Dietary enrichment of edible insects with omega 3 fatty acids

Growth performance, proximate composition and fatty acid profile of black soldier fly larvae reared on two grape pomace varieties

The black soldier fly (Hermetia illucens) is attracting increasing interest for its ability to convert low-value substrates into highly nutritious feed. This study aimed at evaluating grape pomace from two varieties (Becuet - B; Moscato - M) as rearing substrates for black soldier fly larvae (BSFL), focusing on the related effects on larval growth performance, proximate composition, and fatty acid profile. A total of six replicates per treatment, and 1 000 BSFL per replica, were used. Larval development was assessed by larvae weight, which was recorded eight times during the trial: the day after the beginning of the trial, and then on days 5, 8, 13, 15, 20, 22, and 27 (day in which the 30% of BSFL reached the prepupal stage). Production and waste reduction efficiency parameters, namely the growth rate, substrate reduction and substrate reduction index, were calculated. The two grape pomace varieties were analysed for their proximate composition and fatty acid profile; the same analyses were conducted on BSFL (30 larvae per replica) that were collected at the end of the trial (day 27). The growth rate of BSFL showed a higher value when the larvae were reared on B substrate (4.4 and 3.2 mg/day for B and M, respectively; P < 0.01). The rearing substrate did not significantly affect the proximate composition of BSFL. The percentage of total lipids (TL) in M-fed BSFL was significantly higher than in B ones. Total saturated (P < 0.001) and monounsaturated fatty acids (P < 0.05) were significantly higher in M-fed BSFL, while an opposite trend was observed for total branched-chain (P < 0.001) and total polyunsaturated fatty acids (P < 0.001). Interestingly, some conjugated linoleic acid (CLA) isomers [i.e., C18:2 c9t11(+t7c9+t8c10) and t9t11] were detected in low amounts in both rearing substrates (total CLA equal to 0.085 and 0.16 g/100 g TL in B and M substrate, respectively). Some CLA isomers (i.e., C18:2 c9t11, t7c9, and t10c12) were also found in BSFL, reaching a total CLA concentration equal to 2.95 and 0.052 g/100 g of TL in B-fed and M-fed BSFL, respectively. This study demonstrates that winery by-products from different grape varieties can significantly affect the development and lipid composition of BSFL. The CLA biosynthesis potential of BSFL opens newsworthy perspectives for a new valorisation of winery by-products to produce full-fat black soldier fly meal and black soldier fly oil enriched in specific fatty acids of potential health-promoting interest.

Evaluation of rapeseed cake as a protein substitute in the feed of edible crickets: A case study using Gryllus assimilis

This paper aimed to investigate the optimization of Gryllus assimilis farming production by examining the effects of replacing soybean meal with rapeseed cake (25-100%) and supplementing it with rapeseed oil. The results reveal no adverse effects of soybean meal replacement on the feed conversion ratio and weight of the harvested crickets. However, incorporating larger quantities of rapeseed cake into the diet increased crude protein and decreased fat content. Moreover, the composition of fatty acids varied significantly, with increased levels of oleic acid and decreased levels of palmitic acid, while a high rapeseed cake content led to a decrease in the atherogenic and thrombogenic index values. The amino acid composition remained unaffected. In conclusion, the study demonstrates that rapeseed cake can serve as a viable substitute for soybean meal in the diet of Gryllus assimilis.

Analysis of Fatty Acid Composition and Volatile Profile of Powder from Edible Crickets (Acheta domesticus) Reared on Apple By-Products

Edible crickets have recently been used as a new alternative protein source with high nutritional value. The nutritional and flavor-related value of edible crickets varies greatly depending on the species, growth conditions and processing conditions. However, few studies have investigated the effects of the diet fed to crickets during their growth phase on flavor. Therefore, in this study, we characterized the flavor-related factors of powder from crickets reared on apple by-products (ACP) by comparing them with those of powder from crickets reared on a control diet (CCP). The fatty acid composition and volatile compounds of each powder were determined using gas chromatography and mass spectrometry, followed by sensory analysis and color measurement. A decrease in unsaturated fatty acids, specifically γ-linolenic acid, α-linolenic acid, arachidonic acid and docosahexaenoic acid, was observed in ACP. A total of 50 volatile compounds were identified, of which 11 were present in only ACP, while 39 were found in both powders. The sensory analysis showed that the overall balance score of ACP was higher than that of CCP, and according to the color measurements, ACP was darker than CCP. These differences between CCP and ACP might have been due to the differences in the chemical composition of the diets fed to the crickets during their growth phase. The results of this study suggest that one of the factors determining the food value of edible crickets, especially in terms of flavor, is the diet they are fed during their growth phase.

The collembolan Sinella dubiosa produces eicosapentaenoic acid

n-3 polyunsaturated fatty acids (n-3 PUFAs), including eicosapentaenoic acid (EPA), are essential nutrients for vertebrate development and physiology. Microorganisms, such as microalgae, produce n-3 PUFAs that are transferred to higher predators in the aquatic food web. However, recent studies have demonstrated that various aquatic invertebrates possess the biosynthetic enzymes required for n-3 PUFA production, raising the possibility that n-3 PUFAs are also produced in certain aquatic invertebrates. In contrast to aquatic invertebrates, it remains unclear whether and how PUFAs are produced in terrestrial invertebrates, including collembolans, one of the most widespread microarthropods in soil ecosystems. In this study, we investigated the biosynthetic capacity of n-3 PUFAs in litter-dwelling Collembola, Sinella dubiosa. We detected EPA in Sinella dubiosa reared on Brewer's yeast, which produced only saturated and monounsaturated fatty acids. Furthermore, metabolic analysis using isotope-labeled fatty acids revealed that oleic, linolenic, and arachidonic acids were metabolized to EPA in Sinella dubiosa. Given that collembolans are food for predatory arthropods and their nutrients are transferred to higher predatory vertebrates in the soil food web, we propose that Collembola serve as an EPA source in soil ecosystems.

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.

