Nutritional Value of Mealworm, Tenebrio molitor as Food Source

Influence of the processing on composition, protein structure and techno-functional properties of mealworm protein concentrates produced by isoelectric precipitation and ultrafiltration/diafiltration

Edible insects represent a great alternative protein source but food neophobia remains the main barrier to consumption. However, the incorporation of insects as protein-rich ingredients, such as protein concentrates, could increase acceptance. In this study, two methods, isoelectric precipitation and ultrafiltration-diafiltration, were applied to produce mealworm protein concentrates, which were compared in terms of composition, protein structure and techno-functional properties. The results showed that the protein content of the isoelectric precipitation concentrate was higher than ultrafiltration-diafiltration (80 versus 72%) but ash (1.91 versus 3.82%) and soluble sugar (1.43 versus 8.22%) contents were lower. Moreover, the protein structure was affected by the processing method, where the ultrafiltration-diafiltration concentrate exhibited a higher surface hydrophobicity (493.5 versus 106.78 a.u) and a lower denaturation temperature (161.32 versus 181.44 °C). Finally, the ultrafiltration-diafiltration concentrate exhibited higher solubility (87 versus 41%) and emulsifying properties at pH 7 compared to the concentrate obtained by isoelectric precipitation.

Improving the nutritional values of yellow mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) larvae as an animal feed ingredient: a review

Yellow mealworm larvae (YML; Tenebrio molitor) are considered as a valuable insect species for animal feed due to their high nutritional values and ability to grow under different substrates and rearing conditions. Advances in the understanding of entomophagy and animal nutrition over the past decades have propelled research areas toward testing multiple aspects of YML to exploit them better as animal feed sources. This review aims to summarize various approaches that could be exploited to maximize the nutritional values of YML as an animal feed ingredient. In addition, YML has the potential to be used as an antimicrobial or bioactive agent to improve animal health and immune function in production animals. The dynamics of the nutritional profile of YML can be influenced by multiple factors and should be taken into account when attempting to optimize the nutrient contents of YML as an animal feed ingredient. Specifically, the use of novel land-based and aquatic feeding resources, probiotics, and the exploitation of larval gut microbiomes as novel strategies can assist to maximize the nutritional potential of YML. Selection of relevant feed supplies, optimization of ambient conditions, the introduction of novel genetic selection procedures, and implementation of effective post-harvest processing may be required in the future to commercialize mealworm production. Furthermore, the use of appropriate agricultural practices and technological improvements within the mealworm production sector should be aimed at achieving both economic and environmental sustainability. The issues highlighted in this review could pave the way for future approaches to improve the nutritional value of YML.

Insects as an alternative protein source for poultry nutrition: a review

This review summarizes the most relevant scientific literature related to the use of insects as alternative protein sources in poultry diets. The black soldier fly, the housefly, the beetle, mealworms, silkworms, earthworms, crickets, and grasshoppers are in the spotlight because they have been identified as an important future source of sustainable animal proteins for poultry feeding. Insect meals meet poultry requirements in terms of nutritional value, essential amino acid composition, nutrient digestibility, and feed acceptance. Furthermore, they are enriched with antimicrobial peptides and bioactive molecules that can improve global health. Results from poultry studies suggest equivalent or enhanced growth performances and quality of end-products as compared to fish meal and soybean meal. To outline this body of knowledge, this article states established threads of research about the nutrient profiles and the digestibility of insect meals, their subsequent effects on the growth and laying performances of poultry as well as the quality of meat, carcass, and eggs. To fully exploit insect-derived products, the effects of insect bioactive molecules (antimicrobial peptides, fatty acids, and polysaccharides) were addressed. Furthermore, as edible insects are likely to take a meaningful position in the feed and food chain, the safety of their derived products needs to be ensured. Some insights into the current knowledge on the prevalence of pathogens and contaminants in edible insects were highlighted. Finally, the effect of insect farming and processing treatment on the nutritive value of insect larvae was discussed. Our overview reveals that using insects can potentially solve problems related to reliance on other food sources, without altering the growth performances and the quality of meat and eggs.

Structural, physicochemical, and immune-enhancing properties of edible insect protein isolates from Protaetia brevitarsis larvae

Edible insects are promising future food resources globally. Herein, the structural, physicochemical, and bio-functional properties of edible insect protein isolates (EPIs) extracted from Protaetia brevitarsis larvae were investigated. The results showed that EPIs have a high total essential amino acid content; moreover, β-sheet is the major secondary protein structure. The EPI protein solution was highly soluble and electrically stable and did not aggregate easily. In addition, EPIs exhibited immune-enhancing properties; EPI treatment of macrophages induced the activation of macrophages and consequently promoted the production of pro-inflammatory mediators (NO, TNF-α, and IL-1β). Moreover, macrophage activation of EPIs was confirmed to occur through the MAPK and NF-κB pathways. In conclusion, our results suggest that the isolated P. brevitarsis protein can be fully utilized as a functional food material and alternative protein source in the future food industry.

Performance of Chouioia cunea reared from a coleopteran alternative host as a biocontrol agent against the invasive lepidopteran pest, Hyphantria cunea

BACKGROUND

Chouioia cunea is a generalist pupal endoparasitoid. Native to Eurasia, the parasitoid has been mass-reared on an alternative lepidopteran host (Antheraea pernyi) to successfully control the exotic invasive lepidopteran pest Hyphantria cunea in China. To solicit more accessible hosts, this study evaluated the potential of an easily cultured coleopteran beetle (Tenebrio molitor) as a substitute for rearing C. cunea through comparing the relative performance of the parasitoids reared from both alternative hosts on H. cunea.

RESULTS

Compared with those reared from A. pernyi, the parasitoids reared from T. molitor (i.e., T. molitor vs. A. pernyi groups) performed equally well in terms of parasitism rate (94.4 vs. 88.9%), number of offspring produced per parasitized host (278 vs. 286), and female body length (1.334 vs. 1.351 mm), hind-tibia length (0.322 vs. 0.324 mm) and number of mature oocytes in the ovarioles (171 vs. 187), or even better based on offspring pre-emergence time (16.0 vs 16.9 days) and percentages of emerged offspring (99.8 vs. 99.1%) and female offspring (97.1 vs. 91.3%). Flight performance testing indicated that young C. cunea adults emerged from T. molitor had a similar percentage of actively flying wasps (76.9 vs. 72.9%) and a lower percentage of inactive wasps (2.3 vs. 10.6%) when compared to those reared from A. pernyi.

CONCLUSION

Given the remarkable adaptability of C. cunea and the vast availability of T. molitor as a common resource insect worldwide, this indigenous parasitoid could be mass-reared on T. molitor to improve the prospect of biological control of H. cunea in its invaded regions. © 2022 Society of Chemical Industry.

