Black Soldier Fly Research Articles

Common soluble carbohydrates affect the growth, survival, and fatty acid profile of black soldier fly larvae Hermetia illucens (Stratiomyidae).

The black soldier fly, Hermetia illucens (L. 1758), is an omnivorous saprophagous insect with a high potential for valorizing organic by-products rich in carbohydrates. Among carbohydrates, H. illucens relies on soluble sugars for the growth and storage lipid synthesis. This study aimed to assess the impact of common soluble sugars on the development, survival, and fatty acid composition of H. illucens. Monosaccharides and disaccharides were individually incorporated into a chicken feed diet. Cellulose was used as a control. Larvae fed glucose, fructose, sucrose, and maltose grew faster than control larvae. In contrast, lactose exhibited anti-nutritional effects on larvae, slowing down growth and reducing final individual weight. However, all soluble sugars produced larvae fatter than the control diet. Notably, the tested sugars shaped the fatty acid profile. Maltose and sucrose increased saturated fatty acid content compared to cellulose. Conversely, lactose increased the bioaccumulation of dietary unsaturated fatty acids. This study is the first to demonstrate the effect of soluble sugars on the fatty acid profile of H. illucens larvae. Our findings highlight that the tested carbohydrates have significant effects on black soldier fly fatty acid composition and can thus determine their final applications.

Partial replacement of soybean with local alternative sources: effects on behavior, cecal microbiota, and intestinal histomorphometry of local chickens

Interest in partially replacing soybean meal in poultry diets with alternative protein sources such as agri-industrial by-products and black soldier fly (BSF, Hermetia illucens) has gained significant attention due to sustainability concerns. This study aimed to evaluate the effects of broiler diets in which soybean meal was partially substituted with agri-industrial by-products with or without BSF larvae meal, on the behavior, intestinal histomorphometry, and microbiome profile of a local broiler chicken strain. There were three dietary treatments. (1) A corn-soybean-based diet (Control), (2) a diet in which soybean was partly replaced (SPR) with local agri-industrial by-products, namely sunflower meal, brewers' dried grain, and wheat middlings, and (3) a diet in which BSF (5%) meal was added to SPR (SPR+BSF). Behavior was recorded on days 14, 35, and 49 at the pen level. On day 55, intestinal segments and cecal contents were collected from eight chickens per pen for histomorphometry and microbiome analysis. Dietary manipulations did not affect the behavior of broiler chickens (P > 0.05) suggesting that the experimental diets had no influence on behavior. A significant interaction between the intestinal segment and diets revealed that the SPR and SPR+BSF diets decreased duodenal villus height (VH) compared to the control diet (P < 0.05). However, this effect was not consistent across all of intestinal segments. Diet did not affect villus height to crypt depth ratio (VH/CD; P > 0.05), indicating no significant impact on the absorptive capacity of the digestive system. Firmicutes and Bacteroidetes were the dominant phyla in the cecal samples. Colidextribacter and Oscillibacter spp. were more abundant in chickens fed the SPR diet compared to those fed the control diet. The SPR+BSF diet resulted in higher abundance of Rikenella and Colidextribacter spp. compared to the control diet, while Desulfovibrio, Ruminococcus torques group, and Lachnoclostridium were more abundant in the ceca of birds fed the SPR diet than those fed SPR+BSF. In conclusion, replacement of soybean with agri-industrial by-products and BSF larvae meal could regulate the cecal microbiota composition without negatively affecting the behavior and intestinal histomorphometry of the local chickens.

