Search

The effect of the particle size of the feed on the larval growth and feed utilization parameters of two mealworm species, Alphitobius diaperinus (Panzer) and Tenebrio molitor L. (Coleoptera: Tenebrionidae), was examined under laboratory conditions. Wheat bran of four different particle sizes (100–250, 500–650, 850–1000 and >2000 μm) was provided as feed to larvae of both species. The larval growth and survival, as well as time to pupation and the amount of feed consumed, were monitored to determine differences among the wheat bran particle sizes within each insect species. Our research results suggest that a finely ground feed with a particle size below 650 μm significantly impact the growth and development of A. diaperinus, as opposed to a feed containing particles larger than 850 μm. Contrariwise, the larvae of T. molitor exhibited no discernible response to the various feed particle sizes that were evaluated. Overall, it was observed that the two mealworm species did not exhibit identical responses for the tested feed particle size, suggesting that this factor is species dependent. [ABSTRACT FROM AUTHOR]

Abstract Plastic waste has recently become a major global environmental concern and one of the biggest challenges has been seeking for alternative management options. Several studies have revealed the potential of several coleopteran species to degrade plastics, and this is the first research paper on plastic-degradation potential by lesser mealworms from Africa. This study evaluated the whole mitogenomic profile of the lesser mealworm to further identify the insect. The ability of the mealworm to consume Polystyrene (PS) was also evaluated alongside its associated gut microbiota diversity. Our results showed a complete circular mitochondrial genome which clustered closely to the Alphitobius genus but also suggested that our insect might be a new subspecies which require further identification. During the PS feeding trials, overall survival rates of the larvae decreased when fed a sole PS diet while PS intake was observed to increase over a 30-day period. The predominant bacteria observed in larvae fed PS diets were Kluyvera, Lactococcus, Klebsiella, Enterobacter, and Enterococcus, while Stenotrophomonas dominated the control diet. These findings demonstrated that the newly identified lesser mealworm can survive on a PS diet and has a consortium of important bacteria strongly associated with PS degradation. This work provides a better understanding of bioremediation applications, paving the way for further research into the metabolic pathways of plastic-degrading microbes and bringing hope to solving plastic waste pollution while providing high-value insect protein towards a circular economy.

Plastic waste has recently become a major global environmental concern and one of the biggest challenges has been seeking for alternative management options. Several studies have revealed the potential of several coleopteran species to degrade plastics, and this is the first research paper on plastic-degradation potential by lesser mealworms from Africa. This study evaluated the whole mitogenomic profile of the lesser mealworm to further identify the insect. The ability of the mealworm to consume Polystyrene (PS) was also evaluated alongside its associated gut microbiota diversity. Our results showed a complete circular mitochondrial genome which clustered closely to the Alphitobius genus but also suggested that our insect might be a new subspecies which require further identification. During the PS feeding trials, overall survival rates of the larvae decreased when fed a sole PS diet while PS intake was observed to increase over a 30-day period. The predominant bacteria observed in larvae fed PS diets were Kluyvera, Lactococcus, Klebsiella, Enterobacter, and Enterococcus, while Stenotrophomonas dominated the control diet. These findings demonstrated that the newly identified lesser mealworm can survive on a PS diet and has a consortium of important bacteria strongly associated with PS degradation. This work provides a better understanding of bioremediation applications, paving the way for further research into the metabolic pathways of plastic-degrading microbes and bringing hope to solving plastic waste pollution while providing high-value insect protein towards a circular economy. [ABSTRACT FROM AUTHOR]

Insect-based food ingredients are emerging as sustainable protein sources, but their production requires ensuring microbial safety and inactivation of endogenous enzymes to avoid undesirable proteolysis, without compromising protein structure. While traditional thermal processing affects the protein structure, the potential of pulsed electric field (PEF) technology to inactivate microorganisms in lesser mealworm and house cricket slurries at pH 3 while simultaneously retaining the native protein structure is yet unexplored.Lesser mealworm and house cricket slurries at pH 3 were subjected to continuous and batch PEF treatments with varying intensities (0–450 kJ/kg). Microbial inactivation (aerobes, anaerobes, yeasts, and moulds), temperature changes, protein solubility, protein structure (SDS-PAGE and FTIR), and endogenous protease activity were assessed.For both insect species, high-intensity PEF (>150 kJ/kg) achieved up to 5 log microbial reduction, but increased temperatures up to 75 °C, altering protein structure. Low-intensity PEF did not affect protein conformation and protease activity, but was not effective in microbial inactivation (