Analysis of the Composition of Different Instars of Tenebrio molitor Larvae using Near-Infrared Reflectance Spectroscopy for Prediction of Amino and Fatty Acid Content

Insects are a sustainable protein source for food and feed. The yellow mealworm (Tenebrio molitor L.) is a promising candidate for industrial insect rearing and was the focus of this study. This research revealed the diversity of Tenebrio molitor larvae in the varying larval instars in terms of the nutritional content. We hypothesized that water and protein are highest in the earlier instar, while fat content is very low but increases with larval development. Consequently, an earlier instar would be a good choice for harvest, since proteins and amino acids content decrease with larval development. Near-infrared reflectance spectroscopy (NIRS) was represented in this research as a tool for predicting the amino and fatty acid composition of mealworm larvae. Samples were scanned with a near-infrared spectrometer using wavelengths from 1100 to 2100 nm. The calibration for the prediction was developed with modified partial least squares (PLS) as the regression method. The coefficient for determining calibration (R²_C) and prediction (R²_P) were >0.82 and >0.86, with RPD values of >2.20 for 10 amino acids, resulting in a high prediction accuracy. The PLS models for glutamic acid, leucine, lysine and valine have to be improved. The prediction of six fatty acids was also possible with the coefficient of the determination of calibration (R²_C) and prediction (R²_P) > 0.77 and >0.66 with RPD values > 1.73. Only the prediction accuracy of palmitic acid was very weak, which was probably due to the narrow variation range. NIRS could help insect producers to analyze the nutritional composition of Tenebrio molitor larvae fast and easily in order to improve the larval feeding and composition for industrial mass rearing.

Influence of Dietary Protein Content on the Nutritional Composition of Mealworm Larvae (Tenebrio molitor L.)

The use of insects as livestock feed is becoming increasingly accepted because they provide an important source of protein. The purpose of this study was to investigate the chemical composition of mealworm larvae (Tenebrio molitor L.) reared on a range of diets that differed in nutritional composition. Focus was placed on the influence of dietary protein content on larval protein and amino acid composition. For the experimental diets, wheat bran was chosen as the control substrate. The following types of flour-pea protein, rice protein, sweet lupine, and cassava, as well as potato flakes, were mixed with wheat bran and used as the experimental diets. An analysis of the moisture, protein, and fat content was then carried out for all diets and larvae. Furthermore, the amino acid profile was determined. It was shown that supplementing the feed with pea and rice protein was most suitable in terms of high protein yield in larvae (70.9-74.1% dry weight) with low fat content (20.3-22.8% dry weight). The total amino acid content was highest in larvae that were fed with a mixture of cassava flour and wheat bran (51.7 ± 0.5% dry weight), as well as the highest content of essential amino acids (30.4 ± 0.2% dry weight). Moreover, a weak correlation between larval protein content and diet was identified, yet a stronger influence of dietary fats and carbohydrates on larval composition was found. This research could result in improved formulations of artificial diets for Tenebrio molitor larvae in the future.

Hemp Waste as a Substrate for Hermetia illucens (L.) (Diptera: Stratiomyidae) and Tenebrio molitor L. (Coleoptera: Tenebrionidae) Rearing

The proper treatment of cannabis agricultural wastes can reduce the environmental impact of its cultivation and generate valuable products. This study aimed to test the potential of cannabis agricultural wastes as a substrate for the rearing of black soldier fly larvae (BSFL) and yellow mealworms (MW). In the case of BSFL, replacing the fibre component (straw) in the substrate with the hemp waste can increase the nutritional value of the substrate and led to bigger larvae. The bigger larvae had lower P and Mg, and higher Fe and Ca. Crude protein also varied based on the size of larvae and/or the content of protein in the initial substrate, which was boosted by replacing straw with hemp material. No other cannabinoids than cannabidiolic acid (CBDA), cannabigerolic acid (CBGA), and cannabidiol (CBD) were found in significant amounts in the larvae. In the case of MW, the larvae grew less on the hemp material in comparison to wheat bran. Replacing wheat bran with the hemp material led to smaller larvae with higher Ca, Fe, K, and crude protein content, but lower Mg and P values. No cannabinoids were detected in the MW fed with the hemp material.

Near-Infrared Reflectance Spectroscopy for Quantitative Analysis of Fat and Fatty Acid Content in Living Tenebrio molitor Larvae to Detect the Influence of Substrate on Larval Composition

Several studies have shown that mealworms (Tenebrio molitor L.) could provide animals and humans with valuable nutrients. Tenebrio molitor larvae were studied to determine whether their rearing diets affected their fat and fatty acid content and to ascertain if it is possible to detect the changes in the larval fat composition using near-infrared reflectance spectroscopy (NIRS). For this reason, a standard control diet (100% wheat bran) and an experimental diet, consisting of wheat bran and the supplementation of a different substrate (coconut flour, flaxseed flour, pea protein flour, rose hip hulls, grape pomace, or hemp protein flour) were used. The results showed lesser weight gain and slower growth rates for larvae raised on diets with a high fat content. A total of eight fatty acids were identified and quantified, where palmitic, oleic, and linoleic acids were the most prevalent and showed a correlation between larval content and their content in the rearing diets. There was a high content of lauric acid (3.2-4.6%), myristic acid (11.4-12.9%), and α-linolenic acid 8.4-13.0%) in mealworm larvae as a result of the high dietary content of these fatty acids. NIR spectra were also influenced by the fat and fatty acid composition, as larval absorbance values differed greatly. The coefficient of the determination of prediction (R²_P) was over 0.97, with an RPD value of 8.3 for the fat content, which indicates the high predictive accuracy of the NIR model. Furthermore, it was possible to develop calibration models with great predictive efficiency (R²_P = 0.81-0.95, RPD = 2.6-5.6) for all fatty acids, except palmitoleic and stearic acids which had a low predictive power (R²_P < 0.5, RPD < 2.0). The detection of fat and fatty acids using NIRS can help insect producers to quickly and easily analyze the nutritional composition of mealworm larvae during the rearing process.

Serum Metabolomics and Proteomics to Study the Antihypertensive Effect of Protein Extracts from Tenebrio molitor

Hypertension is the leading risk factor for premature death worldwide and significantly contributes to the development of all major cardiovascular disease events. The management of high blood pressure includes lifestyle changes and treatment with antihypertensive drugs. Recently, it was demonstrated that a diet supplemented with Tenebrio molitor (TM) extracts is useful in the management of numerous pathologies, including hypertension. This study is aimed at unveiling the underlying mechanism and the molecular targets of intervention of TM dietary supplementation in hypertension treatment by means of proteomics and metabolomics techniques based on liquid chromatography coupled with high-resolution mass spectrometry. We demonstrate that serum proteome and metabolome of spontaneously hypertensive rats are severely altered with respect to their normotensive counterparts. Additionally, our results reveal that a diet enriched with TM extracts restores the expression of 15 metabolites and 17 proteins mainly involved in biological pathways associated with blood pressure maintenance, such as the renin–angiotensin and kallikrein–kinin systems, serin protease inhibitors, reactive oxygen scavenging, and lipid peroxidation. This study provides novel insights into the molecular pathways that may underlie the beneficial effects of TM, thus corroborating that TM could be proposed as a helpful functional food supplement in the treatment of hypertension.

Insects in Pet Food Industry-Hope or Threat?

Due to the increasing global population, the world cannot currently support the well-known techniques of food production due to their harmful effects on land use, water consumption, and greenhouse gas emissions. The key answer is a solution based on the use of edible insects. They have always been present in the diet of animals. They are characterized by a very good nutritional value (e.g., high protein content and contents of essential amino acids and fatty acids, including lauric acid), and products with them receive positive results in palatability tests. Despite the existing literature data on the benefits of the use of insects as a protein source, their acceptance by consumers and animal caregivers remains problematic. In spite of the many advantages of using insects in pet food, it is necessary to analyze the risk of adverse food reactions, including allergic reactions that may be caused by insect consumption. Other hazards relate to the contamination of insects. For example, they can be contaminated with anthropogenic factors during breeding, packaging, cooking, or feeding. These contaminants include the presence of bacteria, mold fungi, mycotoxins, and heavy metals. However, insects can be used in the pet food industry. This is supported by the evolutionary adaptation of their wild ancestors to the eating of insects in the natural environment. The chemical composition of insects also corresponds to the nutritional requirements of dogs. It should be borne in mind that diets containing insect and their effects on animals require careful analysis. The aim of this article is to discuss the nutritional value of insects and their possible applications in the nutrition of companion animals, especially dogs.

