are scarce. This study evaluated the oviposition behavior of the yellow mealworm (Tenebrio molitor L. (Coleoptera, Tenebrionidae)) on substrates of common oat (Avena sativa L. (Poales: Poaceae)), common wheat (Triticum aestivum L. (Poales: Poaceae)), rapeseed (Brassica napus L. (Brassicales: Brassicaceae)), and pure sand. Females laid the most eggs on oat and wheat substrates, while oviposition on sand was reduced by 22%. The chemoreceptors located in the antennae of T. molitor were found not to influence oviposition. Hexane extracts of oat flour were found to contain oviposition-inhibiting compounds, identified as fatty acids. Behavioral tests showed that oleic, palmitic, linoleic, and stearic acids inhibited oviposition at concentrations ranging from 5% to 0.5%. A lower concentration (0.05%) did not have this effect. Additionally, linoleic, palmitic, and oleic acids exhibited repellent properties, whereas stearic acid did not. These findings provide valuable insights into optimizing substrate composition to enhance T. molitor reproduction. This has applications for small-scale laboratory research and large-scale industrial production, supporting the use of T. molitor as an alternative protein source for feed and food.

Utilising common bean and strawberry vegetative wastes in yellow mealworm (Tenebrio molitor) substrates: effects of pre-treatment on growth and composition

Integrating plant production with insect farming, termed "entomoponics," involves using plant waste as a substrate for insect rearing, while returning insect frass to fertilise the plants. In this study, vegetative wastes from strawberry (Fragaria x ananassa), and common bean (Phaseolus vulgaris), were incorporated into a wheat bran-based substrate for rearing the yellow mealworms (MW; Tenebrio molitor). The wastes were either autoclaved or autoclaved then fermented with the fungus Trichoderma reesei, and mixed in a 50:50 ratio with wheat bran. Replacing 50% of the wheat bran with autoclaved beans waste did not significantly affect MW yield, but the yield was reduced when beans wastes were fermented or left untreated. Incorporating beans waste, whether treated or untreated, increased the Ca, K, and Fe content in the MW. Incorporating strawberry vegetative waste into the substrate compensated the yield regardless of the pre-treatment, but enhanced Mn, Zn, and Fe levels in the produced MW. Plant flavonoids were reduced when the wastes were pre-treated and did not accumulate in the MW biomass. These findings provide insights into using plant vegetative wastes as a partial supplement in MW rearing substrates, and the potential effects on the growth and nutritional composition of the resulting MW biomass.

Yellow mealworm (Tenebrio molitor) meal replacing dietary fishmeal alters the intestinal microbiota, anti-oxidation and immunity of large yellow croaker (Larimichthyscrocea).

Yellow mealworm (Tenebrio molitor) meal replacing dietary fishmeal alters the intestinal microbiota, anti-oxidation and immunity of large yellow croaker (Larimichthyscrocea).

Double trouble? Quantifying the risk from co-exposure to multiple pathogens in Tenebrio molitor at different CO2 concentrations.

The insect mass-rearing industry to produce feed and food is expanding rapidly. Insects in production frequently encounter multiple pathogens and environmental stressors simultaneously, which can lead to significant economic losses. Our understanding of the interactions between different stressors remains limited, and existing methods primarily focus on determining overall patterns of additivity, synergism, or antagonism. However, the interactions between different stressors may exhibit more intricate response patterns, such as time or dose dependency. With the expanding industry of insect production, it becomes vital to conduct comprehensive risk assessment of diseases, using approaches that can detect both lethal and sublethal effects. Here, we assessed the risk of co-exposure to a fungal (Metarhizium brunneum) and a bacterial (Bacillus thuringiensis) pathogen in the yellow mealworm (Tenebrio molitor) at ambient and elevated carbon dioxide (CO2) concentrations. We assessed total larval biomass per treatment group, survival, and individual weight gain 14 and 20days after pathogen exposure. To analyse the data, we used a mixture toxicity (MIXTox) model, which identifies dose ratio or dose level dependency in addition to overall antagonism or synergism. The interactions between the two pathogens were mostly antagonistic or additive at both CO2 concentrations and time points, indicating that the observed effects during co-exposure did not exceed the expected combined effects of the individual exposure. We did not find evidence that the interactions between the pathogens substantially change at elevated CO2. The antagonistic interactions measured in the bioassays are likely to be indirect via the insect host, as we did not detect direct inhibition between the two pathogens in in vitro experiments. Here we show that using the MIXTox model is a powerful tool to assess the effects of co-exposure to pathogens and quantify risk of disease in mass-reared insects.