Nutritional Value of Banded Cricket and Mealworm Larvae

Insect farming is more ecological than traditional animal farming, as it requires less water and contributes to lower greenhouse gas emissions. In our study, banded cricket (BC) and mealworm larvae (ML) were analyzed. The proximate composition was determined according to Association of Official Analytical Chemists. The mineral content was determined by colorimetry and mass spectrometry. Fatty acid methyl esters (FAMEs) were obtained from the samples and separated using a gas chromatography apparatus, coupled with a mass spectrometer. Our research confirmed that insects are a rich source of protein, with ML containing significantly more protein than BC (74.41 and 65.66 g/100 g dry matter (DM), respectively). In terms of the content of macrominerals, ML was significantly richer than BC, especially in terms of magnesium content (8.75 g/100 g DM). In terms of the content of saturated fatty acids, BC contained almost twice as much as ML (40.05 and 24.74% of the sum of fatty acids, respectively). EPA and DHA were only detected in the fat of BC. The presented results prove that both ML and BC can be good sources of protein both in human and companion animal diets. The component that is predominantly high in insects is fat, with a favorable fatty acid profile, especially in terms of polyunsaturated fatty acids. This study contributes new knowledge on the nutritional value of edible insects. In this research, we included three different nitrogen conversion factors for crude protein content. Our results partially confirm previous studies by other authors, although they provide new information on the content of fatty acids.

Bioproduction of n-3 polyunsaturated fatty acids by nematode fatty acid desaturases and elongase in Drosophila melanogaster

n-3 polyunsaturated fatty acids (n-3 PUFAs), including α-linolenic acid and eicosapentaenoic acid (EPA), are essential nutrients for vertebrates including humans. Vertebrates are n-3 PUFA-auxotrophic; hence, dietary intake of n-3 PUFAs is required for their normal physiology and development. Although fish meal and oil have been utilized as primary sources of n-3 PUFAs by humans and aquaculture, these traditional n-3 PUFA sources are expected to be exhausted because of the increasing consumption requirements of humans. Hence, it is necessary to establish alternative n-3 PUFA sources to reduce the gap between the supply and demand of n-3 PUFAs. Here, we investigated whether insects, which are considered as a novel source of essential nutrients, could store n-3 PUFAs by the forced expression of n-3 PUFA biosynthetic enzymes. We utilized Drosophila as an insect model to generate transgenic strains expressing Caenorhabditis elegans PUFA biosynthetic enzymes and examined their effects on the proportion of fatty acids. The ubiquitous expression of methyl-end desaturase FAT-1 prominently enhanced the proportions of α-linolenic acid, indicating that FAT-1 is useful for metabolic engineering to fortify α-linolenic acid in insect. Furthermore, the ubiquitous expression of nematode front-end desaturases (FAT-3 and FAT-4), PUFA elongase (ELO-1), and FAT-1 led to EPA bioproduction. Hence, nematode PUFA biosynthetic genes may serve as powerful genetic tools for enhancing the proportion of EPA in insects. This study represents the first step toward the establishment of n-3 PUFA-producing insects.

Potentiality Assessment of the Acetylcholinesterase-Inhibitory Activity of Olive Oil with an Additive Edible Insect Powder

Edible insects (Alphitobius diaperinus Panzer, Gryllus campestris, Tenebrio molitor, Chorthippus biguttulus) are rich in nutrients that potentially inhibit acetylcholinesterase (AChE), but also improve cognition. The aim of this study was to evaluate four varied species of freeze-dried edible insects (purchased from a store); their nutrient composition, including fat, total phenolic compounds, vitamins, and antioxidant properties; and the potential inhibitory effect of AChE. An additional goal was to obtain olive oil with the addition of edible insects. Such oil was characterized by high oxidizing properties and showed high affinity to AChE. The results showed that mealworms and grasshoppers had the highest content of fats (PUFA/SFA) and phenolic compounds. These insects also showed a high content of vitamins, which correlated with the highest affinity for AChE. Therefore, they were added as a functional additive to olive oil. Olive oil with the addition of edible insects showed a higher affinity for AChE and enriched the olive oil with vitamin C and B vitamins.

Yeast enrichment facilitated lipid removal and bioconversion by black soldier fly larvae in the food waste treatment

Food waste can be converted into insectile fatty acids (FAs) by the larvae of black soldier fly (BSFL), Hermetia illucens, for use in the feed sector or as a source of biodiesel. However, waste oil was less decomposed than carbohydrate or protein in frass due to the limitation of larval lipid metabolism. In this study, 10 yeast strains were screened, corresponding to six species, to examine their capacity of improving lipid transformation performance by BSFL. The species of Candida lipolytica was superior to the other five species, which exhibited significantly higher lipid reduction rate (95.0-97.1 %) than the control (88.7 %), and the larval FA yields achieved 82.3-115.5 % of the food waste FA matters, suggesting that BSFL not only transformed waste oil but also biosynthesized FAs from waste carbohydrate and other substances. Further, the CL2 strain of Candida lipolytica was examined for treating food waste containing high lipid content (16-32 %). The lipid removal rate was found improved from 21.4 to 42.3 % (control) to 80.5-93.3% in the waste containing 20-32 % lipid. The upper limit of lipid content that could be endured by BSFL was ≈16 %, and the CL2-enrichment elevated the upper limit to ≈24 %. Fungal community analysis indicated that Candida spp. accounted for the lipid removal improvement. The Candida spp. CL2 strain may facilitate the lipid reduction and transformation by BSFL through microbial catabolizing and assimilation of waste FAs. Altogether, this study suggests that yeast enrichment is feasible in improving lipid transformation by BSFL especially for food waste exhibiting high lipid content.

Chitin and omega-3 fatty acids in edible insects have underexplored benefits for the gut microbiome and human health

A healthy gut microbiome is critical for nutrient metabolism, pathogen inhibition and immune regulation, and is highly influenced by diet. Edible insects are good sources of protein and micronutrients, but unlike other animal-derived foods, they also contain both dietary fibre and omega-3 fatty acids that can modulate gut microbiota. Here we explore the potential impacts of insect consumption on the microbiome. Laboratory, animal and human studies indicate that insect fibre in the form of chitin and its derivatives can modify gut microbiota with beneficial outcomes. Some insects also contain favourable omega-3/omega-6 ratios. We identify gaps in the literature-especially a dearth of human studies-that must be addressed to better understand health impacts of entomophagy. Insects, already eaten across the globe, can be farmed using fewer resources than conventional livestock. Widening the research scope offers an opportunity to advance use of edible insects to address interconnected environmental and health challenges.