Insects as Feed for Companion and Exotic Pets: A Current Trend

Simple Summary

Currently, there is a wide variety of insect-based pet foods and treats; however, there are several questions about the nutritional contribution of insects for dogs and cats, their health effects, safety aspects and the legal framework for their use as ingredients or feed. The insect-based ingredients used are mainly meal and fat from black soldier fly larvae, mealworm larvae and adult house crickets. There are few studies on the use of insects as food ingredients for pets, and most of them have studied some aspects in dogs. It has been said that they do not affect health, are well accepted and tolerated, do not alter the microbiota and could have the potential to be used as hypoallergenic ingredients. Insects provide a high nutritional value, with a high content of protein and amino acids with good digestibility for dogs. In cats, there is scarce information and more studies are needed. In exotic pets, their use is generalized. Dog owners are willing to use insects as ingredients, but in processed formats such as meal or as part of food or treats. Future research should focus on safety issues and effects on the health, nutrition and feeding behavior of traditional pets, such as dogs and cats.

Abstract

The objective of this review was to carry out a comprehensive investigation of the benefits of incorporating insects as a pet food ingredient and the implications this can have in determining a market demand for insect-based pet foods. Black soldier fly larvae (Hermetia illucens), mealworm larvae (Tenebrio molitor) and adult house crickets (Acheta domesticus) are currently used in pet food. These insects are widely fed to exotic pets, mainly in whole, live or dehydrated formats. They are also incorporated as meal or fat and are offered to cats and dogs as dry or wet food and treats. Scientific studies about the use of insects for dog and cat feed are scarce. Most studies are in dogs. Research shows that insect nutrients, mainly amino acids, have high digestibility, are beneficial to health, do not have any detrimental effect on the gut microbiota and are accepted by dogs. In several countries, insects are approved for use in pet food and commercialization has spread throughout the world. Pet owners are willing to try foods made with insect meal for their pets. In conclusion, the use of insects in pet food is a reality that is taking on more and more prominence.

Comparison of Nutritional Profiles of Super Worm (Zophobas morio) and Yellow Mealworm (Tenebrio molitor) as Alternative Feeds Used in Animal Husbandry: Is Super Worm Superior?

Edible insects are acknowledged as a valuable nutritional source and promising alternative to traditional feed ingredients, while the optimization of rearing conditions is required for their wider utilization in the animal feed industry. The main goal of this study was to compare and optimize the rearing conditions of the two species’ larvae and identify the most favorable nutritive composition of the full-fat larval meal. For that purpose, Tenebrio molitor (TM) and Zophobas morio (ZM) were reared on three different substrates and harvested after three time periods. An artificial neural network (ANN) with multi-objective optimization (MOO) was used to investigate the influence between the observed parameters as well as to optimize and determine rearing conditions. The optimization of the larval rearing conditions showed that the best nutritive composition of full-fat larval meal was obtained for ZM larvae reared on a mixture of cabbage, carrot and flaxseed and harvested after 104 days. The best nutritive composition contained 39.52% protein, 32% crude fat, 44.01% essential amino acids, 65.21 mg/100 g Ca and 651.15 mg/100 g P with a favorable ratio of 1.5 of n6/n3 fatty acids. Additionally, the incorporation of flaxseed in the larval diet resulted in an increase in C18:3n3 content in all samples.

Nutritive Value of Wheat Bran Diets Supplemented With Fresh Carrots and Wet Brewers' Grains in Yellow Mealworm

We evaluated the effect of supplementation of a wheat bran (WB) diet with fresh carrots (FC) or wet brewer's grains (WBG) on the growth performance and chemical composition of Tenebrio molitor larvae. Additionally, a digestibility trial was performed to determine the nutritional value of the raw materials used. The control diet was based on WB-only. Two other diets were formulated in which WB was supplemented with FC (FC diet) or with WBG (WBG diet). The experiment was conducted in trays (12 per treatment) and lasted 90 d. Larval weight, feed intake, and excreted feces were controlled in each tray the experiment. The digestibility trial was performed from 48 to 62 d post-hatch. Results showed digestibility coefficients of ashes, crude protein, and gross energy were significantly higher in FC diet compared with the other diets. Consequently, both digestible energy (DE) and digestible protein (DP) contents of FC were also significantly higher than those obtained for WB and WBG diets (on av. +1.12 megajoule [MJ] DE and +9.15 g DP per kg dry matter [DM]; P < 0.003). Mealworms fed FC diet showed significantly higher final weight and average daily gain than those fed the WBG diet (+12.4%), being higher in WBG than in WB diet (+3.5%). Dietary treatment did not affect DM, ashes, ether extract, and crude protein content of mealworms obtained. Some dietary effects on amino acid and fatty acid composition were observed. This study provides novel data and a unique experimental approach to assess the nutritional value of raw materials in mealworms.

Development of Healthy Protein-Rich Crackers Using Tenebrio molitor Flour

Entomophagy is still a widespread practice in Africa and Asia, although it is declining due to the westernization of diets. Today, the issue of its rehabilitation is underway; indeed, the nutritional economic and ecological stakes of this consumption are strategic. It can be considered an important way to face the scarcity of natural resources, environmental pressures due to the increasing world population, and demand for protein. Tenebrio molitor larvae flour was recently approved by the European Food Safety Authority (EFSA) as a novel food. The aim of the present work was to create protein-rich healthy cracker from insect flour, achieving the claim “source of protein” with a target market focused on the healthy products for consumption on the go. Contents of T. molitor flour from 2 to 20% (%w/w) were tested, using a previously optimized formulation and the comparison in terms of nutritional, physical, and sensory properties with a standard formulation was performed. T. molitor incorporation allowed an improvement in the nutritional profile of snacks, through an increase of 15% in protein content and an enrichment in minerals (namely potassium, phosphorus, copper, and zinc). The crackers containing a 6% of insect flour were the most appreciated by the panelists. The incorporation of T. molitor induced a reduction in firmness and an increase in crispness, resulting from the impact of the protein on the structure. This aspect has a positive impact with respect of the acceptance of snacks—70% of the panelists consider the possibility to buy the crackers with 6% enrichment. A darkening of the samples with the increase in the incorporation of T. molitor flour was also observed, accompanied by a reduction of about 20% of the L* values. Globally, insect protein can play an important role in redesigning food diets, making them more sustainable, with less environmental impact and equally balanced.

Nutritional composition of various insects and potential uses as alternative protein sources in animal diets -A review

The aim of the present investigation is to determine the nutritional composition of various insects and their potential uses as alternative protein sources in animal diets. The feeding industry is to develop a production system that uses accessible resources, such as feed resources, and concentrate on their potential impacts on production yield and nutritional quality. Invertebrate insects, such as black soldier flies, grasshopper mealworms, housefly larvae, and crickets, have been naturally as human food and as nonruminants and aqua culture while for ruminants are of limitations. Insects can be mass-produced, participating in a circular economy that minimizes or eliminates food- and feed-waste through bioconversion. Although the model for formula-scale production of insects as feed for domestic animals has been explored for a number of years, significant production and transformation of conventional protein resources remains to be deeply investigated. This review will focus on the nutritional composition of various insects and their potential uses as alternative protein sources, as well as their roles for potential use to promote and support sustainable animal production. Furthermore, nutritional compositions, such as high protein, lauric acid omega 6, and omega 3, and bioactive compounds, such as chitin, are of great potential use for animal feeding.