Briquetting of black soldier fly frass as a post-harvest stabilization strategy

ABSTRACT The production–consumption cycle needs a transition towards a circular economy where waste valorization is included. This study investigated briquetting as a stabilization method for black soldier fly frass (BSFF) with faecal matter, pig manure, and poultry manure as the larvae feed. Herein, dried BSFF was pyrolyzed at 350 °C for 2 h to produce biochar then mixed with charcoal dust in equal ratio to produce biobriquettes through densification, with cassava gel (10 wt%) as binder. One-way ANOVA showed statistical significance in carbon, nitrogen, hydrogen, and oxygen. There were significant differences (p < 0.05) between the calorific value, moisture content, ash content, volatile matter, and fixed carbon of the briquettes. The fixed carbon, volatile matter, moisture, and ash content ranged from 29.66 ± 0.86 to 42.01 ± 0.92, 29.26 ± 0.52 to 32.59 ± 0.80, 2.95 ± 0.1 to 5.08 ± 0.04, and 21.48 ± 0.14 to 37.20 ± 0.29, respectively. The calorific value of the produced briquettes ranged from 16.25 ± 0.57 to 20.70 ± 0.53 MJ/kg, which exceeds the minimum requirement of 14.5 MJ/kg recommended for non-woody briquettes. During combustion, concentrations of NOx, N2O, CO, and CO2 varied significantly across the treatments with the acacia charcoal having the highest concentration of CO. Briquetting is a potential stabilization method for frass resulting in waste reduction, bioenergy production, reduced adverse effects of climate change, and enhanced sustainability.

Assessing the Scope of Black Soldier Fly Larvae (Hermetia Illucens) Incorporating it into Sustainable Development

The aim of the study is to gain comprehensive understanding of the practical ways to use BSFs to convert organic solid wastes into alternative energy sources.

Evaluating the Influence of Nutrient-Rich Substrates on the Growth and Waste Reduction Efficiency of Black Soldier Fly Larvae

Background: The black soldier fly (Hermetia illucens) has emerged as a promising tool in sustainable waste management, owing to its larvae’s ability to efficiently convert organic waste into valuable biomass. Objective: This study investigates the impact of various substrate compositions on the growth, waste reduction efficiency, and bioconversion rate of black soldier fly (BSF) larvae (Hermetia illucens). The aim is to optimize feeding strategies to enhance the effectiveness of BSF larvae in sustainable waste management and protein production. Methods: A controlled experiment was conducted over a 20-day period, using four different substrate types: 100% sludge, 75% sludge + 25% chicken feed, 25% sludge + 75% chicken feed, and 100% chicken feed. Each treatment had three replicates with 100 larvae each. Larval growth metrics, including weight and width, were recorded bi-daily. The waste reduction efficiency and bioconversion rate were calculated based on the remaining substrate weight and larval biomass, respectively. Elemental analysis was performed to determine the impact of substrate type on the accumulation of various elements in the larvae. Results: Significant differences were observed in larval growth, waste reduction efficiency, and bioconversion rates across the different substrates. The 100% chicken feed substrate led to the highest larval growth (M = 0.0881 g/day, SD = 0.0042) and bioconversion rate (M = 7.52%, SD = 0.34), while the 100% sludge substrate achieved the highest waste reduction rate (M = 86.2%, SD = 2.15). ANOVA tests indicated that substrate composition significantly affected these outcomes (p < 0.05). Elemental analysis showed substantial variations in the concentrations of calcium, cadmium, and nickel among the substrates, with the 100% sludge substrate having the highest nickel accumulation (M = 0.2763 ppm, SD = 0.023), significantly different from the other treatments (p < 0.001). Conclusions: The results demonstrate that substrate composition is crucial for optimizing BSF larvae growth and waste reduction efficiency. Nutrient-rich substrates, such as chicken feed, significantly enhance bioconversion rates and larval biomass production, although careful consideration of elemental accumulation, especially heavy metals, is essential for safe application in animal feed.