An Acyl Carrier Protein Gene Affects Fatty Acid Synthesis and Growth of Hermetia illucens

Acyl carrier protein (ACP) is an acyl carrier in fatty acid synthesis and is an important cofactor of fatty acid synthetase. Little is known about ACP in insects and how this protein may modulate the composition and storage of fatty acids. We used an RNAi-assisted strategy to study the potential function of ACP in Hermetia illucens (Diptera: Stratiomyidae). We identified a HiACP gene with a cDNA length of 501 bp and a classical conserved region of DSLD. This gene was highly expressed in the egg and late larval instars and was most abundant in the midgut and fat bodies of larvae. Injection of dsACP significantly inhibited the expression level of HiACP and further regulated the fatty acid synthesis in treated H. illucens larvae. The composition of saturated fatty acids was reduced, and the percentage of unsaturated fatty acids (UFAs) was increased. After interfering with HiACP, the cumulative mortality of H. illucens increased to 68.00% (p < 0.05). H. illucens growth was greatly influenced. The development duration increased to 5.5 days, the average final body weights of larvae and pupae were decreased by 44.85 mg and 14.59 mg, respectively, and the average body lengths of larvae and pupae were significantly shortened by 3.09 mm and 3.82 mm, respectively. The adult eclosion rate and the oviposition of adult females were also severely influenced. These results demonstrated that HiACP regulates fatty acid content and influences multiple biological processes of H. illucens.

Insect biorefinery: A circular economy concept for biowaste conversion to value-added products

With rapid growing world population and increasing demand for natural resources, the production of sufficient food, feed for protein and fat sources and sustainable energy presents a food insecurity challenge globally. Insect biorefinery is a concept of using insect as a tool to convert biomass waste into energy and other beneficial products with concomitant remediation of the organic components. The exploitation of insects and its bioproducts have becoming more popular in recent years. This review article presents a summary of the current trend of insect-based industry and the potential organic wastes for insect bioconversion and biorefinery. Numerous biotechnological products obtained from insect biorefinery such as biofertilizer, animal feeds, edible foods, biopolymer, bioenzymes and biodiesel are discussed in the subsequent sections. Insect biorefinery serves as a promising sustainable approach for waste management while producing valuable bioproducts feasible to achieve circular bioeconomy.

The Review of Cooking, Drying, and Green Extraction Methods on General Nutritional Properties of Mealworms and Locusts

The processing of edible insects as an alternative source of nutrition may be a key driver in the development of a sustainable food and feed system. This review will study two industrial types of insects-mealworms and locusts-and summarize evidence related to the impact of processing on their micro- and macronutritional characteristics. The focus will be on their potential use as food for human consumption as opposed to animal feed. Literature has indicated that these two insects have the potential to provide protein and fat qualities comparable to or better than traditional mammalian sources. For example, mealworms-the larval form of the yellow mealworm beetlepossess a higher fat content, while adult locusts are rich in fibers, especially chitin. However, due to the different matrix and nutrient compositions, the processing of mealworms or locusts at a commercial scale needs to be tailored to minimize nutritional loss and maximize cost efficiency. The stages of preprocessing, cooking, drying, and extraction are the most critical control points for nutritional preservation. Thermal cooking applications such as microwave technology have demonstrated promising results, but the generation of heat may contribute to a certain nutritional loss. In an industrial context, drying using freeze dry is the preferred choice due to its uniformity, but it can be costly while increasing lipid peroxidation. During the extraction of nutrients, the use of green emerging technologies such as high hydrostatic pressure, pulsed electric field, and ultrasound may provide an alternative method to enhance nutrient preservation.

Graphical Abstract

Chronological and Carbohydrate-Dependent Transformation of Fatty Acids in the Larvae of Black Soldier Fly Following Food Waste Treatment

Although black soldier fly larvae (BSFL) can convert food waste into insectile fatty acids (FAs), the chronological and diet-dependent transformation of larval FAs has yet to be determined. This study focused on the dynamics of larval FA profiles following food waste treatment and characterized factors that may drive FA composition and bioaccumulation. Larval FA matters peaked on Day 11 as 7.7 ± 0.7% of food waste dry matter, maintained stably from Day 11-19, and decreased slightly from Day 19-21. The BSFL primarily utilized waste carbohydrates for FA bioconversion (Day 0-11) and shifted to waste FAs (Day 7-17) when the carbohydrates were close to depletion. The optimal time window for larvae harvest was Days 17-19, which fulfilled both targets of waste oil removal and larval FA transformation. Larval FAs were dominated by C12:0, followed by C18:2, C18:1, and C16:0. The waste-reducing carbohydrate primarily accounted for larval FA bioaccumulation (r = -0.947, p < 0.001). The increase in diet carbohydrate ratio resulted in the elevation of larval C12:0 yield, which indicated that larval C12:0-FA was primarily biosynthesized from carbohydrates and further transformed from ≥C16 FAs. This study elucidates the bioaccumulation process of larval FAs for food waste treatment and highlights the importance of waste carbohydrates for both the composition and transformation of larval FAs.

A review of black soldier fly (Hermetia illucens) as a potential alternative protein source in broiler diets

Since per capita global meat utilization is predicted to increase to 40% from 2019 to 2050, global use of cultivable land in livestock, poultry, and feed production is 30%. Use of alternative protein sources as animal feed can be a solution to minimize cropland usage in conventional feed production. Commonly used protein sources in animal diets like soybean meal and fish meal are facing challenges of high demand, but the current production might not fulfill their dire need. To overcome this issue, the discovery of alternative protein sources is the need of the hour, insect meals like black soldier fly (BSF) are one of these alternative protein sources. These flies are non-infectious, bite-less, can convert the variant types of organic waste (food wastes, animal and human excreta) proficiently into rich profile biomass with reduced harmful bacteria count and do not serve as a vector in disease transmission. Based on the substrate used, the BSF larvae protein, fat and ash contents vary from 37-63%, 7-39% and 9-28% on dry matter basis, respectively. Previous studies have reported that using BSF and its byproducts as alternative protein sources in broiler diets with partial or complete replacement of conventional protein sources. In this review, a brief introduction to insect meal, BSF origin, life cycle, nutritional profile, influences on growth performance, carcass characteristics, fatty acid profile of meat, biochemical properties of blood, gut morphology and microbiota of the caecum along with its influence on laying performance of layers has been discussed in detail. Studies have concluded the partial replacement of conventional protein sources with BSF is possible, whereas complete replacement may cause poor performance due to reduced digestibility up to 62% attributable to chitin content (9.6%). Further studies to corroborate the effect of dietary BSF on growth performance, carcass characteristics, fatty acid profile of meat, and gut morphology and caecum microbiota are required to standardize the inclusion levels in feeds for higher performance of poultry.