Development of Nutraceutical Ice Creams Using Flour Yellow Worm Larvae (Tenebrio molitor), Chia (Salvia hispanica), and Quinoa (Chenopodium quinoa)

Functional ice creams were developed by adding larvae of the insect Tenebrio molitor mixed with a seed (Salvia hispanica) and a pseudocereal (Chenopodium quinoa) to strawberry-cranberry ice cream. The objective was to increase micronutrients, macronutrients, and antioxidants, thus rendering the product a food complement. Four ice cream formulations were manufactured: the control strawberry-cranberry ice cream and three experimental mixtures, one of them with an addition of Tenebrio larvae (HT) and two others with a combination of Tenebrio larvae, chia (HTC), and quinoa (HTQ). The ice creams were submitted to proximate chemical analysis: mineral, fatty acid, vitamin, and one antioxidant (cyanidin 3 glucoside) determination. The strawberry-cranberry ice cream was used as a control formulation to evaluate if there were significant differences among nutrients, to which a Dunnett test with a critical value of α = 0.05% was applied. The three formulations that were studied showed a significant increase in the analyzed micronutrients and macronutrients compared to the control formulation. We observed increases of up to 62% in lipid content in the HTC formulation, while an increase of 41% in the protein content of the HT formulation was observed. We quantified an increase and enrichment of vitamins and minerals in the manufactured products, so that their nutritional value was significantly enhanced. In the determination of cyanidin 3 glucoside, we found that the formulation to which chia had been added showed an increase of 74% as compared to the control ice cream; this is important because anthocyanins are a group of flavonoids that stand out for their antioxidant and antimutagenic capabilities.

Tenebrio molitor as a source of interesting natural compounds, their recovery processes, biological effects, and safety aspects

Nowadays, it is urgent to produce in larger quantities and more sustainably to reduce the gap between food supply and demand. In a circular bioeconomy vision, insects receive great attention as a sustainable alternative to satisfy food and nutritional needs. Among all insects, Tenebrio molitor (TM) is the first insect approved by the European Food Safety Authority as a novel food in specific conditions and uses, testifying its growing relevance and potential. This review holistically presents the possible role of TM in the sustainable and circular solution to the growing needs for food and nutrients. We analyze all high value-added products obtained from TM (powders and extracts, oils and fatty acids, proteins and peptides, and chitin and chitosan), their recovery processes (evaluating the best ones in technical and environmental terms), their nutritional and economical values, and their biological effects. Safety aspects are also mentioned. TM potential is undoubted, but some aspects still need to be discussed, including the health effects of substances and microorganisms in its body, the optimal production conditions (that affect product quality and safety), and TM capacity to convert by-products into new products. Environmental, economic, social, and market feasibility studies are also required to analyze the new value chains. Finally, to unlock the enormous potential of edible insects as a source of nutritious and sustainable food, it will be necessary to overcome the cultural, psychological, and regulatory barriers still present in Western countries.

Yellow Mealworm and Black Soldier Fly Larvae for Feed and Food Production in Europe, with Emphasis on Iceland

Insects are part of the diet of over 2 billion people worldwide; however, insects have not been popular in Europe, neither as food nor as a feed ingredient. This has been changing in recent years, due to increased knowledge regarding the nutritional benefits, the need for novel protein production and the low environmental impact of insects compared to conventional protein production. The purpose of this study is to give an overview of the most popular insects farmed in Europe, yellow mealworm, Tenebrio molitor, and black soldier fly (BSF), Hermetia illucens, together with the main obstacles and risks. A comprehensive literature study was carried out and 27 insect farming companies found listed in Europe were contacted directly. The results show that the insect farming industry is increasing in Europe, and the success of the frontrunners is based on large investments in technology, automation and economy of scale. The interest of venture capital firms is noticeable, covering 90% of the investment costs in some cases. It is concluded that insect farming in Europe is likely to expand rapidly in the coming years, offering new proteins and other valuable products, not only as a feed ingredient, but also for human consumption. European regulations have additionally been rapidly changing, with more freedom towards insects as food and feed. There is an increased knowledge regarding safety concerns of edible insects, and the results indicate that edible insects pose a smaller risk for zoonotic diseases than livestock. However, knowledge regarding risk posed by edible insects is still lacking, but food and feed safety is essential to put products on the European market.

Insect Larvae Meal (Hermetia illucens) as a Sustainable Protein Source of Canine Food and Its Impacts on Nutrient Digestibility and Fecal Quality

Insect larvae meal has been proposed as a sustainable protein source for animal diets. This study aimed to provide information on including black soldier fly larvae meal (BSFL; Hermetia illucens) in comparison to poultry meal (PM) in the canine diet with regard to digestibility and fecal characteristics. In light of this trend, the levels of PM or BSFL meal were added to replace about 30% of dry matter of the basic extruded diet. Six Beagle dogs (BW 9.64 kg) were included in a cross-over experiment. Dogs fed a BSFL meal-based diet showed higher (p < 0.05) apparent protein digestibility (82.3%) compared to those offered a PM-based diet (80.5%). Apparent digestibility for fat was higher (p < 0.05) in groups fed the BSFL meal-based diet (94.5%) compared to those offered the PM-based diet (91.6%). The fecal consistency scores for dogs fed both diets were within an acceptable range (well-formed and firm). Fecal dry matter content was higher (p < 0.05) for dogs fed the PM-based diet (33.0%) compared to those offered the BSFL meal-based diet (28.0%). Including BSFL meal in dog food can be an appropriate source of protein without any negative effects on nutrient digestibility and fecal quality.

Impact of Diets Including Agro-Industrial By-Products on the Fatty Acid and Sterol Profiles of Larvae Biomass from Ephestia kuehniella, Tenebrio molitor and Hermetia illucens

Simple Summary

Insects are a promising source of lipids. Their fatty acid compositions can vary as a function of diet composition, rearing conditions and developmental stage. In the present study, different agro-industrial by-products were used to feed the insects. Then, the fatty acids and sterols were determined. Notably, these profiles were assessed for the first time for E. kuehniella. According to our results, fatty acid profiles showed differences depending on diet composition, but mostly depended on species. Sterols varied significantly as a function of diet composition and species, showing low cholesterol and high campesterol and β-sitosterol levels in H. illucens, and high cholesterol and low campesterol contents in T. molitor and E. kuehniella. These results suggest that insects are an interesting alternative source of fat for humans and animals, which might promote the use of insects for circular economy practices.

Abstract

Rearing insects on agro-industrial by-products is a sustainable strategy for the circular economy while producing valuable products for feed and foods. In this context, this study investigated the impact of larvae diet containing agro-industrial by-products on the contents of fatty acids and sterols of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae), Tenebrio molitor (L.) (Coleoptera: Tenebrionidae), and Hermetia illucens (L.) (Diptera: Stratiomyidae). For each insect, selected diets were formulated using single or combined agro-industrial by-products (i.e., apricot, brewer’s spent grain and yeast, and feed mill) and compared to a control diet. Fatty acid profiles showed differences depending on diet composition, but mostly depended on species: H. illucens was characterized by the abundance of C12:0, C16:0 and C18:2, whereas C:16, C18:1(n-9c), and C18:2(n-6c) were predominant in T. molitor and E. kuehniella. Sterols significantly varied as a function of diet composition and species. H. illucens showed low cholesterol levels and high campesterol and β sitosterol levels (0.031, 0.554 and 1.035 mg/g, respectively), whereas T. molitor and E. kuehniella had high cholesterol and low campesterol contents (1.037 and 0.078 g/kg, respectively, for T. molitor; 0.873 and 0.132 g/kg, respectively, for E. kuehniella).