Amino acid requirements of yellow mealworm and black soldier fly larvae

Abstract In order to achieve optimal growth and health of farm animals, a different amount/ratio of essential amino acids in the feed is necessary in each phase of life. Knowledge about which amino acids are essential and in which quantities/proportions they are best administered has already greatly advanced the pig and poultry sector and is still being generated today. For the still young, rapidly developing insect sector, this knowledge could mean a major step forward towards breeding optimization. Therefore, in this research the needs of the 2 most commercially reared insect species, namely mealworms (Tenebrio molitor) (MW) and black soldier fly larvae (Hermetia illucens) (BSF), were investigated. The focus was on requirements for lysine, methionine, threonine, phenylalanine and tryptophan based on evidence from the literature and those of pigs. Semi-artificial diets based on at least 25% wheat bran (MW) and chicken feed/water (30/70) (BSF) (basic feed important for structure and certain micronutrients) supplemented with sugar and synthetic amino acids were tested. The diets were isoenergetic and isoproteinous. Of the amino acids studied, one was administered in different doses per experiment. The non-essential glutamic acid was used as a substitute at lower doses. Growth, as measured by weight gain, and survival were observed. The following results were for MW and BSF respectively. For lysine from a content of 0.35 g/100 g diet and 0.53 g/100 g diet no extra growth was noticeable. For methionine this was from 0.13 g/100 g and 0.16 g/100 g. Each time more threonine was given, a significant difference could be noticed and the minimum doses were around 0.42 g/100 g and 0.49 g/100 g. With tryptophan, for MW, there were no differences between the different concentrations. At the lowest dose of 0.06 g/100 g the maximum growth was already reached, whereas for BSF this was at 0.13 g/100 g.

Estimation of the digestible energy value of fat obtained from black soldier fly larvae (Hermetia illucens) for growing pigs

ABSTRACT An experiment was conducted to determine the digestible energy (DE) of insect fat (IF) from black soldier fly larvae (BSLF) for growing pigs. Saturated fatty acids (SFA) were the dominant group of fatty acids in the IF, with lauric acid (C12:0) and palmitic acid (C16:0) comprising the greatest concentrations in this group. Linoleic acids (C18:2) and oleic acids (C18:1) were the main unsaturated fatty acids. The IF contained 37.63 MJ/kg gross energy and 2.55 g/kg nitrogen. During the experiment, a DE bioassay was performed wherein growing pigs were fed one of the two experimental diets (either a maize–wheat–barley–soy basal diet or a diet containing 50 g/kg IF plus 950 g/kg of the basal diet). The DE of the IF was calculated based on the differences between the DE values of basal and test diet (substitution method). The DE of the IF was determined to be 36.86 MJ/kg. The IF contains a DE level comparable to vegetable oils, including soybean, rapeseed, corn and palm oils. The results showed that the examined fat from BSLF is a good source of available energy and can be incorporated in pig diets as an alternative energy source.

An investigative study to utilise the Fusarium-damaged wheat as a feedstock for the black soldier fly larvae (Hermetia illucens)

Abstract This study investigated Fusarium-damaged wheat kernels (FDK) as a potential feeding substrate for black soldier fly larvae (Hermetia illucens; BSFL). Fusarium-damaged kernels are considered unsuitable for food and feed due to the presence of mycotoxins. Mycotoxins, like deoxynivalenol (DON), pose health risks when consumed by animals at concentrations exceeding the limits established by the Canadian Food Inspection Agency. However, BSFL have shown higher tolerance to mycotoxins, suggesting that FDK may be used as a feeding substrate for BSFL intended for animal consumption. To assess this, three FDK-based diets with varying concentrations of DON (4.49 ± 0.08 ppm, 6.04 ± 0.02 ppm, and 6.83 ± 0.04 ppm) and a healthy wheat-based diet (0 ppm DON; control diet) were formulated to grow the larvae. The diets were fed to larvae to assess their preference based on DON concentration. Concurrently, the accumulation of DON in BSFL biomass and its effects on growth parameters were evaluated. The larvae showed no preference for any DON concentration. The DON levels accumulated in the BSFL biomass were minimal, regardless of the DON concentration in the feed (), with the highest recorded at 0.87 ± 0.04 ppm compared to 6.83 ± 0.06 ppm in the diet. Despite the potential harm of FDK to animals, the growth parameters of BSFL improved, with larvae on FDK-based diets reaching a live body weight of 185.0 ± 3.2 mg compared to 177.6 ± 4.2 mg for the control on Day 15. The nutritional profile remained nearly identical across all DON concentrations (∼41% crude lipid and ∼39% crude protein in dried biomass). These findings suggest that BSFL raised on FDK-based diets can be used effectively for feed purposes.