Authentication of EU-Authorized Edible Insect Species in Food Products by DNA Barcoding and High-Resolution Melting (HRM) Analysis.

The consumption of edible insects is a promising approach to meet the increasing global demand for food. Commercialization of edible insects in the EU is regulated by the Novel Food regulation. To date, the yellow mealworm (Tenebrio molitor larva), the migratory locust (Locusta migratoria), the house cricket (Acheta domesticus), and the buffalo worm (Alphitobius diaperinus larva) have been authorized in the EU for human consumption. We aimed to develop a method based on DNA barcoding and high-resolution melting (HRM) analysis for the identification and differentiation of these four EU-authorized edible insect species in food. A primer pair previously designed for DNA metabarcoding, targeting a ~200 bp sequence of mitochondrial 16S rDNA, allowed discrimination between the four insect species in highly processed food. However, house cricket and migratory locust could not unambiguously be differentiated from tropical house cricket, desert locust, superworm, cowpea weevil, and sago worm, respectively. This problem could be solved by designing primers specific for house cricket and migratory locust. By combining these primers with the insect primers, additional polymerase chain reaction (PCR) products for house cricket and migratory locust were obtained, resulting in more complex melt curves compared to the unauthorized insect species. The optimized PCR-HRM assay is a very cost-efficient screening tool for authentication of EU-authorized edible insect species in food.

Evaluating Tenebrio molitor (Coleoptera: Tenebrionidae) for the reduction of fumonisin B1 levels in livestock feed.

The yellow mealworm, Tenebrio molitor, L., can be an important component of the circular economy because of its ability to transform a variety of agricultural wastes and byproducts into valuable livestock feed. Analysis of their ability to endure toxins coupled with their potential to transfer contaminants to higher trophic levels is not complete. Fumonisins, produced primarily by Fusarium verticillioides (Hypocreales: Netriaceae) (Sacc.) Nirenberg (1976), are mycotoxins likely to be encountered by T. molitor in corn and other grain byproducts. Tenebrio molitor larvae were reared on a simulated diet of corn and other grain byproducts treated with a range of maximum recommended fumonisin B1 levels for different livestock feeds. We observed that T. molitor were able to survive, grow, and reduce by excretion and metabolism their retained fumonisin B1 levels by up to 99.7% compared to the diet they consumed. Unknown metabolic processes were inferred from the significantly reduced content of fumonisin B1 in the frass (63.1% to 73.2%) as compared to the diet and by the first report of long-chain acylated fumonisin B1 derivatives in insect frass.

The Development of Yellow Mealworm (Tenebrio molitor) as a Cheap and Simple Model to Evaluate Acute Toxicity, Locomotor Activity Changes, and Metabolite Profile Alterations Induced by Nanoplastics of Different Sizes.

Due to the wide uses of plastic products, nanoplastics are ubiquitous contaminants in the environment. Hence, extensive studies used various models to evaluate the toxicity of nanoplastics. In the present study, we developed yellow mealworm (Tenebrio molitor) as an alternative model to investigate the acute toxicity of nanoplastics. Our results showed that microinjection with 500 mg/kg nanoplastics significantly increased death rate of yellow mealworms after 24 or 48 h, with 100 nm particles being more effective compared with 20 nm ones. Meanwhile, dose-dependent increase of death rate was observed in yellow mealworms after injection with 2-200 mg/kg 100 nm nanoplastics. Exposure to 2 mg/kg 100 nm but not 20 nm nanoplastics also led to hyperactivity of yellow mealworms. Both types of nanoplastics altered metabolite profiles, that 20 nm nanoplastics significantly up-regulated and down-regulated 9 and 12 metabolites, whereas 100 nm nanoplastics significantly up-regulated and down-regulated 16 and 25 metabolites, respectively. Enrichment analysis revealed that 100 nm but not 20 nm nanoplastics significantly affected alpha-linolenic acid metabolism (ko00592) and purine metabolism (ko00230). For the metabolites belonging to these pathways, 100 nm nanoplastics significantly up-regulated stearidonic acid but down-regulated guanine. Combined, these results revealed size-dependent effects of nanoplastics on acute toxicity, hyperactivity and metabolite profile changes in yellow mealworms. These results also indicated the potential uses of yellow mealworms as a cheap and simple model to evaluate the toxicity of nanoplastics.

Cross-Cultural Perspectives on Insect-Based Foods: Insights from Consumers in Greece and Ireland.