Exercise training has morph-specific effects on telomere, body condition and growth dynamics in a color-polymorphic lizard

Alternative reproductive tactics (ARTs) are correlated suites of sexually selected traits that are likely to impose differential physiological costs on different individuals. While moderate activity might be beneficial, animals living in the wild often work at the margins of their resources and performance limits. Individuals using ARTs may have divergent capacities for activity. When pushed beyond their respective capacities, they may experience condition loss, oxidative stress, and molecular damage that must be repaired with limited resources. We used the Australian painted dragon lizard that exhibits color polymorphism as a model to experimentally test the effect of exercise on body condition, growth, reactive oxygen species (ROS) and telomere dynamics - a potential marker of stress and aging and a correlate of longevity. For most males, ROS levels tended to be lower with greater exercise; however, males with yellow throat patches - or bibs - had higher ROS levels than non-bibbed males. At the highest level of exercise, bibbed males exhibited telomere loss, while non-bibbed males gained telomere length; the opposite pattern was observed in the no-exercise controls. Growth was positively related to food intake but negatively correlated with telomere length at the end of the experiment. Body condition was not related to food intake but was positively correlated with increases in telomere length. These results, along with our previous work, suggest that aggressive - territory holding - bibbed males suffer physiological costs that may reduce longevity compared with non-bibbed males with superior postcopulatory traits.

The Influence of Drying Methods on the Chemical Composition and Body Color of Yellow Mealworm (Tenebrio molitor L.)

To preserve the quality of the yellow mealworm, different drying methods are being explored by farmers and processors. However, the energy costs associated with these methods are usually high for smallholder insect-rearing farmers. Thus, the core aim of this study was to investigate different drying procedures and their impact on the chemical composition of yellow mealworm larvae. Yellow mealworms (exposed to sun, oven and freeze drying) were later analyzed for their chemical composition and body color. Crude protein (CP) content of freeze and oven-dried mealworms were similar (p > 0.05), but higher (p < 0.05) than those of the sun-dried samples. The b (yellowness) color of the sun-dried samples scored the lowest value (p < 0.05) in comparison with both oven and freeze-dried samples. The majority of the essential amino acids were higher (p < 0.05) in the sun-dried mealworms than both oven and freeze-dried samples. Similarly, the fat content of sun-dried mealworms was higher (p < 0.05) than if they had been oven or freeze dried. However, SFA (saturated fatty acids), PUFA (polyunsaturated fatty acids) and n-6 fatty acids were similar (p > 0.05) for all drying methods. We, therefore, conclude that sun drying resulted in the same nutritional composition as freeze and oven drying despite the noted color changes. Freeze and oven-drying strategies can be used to formulate mealworm-based feed and food products without noticeable nutritional changes. For the benefit of small-scale insect-rearing farmers, an appropriate drying technology that is affordable and easy to use should be developed considering the needs and experiences of these farmers.

The Feasibility of Using Yellow Mealworms (Tenebrio molitor): Towards a Sustainable Aquafeed Industry

Simple Summary

The expansion of the aquaculture industry depends mainly on aquafeed availability at reasonable prices. The common ingredients of aquafeed (e.g., fish and soybean meals) are not sustainable due to a lack of resources and increasing prices. Seeking alternative non-traditional ingredients is among the choices of nutritionists to produce high-quality feed at a feasible cost. Yellow mealworms (Tenebrio molitor) (TM) have been introduced to the feed industry as protein sources of a circular economy. Many studies have investigated the possibility of including T. molitor meals as a substitute for fish and soybean meals in aquafeed. Thus, this review exclusively presents an assemblage of the literature on the possibility of including T. molitor in aquafeed as a suggestion for the sustainability of the aquaculture industry.

Abstract

The success of the aquafeed industry mainly depends on the availability of raw ingredients with high nutritional value, such as fishmeal (FM). However, the increased demand for FM elevates its prices and leads to high feed costs. Thus, there is an urgent need to find suitable alternatives for FM in fish diets to achieve sustainability in aquaculture. Currently, attention is being paid to the possibility of using insect meals as FM substitutes in aquafeed because of their relatively high nutritional quality. TM is one of those insects that can be regarded as a unique candidate because of its relatively high nutritional value. TM are rich sources of essential amino acids (methionine), lipids, and fatty acids, which vary based on the developmental stage of the worms. Although TM have an abundant amount of chitin as a fiber source and other anti-nutritional factors, numerous studies have investigated the efficacy of partial or complete substitution of FM by T. molitor in fish diets. In this context, we reviewed the current research findings on the achievable inclusion levels of T. molitor versus FM substitution in the diets of several finfish and shellfish species. We discussed the potential use of T. molitor as an FM substitute in fish diets and evaluated its effects on growth, biometric indices, and body composition. Besides, the hematological parameters, immunological responses, antioxidative efficacy, intestinal health status, and sensory criteria of fish fed T. molitor-based diets were also assessed.

Comparative study of composition, antioxidant and antimicrobial activity of two adult edible insects from Tenebrionidae family

In the case of Tenebrionidae family insects, studies focus on larval stage, leaving a lack of information regarding other stages. Therefore, this study was performed in order to understand the differences between the nutritional composition and the bioactivity of two species of this family in their adult stage, fed with a specific diet. Adult beetles of both species were defatted, lyophilized and protein extracted with buffer. Proximal and phytochemical analysis of the extracts of each insect were performed, along with protein extract and hydrolysis analysis by Tris-Tricine and Tris Glycine SDS PAGE. This analysis showed that T. molitor contained more protein and fat than U. dermestoides but contained less crude fiber. The protein extraction was made with PBS, where 130 and 45 kDa bands showed predominant for U. dermestoides, and less protein was present for T. molitor. Antioxidant and antimicrobial activities of the enzymatic protein hydrolysates and protein crude extracts were determined. Presence of protein associated with the antioxidant activity were found in both insects. Nonetheless U. dermestoides had a higher antioxidant activity with the protein extract in contrast with the higher antioxidant activity shown by U. dermestoides once the extracts were digested. After proteolysis, protein extracts showed an increasing antioxidant activity, plus, the ability to inhibit microbial growth of Proteus, Shigella and Bacillus. Insect protein hydrolysates with protease open the possibility for the use of these beetles as new sources of encrypted peptides for microbiological control once characterized.

Mealworm (Tenebrio molitor Larvae) as an Alternative Protein Source for Monogastric Animal: A Review

Simple Summary

Tenebrio molitor (T. molitor) larvae, known as mealworm, have been considered a good protein source for monogastric animals. They have a high quantity and quality of protein content and amino acid profile. The inclusion of T. molitor larvae in broiler diets improved the growth performance without having negative effects on carcass traits and blood profiles in broiler chickens, or had no influence on the growth performance and carcass yield of broiler chickens. The supplementation of T. molitor larvae improved the growth performance and protein utilization of weaning pigs. Furthermore, the replacement of fishmeal with T. molitor larvae resulted in no difference in the growth performance and nutrient digestibility of weaning pigs. However, there are some challenges regarding biosafety, consumer’s acceptance, and price for the use of T. moiltor larvae in animal feed. Consequently, T. molitor larvae could be used as an alternative or sustainable protein source in monogastric animal feed.