The botanical insecticide market is growing because of limitations placed on the use of certain synthetic chemical insecticides. In this sense, the lesser mealworm Alphitobius diaperius (Coleoptera: Tenebrionidae) is the main poultry pest. The insect causes weight loss and damage to the digestive system of poultry, and it is a vector and reservoir of pathogens. Consequently, this study explored the following hypotheses: (i) essential oils (EOs) derived from Mentha spp. are toxic to A. diaperius; (ii) these EOs are compatible with Beauveria bassiana, the natural enemy of the poultry pest, that parasite A. diaperinus; (iii) these EOs also exhibit activity against bacteria that are pathogenic to poultry. In topical applications and ingestion tests, EOs from Mentha arvensis, Mentha spicata, and Mentha piperita were toxic to A. diaperinus. Chromatographic analyses revealed that menthol is the predominant compound in M. arvensis and M. piperita, whereas carvone is the major compound in M. spicata. Both (−)- and (+)-menthol, along with (−)- and (+)-carvone, underwent testing with A. diaperinus. Nevertheless, their activity was not as potent as those of the EOs, suggesting a possible synergistic and/or additive effect. The EOs did not have any adverse effects on the conidial germination, vegetative growth, or conidia production per colony of the entomopathogenic fungus B. bassiana. Consequently, these EOs are compatible with this natural enemy. The EO extracted from M. spicata exhibited significant toxicity against Staphylococcus aureus (ATCC 25923), whereas the remaining EOs displayed moderate toxicity against this bacterium. The EOs derived from Mentha spp., as assessed in this study, hold promise for the development of botanical insecticides tailored for the control of A. diaperinus. These insecticides are selective in favor of the natural enemy B. bassiana and can also serve as effective sanitizers, thanks to their antibacterial properties. [ABSTRACT FROM AUTHOR]

Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), commonly known as the lesser mealworm, is a significant pest that infests stored grains and other amylaceous commodities. In addition, the species has also been recognized as a viable and environmentally friendly protein source. However, there is still a lack of comprehensive research on the developmental response of this species across various temperature and moisture conditions. This study investigates the impact of temperature and moisture content of the commodity on the population growth of the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae). In the first series of bioassays, the progeny production of A. diaperinus adults was recorded after 50 days of incubation under a range of temperatures from 25 to 40 °C in cracked soft wheat with 11.3% moisture content, while in the second series, the moisture content of the wheat was adjusted to 5, 10, 15, and 20%, at 30 °C. Our results show that temperature largely influences parental adult mortality of A. diaperinus. The most suitable temperatures for optimal larval development and adult survival were found to be within the spectrum of 25 to 32 °C. Moreover, we found that the moisture content of the wheat that served as rearing media was also a factor of significance, since a gradual decrease in the larval numbers was observed with an increase in the moisture content. The findings of this study provide data to further enhance the pest control strategies of A. diaperinus in poultry farms but also to establish mass rearing standards and facilitate the production of the species for efficient use as food and feed. [ABSTRACT FROM AUTHOR]

During the processing of insects for food and feed applications, thermal treatments are often used for decontamination purposes. However, these treatments denature proteins comprising their functional properties. Milder methods for microbiological decontamination can be used, such as microfiltration. Therefore, in this study dead-end microfiltration (0.2 µm poly-ethersulphone membrane) was tested for decontamination of soluble fractions of lesser mealworms and house crickets obtained at pH values of 3 and 8. The results showed that deadend microfiltration was successful in the removal of microorganisms (total viable count), removing the need for thermal treatments for the permeates. Protein recovery in the permeate was relatively low (14-43 %). Lesser mealworms at pH 3 gave the highest protein recovery in the permeate (43 %), as explained by the activity of endogenous proteases producing soluble peptides during microfiltration. Confocal imaging showed that the efficiency of microfiltration was reduced by membrane fouling caused by protein aggregation. The presence of lipids in the pre-filtrate does not hamper the permeate protein recovery. In conclusion, dead-end microfiltration with a 0.2 µm membrane is successful in achieving microbial stability. A pH of 3 is recommended during the extraction process to obtain a higher protein recovery. [ABSTRACT FROM AUTHOR]

