Overview of antimicrobial compounds from African edible insects and their associated microbiota

This review discusses advances in the identification and bioactivity analysis of insect antimicrobial peptides (AMP) compounds, with a focus on small molecules associated with the microbiota of selected African edible insects. These molecules could be used as templates for developing next-generation drugs to combat multidrug-resistant pathogens. Previous research indicates that each insect species produces a distinct antimicrobial peptide that acts against specific microorganisms. The article analyzes several likely AMP-producing insects and their compounds. Edible insect-produced AMPs/small molecules’ chemistry receives little attention as researchers have concentrated on the discovery of antibacterial and antifungal peptides/polypeptides in plants

The nutritional profile of the yellow mealworm larvae (Tenebrio molitor) reared on four different substrates

DATA AVAILABILITY : Data will be made available on request.The utilisation of Tenebrio molitor L. (the yellow mealworm) as a cheaper, alternative and readily available ingredient for food and feed is gaining interest globally. However, there has been limited research on locally and readily available substrates for mealworm mass rearing in South Africa. This study evaluated the impact of four substrates; wheat bran (control diet), wheat flour, maize flour, and Lucerne (pellets) on the rearing of mealworm larvae under controlled conditions over two generations and analysed the nutrient composition using standard nutritional analysis techniques. The results revealed that the crude protein contents of T. molitor larvae ranged between 28 – 36 % when raised on different substrates and varied significantly in the order Lucerne > wheat bran > wheat flour > maize flour. The major minerals found in the larvae included sodium, magnesium, phosphorus, potassium, copper, and zinc. The larvae were also rich in saturated, mono and polyunsaturated Fatty Acids (FAs) with oleic, linoleic, and palmitic as the main FAs. The nutritional profiles of first- and second-generation larvae raised on the same substrates remained the same. Wheat flour was found to be the best alternative to wheat bran. The finding demonstrates the suitability of local, inexpensive substrates for commercial production of yellow mealworm without compromising their nutritional quality and utilisation for food and feed.The South African National Research Foundation (NRF) Incentive Funding for Rated Researchers (Grant no. 109380), NRF Research Development Grant for Y- Rated Researchers’ (Grant no. 116347) and the PI grant from the South African Research Chair in Mathematical Models and Methods in Bio-engineering and Biosciences (SARChI M3B2) at the University of Pretoria.https://www.elsevier.com/locate/fufohj2024Zoology and EntomologySDG-01:No povertySDG-02:Zero HungerSDG-03:Good heatlh and well-beingSDG-05:Gender equalitySDG-08:Decent work and economic growthSDG-10:Reduces inequalitiesSDG-11:Sustainable cities and communitiesSDG-13:Climate actionSDG-15:Life on lan

Can black soldier fly Desmodium intortum larvae-based diets enhance the performance of Cobb500 broiler chickens and smallholder farmers’ profit in Kenya?

This study aimed to evaluate the performance of broiler chickens fed on black soldier fly larvae (BSFL) (Hermetia illucens) and Greenleaf desmodium (Desmodium intortum)-based meals. Study findings show the BSFL-Desmodium mixture could be a valuable replacement for the protein component in conventional feed. Growth performance, carcass quality, and profitability of the poultry were evaluated under various commercial pathways (doorstep, retail, whole, and assorted). The poultry sector is one of the fastest growing industries in Kenya. The highest volume of both poultry, meat, and eggs is produced by local backyard systems characterized by low input and low productivity.Push-Pull for Sub-Saharan Africa Projec

Diversity, host plants and potential distribution of edible Saturniid Caterpillars in Kenya

Saturniids are big colorful caterpillars with spines on their bodies, usually found in shrubs and trees in Sub-Saharan Africa. They are rich in proteins, vitamins, and minerals. The study identifies edible saturniids, diversity, their host plants, their current distribution and to predict possible effects of climate change on their distribution. The paper provides detailed information (including photographs) of seven species of edible saturniids namely Gonimbrasia zambesina, Gonimbrasia krucki, Bunaea alcinoe, Gonimbrasia cocaulti, Gonimbrasia belina, Gynanisa nigra and Cirina forda. Despite being highly nutritious, the diversity of edible saturniid caterpillars has not been studied in Kenya.Federal Ministry for Economic Cooperation and DevelopmentBioInnovate Africa ProgrammeAustralian Centre for International Agricultural Research (ACIAR

In situ nitrogen mineralization and nutrient release by soil amended with black soldier fly frass fertilizer

Black soldier fly frass fertilizer (BSFFF) is effective on crop performance, but information on nitrogen mineralization and nutrient release capacity of soils amended with BSFFF is lacking. This study utilized field incubation experiments to investigate the ammonification, nitrification, microbial populations, and quantities of nutrients released by soils amended with BSFFF and commercial organic fertilizer (SAFI) for a period equivalent to two maize cropping seasons. The paper provides a detailed breakdown and analysis of results. BSFFF has a high potential to supply adequate nutrients for optimal crop production. Higher population of soil bacteria and fungi underline its potential for improving biological soil fertility.Norwegian Agency for Development CooperationNetherlands Organization for Scientific ResearchWOTRO Science for Global Development (NWO-WOTRO)Rockefeller Foundatio