Potential of Insect Life Stages as Functional Ingredients for Improved Nutrition and Health

This study aimed to provide information on the nutrients of the edible larval stage of Gonimbrasia cocaulti (GC) for the first time, while exploring the potential nutrient content of the pupal life stages of the domestic silkworm (Bombyx mori; BM) and the Eri silkworm (Samia Cynthia ricini; SC). The three insects were analyzed for fatty acids, minerals, proximate composition and vitamins. Among the fatty acids, linoleic, a polyunsaturated fatty acid, was approximately threefold higher in GC than in the silkworms. The Ca, Fe and K contents were highest in GC. However, the Zn and Na contents were highest in BM, while Mg content was predominant in SC. The crude protein content of the various developmental life stages of the edible caterpillars and pupae ranged between 50 and 62%. Further, the fiber content of GC was substantially higher compared to the pupal stages of the two silkworm species. The vitamin (B₆, B₉, B₁₂ and α-tocopherol) levels of the two insect life stages were considerably high. These insects are comparably rich in nutrients with potential suitability to be utilized in food fortification and thus ease pressure on the over-reliance on animal and plant-based sources, which are becoming unsustainable.

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.

Human consumption of insects

Farming edible insects can help improve food security and boost developing economies.

Nutritional Composition, Phenolic Compounds and Antioxidant Activity of Different Samples of Water Boatmen Eggs (Hemiptera: Corixidae)

The group of aquatic insects collectively called "water boatmen" or "Axayacatl" (Hemiptera: Corixidae) and their eggs, called "Ahuahutle", have been consumed and cultivated since the pre-Hispanic era in Mexico. Nevertheless, food composition databases contain limited information on the nutritional composition of these eggs. This work evaluates the macronutrients and bioactive compounds of water boatmen eggs obtained from three different locations in Mexico. The primary analyses to be determined for the first time were some bioactive compounds in the eggs, such as phenolic compounds, total flavonoids, condensed tannins content, antioxidant activity (DPPH and ABTS), and, additionally, fatty acids and proximal composition. The results showed that the sample from Hidalgo (AMC) presented the highest number of phenolic compounds (855.12 ± 0.52), followed by ALT (125.52 ± 0.05) and, with the lowest amount, AMT (99.92 ± 0.13), all expressed in an mg GAE/g sample. ALT indicated the highest mol TE/g sample concentration for ABTS (25.34 ± 0.472) and DPPH (39.76 ± 0.054), showing a significant difference in the DPPH method with the AMT samples. The three Corixidae egg samples had between 15 to 18 different fatty acid profiles, and there were statistically significant differences (Student's t-test ≤ 0.05) between the means using MSD. The total fats of the three samples were between 12.5 and 15.5 g/100 g dry basis. In addition, Corixidae eggs are excellent protein sources. Thus, water boatmen's eggs can be considered to be a food rich in bioactive compounds.

Full-fat insect meals in ruminant nutrition: in vitro rumen fermentation characteristics and lipid biohydrogenation

BACKGROUND

The most used protein sources in ruminant nutrition are considered as having negative impacts in terms of environmental sustainability and competition with human nutrition. Therefore, the investigation of alternative and sustainable feedstuffs is becoming a priority in ruminant production systems.

RESULTS

This trial was designed to evaluate eight full-fat insect meals (Acheta domesticus - ACD; Alphitobius diaperinus - ALD; Blatta lateralis - BL; Gryllus bimaculatus - GB; Grylloides sygillatus - GS; Hermetia illucens - HI; Musca domestica - MD; and Tenebrio molitor - TM) as potential protein and lipid sources in ruminant nutrition. Fermentation parameters and fatty acids (FA) of rumen digesta after 24-h in vitro ruminal incubation of the tested insect meals were measured and compared with those of three plant-based meals (soybean meal, rapeseed meal and sunflower meal) and fishmeal (FM). Similarly to FM, the insect meals led to a significantly lower total gas production (on average, 1.75 vs. 4.64 mmol/g dry matter-DM), methane production (on average, 0.33 vs. 0.91 mmol/g DM), volatile FA production (on average, 4.12 vs. 7.53 mmol/g DM), and in vitro organic matter disappearance (on average, 0.32 vs. 0.59 g/g) than those observed for the plant meals. The insect meals also led to lower ammonia of rumen fluid, when expressed as a proportion of total N (on average, 0.74 vs. 0.52 for the plant and insect meals, respectively), which could be an advantage provided that intestinal digestibility is high. Differences in ruminal fermentation parameters between the insect meals could be partially explained by their chitin, crude protein and ether extract contents, as well as by their FA profile. In particular, high content of polyunsaturated FA, or C12:0 (in HI), seems to partially inhibit the ruminal fermentations.

CONCLUSIONS

The tested full-fat insect meals appear to be potentially an interesting protein and lipid source for ruminants, alternative to the less sustainable and commonly used ones of plant origin. The FA profile of the rumen digesta of ACD, ALD, GB, GS and TM, being rich in n-6 polyunsaturated FA, could be interesting to improve the quality of ruminant-derived food products.

Nutritional Composition, Health Benefits, and Application Value of Edible Insects: A Review

For thousands of years, edible insects have been used as food to alleviate hunger and improve malnutrition. Some insects have also been used as medicines because of their therapeutic properties. This is not only due to the high nutritional value of edible insects, but more importantly, the active substances from edible insects have a variety of biofunctional activities. In this paper, we described and summarized the nutritional composition of edible insects and discussed the biological functions of edible insects and their potential benefits for human health. A summary analysis of the findings for each active function confirms that edible insects have the potential to develop functional foods and medicines that are beneficial to humans. In addition, we analyzed the issues that need to be considered in the application of edible insects and the current status of edible insects in food and pharmaceutical applications. We concluded with a discussion of regulations related to edible insects and an outlook on future research and applications of edible insects. By analyzing the current state of research on edible insects, we aim to raise awareness of the use of edible insects to improve human health and thus promote their better use and development.

Available for millions of years but discovered through the last decade: Insects as a source of nutrients and energy in animal diets

The aim of this review is to present and discuss the most recent literature about the processing of insect biomass and its impact on nutritive value, further implementation of meals and fats derived from invertebrates to livestock (poultry and swine), aquaculture (salmonids), and companion animal diets and their impact on growth performance, metabolic response, and gastrointestinal microbiota shifts. Additionally, the most important barriers to obtaining unified products in terms of their nutritive value are considered, i.e., to define insects' nutrient requirements, including various technological groups and further biomass processing (slaughtering, drying, and storage). Due to the current limitation in the insect production process consisting of the lack of infrastructure, there is stress on the relatively small amount of insect products added to the animal diets as a functional feed additive. Currently, only in the case of pet nutrition may insects be considered a full replacement for commonly used environmentally harmful and allergenic products. Simultaneously, the least information has been published on this topic. Thus, more scientific data are needed, particularly when the pet food branch and insect-based diets are rapidly growing.