Dietary Influence on Growth, Physicochemical Stability, and Antimicrobial Mechanisms of Antimicrobial Peptides in Black Soldier Fly Larvae

Safe antibiotic substitutes are needed given the rise in antimicrobial resistance, environmental contamination, and stringent antibiotic regulations. Insect-derived antimicrobial peptides (AMPs) are promising candidates due to their antimicrobial activity, stability, and safety. This study investigates the antimicrobial mechanism of crude AMP extracts and their physicochemical characteristics in black soldier fly larvae (BSFL). The results indicated that BSFL reared on a wheat bran diet exhibited significantly improved growth performance and AMP production when compared to the other three diets. AMP extracts showed enhanced antimicrobial activity and physicochemical stability, including temperatures and metal ions except Cu+. Moreover, AMP extracts disrupted the cell membrane and inhibited the cell cycle of Staphylococcus aureus (S. aureus), thus exhibiting antimicrobial activity. Furthermore, transcriptomic and KEGG enrichment analyses identified 509 differentially expressed genes (DEGs) related to the Toll and IMD signaling pathways. STRING and GeneMANIA analyses confirmed the association of these pathways with immune response and AMP secretion. qRT-PCR results showed elevated expression of immune genes (GNBP3, NFKBIA, GADD45, and Spz) in BSFL following S. aureus immunization, consistent with RNA-seq findings. These findings offer a valuable reference for using AMPs as antibiotic substitutes in animal feeds and highlight the need for further research on AMP purification and the synergistic regulation of protein synthesis and AMP production in BSFL.

Black Soldier Fly (Hermetia illucens) Microbiome and Microbe Interactions: A Scoping Review

Black soldier fly (Hermetia illucens, BSF) is farmed worldwide to convert organic waste into usable biomaterials. Studies on the larval microbiome have been carried out to check for symbiotic or pathogenic microbes and their respective functions and fates. Some studies tested these microbes for industrial applications, while others tested the effects of exogenous microbes as probiotics or for substrate pre-processing to improve larval fitness, bioconversion rates, or nutritional qualities. This review examined all peer-reviewed literature on these topics to consolidate many disparate findings together. It followed the PRISMA guidelines for scoping reviews. The results found no evidence of globally conserved core microbes, as diet strongly correlated with gut microbiome, but some genera appeared most frequently in BSF larval guts worldwide regardless of diet. The gut microbes undoubtably assist in digestion, including pathogen suppression, and so microbial probiotics show promise for future investigations. However, the common gut microbes have not been explored as probiotics themselves, which would be a promising direction for future work. The impacts of BSF bioconversion on pathogens varied, so each rearing facility should investigate and manage their pathogen risks independently. The data summarized in this study provide useful reference points for future investigations into BSF–microbe interactions.

Effect of patulin on the growth and nutrient composition of black soldier fly larvae