Abstract

Edible insects have been used as an alternative protein source for food and animal feed, and the market size for edible insects has increased. Tenebrio molitor larvae, also known as mealworm and yellow mealworm, are considered a good protein source with nutritional value, digestibility, flavor, and a functional ability. Additionally, they are easy to breed and feed for having a stable protein content, regardless of their diets. Therefore, T. molitor larvae have been produced industrially as feed for pets, zoo animals, and even for production animals. To maintain the nutrient composition and safety of T. molitor larvae, slaughtering (heating or freezing) and post-slaughtering (drying and grinding) procedures should be improved for animal feed. T. molitor larvae are also processed with defatting or hydrolysis before grinding. They have a high quality and quantity of protein and amino acid profile, so are considered a highly sustainable protein source for replacing soybean meal or fishmeal. T. molitor has a chitin in its cuticle, which is an indigestible fiber with positive effects on the immune system. In studies of poultry, the supplementation of T. molitor larvae improved the growth performance of broiler chickens, without having negative effects on carcass traits, whereas some studies have reported that there were no significant differences in the growth performance and carcass yield of broiler chickens. In studies of swine, the supplementation of T. molitor larvae improved the growth performance and protein utilization of weaning pigs. Furthermore, 10% of T. molitor larvae showed greater amino acid digestibility than conventional animal proteins in growing pigs. However, there are some challenges regarding the biosafety, consumer’s acceptance, and price for the use of T. moiltor larvae in animal feed. Consequently, T. molitor larvae could be used as an alternative or sustainable protein source in monogastric animal feed with a consideration of the nutritional values, biosafety, consumer’s acceptance, and market price of T. molitor larvae products.

Insect Fat in Animal Nutrition – A Review

The aim of this review is to discuss the usage of insect fats as an energy source in animal nutrition. Insects are a rich carrier of proteins, fat, and minerals. They are successfully introduced in animal diets (poultry, swine, rabbits, fish, and pets) as a source of many nutrients, including energy and essential fatty acids (FAs). The insects’ fat content and quality are highly affected by the type of substrate provided to the insects during the rearing period. The majority of the studies have shown that insect fats may be used as promising substitutes for conventional energy resources in animal nutrition without adverse effects on growth performance and feed utilization. They can positively affect meat quality by increasing the level of long-chain polyunsaturated FAs but may also positively influence animals by regulating the gut microbiota and stimulating the immune system. In conclusion, insect fat supplementation showed promising results in terms of their application in animal nutrition. However, compared to insect protein application, very few studies have been performed on insect fats. Therefore, because of the fat quality and content of insects, there is a need to extend experimentation regarding their implementation in animals’ diets as a replacement for conventional dietary energy resources.

Evaluation of Organic Wastes as Substrates for Rearing Zophobas morio, Tenebrio molitor, and Acheta domesticus Larvae as Alternative Feed Supplements

Simple Summary

The yellow mealworm, super worm, and house cricket are among the most widely produced insects, with high feed conversion efficiency. However, their nutritional composition and development rate generally vary with environmental conditions. From an economic point of view, rearing conditions such as diet, temperature, and time, and insect performance such as mortality and nutritional value are the most important factors. During their intensive growth period at room temperature, when fed a diet of vegetable waste, garden waste, cattle manure, or horse manure with 10% chicken feed, the worms performed better in terms of survival, but presented lower weight. Moreover, they showed differences in growth intensity with time. The yellow mealworm and super worm presented a relatively high fat concentration. House cricket is specifically high in protein; however, its nutritional composition is affected by the rearing substrate, and it was more sensitive to the low-value substrates. Feeding nutrient-poor diets resulted in a low protein concentration and high fat concentration in the larvae of all three species.

Abstract

Studies have focused on identifying combinations of insects and organic waste to optimise bio-conversion. Here, the effects of different diets (10% chicken feed complemented with 90% vegetable waste, garden waste, cattle manure, or horse manure) on growth and survival rates, and nutritional value of Zophobas morio and Tenebrio molitor larvae, and Acheta domesticus were investigated. Compared with chicken feed, organic waste decreased the individual larval weight, although green waste showed fewer negative effects than the manure. The macronutrient concentrations in garden waste were moderate compared with chicken feed, and vegetable waste was the poorest diet in terms of nutrient concentration, as revealed by the principal component analysis (PCA). There was no difference in weight between larvae reared on garden waste and those reared on vegetable waste. Tenebrio molitor and A. domesticus showed the maximum growth rates at 71–101 and 36–66 days of age at 22.5 ± 2.5 °C, respectively. The PCA showed that the protein and fibre concentrations were inversely proportional to fat concentration in the larvae. Acheta domesticus was rich in proteins, whereas Z. morio and T. molitor were rich in fat. Feeding nutrient-poor diets resulted in a lower protein and a higher fat concentration in the larvae.

Recycling of spent mushroom substrate: Utilization as feed material for the larvae of the yellow mealworm Tenebrio molitor (Coleoptera: Tenebrionidae)

Spent mushroom substrate is made from the waste remaining after the harvest of mushrooms. Here, we evaluated the potential of five spent edible fungi (Auricularia cornea, Lentinus edodes, Pleurotus eryngii, P. citrinopileatus and P. ostreatus) substrates as feed sources for Tenebrio molitor larvae. Young larvae did not survive on any substrate except the spent L. edodes substrate (36.7%). The survival rates in young larvae were similar among the different diets in which wheat bran or rice bran was replaced with 0, 20, 30, 40, 50, or 60% spent L. edodes substrate. The weights of the surviving larvae were decreased only when 70% of wheat bran and > 40% of rice bran was replaced with spent L. edodes substrate. In addition, the middle-aged larvae fed wheat bran only were significantly larger than those fed diets with 30~60% spent L. edodes substrate in dry feed, but the larvae of all treatments failed to pupate. Whereas the green feed was added in dry feed, there were no significant differences in pupal weight, pupation rate, pupal duration, adult emergence, or deformed adults among the three treatments in middle-aged larvae that were fed on diets containing 0, 30, or 40% spent L. edodes substrate. Collectively, these results suggest that spent L. edodes substrate has considerable potential to be used as a partial replacement (< 40%) of conventional feed for T. molitor, and spent mushroom substrate waste may be recycled as feed material for resource insects.

Evaluation of Subchronic Oral Dose Toxicity of Freeze-Dried Skimmed Powder of Zophobas atratus Larvae (frpfdZAL) in Rats

Zophobas atratus (Coleoptera: Tenebrionidae), the giant mealworm beetle, is known as an edible insect containing a high protein content which may serve as new sources of human food and animal feed. However, potential toxicity and food safety analyses of Z. atratus have not been previously investigated. Therefore, in this study, we aimed to evaluate toxicity of freeze-dried skimmed powder of Z. atratus larvae (frpfdZAL), known as the super mealworm. Toxicological assessments were performed at the doses of 1250, 2500, and 5000 mg/kg/day in a 2- and a 13-week oral repeated-dose toxicity study of frpfdZAL in male and female Sprague-Dawley (SD) rats in accordance with the Organisation for Economic Co-operation and Development (OECD) guidelines and the principles of Good Laboratory Practice (GLP). No toxicological changes in clinical signs, body weights, water and food consumption, urinalysis, hematology, clinical biochemistry, gross findings, and histopathological examinations were observed. In conclusion, the no-observed-adverse-effect level (NOAEL) of frpfdZAL was 5000 mg/kg/day and target organ was not identified in both sexes of rats. In addition, frpfdZAL did not induce increases of serum ImmunoglobulinE (IgE), an identifier of allergic reactions in rats. Collectively, these results suggest that frpfdZAL is safe with no adverse effects, and able to be applied as an edible ingredient or other biological uses.