Influence of Different Diets on Growth and Nutritional Composition of Yellow Mealworm

Insects are a pathway through which agro-food waste can become a high-quality source of nutrients for both livestock and humans. Yellow mealworm (Tenebrio molitor L., Coleoptera: Tenebrionidae) larvae are currently one of the insect species permitted for consumption, and they are reared on a large scale in Europe. This study evaluated the effect of seven diets containing byproducts such as wheat, rye bran, rapeseed meal, rapeseed cake, flax, and milk thistle cakes on the insect’s growth performance, feed conversion ratio (FCR), efficiency of conversion of ingested feed (ECI), nutritional quality of the larvae, and the composition of fats and fatty acids they contained. The lowest FCR based on the fresh and dry basis was 3.32 and 2.01, respectively. The ECI values were statistically different for larvae reared on different experimental diets (mean value 45.7%). As for the nutritional profile, protein and fats ranged from 43.6 to 53.4% d.m. and from 22.3 to 30.0% d.m., respectively. The major fatty acids in all samples were oleic acid (32.97–46.74% of total fatty acids (TFA)), linoleic acid (22.79–38.98% of TFA), and palmitic acid (12.80–17.81% of TFA). This study offers a new opportunity to use and efficiently convert cheap industrial byproducts using yellow mealworms.

Human Consumption of Insects in Sub-Saharan Africa: Lepidoptera and Potential Species for Breeding

There are 472 edible insect species in sub-Saharan Africa, of which 31% are Lepidoptera. Wild harvesting is still the main source of supply for these prized species to this day, with some harvesting techniques negatively impacting the environment. The successful production of edible caterpillars requires the appropriate and efficient implementation of husbandry techniques and practices. In this review, we present current literature on edible caterpillars. We provide a general overview of their life history, nutritional composition, and availability associated with specific host plants, with emphasis on semi-domestication and rearing practices that should replace wild harvest. Based on the assimilated information, a proposal of potential species for farming is provided, with details on key characteristics of development cycles to promote the establishment and development of sustainable farms of edible caterpillars at small and large scales. Such advances would contribute toward reducing anthropological pressure related to the exploitation of these food resources, as well as the environmental footprint of this widespread practice.

Biowaste and by-products as rearing substrates for black soldier fly (Hermetia illucens) larvae: Effects on larval body composition and performance

Black soldier fly (Hermetia illucens) larvae can convert biowaste and by-products into body mass high in protein (~40% dry matter, DM) and lipid (~30% DM). However, the type of rearing substrate also affects the larval body composition and thus its nutritional value. Hitherto, it remains unclear how and to what extent the larval body composition can be altered by the substrate. This study was therefore performed to examine the possibilities of modifying larval body composition using different rearing substrates. To investigate this, 5-days old larvae were reared for seven days on different locally available waste and by-products: brewer’s spent grain, mitigation mussels (Mytilus edulis), rapeseed cake, and shrimp waste meal (Pandalus borealis). Larval composition and performance were compared to larvae reared on a commercial chicken feed as well as a mixed feed (mixture of chicken feed and by-products, with a similar macronutrient composition to chicken feed). Larval body weight was recorded daily to determine growth over time whereas larvae and substrates were sampled at the start and end of the trial and analysed for their nutritional composition. The type of rearing substrate affected both larval body composition and growth performance. There was a clear relation between the nutritional composition of the substrate and larvae for certain fatty acids. Larvae reared on marine-based waste substrates contained a higher share of omega-3 fatty acids than larvae reared on the other substrates, indicating an accumulation of omega-3 fatty acids from the substrate. There was a strong positive linear correlation between the ash content in the substrate and larvae whereas larval lipid, protein, amino acid, and chitin content seemed more affected by larval development. Overall, this study showed that the rearing substrate affects larval composition and development, and that larval composition of certain nutrients can be tailored depending on further food and feed applications.

Modulating the Fatty Acid Profiles of Hermetia illucens Larvae Fats by Dietary Enrichment with Different Oilseeds: A Sustainable Way for Future Use in Feed and Food

Edible insects such as the black soldier fly Hermetia illucens L. represent a potential and sustainable source of nutrients for food and feed due to their valuable nutritional composition, which can be modulated through dietary enrichment. The high content of saturated fatty acid (FA) of Hermetia illucens larvae fats can be modulated through dietary enrichment as a result of adding vegetable oils in the rearing substrate. Therefore, the present research aims to highlight the effects of a 10% addition of vegetable oils from five dietary fat sources (linseed oil, soybean oil, sunflower oil, rapeseed oil, and hempseed oil) on the growth, development, reproductive performance, and the fat and fatty acids profile of H. illucens. Oil inclusion in the larval diet improved (p < 0.05) the weight of larvae, prepupae, pupae, and imago without influencing (p > 0.05) the egg clutch weight and the number of eggs in the clutch. In addition, the larvae fatty acid profile was different (p < 0.001) according to the oil type, because the unsaturated FAs (UFA) increased from 11.23 to 48.74% of FAME, as well as according to the larvae age, because the saturated FAs decreased from 85.86 to 49.56% of FAME. Linseed oil inclusion led to the improvement of the FA profile at 10 days age of larvae, followed by hempseed and rapeseed oil. These three dietary treatments recorded the highest concentrations in UFA (29.94−48.74% of FAME), especially in polyunsaturated FA (18.91−37.22% of FAME) from the omega-3 series (3.19−15.55% of FAME) and the appropriate n−6/n−3 ratio. As a result, the degree of the lipid polyunsaturation index increased (17.76−41.44) and the value of the atherogenic (3.22−1.22) and thrombogenic (1.43−0.48) indices decreased. Based on the obtained results, it can be concluded that enriching the larval diet with these oils rich in UFA can modulate the larvae FA profile, making them suitable sources of quality fats for feed and indirectly for food.