Abstract Black solider fly (BSF, Hermetia illucens) is a common insect in most part of North America, Europe, and Asia, and it is one of the most promising alternative protein sources for animal consumption. BSF can be fed on food waste and agricultural byproducts, which are usually contaminated with mycotoxins. Therefore, it is important to study the fate of mycotoxins in BSF and how mycotoxins will affect the growth and nutrient composition of BSF. Patulin is one of the major mycotoxins found in rotten fruits and consumption of patulin contaminated food can cause both long term and short-term health problems in both human and livestock. In this study clean and patulin spiked apple puree were provided to 50 three days old black soldier fly larvae (BSFL) for 3, 6, 9 and 17 days. Patulin bioaccumulation and degradation by BSFL, survival rate, weight gain and nutrient composition of BSFL were evaluated. During the treatment period, no patulin bioaccumulation was found in BSFL. BSFL was able to degrade patulin and convert patulin into (E)-ascladiol. By day 17, BSFL degraded 89.7% of patulin, 5.7% of patulin was converted into (E)-ascladiol, and 10.3% of patulin remained in its original form. While patulin treatment led to lower biomass and growth rate in BSFL, greater protein content and lower lipid content was observed in patulin treated BSFL. Thus, we conclude that BSFL do not accumulate patulin, and it is able to degrade patulin and converts patulin into its derivatives. The applied patulin negatively affects the development of BSLF resulting in lower biomass, growth rate and lipid content, but it induces higher protein content in BSFL.

Use of zoohumus extracts in soybean cultivation under regulated agroecosystem conditions

A model experiment was conducted in the laboratory conditions of the climate chamber to study the effect of liquid extract of black soldier fly zoohumus prepared in different ways on the growth rates and germination of seeds of the early ripening soybean variety EN Argenta. The zoohumus suspension was used in all variants at a dose of 0.2% (2000 ppm). As an additional background, a complex fertilizer containing the necessary plant nutrients in the form of various mineral salts was added. Analysis of the experimental data showed that the highest percentage of plant germination was recorded in the variant with the introduced aqueous suspension of zoohumus without centrifugation and without sterilization, and amounted to 94%. Against the background of pure organic matter, an increase in shoot biomass by an average of 22% was recorded. However, here the variant with sterilization, but without centrifugation of the zoohumus suspension, stood out. Against the background of the organomineral environment, the weight and height of the plants were higher, but stagnation in growth was noted, probably due to oversaturation in the feeding regime and the formation of chelate complexes of prolonged absorption. Thus, an aqueous suspension of zoohumus obtained by sterilization without additional centrifugation is the best way to prepare samples of raw materials for further use in sterile experiments. Centrifugation reduces the amount of enzymes and nutritional compounds, which negatively affects the quality of the suspension, and additional sterilization releases an additional amount of low-molecular compounds into the environment, which can feed microorganisms.

Rethinking Amino Acid Nutrition of Black Soldier Fly Larvae (Hermetia illucens) Based on Insights from an Amino Acid Reduction Trial

Rearing black soldier fly larvae (BSFL) in order to utilize biogenic materials is of increasing interest in the context of sustainable animal production. However, little is known about the amino acid (AA) requirements of this animal species. Therefore, a feeding experiment with BSFL was conducted, in which lysine, methionine, cysteine, arginine, phenylalanine, or histidine was reduced by 65% or methionine was increased by 65%. Reductions in single AAs in the substrate did not negatively impact BSFL growth, while the addition of methionine improved the growth performance, indicating that methionine was a limiting nutritional factor for maximal productivity. Differences in dietary AA profiles had no impact on the AA profile of the BSFL biomass. However, balance calculations for individual AAs indicated that the substrate microbiome was capable of synthesizing and balancing those AAs for microbial protein synthesis. While both the BSFL and microbiome utilized all free AAs, suggesting that supplemental AAs can be effective additives in BSFL production, this microbial AA synthesis avoided the negative performance impacts of BSFL provoked by severe AA reductions. The quantification of these effects suggested that the microbiome could add up to 35% to the overall AA supply in order to overcome AA deficiency. This effect may not necessarily ensure maximal BSFL productivity, as demonstrated by the extra addition of methionine to the substrate. Our research indicated that BSFL nutrition should consider interactions between substrate composition and microbial activity.