Simple Summary: This study evaluated the minimum as well as the maximum label dose of d-tetramethrin plus acetamiprid applied on plastic, glass, metal, wood, and ceramic surfaces, against adults of both species, in terms of immediate and delayed mortality. All T. molitor died after a 7-day exposure to the maximum dose at all tested surfaces when food was absent. In the presence of food, only glass-, metal-, and ceramic-treated surfaces killed all adults at the same dose. Even the minimum dose provided 100% mortality on glass, metal, and ceramic surfaces in both food scenarios. In the case of A. diaperinus, only the maximum dose caused the death of all exposed individuals on glass (with food) and on glass and plastic (no food). Overall, the maximum dose of d-tetramethrin plus acetamiprid is effective against the tested species on certain types of surfaces. Tenebrio molitor L. (Coleoptera: Tenebrionidae) and Alphitobius diaperinus Panzer (Coleoptera: Tenebrionidae) are two common tenebrionids occurring in grain storages. In this study, we assessed the immediate and delayed mortalities caused by d-tetramethrin plus acetamiprid on five different surfaces, i.e., plastic, glass, metal, wood, and ceramic, against adults of the two species. The tests included two label doses of the insecticide (minimum and maximum) and two food scenarios (food and no food). Generally, the maximum dose was more efficient than the minimum dose, and the presence of food resulted in lower observed mortalities than when food was absent. Tenebrio molitor was more susceptible than A. diaperinus, at all dose, food, and surface scenarios. At delayed bioassays, both doses killed all T. molitor on plastic, while on wood, mortality ranged between 80.6 and 100.0%, regardless of the food scenario. Concerning A. diaperinus, delayed mortalities ranged among treated surfaces, food scenarios, and dose from 58.3 to 100.0%. The insecticide killed the most individuals when it was treated on glass, while when it was applied on wood caused the death of the least individuals. Concerning plastic, metal, and ceramic surfaces, no general trend was observed. The maximum dose of the tested insecticide provides elevated mortalities for both species when food is absent. [ABSTRACT FROM AUTHOR]

The lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), is an important pest of stored products and at the same time a species with great potential as food and feed that has recently attracted increasing interest as nutrient source. Future predictions show a massive increase of insect meals' production in the near future, therefore, as expected in the case of other durable stored products, insect meals may get infested by insects during their storage. In this context and as a continuance of our previous study on the susceptibility of meal of the yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae), to storage insect infestations, the objective of this study was to test the susceptibility of A. diaperinus meals to infestations of three stored products pests, namely A. diaperinus itself, T. molitor , and the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). The population growth of the three species was evaluated on pure A. diaperinus meal, as well as on A. diaperinus meal-based substrates with different percentages of wheat bran (0, 25, 50, 90, and 100% bran). Our results showed that all three insect species tested were able to grow and develop on the A. diaperinus meal-based substrates evaluated, giving in a short time high population densities. This study confirms again our initial theory for insect infestations during storage of insect-based products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Insect residues can be biotransformed by lactic acid bacteria without a carbon source. • Deproteinization of 29 % achieved after 120 h of incubation by L. brevis. • Lactic acid bacteria biomass increased by 2 log 10 CFU/mL in only 48 h. • Biotransformation led to the formation of peptides with antioxidant activity. Processing of edible insects typically involves fractionating into high-value food ingredients, which results in by-products containing chitin and insoluble proteins. This study examined the effectiveness of lactic acid bacteria (LAB) in removing proteins from chitin in insect processing residues. Lesser mealworm processing residues were biologically treated for 48 and 120 h using LAB strains without added carbon sources. Results showed partial deproteinization, up to 29 % with Levilactobacillus brevis after 120 h. Most LAB grew up to 2 log 10 colony-forming units/mL in the first 48 h. Confocal microscopy and Fourier-transform infrared spectra indicated that some protein remained attached to chitin. The molecular weight of solubilized proteins was affected by strain and time of incubation, with antioxidant activity increasing significantly after 120 h with Lacticaseibacillus paracasei. The biological treatment of insect processing streams can be a sustainable approach to producing high amounts of LAB biomass with subsequent protein solubilization and chitin release. [ABSTRACT FROM AUTHOR]

