Search Results (46)

Regional soil conditions may affect edible insect nutrients through associated changes in host plants and bacterial communities, but these relationships remain poorly understood. Here, we compared soils, soybean leaves, larval gut bacteria, and nutritional composition of Clanis bilineata tsingtauica across three sites. Soil nutrient parameters were measured before and after larval inoculation, bacterial communities were analyzed in soil, leaves, and larvae, and larval amino acid, protein, and fatty acid profiles were determined. Available potassium increased 1.17-fold in Lianyungang; several nutrients decreased in Huaian, whereas soil pH decreased by 4.0% in Nanjing. Larvae from Lianyungang contained higher levels of several amino acids (Serine, Glycine, etc.), whereas those from Huaian had higher saturated and unsaturated fatty acid contents (Stearic acid, Elaidic acid, etc.). Genus-level overlap analysis showed partial taxonomic overlap among soil, leaves, and larvae, and the number of shared genera generally declined from soil to leaves to larvae, consistent with compartment-specific filtering. Correlation analyses further indicated that soil nutrients, especially available phosphorus and available potassium, were significantly correlated with dominant bacterial genera and with specific larval amino acid and fatty acid traits. Overall, these findings suggest that regional soil background is associated with coordinated variation in soybean-associated bacteria, larval gut bacteria, and the nutritional composition of C. bilineata tsingtauica larvae. Full article

Pollen limitation compromises honey bee health and pollination services, and existing pollen substitutes are typically formulated around crude protein content while lacking the long-chain omega-3 fatty acids naturally present in pollen and bee-collected re-sources. To address both protein and fatty acid gaps in current substitutes, this study evaluated marine-protein and insect-larvae-based diets. We assessed how formulations using Asian seabass (Lates calcarifer) and insect larvae affect the nutrition, physiology, longevity, and gut microbiota of Apis mellifera L. Newly emerged bees were fed for 35 days on: sugar syrup (negative control), sugar syrup and natural pollen (positive control), or four experimental diets: seabass-based (SB), or SB supplemented with meal-worm (SBM), or wax moth (SBW), or black soldier fly (SBB). Experimental diets (12.48–15.59% crude protein, vs. 17.24% in natural pollen) while SB supplied eicosapentaenoic acid (39.3–53.3 mg/100 g) and docosahexaenoic acid (37.2–52.3 mg/100 g), and SBB was additionally rich in lauric acid (604.3 mg/100 g). SBB- and SBM-fed bees exhibited the greatest hypopharyngeal gland development (0.123 mm and 0.115 mm, respectively, vs. 0.060 mm in sugar-only controls), with no significant difference from SB alone. All SB-based diets supported significantly greater survival than the sugar-only control (log-rank p < 0.0001) and did not differ significantly from the natural pollen treatment with SBB showing the highest and most consistent day-35 survival (81.1%). All sea-bass-based diets significantly altered the gut microbial community structure, promoting short-chain fatty acid (SCFA)-associated bacteria such as Faecalibacterium prausnitzii and Blautia wexlerae. This enrichment may reflect not only the omega-3 and lauric acid content of the diets but also the presence of substrates that can be utilized by gut microbes, which may exert prebiotic-like effects by favoring SCFA-producing bacteria. These results demonstrate that marine and insect-derived nutrients can supply protein while also providing beneficial lipids and microbially utilizable substrates that promote the enrichment of beneficial SCFA-associated bacteria not typically dominant in the honey bee gut. These enriched diets, particularly SBB, are promising candidates war-ranting further evaluation at the colony and field levels. Full article

Bumblebees are dominant pollinators threatened by environmental antibiotic residues. This study investigated sublethal chloramphenicol (12 and 120 μg/L) effects on Bombus terrestris after 15 days’ exposure. The results showed that chloramphenicol exposure had no significant effect on the survival rate and cumulative food intake of bumblebees, confirming the sublethal property of the tested concentrations. However, chloramphenicol significantly dysregulated the expression of genes related to learning–memory (DopR2, Oamb, NMDA), immunity (abaecin, defensin) and detoxification (cyp9Q6) in bumblebees. High-dose chloramphenicol significantly increased carboxylesterase activity and reduced malondialdehyde content, while superoxide dismutase activity remained unchanged. In addition, chloramphenicol exposure significantly reshaped the gut microbiota structure of bumblebees, reduced the abundance of core beneficial symbiotic bacteria, and increased the proportion of drug-resistant bacteria. Our findings indicate that sublethal concentrations of chloramphenicol can impair bumblebee health through multiple pathways, including regulating gene expression, altering antioxidant enzyme activity and disrupting gut microbiota homeostasis. This study provides multi-dimensional toxicological data and a scientific basis for the ecological risk assessment of agricultural antibiotic residues to pollinator insects. Full article