The effect of phenotyping, adult selection, and mating strategies on genetic gain and rate of inbreeding in black soldier fly breeding programs

BackgroundThe aim of this study was to compare genetic gain and rate of inbreeding for different mass selection breeding programs with the aim of increasing larval body weight (LBW) in black soldier flies. The breeding programs differed in: (1) sampling of individuals for phenotyping (either random over the whole population or a fixed number per full sib family), (2) selection of adult flies for breeding (based on an adult individual’s phenotype for LBW or random from larvae preselected based on LBW), and (3) mating strategy (mating in a group with unequal male contributions or controlled between two females and one male). In addition, the numbers of phenotyped and preselected larvae were varied. The sex of an individual was unknown during preselection and females had higher LBW, resulting in more females being preselected.ResultsSelecting adult flies based on their phenotype for LBW increased genetic gain by 0.06 genetic standard deviation units compared to randomly selecting from the preselected larvae. Fixing the number of phenotyped larvae per family increased the rate of inbreeding by 0.15 to 0.20% per generation. Controlled mating compared to group mating decreased the rate of inbreeding by 0.02 to 0.03% per generation. Phenotyping more than 4000 larvae resulted in a lack of preselected males due to the sexual dimorphism. Preselecting both too few and too many larvae could negatively impact genetic gain, depending on the breeding program.ConclusionsA mass selection breeding programs in which the adult fly is selected based on their larval phenotype, breeding animals mate in a group and sampling larvae for phenotyping at random over the whole population is recommended for black soldier flies, considering the positive effect on rates of genetic gain and inbreeding. The number of phenotyped and preselected larvae should be calculated based on the expected female weight deviation to ensure sufficient male and female candidates are selected.

Effect of black soldier fly (Hermetia illucens) larvae meal and oil on the performance, biochemical profile, intestinal health and gut microbial dynamics in laying hens

This study investigated the effect of incorporating black soldier fly (BSF) larvae meal and oil on laying hens' performance, egg quality, serum profile, intestinal structure, and gut health. A total of 378 Lohmann laying hens (age 48 wk) were randomly assigned to 6 treatments with 3 replicates of 21 hens each. Following 7 d acclimation, the trail was conducted for 8 weeks. The dietary groups include: basal corn-soybean meal diet (S) without BSF (BSO) oil (S+BSO 0), S with BSF oil (S+BSO 100), BSF meal (9 %) without BSF oil (BSF 9+BSO 0), BSF meal (9 %) with BSF oil (BSF 9+BSO 100), BSF meal (18 %) without BSF oil (BSF 18+BSO 0), and BSF meal (18 %) with BSF oil (BSF 18+BSO 100). The results showed that the BSF 18 + BSO 100 diet significantly reduced egg weight (P < 0.001) compared to other dietary treatments. The addition of BSF meal reduced feed intake (P < 0.001) and the Haugh units (P < 0.05) in hens fed 18 % BSF meal with and without BSO. The jejunum villus area, crypt depth, and intestinal wall thickness increased with the increase in the inclusion of BSF larvae meal (P < 0.001). The ileum villus height, crypt depth and intestinal wall thickness increased (P < 0.001) at 9 % BSF meal and then decreased at 18 % BSF meal with and without BSF oil. The bacteria genera Ruminococcus, Clostridiales, Bacteroidales, Ruminococcus torques, and Intestinimonas were positively associated with the dietary treatments, while Prevotellaceae UCG-001, Clostridium, and Faecalibacterium were negatively associated with the dietary treatments. The inclusion of BSF meal and oil enriched the functional network of several pathways, including ascorbate and aldarate metabolism, D-arginine and D-ornithine metabolism, and fatty acid metabolism, highlighting the positive effects of BSF larvae meal and oil on the chicken gut microbiota. In conclusion, BSF meal at 9 % with BSF oil and BSF meal at 18 % without BSF oil can be incorporated into the diet without impairing the performance and gut health of laying hens.