Nitrogen-to-Protein Conversion Factors for Edible Insects on the Swiss Market: T. molitor, A. domesticus, and L. migratoria

With an increasing worldwide demand for animal protein, insects are becoming a promising sustainable option for meat protein replacement. However, reported protein contents of insects are often overestimated when calculated as "crude protein" = 6.25 × nitrogen content (N), compared to true protein contents quantified from the sum of amino acid (AA) residues. In this study, the main two types of usual nitrogen-to-protein conversion factors k p and k A were determined on the basis of true protein/total nitrogen and true protein/protein nitrogen, respectively, with focus on the three insect species legally sold on the Swiss food market. T. molitor (mealworm larvae), A. domesticus (house crickets), and L. migratoria (locusts) from various breeders were analyzed for total and amide nitrogen, chitin, and AA composition. Careful control experiments of insect samples spiked with a protein standard were conducted to establish the recovery of true protein, which was with >95% excellent. Mealworms, crickets, and locusts exhibited similar AA-profiles and true protein contents of 51, 55, and 47 g/100 g (dry weight basis), respectively. Specific conversion factors k p showed little variability between the three insect species with 5.41, 5.25, and 5.33 for mealworms, crickets, and locusts, respectively, and confirmed an average ~17% overestimation of protein contents when using 6.25 × N. The determined average k p of 5.33 is supported by extracted literature data and is suggested for general use instead of 6.25 × N to calculate more accurate insect protein contents, whereas the average pure protein conversion factor k A of 5.6 is proposed for use in the case of insect protein isolates.

Nutritional Value of the Larvae of the Alien Invasive Wasp Vespa velutina nigrithorax and Amino Acid Composition of the Larval Saliva

The systematic investigations on the value of social wasps as a food resource are deficient, in spite of the long history of the utilization of social wasps as food and pharmaceutical bioresources. Vespa velutina nigrithorax is an invasive alien wasp species that is currently dominating in East Asia and Europe, bringing huge economic damages. As a control over alien species is made when the valuable utilization of the invasive species as a potential resource are discovered, investigations on the potential of V. v. nigrithorax as a useful bioresource are also in demand. Nutritional and heavy metal analyses of the larvae revealed their balanced and rich nutritional value and safety as a food resource. The larval saliva amino acid composition was investigated for further study on amino acid supplementation and exercise enhancement.

Ontogenic Development of Digestive Enzymes in Mealworm Larvae (Tenebrio molitor) and Their Suitable Harvesting Time for Use as Fish Feed

Mealworm larvae (Tenebrio molitor) are edible insects consumed in feed and food. In the current study, the optimal harvesting time of mealworm larvae for use as aquafeed was investigated during the ages of 30-90 days after hatching (DAH). Development of digestive enzymes, proximate composition, and in vitro protein digestibility using digestive enzymes from African catfish (Clarias gariepinus) and Nile tilapia (Oreochromis niloticus), were used as criteria. The specific activities of pepsin and trypsin significantly decreased with age (p < 0.05) from the first harvesting time until 50 and 45 DAH, respectively, while steadiness in these enzyme activities was observed onwards. Chymotrypsin specific activity appeared constant across all harvesting times. The specific activity of amylase significantly decreased in the later stages of development, while cellulase exhibited a different pattern suggesting it has a major role in dietary fiber utilization relative to starch. Regarding proximate compositions of the mealworm larvae, the moisture and ash contents decreased significantly with age, while the protein content exhibited the opposite trend with the highest contents from 60 to 90 DAH. Crude lipid was generally fairly constant, but its lowest value was observed in the earliest stage. In vitro protein digestibility was not significantly different across all harvesting times for both fish species, except for the significantly decreased digestibility value at 65 DAH relative to 30 and 35 DAH for Nile tilapia. However, based on the economic benefits of time for growth increment and proximate chemical composition, approximately 60 DAH is proposed as suitable for harvesting mealworm larvae to be used in fish feed.

Cafeteria-Type Feeding of Chickens Indicates a Preference for Insect (Tenebrio molitor) Larvae Meal

This study aimed to determine whether broiler chickens display a preference for Tenebrio molitor larvae (TM) meal by evaluating ingredient acceptability and birds' performance. Sixty 14-day-old male chickens were assigned into two treatment groups (5 birds/pen, n = 6) in a cafeteria-type study: the control (C) group, and the TM group. Each pen was equipped with one bell drinker and four through feeders allocated side by side; all feeders of the C group contained a complete standard diet whereas each feeder of the TM group contained one of the following ingredients: ground corn, extruded semi-whole soybean, vitamin-mineral supplement mixture, and TM meal. Feed intake was recorded daily and growth was monitored periodically up to day 32. Chickens which had access to individual feed components showed a delay to display preference for TM, but consumed, overall, up to 50% of the total intake as TM meal. Feed intake and growth performance were lower in all periods for TM group (p < 0.02), whereas feed conversion ratio was improved on days 22-28 and days 29-32 of age (p < 0.01). Data from bivariate and multidimensional analysis indicate that birds started to reach a balance of ingredient intake at 25 days of age, showing a high correlation between consumption of each ingredient and the day of the experiment. Chickens exhibited a preference for T. molitor meal, resulting in improved feed efficiency, which allows us to conclude that it can be a suitable feed alternative for poultry.

Novel hepatoprotective peptides derived from protein hydrolysates of mealworm (Tenebrio molitor)

In the present study, we hypothesized that protein hydrolysates of mealworm (Tenebrio molitor) which is known to exert significant scavenging activity toward reactive oxygen species (ROS) might protect liver cells against ROS-induced cytotoxicity. Therefore, hepatoprotective effects of protein hydrolysates of mealworm and their underlying mechanisms were investigated in AML12 mouse liver cells and the responsible peptides were further identified. Pretreatment with the mealworm alcalase hydrolysate (MAH; <1 kDa) showed the highest protective effect against H₂O₂-induced cytotoxicity in AML12 cells among three mealworm hydrolysates produced by different proteases (alcalase, flavourzyme, and neutrase). Further mechanistic studies demonstrated that MAH reduces ROS levels through increasing NF-E2-related factor 2-mediated expression of catalase, heme oxygenase-1, and genes involved in glutathione synthesis. Moreover, two novel hepatoprotective peptides, Ala-Lys-Lys-His-Lys-Glu and Leu-Glu, which shared similar mechanisms of action with MAH were identified. These results suggest that MAH and the two peptides represent potential sources of natural hepatoprotective agents.