In the context of globalization, cross-cultural studies have become increasingly important for understanding differences in consumer acceptance of various foods. This study examines and compares the acceptance of insect-based foods between consumers in Greece and Ireland, two EU countries where insect-based foods are not widely available. An online survey was distributed in both countries and responses from 489 participants (Greece: n = 283; Ireland: n = 206) were analysed, using non-parametric tests for the quantitative data, and a combination of thematic and content analysis for the qualitative data. Overall, the Mann-Whitney U test showed that participants from Greece were significantly less willing to consume insect-based foods than those in Ireland. Among EU-approved insects, the Friedman test showed that participants in Ireland significantly preferred yellow mealworms over house crickets and migratory locusts, whereas participants in Greece showed no significant preference among these species. Both groups were more willing to consume insect-based foods when the insects were not visible, while they differed in their preference of inclusion percentage of insect protein in foods. However, no differences were found in the willingness to consume different types of non-visible insect products. The Mann-Whitney U test showed that participants in Ireland could be more influenced to consume insect-based foods by external factors, with live demonstrations by chefs being the most influential. However, family members would be the most influencing factor for those from Greece. Nuances in participants' willingness to buy insect-based foods are presented and discussed. These findings could inform strategies aimed at increasing the acceptance of insects as food among consumers in European countries with limited exposure to such products.

A Trade-Off Between Antimicrobial Peptide Resistance and Sensitivity to Host Immune Effectors in Staphylococcus aureus InVivo.

Antimicrobial peptides (AMPs) are essential immune effectors of multicellular organisms. Bacteria can evolve resistance to AMPs. Surprisingly, when used to challenge the yellow mealworm beetle, Tenebrio molitor, Staphylococcus aureus resistant to an abundant AMP (tenecin 1) of the very same host species did not increase host mortality or bacterial load compared to infections with wild-type S. aureus. A possible explanation is that antimicrobial resistance is costly due to the collaterally increased sensitivity of AMP-resistant strains to other immune effectors. Here, we study the sensitivity of a group of AMP-resistant S. aureus strains (resistant to tenecin 1 or a combination of tenecin 1 + 2) to other immune effectors such as phenoloxidase and other AMPs invivo. Using RNAi-based knockdown, we investigate S. aureus survival in insect hosts lacking selected immune effectors. We find that all except one AMP-resistant strain displayed collateral sensitivity toward phenoloxidase. Some AMP-resistant strains show sensitivity to components of the yellow mealworm beetle AMP defense cocktail. Our findings are consistent with the idea that resistance to AMPs does not translate into changes in virulence because it is balanced by the collaterally increased sensitivity to other host immune effectors. AMP resistance fails to provide a net survival advantage to S. aureus in a host environment that is dominated by AMPs.

In vitro and in vivo investigations on the use of yellow mealworm (Tenebrio molitor) as a novel protein feed ingredient for fattening lambs

In vitro and in vivo investigations on the use of yellow mealworm (Tenebrio molitor) as a novel protein feed ingredient for fattening lambs

Combining Tenebrio molitor frass with inorganic nitrogen fertilizer to improve soil properties, growth parameters, and nutrient content of Sonchus oleraceus crop

Combining Tenebrio molitor frass with inorganic nitrogen fertilizer to improve soil properties, growth parameters, and nutrient content of Sonchus oleraceus crop

Insect frass fertilizer as soil amendment for improved forage and soil health in circular systems

Insect farming is expected to increase in coming years, thus generating high quantities of frass (insect excreta). Frass valorization hinges on basic agronomic research prior to industry upscaling. Here, we investigated soil physiochemical properties, SMAF (Soil Management Assessment Framework) soil health, CO2 efflux, and bermudagrass [Cynodon dactylon (L.) Pers.] yield and quality as affected by yellow mealworm (Tenebrio molitor L.) frass [3400 and 6800 kg ha−1, low (LF) and high (HF) rates], poultry litter (PL; 3400 kg ha−1), and ammonium nitrate (AN; 67 kg N ha−1). HF increased soil C, N, P, K, and Mg by 10, 12, 44, 58, and 61%, respectively, compared to AN. Even LF increased soil P, K, and Mg by 37, 31, and 32%, respectively, relative to AN. Compared to PL, HF increased soil N, K, and Mg by 12, 30, and 35%, respectively. After two years, HF increased soil C and N stocks 2- and 3-fold, respectively, relative to AN. Forage yield and quality were similar among amendments, while SMAF and CO2 were unaffected. Frass substantially improved soil fertility and maintained forage yield, underscoring its biofertilizer value and potential to increase circularity in agroecosystems under the global backdrop of reduced availability of non-renewable fertilizers.