Stored-product commodities are attacked by numerous insect species. The adulticidal effects of entomopathogenic nematodes (EPNs) on grains remain uninvestigated. Thus, in the current study, seven doses of the EPNs Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), Steinernema carpocapsae (Weiser) (Rhabditida: Steinernematidae), and Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae) were inoculated on wheat kernels against adults of Trogoderma granarium Everts (Coleoptera: Dermestidae), Tenebrio molitor L. (Coleoptera: Tenebrionidae), and Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae). Complete mortality (100.0%) of T. granarium was recorded after exposure for eight days to the highest dose of 50,000 Infective Juveniles/mL (IJs/mL) of all tested EPN species. At the same exposure interval, 62.2%, 85.6%, and 76.7% of T. molitor were killed by 50,000 IJs/mL of H. bacteriophora, S. carpocapsae, and S. feltiae, respectively. The highest mortality of A. diaperinus (11.1%) was documented eight days post-exposure to 50,000 IJs/mL of H. bacteriophora. In general, T. granarium was highly susceptible, followed by T. molitor and A. diaperinus. Concerning EPN species, S. carpocapsae exhibited the highest insecticidal capacity, followed by S. feltiae and H. bacteriophora. Trogoderma granarium and T. molitor can be sufficiently managed by the highest dose of 50,000 IJs/mL of all three EPNs and by S. carpocapsae, respectively. However, A. diaperinus was not affected by any EPNs. [ABSTRACT FROM AUTHOR]

The lesser mealworm Alphitobius diaperinus Panzer (Coleoptera: Tenebrionidae), an important insect pest of stored-product commodities and poultry production systems, is regarded among the most difficult species to control. It has developed resistance to many chemical insecticides, and though various cultural and biological methods have been assessed and identified as possible factors for its control, none are currently implemented. Entomopathogenic nematodes are often successfully employed as alternative to chemicals biocontrol agents of various insect species, including pests of stored products; nevertheless, their evaluation as potential biocontrol factors of the lesser mealworm is not efficiently scrutinized. In the current study, single A. diaperinus larvae were exposed to six doses of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), Steinernema carpocapsae (Weiser) (Rhabditida: Steinernematidae), and Steinernema feltiae (Filipjev) (Rhabditida: Steinernematidae), for 4 and 8 d, and mortality was recorded at 3 different temperature regimes, i.e., 25 oC, 30 oC, and 35 oC. The study concludes that S. carpocapsae and S. feltiae are both highly virulent against A. diaperinus larvae and may be considered as promising biological control agents for reducing lesser mealworm infestations when applied at a rate of 70 IJs/cm2 at 25 oC. When assessed at 30 oC, both species were effective at the same rate though causing lower mortality of ~60% and ~50%, respectively, whereas their efficacy was low at 35 oC., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on frozen and dried formulations from whole lesser mealworm (Alphitobius diaperinus larva) as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The term lesser mealworm refers to the larval form of the insect species Alphitobius diaperinus. The NF comprises the frozen and freeze-dried formulations of the lesser mealworm as whole or in the form of a paste or powder. Apart from water in the frozen formulations (whole, paste), the main components of the NF are crude protein and fat, besides smaller amounts of digestible carbohydrates and fibre (chitin). The Panel notes that the levels of contaminants in the NF depend on the concentration of such substances in the insect feed. The Panel notes furthermore that the true protein levels in the NF are overestimated when using the nitrogen-to-protein conversion factor of 6.25, due to the presence of non-protein nitrogen from chitin. The applicant proposed to use the NF formulations added as an ingredient to various food products such as cereal bars, pasta, meat imitates and bakery products. The target population is the general population. Additionally, the applicant proposed to use the NF as a food supplement in adults. The Panel notes that, considering that the NF will not be the sole source of dietary protein, and the composition of the NF and the proposed conditions of use, the consumption of the NF is not nutritionally disadvantageous. The submitted subchronic 90-day toxicity study with the NF as testing material did not raise safety concerns. The Panel considers that the consumption of the NF may induce primary sensitisation and allergic reactions to lesser mealworm proteins and may cause allergic reactions in subjects with allergy to crustaceans and dust mites. Additionally, allergens from the feed may end up in the NF. Allergenicity aside, the Panel concludes that the NF is safe under the proposed uses and use levels. [ABSTRACT FROM AUTHOR]