Antibacterial peptides from black soldier fly (Hermetia illucens) larvae: mode of action and characterization

Antibacterial peptides from black soldier fly larvae extract were prepared using Flash column chromatography. Three out of five fractions (F2, F3 and F4) showed antibacterial activity against Listeria monocytogenes DMST 17303 with a minimum inhibitory concentration (MIC) of 1 mM, followed by Salmonella enterica Enteritidis DMST 15679 and Escherichia coli O157:H7 DMST 12743 with a MIC ranging from 4 to 8 mM. Due to the higher yield, F2 and F3 were further analyzed on their mode of action against L. monocytogenes DMST 17303. Both fractions, particularly F2, exerted antibacterial activity through inducing bacterial cell membrane disintegration and interaction with intracellular compounds including fatty acids, proteins, and nucleic acids. The F3 did not show significant hemolytic activity up to 4 mM, while F2 showed lower than 5% hemolysis up to 8 mM. Time-to-kill analysis revealed that F2 was more effective and exerted a sustainable killing effect after 2 and 4 h, depending on the concentration of 1 and 2×MIC, respectively, while the F3 at 2×MIC could completely kill the test bacteria within 24 h. Among the identified peptides in the fractions, those with charged, either positively or negatively, and moderate hydrophobicity of ranging 6.68–15.70, namely CGPPRQGPFPR, HLEEELK, LEEAEERAD, TEELEEAKKK, and KGNSELEEAKKK, are potential antimicrobial peptides.

Nutritional composition of black soldier fly (Hermetia ilucens) larvae reared on vegetable wastes: effects on growth of village chickens

Context Black soldier fly larvae are a promising alternative ingredient in poultry feed. They might be able to replace soybean and fishmeal because the have high concentrations of protein and fat, and are also rich in vitamins and minerals, and because partial replacement of soybean and total replacement of fishmeal produce no adverse effect on the growth performance of village chickens. Therefore, they are a suitable replacement for these traditional ingredients in poultry feed. Aims This study determines the nutritive values of black soldier fly larvae and evaluates the effects of feeding diets containing black soldier fly larvae on the growth performance of village chickens. Methods Samples of black soldier fly larvae were subjected to proximate analysis before a total of 280 1-day-old village chicks were randomly divided into four groups. All groups were fed a basal diet with partial replacements of corn and soybean with black soldier fly larvae at 0% (Control), 5% (T1), 10% (T2) and 15% (T3) for 70 days. Each treatment group consisted of seven replicates, with 10 birds per replicate. The bodyweights, bodyweight gains and feed conversion rates were determined. Key results Dry rendered black soldier fly larvae contained 773.0 ± 0.08 g/kg dry matter, 36.1 ± 0.09 g/kg ash, 408.8 ± 0.28 g/kg crude protein, 283.0 ± 0.16 g/kg ether extract and 40.9 ± 0.44 g/kg crude fibre. The larvae also contained 2.041 MJ/kg of metabolisable energy, 20.4 g/kg of calcium and adequate concentrations of vitamins. The feeding trial showed an average bodyweight gain of 1231.45 ± 23.37 g and feed conversion ratio of 2.03 ± 0.15, which were most efficient with Diet T3. Conclusions Inclusion of 15% black soldier fly larvae in diets can enhance the growth performance of village chickens without adverse effects. Implications Partial replacement of soybean and total replacement of fishmeal in the diet of chickens by black soldier fly larvae are not affecting the growth performance of village chickens but might reduce the feed cost.

Multiple diptericins of the black soldier fly (Hermetia illucens) differentially respond to bacterial challenges.