Liquid Chromatography-Tandem Mass Spectrometric (LC-MS/MS) Determination of Allergenic Proteins in Edible Flour Derived from Yellow Mealworms

Entomophagy offers significant benefits but also poses allergen risks. This study examined the presence of allergenic proteins in freeze-dried yellow mealworm powder using LC-MS/MS with electrospray ionization in positive mode. Allergenic peptides were identified and compared with plant- and animal-based allergens listed under EU Regulation 1169/2011, utilizing certified reference materials. The findings reveal the presence of tropomyosin, which may trigger allergic reactions in individuals with crustacean allergies. The larvae’s diet did not significantly influence allergen content. This research underscores the need for robust legislation to ensure safety in insect production and consumption, supporting the growth of the edible insect industry.

Exploitation of the Nutraceutical Potential of the Infesting Seaweed Chaetomorpha linum as a Yellow Mealworms' Feed: Focus on Nutrients and Antioxidant Activity.

According to the Sustainable Blue Economy Communication, the Farm to Fork Strategy, and the European Green Deal, novel business models supporting the use of resources from oceans and seas are of primary importance. Interestingly, several infesting seaweeds are consumed as foods in Asia and are fundamental ingredients in several traditional dishes. Herein, according to the circular economy approach, we investigate the use of Chaetomorpha linum (CL) as a Tenebrio molitor larvae feed in different percentages: 20%, 50%, and 100%, respectively. We analyzed the effects of CL on the survival and biometric parameters of larvae. The survival rate remained comparable to the control, while the mean weight was inversely proportional to the CL%. The nutrient composition was substantially different from the control, showing increased protein and reduced fat content. Analysis of the secondary metabolites revealed a better fatty acid composition, rich in PUFA, with lipid nutritional indexes comparable to seaweeds and crabs. The simulated gastrointestinal digestion highlights the increased content of essential amino acids, and a two times higher antioxidant activity with respect to the control. Taken together, our results confirm that CL can be used as a TML supplement, with beneficial effects in protein content and fat quality.

Dietary Supplementation of Solid-state Fermented Yellow Mealworm (Tenebrio molitor) Larvae Meal Enriched by Lactobacillus sp. in Guppy (Poecilia reticulata)

The current study examined the dietary solid-state fermented yellow mealworm (Tenebrio molitor) larvae meal inclusion on growth performance, gut microbiota, body composition, liver and intestinal histology and histomorphometric parameters in the guppy (Poecilia reticulata) for 84 days. Guppies were fed diets included with no supplementation (C); 4 g/kg yellow mealworm larva meal (G1), 4 g/kg solid-state fermented with Lactobacillus brevis yellow mealworm larvae meal (G2), 4 g/kg solid-state fermented with Lactobacillus plantarum yellow mealworm larvae meal (G3), the combination of 2 g/kg solid-state fermented with L. brevis plus 2 g/kg solid-state fermented with L. plantarum yellow mealworm larvae meal (G4). For female guppies, the growth performance of the G4 group clearly differed from all groups with the synergistic effect of solid-state fermented with L. plantarum plus L. brevis. In male guppies, G3 and G4 groups showed the highest growth performance values among all groups. The intestinal microbiota of guppies was clearly varied with supplementation groups. Fusobacteria was the most abundant phylum in C, G1, G2 and G3 groups. However, Proteobacteria showed the most intensity in the G4 group. Intestinal villus height, width and surface area were positively affected in solid-state fermented yellow mealworm larvae meal supplementation groups, reaching higher values in G3 and G4 groups. In conclusion, solid-state fermented yellow mealworm larvae meal via 2 g/kg L. plantarum plus 2 g/kg L. brevis can improve growth performance by modulating the gut microbiota of guppies.

The effect of processing on the nutritional values of yellow mealworm and Jamaican field cricket

Abstract Despite extensive research on the nutritional value of edible insects, there is insufficient data on how processing methods affect their chemical composition. In this study, our objective was to assess the effects of boiling, roasting, oven drying, and microwave heating on the nutritional value of insects euthanized via blanching or freezing. Results indicated that both the methods of killing and culinary treatment significantly influenced the nutritional value of yellow mealworms (Tenebrio molitor) and Jamaican field crickets (Gryllus assimilis). Blanched and boiled yellow mealworm larvae contained the lowest level of protein (54.76 g/100 g dry matter (DM)), and the highest content of fat (35.28 g/100 g DM), while blanched, oven-dried Jamaican field crickets yielded the highest levels of protein (72.95 g/100 g DM) and the lowest levels of fat (13.31 g/100 g DM). Culinary treatments uniformly resulted in increased proportions of polyunsaturated fatty acids (PUFAs) and a decrease in the percentage of saturated fatty acids (SFAs) compared to the raw samples. In contrast to fats, the amino acid composition and protein quality, assessed via the essential amino acid index, remained almost unchanged regardless of the type of culinary treatment. Similarly, the profile of volatile compounds was not significantly affected by the culinary treatment. Although acrylamide was undetectable in raw samples, safe levels (0.02-0.13 μg/g DM) were observed in treated samples. Given the rarity of raw insect consumption, gaining insights into the nutritional content of prepared insect-based dishes is of paramount importance. Thus, forthcoming research that is focused on potential risk compounds linked to thermal processing, as well as strategies aimed at mitigating their presence in insect-based foods, may hold significant relevance.