During the last decade, insects have shown up as a promising answer to the increasing animal protein demand for a continuously growing human population. A wide spectrum of substrates of plant origin can be currently used as insect feed; the sustainability of insect rearing though greatly increases when organic side-streams and wastes are valorized and upcycled through their bioconversion with insects. Additionally, the exploitation of low-cost organic residues as insect feed can also significantly suppress the rearing cost and, consequently, the price of the insect meal. In this context, the aim of our work was to evaluate organic side-streams, generated through several agro-industrial processes, as feeding substrates for the larvae of the lesser mealworm, Alphitobius diaperinus. In a laboratory trial, eleven agricultural side-streams were provided to larvae singly to assess their potential to support complete larval development, whereas in the second trial, larvae were fed two groups of isoproteinic diets consisting of the side-streams that performed well in the first trial. Our results showed the suitability of several agricultural side-streams as feed for A. diaperinus larvae, e.g., barley by-products (classes I and II), sunflower meal, cotton cake and oat sidestream, which, when fed singly, efficiently supported larval growth, resulting in high survival rates and final larval weights, comparable to the control. Similarly, several of the side-streams-based diets tested were shown to be suitable for A. diaperinus rearing. These results aim to contribute to the utilization of agricultural side-streams singly or in composed diets for the rearing of A. diaperinus larvae. [ABSTRACT FROM AUTHOR]

Simple Summary: Poultry meat production and consumption continue to grow worldwide; therefore, the safety of poultry products is a priority for consumers, producers, and governing authorities. Thus, it is essential to find an effective solution to maintain proper hygiene in poultry production. One such tool is a water-based slow-release biocidal paint that contains insecticidal and antimicrobial compounds. In this study it was assumed that biocidal paint could be useful in controlling insect pests such as Alphitobius diaperinus and reducing microbiological contamination of air and litter and have a beneficial effect on microclimate in poultry houses. The results suggest that the tested biocidal paint could be an effective alternative to other insecticides and disinfectants. Additionally, the research is of a practical nature and may be very useful for poultry producers in controlling A. diaperinus populations and maintaining proper hygiene in poultry houses. Effective disinfection and disinsection are the keys to successful operation of modern poultry farms and the safety of poultry products. The cleaning and disinfection of poultry houses are important aspects of farm hygiene management. The correct execution of all steps of cleaning, disinfection, and disinsection procedures and the use of appropriate products are crucial for the prevention and control of zoonotic and animal diseases. In this study it was assumed that a water-based slow-release biocidal paint could be useful in controlling insect pests such as Alphitobius diaperinus and reducing microbiological contamination of air and litter in poultry houses and have a beneficial effect on microclimate in poultry houses. Therefore, the locations of A. diaperinus in the poultry houses, the microbiological contamination of air and litter, as well as the microclimatic conditions in the houses and the physicochemical parameters of the litter were evaluated. The results suggest that the tested biocidal paint could be an effective alternative to other insecticides and disinfectants. Additionally, the research is of a practical nature and may be very useful for poultry producers in controlling A. diaperinus populations and maintaining proper hygiene in poultry houses. Further research is needed. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we used etofenprox, deltamethrin, and the combination of piperonyl butoxide+acetamiprid+d-tetramethrin as surface treatments on concrete (with or without food) to evaluate the short- and long-term mortalities of the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) small and large larvae. Concerning short-term mortality, etofenprox killed 97.8% and 80.0% of the small and large larvae, respectively, 7 days post-exposure on concrete without food. Deltamethrin caused complete (100.0%) mortality to small larvae without food (3 days post-exposure), small larvae with food, and large larvae without food (5 days post-exposure), and 98.9% mortality to large larvae with food after 5 days of exposure. Piperonyl butoxide+acetamiprid+d-tetramethrin killed all small larvae without food 5 days post-exposure. Concerning long-term mortality, all small larvae exposed to etofenprox died on concrete without food, while piperonyl butoxide+acetamiprid+d-tetramethrin caused 85.0% mortality to small larvae on concrete with food. Overall, deltamethrin was the most efficient active ingredient for the management of both small and large larvae of A. diaperinus. The lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) is an important stored-product pest for the poultry industry as it is a vector of dangerous pathogens for humans. In the present study, we evaluated the short- and long-term mortalities of small and large larvae of A. diaperinus when they were exposed to concrete-covered Petri dishes treated with etofenprox, deltamethrin, and the combination of piperonyl butoxide+acetamiprid+d-tetramethrin. Small and large larvae were exposed to each insecticide applied on concrete surfaces with or without food. The short-term mortality was recorded after 1 day, 3 days, 5 days, and 7 days, while the long-term mortality was recorded 7 days after the transport of the larvae alive to pesticide-free concrete-covered dishes. Regarding short-term mortality levels, 97.8% and 80.0% of the small and large larvae, that were exposed to etofenprox without food, died after 7 days of exposure, respectively. Concerning deltamethrin, all tested small larvae were killed after 3 days (without food) and 5 days (with food) of exposure. For large larvae, deltamethrin caused 98.9% (with food) and 100.0% (without food) mortality levels after 5 days of exposure. The combination of piperonyl butoxide+acetamiprid+d-tetramethrin caused high mortality levels to small larvae, i.e., 84.4% and 100.0% on dishes with and without food, respectively, but low to moderate mortality levels to large larvae that did not exceed 67.8% after 7 days of exposure. Long-term mortality varied vastly among the tested insecticides. Etofenprox killed 100.0% of the small larvae on concrete without food, but 24.0% of the large larvae exposed to concrete containing food. Deltamethrin did not provide long-term mortality to large larvae when food was present. Piperonyl butoxide+acetamiprid+d-tetramethrin caused mortality rates that overall varied from 33.5% (large larvae on concrete with food) to 85.0% (small larvae on concrete with food). In conclusion, deltamethrin killed almost all exposed larvae at exposures of ≤5 days, regardless of their size and the presence of food on the concrete. [ABSTRACT FROM AUTHOR]