A Novel Strategy for the Production of Edible Insects: Effect of Dietary Perilla Seed Supplementation on Nutritional Composition, Growth Performance, Lipid Metabolism, and Δ6 Desaturase Gene Expression of Sago Palm Weevil (Rhynchophorus ferrugineus) Larvae

The nutritional value, growth performance, and lipid metabolism of sago palm weevil larvae (Rhynchophorus ferrugineus, SPWL) raised on plant-based diets (soybean, rice bran, and ground sago palm trunk (GSPT)), supplemented with various concentrations (0, 3, 7, 15, and 20%) of perilla seed (PS) were compared with traditional diets i.e., regular GSPT (control) and GSPT supplemented with pig feed. All supplemented diets rendered SPWL with higher lipid and protein contents (p < 0.05). Supplementing with 7−20% PS enhanced α-linoleic acid content in SPWL, resulting in a decrease in the n-6:n-3 ratio to a desirable level. Dietary PS supplementation increased Δ9 (18), total Δ9 and Δ5 + Δ6 desaturase indexes, fatty acid (FA) unsaturation, and the polyunsaturated FA:saturated FA ratio in SPWL, while lowering atherogenicity index, thrombogenicity index, and Δ6 desaturase (fads2) gene expression. Boosting with 7% PS improved the majority of growth parameters and enhanced essential amino acid and mineral contents (p < 0.05).

The Effect of Substrate on the Nutrient Content and Fatty Acid Composition of Edible Insects

Simple Summary

The search of new sustainably produced protein sources for food and feed is vigorously under investigation. One promising possibility is to increase the use of edible insects as a part of our diet. The nutrient content of edible insects, in particular, a high content of good quality protein and unsaturated fatty acids with essential fatty acids, is an important health aspect when screening the most potential insect species for human consumption. Based on this review, the substrate affects the nutrient content of insects. Moreover, our correlation calculations demonstrated that the fatty acid content of the substrate influences the nutritional value of insects. In general, high content of unsaturated fatty acids in the substrate increased the amount of unsaturated fatty acids in insects. For example, the content of essential fatty acids, linoleic and alpha linolenic acids, can be raised by feeding insects with modified substrate. Thus, edible insects can be a healthy protein source to ease the increased demand for high quality food.

Abstract

Demand for new food sources and production methods is increasing due to overall population growth, as well as the aim towards more sustainable use of natural resources and circular economy. Edible insects already used in many parts of the world have recently attracted interest as a new protein source in Europe, and novel food acceptance procedures are ongoing in the European Union for several insect species. In this paper, the effects of substate on the nutritional value, especially the fatty acid composition, of edible insects were reviewed and correlation calculations performed. The nutritional value of edible insects is an important health aspect, in particular, a high content of good-quality protein and unsaturated fatty acids with essential fatty acids, and an optimal fatty acid n6/n3 ratio. On the basis of our findings, the nutrient content of insects can be modified by using a feed substrate carefully designed for each individual insect species. In addition, our correlation calculations demonstrated that the contents of linoleic and alpha linolenic acids in insects reflected the contents of these acids in the substrate. In conclusion, optimizing the composition and structure of the substrate and rearing conditions and duration for each insect species might also aid standardization of the nutritional composition of edible insects.

Improved long-chain omega-3 polyunsaturated fatty acids in sago palm weevil (Rhynchophorus ferrugineus) larvae by dietary fish oil supplementation

The nutritional values of sago palm weevil larvae (SPWL) reared on mixed plant-based diets (ground sago palm trunk (GS), cornmeal, rice bran, soybean, and perilla seed), containing different levels of dietary fish oil (FO) were compared to those reared on commercial pig feed (PF) and GS. Increased FO content resulted in an increase in ω-3 fatty acids (FA) in SPWL (p < 0.05), especially α-linolenic acid and eicosapentaenoic acid. When fed FO-fortified diets instead of PF, the health-promoting indices of the SPWL lipid improved significantly (e.g., decreased ω-6/ω-3 ratio, thrombogenicity index, and hypercholesterolemic FA with increased PUFA content). The lipid, protein, and mineral contents of SPWL were increased while growth performance was maintained on a 1.5% FO-fortified diet. Higher FO levels (3-5%) had a negative impact on the nutritional values and growth performance of the SPWL. Thus, there was a reasonable chance of developing a high-nutrient alternative insect for human consumption.

Improving the Lipid Profile of Black Soldier Fly (Hermetia illucens) Larvae for Marine Aquafeeds: Current State of Knowledge

The replacement of fish meal and fish oil by insect-based ingredients in the formulation of marine aquafeeds can be an important step towards sustainability. To pursue this goal, the modulation of the lipid profile of black soldier fly larvae (Hermetia illucens) has received great attention. While its nutritional profile can shift with diet, the ability to modulate its lipidome is yet to be understood. The present work provides an overview of the lipid modulation of H. illucens larvae through its diet, aiming to produce a more suitable ingredient for marine aquafeeds. Marine-based substrates significantly improve the lipid profile of H. illucens larvae, namely its omega-3 fatty acids profile. An improvement of approximately 40% can be achieved using fish discards. Substantial levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two essential fatty acids for marine fish and shrimp species, were recorded in H. illucens larvae fed on fish discards and coffee silverskin with Schyzochytrium sp. Unfortunately, these improvements are still deeply connected to marine-based bioresources, some still being too costly for use at an industrial scale (e.g., microalgae). New approaches using solutions from the biotechnology toolbox will be decisive to make H. illucens larvae a feasible alternative ingredient for marine aquafeeds without having to rely on marine bioresources.

Poultry Meat and Eggs as an Alternative Source of n-3 Long-Chain Polyunsaturated Fatty Acids for Human Nutrition

The beneficial effects of n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) on human health are widely known. Humans are rather inefficient in synthesizing n-3 LC-PUFA; thus, these compounds should be supplemented in the diet. However, most Western human diets have unbalanced n-6/n-3 ratios resulting from eating habits and the fact that fish sources (rich in n-3 LC-PUFA) are not sufficient (worldwide deficit ~347,956 t/y) to meet the world requirements. In this context, it is necessary to find new and sustainable sources of n-3 LC-PUFA. Poultry products can provide humans n-3 LC-PUFA due to physiological characteristics and the wide consumption of meat and eggs. The present work aims to provide a general overview of the main strategies that should be adopted during rearing and postproduction to enrich and preserve n-3 LC-PUFA in poultry products. The strategies include dietary supplementation of α-Linolenic acid (ALA) or n-3 LC-PUFA, or enhancing n-3 LC-PUFA by improving the LA (Linoleic acid)/ALA ratio and antioxidant concentrations. Moreover, factors such as genotype, rearing system, transport, and cooking processes can impact the n-3 LC-PUFA in poultry products. The use of a multifactorial view in the entire production chain allows the relevant enrichment and preservation of n-3 LC-PUFA in poultry products.