Addition of Olive Pomace to Feeding Substrate Affects Growth Performance and Nutritional Value of Mealworm (Tenebrio Molitor L.) Larvae

The well-recognized efficiency of Tenebrio molitor larvae to convert low quality organic matter into a nutritionally valuable biomass was exploited to manage solid wastes coming from the olive oil industry, which represent a severe environmental challenge in the Mediterranean area. Three organic pomace-enriched substrates (mixtures middlings/pomace 3:1, 1:1, and 1:3) were assessed, together with 100% organic wheat flour and 100% organic middlings as control feeds. A feeding substrate made up of 25% olive pomace and 75% wheat middlings appeared to be the best compromise between growth performance (larval and pupal weights, survival rate, development time) and nutritional properties of mealworm larvae. In fact, larvae fed the 3:1 feed showed the highest dry matter (DM) yield (38.05%), protein content (47.58% DM), and essential/non-essential amino acids ratio (1.16). Fat content (32.14% DM) and fatty acid composition were not significantly different than those of larvae fed more pomace-enriched feeds.

Effects of mealworm (Tenebrio molitor) larvae hydrolysate on nutrient ileal digestibility in growing pigs compared to those of defatted mealworm larvae meal, fermented poultry by-product, and hydrolyzed fish soluble

OBJECTIVE

To investigate effect of mealworm (Tenebrio molitor) larvae hydrolysate on nutrient ileal digestibility compared to those of dried mealworm larvae meal, fermented poultry by-product, and hydrolyzed fish soluble in growing pigs.

METHODS

A total of 12 crossbred ([Landrace×Yorkshire]×Duroc) growing pigs with average body weight of 28.70±0.32 kg were surgically equipped with simple T-cannulas. A total of 12 pigs were assigned to individual metabolic crates and allotted to one of four treatments with 3 replicates in a fully randomized design.

RESULTS

Apparent ileal digestibility (AID) of dry matter (DM) was the highest in pigs fed HML diet. AIDs of crude protein (CP) were higher in pigs fed HML and DMLM diets than those in pigs fed the other two diets. AID of total amino acid was higher (p = 0.06) in pigs fed HML diet. AIDs of lysine (Lys), methionine (Met), and threonine (Thr) were similar in pigs fed DMLM and HML diets, but were higher (p = 0.05, p<0.05, and p = 0.05, respectively) than those in pigs fed FPBM or HFS diet. Pigs fed HML diet had higher standardized ileal digestibilities (SIDs) of DM and CP (p<0.05 and p<0.05, respectively) compared to pigs fed the other FPBM and HFS diets. SIDs of total amino acid were not different (p = 0.06) between treatments. For SIDs of Lys, Met, and Thr, pigs fed HML and DMLM diets showed higher SIDs (p = 0.05, p<0.05, and p<0.05, respectively) than pigs fed FPBM and HFS diets. SIDs of non-essential amino acids (aspartic acid, glycine, and alanine) were higher (p<0.05, p< 0.05, and p<0.05, respectively) in pigs fed HML, FPBM, and DMLM diets than those in pigs fed the HFS diet. AID and SID of glutamic acid were higher in pigs fed HML and FPBM diets.

CONCLUSION

In conclusion, dietary supplementation of mealworm larvae hydrolysate had higher digestibility in DM, CP, Lys, Met, and Thr compared to dietary supplementation with fermented poultry by-product and hydrolyzed fish soluble.

Could Defatted Mealworm (Tenebrio molitor) and Mealworm Oil Be Used as Food Ingredients?

Before edible insects may be used as an alternative food, it is necessary to develop basic product forms and evaluate their characteristics. We made two basic commercial products (defatted powder and oil) from mealworm, a popular edible insect. The defatted mealworm powder possessed a sufficient amount of protein, and it had a savory taste due to plentiful free amino acids. Additionally, it had abundant minor nutrients and bioactive compounds. The physicochemical properties of mealworm oil were very similar to vegetable oil, and mealworm oil was also abundant in bioactive nutrients, especially γ-tocopherol. In addition, the predicted shelf life of mealworm oil was suitable for commercial use. Moreover, mealworm had high antioxidant and anti-inflammation activities, which may arise from functional peptides and glucosamine derivatives such as chitin and chitosan. In short, the defatted mealworm powder and mealworm oil could be successfully used as novel food ingredients.

The use of yellow mealworm (T. molitor) as alternative source of protein in poultry diets: a review

Protein sources are known to be the second largest component in the poultry sector. Traditionally, fish and soya-bean meals are known to supply very good protein; however, these are restricted in supply and more expensive than energy sources. The prices of soya-bean meal are currently high and tend to fluctuate with changes in climatic conditions and social situations in the countries where it is produced. Developing countries like South Africa have made enormous investments in soya-bean production, despite that the country still imports considerable volumes of this crop and is not self-sufficient. This then means that there is an urgent need to seek for alternative and cost-effective protein sources that can provide the same nutrients as soya-bean and fish meal for poultry production. Tenebrio molitor L. which is commonly known as yellow mealworm has a huge potential to substitute commonly used protein sources in poultry diets. Mealworms are easy to breed and do not require large area for production. Moreover, they have high nutritional value comparable to that of soya-bean and fishmeal. However, the only limiting nutrient for mealworms is calcium which can be easily supplemented in the diets. Therefore, this review sets out to explore the importance of replacing soya bean with mealworms in poultry diets. Furthermore, the life cycle of meal worms will also be discussed.

Edible Insects as a Protein Source: A Review of Public Perception, Processing Technology, and Research Trends

This review summarizes the current trends related to insect as food resources among consumers, industry, and academia. In Western societies, edible insects have a greater potential as animal feed than as human food because of cultural biases associated with harmful insects, although the abundant characteristics of edible insects should benefit human health. Nevertheless, many countries in Asia, Oceania, Africa, and Latin America utilize insects as a major protein source. Using insects can potentially solve problems related to the conventional food-supply chain, including global water, land, and energy deficits. Academic, industry, and government-led efforts have attempted to reduce negative perceptions of insects through developing palatable processing methods, as well as providing descriptions of health benefits and explaining the necessity of reducing reliance on other food sources. Our overview reveals that entomophagy is experiencing a steady increase worldwide, despite its unfamiliarity to the consumers influenced by Western eating habits.

Yellow Mealworm Larvae (Tenebrio molitor) Fed Mycotoxin-Contaminated Wheat-A Possible Safe, Sustainable Protein Source for Animal Feed?

The aim of this study was to determine the potential for accumulation of deoxynivalenol (DON) in yellow mealworm larvae (Tenebrio molitor) reared on high DON Fusarium-infected wheat and investigate the effects on production, survival and nutritional traits. Wheat containing 200 μg/kg DON was used as the control diet. A different source of wheat was sorted into six fractions and mixed to obtain low (2000 μg/kg), medium (10,000 μg/kg) and high (12,000 μg/kg) levels of DON. Each diet was replicated five times with 300 or 200 mealworms per replicate for the feeding and breeding trials, respectively. Trial termination occurred when the first two pupae were observed (32–34 days). There was no difference in the concentrations of DON detected in the larvae between diets that ranged from 122 ± 19.3 to 136 ± 40.5 μg/kg (p = 0.88). Excretion of DON was 131, 324, 230 and 742 μg/kg for control, low, medium and high, respectively. Nutritional analysis of larvae showed maximum crude protein of 52% and crude fat of 36%. Ash, fiber, chitin, fatty-acids and amino-acid content were consistent across diets. Survival was greater than 96% for all life stages and average daily gain ranged from 1.9 ± 0.1 to 2.1 ± 0.1 mg/day per mealworm. Larvae accumulated low levels of DON from Fusarium-infected wheat diets suggesting contaminated wheat could be used to produce a sustainable, safe protein source.