Use of edible insects as an alternative source of proteins in food and feed is increasing. These last years, numerous companies in Europe have started producing insects for food and feed purposes. In the European Union, the use of edible insects for human consumption falls within Regulation (EU) No. 2015/2283 on novel foods. For feed, Commission Regulation (EU) 2017/893 authorizes seven insect species as processed animal proteins for aquaculture. Methods of authentication are required to check the conformity of the products. In this study, we propose a real-time polymerase chain reaction (PCR) method for the specific detection of the lesser mealworm (Alphitobius diaperinus), one of the species included in the shortlist of authorized insects. The selected target is the cadherin gene with a single-copy (per haploid genome) illustrated by our experimental evidence. The PCR test amplified a 134-bp fragment of the cadherin gene. The qualitative method was assessed toward several performance criteria. Specificity was checked against 54 insect species next to other animal and plant species. The sensitivity, efficiency, robustness, and transferability of the PCR assay were also successfully tested. Finally, the applicability of the test was assessed on real-life processed samples (industrial meals) of A. diaperinus. The study also showed that there seems to be a huge confusion on the correct labeling of the marketed mealworms. We did not succeed to get Alphitobius laevigatus samples. They all appeared to belong to the A. diaperinus taxon.

Insect production currently involves thermal processes to ensure microbial safety and inactivate endogenous enzymes, but these processes negatively affect the protein's technological properties. Therefore, this study compared high hydrostatic pressure (HHP) at 200/400/600 MPa for 10 min to blanching at 90 °C for 10 min, on soluble protein fractions (pH 3) from house crickets (Acheta domesticus) and lesser mealworms (Alphitobius diaperinus). HHP significantly reduced the microbial load, especially at 400 and 600 MPa. For aerobic counts of mealworms, blanching (from ∼6 to ∼3 log CFU/mL) was more effective than HHP (∼4 log CFU/mL). HHP preserved the secondary protein structure better than blanching, but was less effective in protease inactivation, though only evident in mealworms. HHP did not affect foaming and emulsification properties but improved protein solubility after pH adjustment to 7 compared to untreated fractions by 14–22%. We thus demonstrate that HHP can be an effective alternative to conventional blanching treatments. The emerging edible insect industry is currently struggling with several challenges. Conventional thermal processes that are often applied can negatively affect the techno-functional protein properties. We demonstrated that high hydrostatic pressure (HHP) can be an effective milder alternative to thermal processes. The evaluated blanching condition did not always negatively affect the functional protein properties, and blanching was more effective in protease inactivation compared to HHP for lesser mealworms. HHP can be of industrial relevance for inactivating house cricket fractions with high protein solubility intended for emulsion applications. Blanching could be better suited to provide proteolytically stable fractions. [Display omitted] • Pressure treatment (HHP) increased protein solubility at pH 7 up to 22% vs. untreated • Unlike blanching (90 °C, 10 min), HHP retained emulsion properties for house crickets • Unlike HHP, blanching increased intermolecular β-sheets showing protein aggregation • Proteases in mealworms were inactivated by blanching, and only partially by HHP [ABSTRACT FROM AUTHOR]