Growth efficiency, intestinal biology, and nutrient utilization and requirements of black soldier fly (Hermetia illucens) larvae compared to monogastric livestock species: a review

In recent years, interest in the larvae of black soldier fly (BSF) (Hermetia illucens) as a sustainable protein resource for livestock feed has increased considerably. However, knowledge on the nutritional and physiological aspects of this insect, especially compared to other conventional farmed animals is scarce. This review presents a critical comparison of data on the growth potential and efficiency of the BSF larvae (BSFL) compared to conventional monogastric livestock species. Advantages of BSFL over other monogastric livestock species includes their high growth rate and their ability to convert low-grade organic waste into high-quality protein and fat-rich biomass suitable for use in animal feed. Calculations using literature data suggest that BSFL are more efficient than broilers, pigs and fish in terms of conversion of substrate protein into body mass, but less efficient than broilers and fish in utilization of substrate gross energy to gain body mass. BSFL growth efficiency varies greatly depending on the nutrient quality of their dietary substrates. This might be associated with the function of their gastrointestinal tract, including the activity of digestive enzymes, the substrate particle characteristics, and their intestinal microbial community. The conceived advantage of BSFL having an environmental footprint better than conventional livestock is only true if BSFL is produced on low-grade organic waste and its protein would directly be used for human consumption. Therefore, their potential role as a new species to better close nutrient cycles in agro-ecological systems needs to be reconsidered, and we conclude that BSFL is a complementary livestock species efficiently utilizing organic waste that cannot be utilized by other livestock. In addition, we provide comparative insight into morpho-functional aspects of the gut, characterization of digestive enzymes, gut microbiota and fiber digestion. Finally, current knowledge on the nutritional utilization and requirements of BSFL in terms of macro- and micro-nutrients is reviewed and found to be rather limited. In addition, the research methods to determine nutritional requirements of conventional livestock are not applicable for BSFL. Thus, there is a great need for research on the nutrient requirements of BSFL.

Characterization, Antioxidant Activities, and Pancreatic Lipase Inhibitory Effect of Extract From the Edible Insect Polyrhachis vicina

Oxidative stress and obesity are critical risk factors for metabolic syndrome. The consumption of functional food ingredients can a viable strategy to alleviate oxidative stress and obesity. In this study, the hydro-ethanolic extract of the edible insect Polyrhachis vicina was prepared and its bioactive components were characterized. The total polyphenol contents, total flavonoid contents, antioxidant and pancreatic lipase (PL) inhibitory activities of the extract were determined in vitro. In total, 60 bioactive components were tentatively identified in the P. vicina extract. Polyphenols and fatty acids were further quantified using LC-MS and GC-MS, respectively. P. vicina extract possessed excellent antioxidant and PL inhibition activities. Salicylic acid, gallic acid, liquiritigenin, and naringenin, which were the major polyphenols in the P. vicina extract, interacted with PL through hydrogen bonding, hydrophilic or hydrophobic and pi-cation interactions. Thus, P. vicina extract can be used as a nutraceutical to alleviate oxidative stress-induced disease and manage obesity.

Growth and Fatty Acid Composition of Black Soldier Fly Hermetia illucens (Diptera: Stratiomyidae) Larvae Are Influenced by Dietary Fat Sources and Levels

A 16-day rearing trial was performed to investigate the influence of two supplemental levels (5% and 10%) of six dietary fat sources (linseed oil, peanut oil, coconut oil, soybean oil, lard oil and fish oil) on the growth, development and nutrient composition of black solider fly larvae. Our results demonstrated that the pre-pupa rate of larvae was linearly influenced by dietary C18:0, C18:3n-3 and C18:2n-6 content (pre-pupa rate = 0.927 × C18:0 content + 0.301 × C18:3n-3 content-0.258 × C18:2n-6 content p < 0.001)), while final body weight was linearly influenced by that of C16:0 (final body weight = 0.758 × C16:0 content, p = 0.004). Larval nutrient composition was significantly affected by dietary fat sources and levels, with crude protein, fat and ash content of larvae varying between 52.0 and 57.5, 15.0 and 23.8, and 5.6 and 7.2% dry matter. A higher level of C12:0 (17.4-28.5%), C14:0 (3.9-8.0%) and C16:1n-9 (1.3-4.3%) was determined in larvae fed the diets containing little of them. In comparison, C16:0, C18:1n-9, C18:2n-6 and C18:3n-3 proportions in larvae were linearly related with those in diets, with the slope of the linear equations varying from 0.39 to 0.60. It can be concluded that sufficient C16:0, C18:0 and C18:3n-3 supply is beneficial for larvae growth. Larvae could produce and retain C12:0, C14:0, and C16:1n-9 in vivo, but C16:0, C18:1n-9, C18:2n-6 and C18:3n-3 could only be partly incorporated from diets and the process may be enhanced by a higher amount of dietary fat. Based on the above observation, an accurately calculated amount of black soldier fly larvae could be formulated into aquafeed as the main source of saturated fatty acids and partial source of mono-unsaturated and poly-unsaturated fatty acids to save fish oil.

Forage-Fed Insects as Food and Feed Source: Opportunities and Constraints of Edible Insects in the Tropics

Farmed insects can provide an alternative protein source for humans, livestock, and fish, while supporting adaptation to climate change, generating income for smallholder farmers, and reducing the negative impacts of conventional food production, especially in the tropics. However, the quantity, nutritional quality and safety of insects greatly relies on their feed intake. Tropical forages (grasses and legumes) can provide a valuable and yet untapped source of feed for several farmed insect species. In this perspective paper, we provide a viewpoint of how tropical forages can support edible insect production. We also highlight the potential of tropical forage-based diets over those using organic agricultural or urban by-product substrates, due to their versatility, low cost, and lower risk of microbial and chemical hazards. The main bottlenecks relate to dependence on the small number of farmed insect species, and in public policy and market frameworks regarding the use of edible insects as food, feed and in industrial processes. This perspective will serve interested stakeholders in identifying urgent issues at the research, ethical, marketing and policy levels that can prevent the emergence of new, insect-based value chains and business models, and the nutritional, economic and environmental benefits they promise.

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.