Due to its significant bioconversion potential, the black soldier fly (BSF), Hermetia illucens, shows great promise as a cost-effective alternative for recycling biological waste. BSF larvae (BSFL) are constantly exposed high levels of pathogenic microorganisms, including bacteria and fungi, which endows BSFL with a robust immune system. Diptericin, a type of glycine-rich antimicrobial peptide (AMP) that exhibits activity against gram-negative bacteria, contains proline-rich domains (P-domains) and glycine-rich domains (G-domains); these domains are separated by a furin cleavage site. Although the presence and expression patterns of BSFL diptericins have been documented, their basic molecular properties remain unclear. To the best of our knowledge, in the present study, we report, for the first time, the molecular characteristics of seven full-length cDNA sequences of H. illucens diptericins and their expression patterns following challenges with gram-positive or gram-negative bacteria. Seven diptericin paralogs are located in tandem on chromosome 2, spanning a total length of 38.6 kb, with an average intergenic distance of approximately 5.5 kb. Sequence analysis revealed that three diptericins (HipDptA/B/C) are pseudogenized due to premature stop codons. In contrast, the other diptericins (HiDpt1/2/3/4) possess mature-sized G-domains rich in glycine at the C-terminus, which are essential for AMP activity, along with proline-rich domain (P-domain) in the N-terminal and either two (HiDpt1/2/3) or one (HiDpt4) putative furin cleavage sites (R-X-R/K-R) between these domains. These furin cleavage sites possibly produce a glycine-rich AMP and one or two additional peptides with unknown functions. Similar to other diptericins, the expression of HiDpt1/2/3/4 mRNAs is predominantly induced by gram-negative bacteria, increasing typically by ≥ 1,000-fold (up to 5,000-fold). Additionally, HiDpt1/3/4 show significant responses to gram-positive bacteria such as Micrococcus luteus, though not as strongly as to gram-negative bacteria. These findings suggest that HiDpts function as a rapid, effective, and broad-spectrum first-line defense mechanism in the BSFL immune system.

Antennal olfactory responses in the black soldier fly Hermetia illucens

The Black Soldier Fly (BSF) is considered as the “crown jewel” of the insect feed industry and circular economy, significantly contributing to the 2030 Sustainable Development Goals by reducing carbon dioxide emissions and enabling circular management of organic waste, animal manure, and plant residues. Despite their industrial importance, limited knowledge about adult BSF biology has hindered optimal mass production. In this context, the present paper aims to explore the olfactory capabilities of both male and female BSF in response to various odorants commonly associated with organic decomposition in substrates suitable for mate encounters and egg laying. This will be achieved by performing electroantennographic recordings and scanning electron microscopy (SEM) observations on the antennal sensilla. Our results demonstrate for the first time the supposed olfactory capabilities of BSF antennae and present a first dataset of substances emitted by decaying organic matter detected by both male and female flies. Additionally, the current EAG recordings allowed comparisons with molecular data previously obtained through in silico and in vitro methods, highlighting the need for caution and strongly supporting a multidisciplinary approach as the best tool for investigating insect chemical ecology. These findings advance our understanding of BSF chemical ecology, which is crucial for effective reproduction and could significantly optimize global breeding systems

A new approach to biotransformation and value of kitchen waste oil driven by gut microorganisms in Hermetia illucens

Hermetia illucens larvae are known for their ability to recycle organic waste, but their capacity to recover waste oils and the role of gut microorganisms in this process are not fully understood. To gain further insights, the biological recovery of waste frying oil into valuable lipids and the influence of gut bacteria on this biotransformation were investigated. The larvae efficiently digested and absorbed waste frying oil, demonstrating their potential for converting various oils into insect fat. The presence of different fatty acids in their diet significantly altered gut bacterial communities, enriching certain genera such as Actinomyces, Enterococcus, and Providencia. Redundancy analysis revealed that the composition and structure of these bacterial communities were predictive of their function in the biotransformation of fatty acids and the lipid biosynthesis in the larvae. Specific bacteria, including Corynebacterium_1, Providencia, Actinomyces, Escherichia-Shigella, and others, were identified to play specialized roles in the digestion and absorption of fatty acids, contributing to lipid synthesis and storage. These findings highlight the potential of Hermetia illucens in the biological recovery of waste frying oil and underscore the crucial role of gut microbiota in this process, offering a sustainable approach to waste management and bioenergy production.