In the recent years, insect meals have been studied as alternative feed ingredients for aquafeeds, due to their adequate nutrient composition and low ecological footprint. These studies involve nutrient digestibility measurements, as they provide valuable information on the ability of fish to utilize insect meal efficiently. In this context, the current study evaluated the nutrient digestibility in European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) fed diets with five different insect meals. For this investigation, diets including 19.5 % of each insect meal from yellow mealworm (Tenebrio molitor – TM), black soldier fly (Hermetia illucens – HI), common housefly (Musca domestica – MD), super worm (Zophobas morio – ZM) or lesser mealworm (Alphitobius diaperinus – AD) and a control fish meal (FM) diet were tested. In European sea bass, TM and MD diets showed similar dry matter, protein, fat, energy, and organic matter ADCs among each other as well as with the FM diet (P > 0.05). However, adjusted protein ADC of TM and ZM diets (93.4 – 93.6 %) were significantly higher (P < 0.05) compared to the FM diet (91.9 %). Fat ADC was similar in all dietary groups (88.6–92.4 %; P > 0.05). The HI diet exhibited significantly lower dry matter, protein and organic matter ADCs compared to the FM diet (P < 0.05). Moreover, the AD diet presented significantly lower digestibility coefficients of dry matter, organic matter and energy than the FM diet (P < 0.05). The dietary contents of crude fiber and ash, and the inclusion of plant feedstuffs correlated negatively with various ADCs (P < 0.05). Regarding gilthead sea bream, the ADCs of dry matter, organic matter, protein, adjusted protein and energy were not affected by the different dietary treatments (P > 0.05). Fat ADC of the TM diet (73.6 %) was significantly lower compared to the other five diets (78.9–84.3 %; P < 0.05). The individual amino acid ADCs values were found to be very high in all experimental diets (90.9 – 98.0 % for European sea bass and 88.9 – 97.2 % for gilthead sea bream). In sea bass, the variation in crude protein and adjusted protein ADCs was strongly reflected on the individual amino acid ADCs. Nevertheless, the "true protein digestibility" as expressed by the sum of amino acids was not affected by the insect inclusion compared to the FM diet (P > 0.05), while a significant difference was observed between the ZM and HI diets (95.9 % and 94.1 % respectively; P < 0.05). In sea bream, the sum of amino acids and the individual amino acid ADC values did not differ among the experimental diets (P > 0.05) except for methionine (P < 0.05). Conclusively, in sea bream all diets exhibited similar overall digestibility. In sea bass, compared to the FM diet, TM and MD diets had similar or even slightly better digestibility, whilst diets HI and AD presented lower overall digestibility. • In sea bream overall digestibility was not affected by the different insect meals. • Diets with Tenebrio molitor or Musca domestica performed equally well in sea bass. • Hermetia illucens or Alphitobius diaperinus diets had lower digestibility. • Insect meal inclusion did not affect true protein digestibility. [ABSTRACT FROM AUTHOR]