Local intestinal microbiota response and systemic effects of feeding black soldier fly larvae to replace soybean meal in growing pigs

Black soldier fly (Hermetia illucens; BSF) larvae as dietary protein source have the ability to deliver nutrients and could possess functional properties that positively support animal productivity and health. More knowledge, however, is needed to assess the impact of feeding a BSF based diet on gut and animal health. Sixteen post-weaned male pigs were randomly assigned to two groups and fed for three weeks with iso-caloric and iso-proteinaceous experimental diets prepared with either soybean meal (SBM) as reference protein source or with BSF as single source of dietary protein. At the end of the trial, the pigs were sacrificed to collect relevant digesta, gut tissue and blood samples to study changes induced by the dietary treatments using ~ omics based analyses. Inclusion of BSF in the diet supports the development of the intestinal microbiome that could positively influence intestinal health. By amine metabolite analysis, we identified two metabolites i.e. sarcosine and methionine sulfoxide, in plasma that serve as markers for the ingestion of insect based ingredients. BSF seems to possess functional properties indicated by the appearance of alpha-aminobutyric acid and taurine in blood plasma of pigs that are known to induce health beneficial effects.

Nutritional Qualities and Enhancement of Edible Insects

Over the last decade, the urgency to find alternative and sustainable protein sources has prompted an exponential increase in the interest in insects as a human food source. Edible insects contribute suitable amounts of energy and protein, fatty acids, and micronutrients to the human diet. Nutritional values of insects can be manipulated to meet specific needs. Edible insects in food-insecure countries can contribute to improving diets and preventing undernutrition. Bioactive compounds in insects may reduce health risks. Food safety risks are low and mainly relate to those of allergenicity. Strategies to overcome barriers to the consumption of insect products include emphasizing their sustainability, increasing their tastiness, and developing the ability to disguise insects in familiar products. A new sector of insects as food and feed is emerging. Major challenges include legislation, lowering prices by automation and cheap substrates, developing insect products that appeal to consumers, and exploring the health benefits. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Insights into the effects of dietary supplements on the nutritional composition and growth performance of sago palm weevil (Rhynchophorus ferrugineus) larvae

Nutritional composition and growth performance of sago palm weevil larvae (SPWL) fed with ground sago palm trunk mixed with different supplements including commercial pig feed, rice bran, cornmeal, soybean meal, and perilla seed were evaluated. SPWL fed with supplemented diets were richer in protein, lipid, and mineral contents (p < 0.05). Marked increases in polyunsaturated fatty acids (10.75-fold) and omega-3 fatty acids (25.42-fold) with the lowest n-6:n-3 ratio, atherogenicity index, and thrombogenicity index were found in SPWL fed with perilla seed (p < 0.05). Perilla seed, cornmeal, and soybean meal improved essential amino acid content and essential amino acid index of SPWL. Growth performance varied, depending on feed compositions, where a comparable or even greater effect was observed in SPWL fed with supplemented diets compared to control. Therefore, plant-based supplements, especially perilla seed, efficiently improved nutritional quality of SPWL, making them more attractive in terms of nutritional and economical value.

Does Consumption of Baker's Yeast (Saccharomyces cerevisiae) by Black Soldier Fly (Diptera: Stratiomyidae) Larvae Affect Their Fatty Acid Composition?

Fatty acids are important compounds for insects, but the requirements for essential fatty acids may differ between insect species. Most of the fatty acids are acquired through the insect's diet; therefore, supplementing the diet with baker's yeast (Saccharomyces cerevisiae Meyen ex E.C. Hansen), which produces unsaturated fatty acids, was predicted to affect the fatty acid composition of the insect. The tested insect was the black soldier fly (BSF) (Hermetia illucens L.), that is used as a source of protein and fat in feed. Therefore, there is importance for BSF larvae (BSFL) nutritional composition, especially the unsaturated fatty acids content, which is one of the nutritional limitations for mammalian diets. The dominant fatty acids of the tested BSFL were the saturated fatty acids: lauric, myristic, and palmitic acids, as found in other BSF studies. Oleic acid (c18:1) and linoleic acid (C18:2) were the abundant unsaturated fatty acids in the BSFL. The proportion of linoleic acid was higher in the substrate with the supplemental yeast; however, this did not affect its proportion in the larvae. The higher proportion of linoleic acid may have been exploited as a source for production of saturated lauric acid. Therefore, providing unsaturated fatty acids to the substrate through supplemental baker's yeast is not the most efficient way to increase the proportion of unsaturated fatty acids in the larvae.

Proteomic Study Reveals Major Pathways Regulating the Development of Black Soldier Fly

Nowadays, biodegrading organic waste, as a solution to confront environmental challenges, has attracted wide attention. A dipteran insect, black soldier fly (BSF), exhibits outstanding capability to convert organic waste into proteins and lipid resources, and thus, much interest has been shown in it. However, information of fundamental biology of BSF is still limited besides its recycling efficiency. In this work, we present a complete proteomic database of BSF at all instars (before prepupa). We further formulated the pathways corresponding to BSF development and built a relationship with the current genetic database. To achieve this, we investigated the proteomics of BSF during different periods. We identified 5036 proteins, and among them, 3905 proteins were annotated in the protein function database. illustrated three pathways related to major physiological processes including the insulin signaling pathway for feeding and growth, fatty acid biosynthesis pathway for fatty acid using, and toll/immune deficiency pathway for immune behavior. The proteins in these three pathways were matched with a published genetic database, and this reference library could be used for future BSF genetic engineering. In conclusion, this work provided a comprehensive protein library of BSF and expands the basic knowledge of BSF for future research.

Sustainable management of Se-rich silkworm residuals by black soldier flies larvae to produce a high nutritional value and accumulate ω-3 PUFA

Waste disposal and utilisation of its important components are pioneering goals for achieving sustainable development and a clean environment. Silkworm pupae (SWP) are considered a by-product of the sericulture industry and may contain a high concentration of selenium (Se) in some regions, making them a potentially hazardous waste posing health risks. This study examined six treatments of Se-rich SWP (0-100%) as a substrate for black soldier fly (BSF) larvae. Growth performance and protein content of BSF larvae were not affected by increasing SWP content. The total fat, mono-, and poly-unsaturated fatty acids in BSF pre-pupae increased with increasing SWP inclusion in the substrate, from P0 (pre-pupae fed control treatment) through P100 (pre-pupae fed 100% SWP treatment), by 18.83, 61.14, and 62.42%, respectively. The results of significance were: (1) BSF pre-pupae did not accumulate Se, maintaining the same amount of Se in their bodies (~0.18 mg/kg); (2) omega-3 fatty acids represented by linolenic acid in BSF increased by 1,223.35% from P0 to P100, with 70.65% recovered from the SWP; (3) valine percentage increased in BSF compared with the percentage of SWP by 25.30%; and (4) BSF larvae were observed reducing SWP waste by more than one-third. BSF larvae can reduce the waste from sericulture industry and exploit the beneficial properties and components of SWP, converting them into safe and highly nutritious products.