Organic waste substrates induce important shifts in gut microbiota of black soldier fly (Hermetia illucens L.) : coexistence of conserved, variable, and potential pathogenic microbes

The sustainable utilization of black soldier fly (BSF) for recycling organic waste into nutrient-rich biomass such as high-quality protein additive, is gaining momentum. Its gut microbiota is thought to play an important role. The study provides the first comprehensive analysis of bacterial and fungal communities of BSF gut across untreated substrates and highlights conserved members, potential pathogens, and their interactions. Findings show most bacteria found in the BSF gut are transient, and are affected by the local environment. The study contributes to establishment of safety measures for future processing of BSF larval meals and the creation of legislation to regulate their use in animal feeds.Australian Centre for International Agricultural Research (ACIAR)Norwegian Agency for Development CooperationNetherlands Organization for Scientific ResearchWOTRO Science for Global Development (NWO-WOTRO)The Rockefeller Foundatio

Integrating temperature-dependent life table data into Insect Life Cycle Model for predicting the potential distribution of <em>Scapsipedus icipe</em> Hugel &amp; Tanga

Scapsipedus icipe Hugel and Tanga (Orthoptera: Gryllidae) is a newly described edible cricket species. Although, there is substantial interest in mass production of S. icipe for human food and animal feed, no information exists on the impact of temperature on their bionomics. Temperature-dependent development, survival, reproductive and life table parameters of S. icipe was generated and integrated into advanced Insect Life Cycle Modeling software to describe relative S. icipe population increase and spatial spread based on nine constant temperature conditions. We examined model predictions and implications for S. icipe potential distribution in Africa under current and future climate. These regions where entomophagy is widely practiced have distinctly different climates. Our results showed that S. icipe eggs were unable to hatch at 10 and 40°C, while emerged nymphs failed to complete development at 15°C. The developmental time of S. icipe was observed to decrease with increased in temperature. The lowest developmental threshold temperatures estimated using linear regressions was 14.3, 12.67 and 19.12°C and the thermal constants for development were 185.2, 1111.1- and 40.7-degree days (DD) for egg, nymph and pre-adult stages, respectively. The highest total fecundity (3416 individuals/female/generation), intrinsic rate of natural increase (0.075 days), net reproductive rate (1330.8 female/female/generation) and shortest doubling time (9.2 days) was recorded at 30°C. The regions predicted to be suitable by the model suggest that S. icipe is tolerant to a wider range of climatic conditions. Our findings provide for the first-time important information on the impact of temperature on the biology, establishment and spread of S. icipe across the Africa continent. The prospect of edible S. icipe production to become a new sector in food and feed industry is discussed

Organic waste substrates induce important shifts in gut microbiota of black soldier fly (Hermetia illucens L.) : coexistence of conserved, variable, and potential pathogenic microbes

The sustainable utilization of black soldier fly (BSF) for recycling organic waste into nutrient-rich biomass, such as high-quality protein additive, is gaining momentum, and its microbiota is thought to play important roles in these processes. Several studies have characterized the BSF gut microbiota in different substrates and locations; nonetheless, in-depth knowledge on community stability, consistency of member associations, pathogenic associations, and microbe–microbe and host–microbe interactions remains largely elusive. In this study, we characterized the bacterial and fungal communities of BSF larval gut across four untreated substrates (brewers’ spent grain, kitchen food waste, poultry manure, and rabbit manure) using 16S and ITS2 amplicon sequencing. Results demonstrated that substrate impacted larval weight gain from 30 to 100% gain differences among diets and induced an important microbial shift in the gut of BSF larvae: fungal communities were highly substrate dependent with Pichia being the only prevalent genus across 96% of the samples; bacterial communities also varied across diets; nonetheless, we observed six conserved bacterial members in 99.9% of our samples, namely, Dysgonomonas, Morganella, Enterococcus, Pseudomonas, Actinomyces, and Providencia. Among these, Enterococcus was highly correlated with other genera including Morganella and Providencia. Additionally, we showed that diets such as rabbit manure induced a dysbiosis with higher loads of the pathogenic bacteria Campylobacter. Together, this study provides the first comprehensive analysis of bacterial and fungal communities of BSF gut across untreated substrates and highlights conserved members, potential pathogens, and their interactions. This information will contribute to the establishment of safety measures for future processing of BSF larval meals and the creation of legislation to regulate their use in animal feeds.The Canadian International Development Research Centre (IDRC) and the Australian Centre for International Agricultural Research (ACIAR), Norwegian Agency for Development Cooperation, the Section for Research, Innovation, and Higher Education (CAP-Africa), the Netherlands Organization for Scientific Research, WOTRO Science for Global Development (NWO-WOTRO) and The Rockefeller Foundation through the International Centre of Insect Physiology and Ecology (icipe).http://www.frontiersin.org/Microbiologyam2022BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