Chitin Analysis in Insect-Based Feed Ingredients and Mixed Feed: Development of a Cost-Effective and Practical Method.

Insects are used as an alternative sustainable, protein-rich ingredient in fish, pet, pig and poultry diets. The significant difference between insect meals and common protein sources is the content of chitin. The nitrogen contained in chitin, which makes up 6.89% of the chitin mass, is detected as crude protein in the analysis and, therefore, deludes the crude protein content in a higher range. In this work, we developed a chitin analysis method that does not require expensive and specialized equipment within insect production and processing industries. The method is based on classical chemical methods such as crude fibre and nitrogen content, making it easily implementable within existing feed analysis. In the process of method validation, a recovery rate of over 95% for chitin in the presence of protein and a standard deviation of < 5% at concentrations as low as 2% was determined. Furthermore, determining chitin at a higher standard deviation of > 10% at concentrations as low as 2% is possible. The method was used to determine the chitin content in various products derived from insect breeding and processing. The chitin content was determined in four insect species (Hermetia Illucens; Tenebrio molitor; Acheta domesticus; Bombyx mori) and different developmental stages of the yellow mealworm (T. molitor), including larvae, pupae and beetles, as well as in commercial pet food. These results also allow for an estimation of the insect protein content, provided that the raw material is known.

IgE-based analysis of sensitization and cross-reactivity to yellow mealworm and edible insect allergens before their widespread dietary introduction

The European Commission authorized the use of dried yellow mealworm (Tenebrio molitor - TM) as a food ingredient under Regulation EU 2021/882. As TM emerges as an important allergen source, sensitization and allergy to TM in various populations need investigation. The aim of this study was to assess the incidence of sensitization to TM before its introduction as a food ingredient in Poland, as well as checking the occurrence of co-sensitivity to TM and other invertebrate allergenic extracts and molecules. This analysis was performed using serum allergen-specific immunoglobulin E (sIgE) results in 6,173 individuals using the ALEX2 test to detect sensitivity to TM and other related allergens. A total of 4.3% of the study population had sIgE to TM extract, with 0.7% of those individuals being mono-sensitized to TM. Sensitization to TM was most commonly associated with a positive response to house cricket and migratory locust allergens. sIgE antibodies against TM significantly more commonly (p < 0.001) co-occurred with sIgE against other invertebrate allergens. Patients with sIgE against TM were most likely sensitised to tropomyosins (49.1% of patients), Niemann-Pick C2 protein (43.8%), group 5/21 allergen (38.6%), class III chitinases (37.1%), and cysteine proteases (34.1%). Based on the serum asIgE levels to TM prior to this ingredient being introduced as a food in Poland, we hypothesised that this primary sensitization may be associated with invertebrate allergies. Our analysis showed that sensitisation to TM was most commonly associated with a positive reaction to house dust mites and shrimp tropomyosins. Therefore, we speculate that individuals allergic to shrimp should exercise caution when consuming foods containing TM.

The structural modifications and techno-functional properties of yellow mealworm protein concentrate is influenced by the presence of residual lipids

Abstract In this study, we compared the impact of partial and total defatting by using hexane and chloroform-methanol respectively, on the lipid and protein profiles, protein structure, and techno-functional properties of a yellow mealworm protein concentrate to address the influence of residuals lipids. The results showed significant changes in the particle size distribution (bimodal versus monomodal), surface hydrophobicity (49.35 vs 21.74 a.u.), and secondary structure of the proteins following defatting. Phospholipids accounted for 60% of the residual lipids content. Although residual lipids after Soxhlet extraction did not notably influence protein solubility except at pH 6 (49.74% after total defatting compared to 59.28% after partial defatting), they negatively impacted foaming properties (foam stability of 100% vs 65% after 30 min) and induced higher emulsifying properties (3.23 vs 2.57 for emulsion stability index) of the mealworm protein extract. Consequently, the residual lipids content after Soxhlet extraction of mealworm protein ingredients appears as an important parameter to consider in determining techno-functional properties.