A convolutional neural network with image and numerical data to improve farming of edible crickets as a source of food—A decision support system

Crickets (Gryllus bimaculatus) produce sounds as a natural means to communicate and convey various behaviors and activities, including mating, feeding, aggression, distress, and more. These vocalizations are intricately linked to prevailing environmental conditions such as temperature and humidity. By accurately monitoring, identifying, and appropriately addressing these behaviors and activities, the farming and production of crickets can be enhanced. This research implemented a decision support system that leverages machine learning (ML) algorithms to decode and classify cricket songs, along with their associated key weather variables (temperature and humidity). Videos capturing cricket behavior and weather variables were recorded. From these videos, sound signals were extracted and classified such as calling, aggression, and courtship. Numerical and image features were extracted from the sound signals and combined with the weather variables. The extracted numerical features, i.e., Mel-Frequency Cepstral Coefficients (MFCC), Linear Frequency Cepstral Coefficients, and chroma, were used to train shallow (support vector machine, k-nearest neighbors, and random forest (RF)) ML algorithms. While image features, i.e., spectrograms, were used to train different state-of-the-art deep ML models, i,e., convolutional neural network architectures (ResNet152V2, VGG16, and EfficientNetB4). In the deep ML category, ResNet152V2 had the best accuracy of 99.42%. The RF algorithm had the best accuracy of 95.63% in the shallow ML category when trained with a combination of MFCC+chroma and after feature selection. In descending order of importance, the top 6 ranked features in the RF algorithm were, namely humidity, temperature, C#, mfcc11, mfcc10, and D. From the selected features, it is notable that temperature and humidity are necessary for growth and metabolic activities in insects. Moreover, the songs produced by certain cricket species naturally align to musical tones such as C# and D as ranked by the algorithm. Using this knowledge, a decision support system was built to guide farmers about the optimal temperature and humidity ranges and interpret the songs (calling, aggression, and courtship) in relation to weather variables. With this information, farmers can put in place suitable measures such as temperature regulation, humidity control, addressing aggressors, and other relevant interventions to minimize or eliminate losses and enhance cricket production

Unlocking the potential of substrate quality for the enhanced antibacterial activity of black soldier fly against pathogens

SUPPORTING INFORMATION : Pearson’s correlation coefficient (r) for proximate analysis and antibacterial activity of hexane extract (Figure S1); concentrations of methylated fatty acid from GC-MS (Table S1); mass of HIL in different growth stages (Table S2); antibacterial activity of HIL extracted with hexane (Table S3); antibacterial activity of HIL extracted with 20% acetic acid (Table S4); and antibacterial activity of HIL extracted with 80% methanol (Table S5).Globally, antibiotics are facing fierce resistance from multidrug-resistant bacterial strains. There is an urgent need for eco-friendly alternatives. Though insects are important targets for antimicrobial peptides, it has received limited research attention. This study investigated the impact of waste substrates on the production of antibacterial agents in black soldier fly (Hermetia illucens L.) larvae (HIL) and their implications in the suppression of pathogens [Bacillus subtilis (ATCC 6051), Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), and Escherichia coli (ATCC 25922)]. The 20% acetic acid (AcOH) extract from market waste had the highest antibacterial activity with an inhibition zone of 17.00 mm, followed by potato waste (15.02 mm) against S. aureus. Hexane extract from HIL raised on market waste also showed a significant inhibitory zone (13.06 mm) against B. subtilis. Minimum inhibitory concentration (MIC) values recorded were 25 mg/mL against all test pathogens. The fastest time-kill of 20% AcOH extract was 4 h against B. subtilis, E. coli, andP. aeruginosa. Lauric acid was also identified as the dominant component of the various hexane extracts with concentrations of 602.76 and 318.17 μg/g in HIL reared on potato and market waste, respectively. Energy from the market waste substrate correlated significantly (r = 0.97) with antibacterial activities. This study highlights the key role of substrate quality and extraction methods for enhancing the production of antibacterial agents in HIL, thus providing new insights into the development of potential drugs to overcome the alarming concerns of antimicrobial resistance.Australian Centre for International Agricultural Research, Norwegian Agency for Development Cooperation, Norad, Novo Nordisk Foundation, the Rockefeller Foundation, Bill & Melinda Gates Foundation, Horizon Europe, the Curt Bergfors Foundation Food Planet Prize Award, Norwegian Agency for Development Cooperation, the Section for Research, Innovation, and Higher Education, Egerton University and icipe core funding provided by the Swedish International Development Cooperation Agency (Sida); the Swiss Agency for Development and Cooperation (SDC); the Australian Centre for International Agricultural Research (ACIAR); the Norwegian Agency for Development Cooperation (Norad); the Federal Democratic Republic of Ethiopia; and the Government of the Republic of Kenya.https://pubs.acs.org/journal/acsodfhj2024ChemistrySDG-03:Good heatlh and well-bein