Tenebrio molitor (Coleoptera: Tenebrionidae) is a suitable candidate for use as a biomass resource, recognized for its large-scale breeding and the high nutritional value of its protein content. Feeding obese Zucker rats the cuticle of T. molitor enhances fatty liver metabolism through the mediation of gut microorganisms. Cuticular proteins are demonstrated to be pivotal in the formation of the insect cuticle throughout the developmental stage. The endocuticle structural glycoprotein (Abd) belongs to the RR-1 subclass, a major group of structural cuticular proteins characterized by the conserved Rebers–Riddiford (RR) motif. Nevertheless, there remains a paucity of research into the molecular properties and functions of SgAbd (endocuticle structural glycoprotein) in Coleoptera. In this study, we successfully identified and described the gene TmAbd5 in T. molitor. The coding sequence of TmAbd5 is 306 bp, corresponding to a 101-aa protein. The functional domain predicted that TmAbd5 consists of a signal peptide and a chitin-binding domain 4 (ChtBD4). Motif prediction analysis indicated that TmAbd5 belongs to the CPR (cuticular proteins with Rebers–Riddiford consensus) family with the RR-1 motif. Expression analysis revealed that TmAbd5 is upregulated in the integument, particularly during the first three days of development in the 13th instar stage. Although the RNAi-mediated silencing of TmAbd5 did not cause apparent phenotypic abnormalities and the insects successfully molted into pupae, histological examination revealed a substantial thickening of the endocuticle at 72 h post-pupation, along with a notable increase in lamellar spacing and a disrupted pore canal. In summary, TmAbd5 contributes to the formation and structural organization of the endocuticle, which provides a theoretical basis for the screening of target genes for cuticle development and for the effective utilization of cuticle resources in T. molitor. Full article

In China, the substantial gap between domestic soybean supply and growing consumption necessitates large-scale soybean imports. The use of cultivated soybean (Glycine max) leaves as feed for the edible insect Clanis bilineata tsingtauica reduces crop yield, posing a threat to national soybean production security. To address this issue, this study evaluated wild soybean (Glycine soja) as a potential alternative feed source. Comparative analyses examined the nutritional and anti-nutritional properties of G. max (cv. Qihuang34) and a laboratory-preserved G. soja germplasm, together with their effects on larval growth performance, nutritional composition, and associated microbiota. G. soja leaves exhibited significantly higher crude fat (5.61% vs. 2.17%), ash (11.07% vs. 9.62%), neutral detergent fiber (23.75% vs. 21.00%), calcium (4.05 g/kg vs. 3.41 g/kg), and phosphorus (2.52 g/kg vs. 2.38 g/kg) than G. max leaves, along with lower trypsin inhibitor levels (p < 0.01) despite higher phytic acid content (p < 0.05). Fifth-instar larvae reared on G. soja leaves showed a 12.9% greater body weight (6.846 g vs. 6.066 g), higher crude protein (672.14 g/kg vs. 555.02 g/kg), total soluble sugar (21.27 mg/g vs. 8.96 mg/g), and soluble protein (26.35 mg/g vs. 24.71 mg/g), but lower crude fat (187.44 g/kg vs. 205.82 g/kg, p < 0.05). 16S rRNA sequencing revealed distinct phyllosphere microbial communities, with G. soja enriched in diverse taxa (e.g., Bacteroidota, Proteobacteria) and G. max dominated by Firmicutes. Corresponding differences were observed in larval gut microbiota, and positive correlations suggested potential microbial transfer from G. soja leaves to larval guts. Overall, G. soja represents a promising alternative feed source for C. bilineata, reducing competition with soybean grain production and supporting sustainable insect farming. Full article

Ayu (Plecoglossus altivelis) is an East Asian amphidromous river fish, yet seasonal microbiota dynamics remain unclear. We investigated ayu in the Dajing Stream (Zhejiang Province, China) by synchronously sampling water microbiota (H), gut content microbiota (N), and gut tissue-associated microbiota (C) across four seasons. Each season, four fish were collected, and an overlapping pooling strategy (abc/abd/bcd) generated three composite replicates for C and N (n = 3 composites/season); water was collected as three field replicates (n = 3/season), yielding 36 samples (12 per niche). Using 16S rRNA amplicon sequencing and COI barcoding of stomach contents, we observed the clearest seasonal differentiation in H and seasonal variation in N consistent with diet shifts, whereas C was comparatively stable. COI signals indicated a diet dominated by aquatic insects in spring/summer, which shifted toward smaller prey (e.g., rotifers) in winter. Together, these results highlight strong niche partitioning and season-linked shifts in water and gut content communities relative to the more stable tissue-associated microbiota. These findings should be interpreted as exploratory and require validation in larger individual-level studies. Full article

While the effects of carbohydrates and fibers on the gut microbiota are well established, the influence of proteins has only recently been explored. In addition, whereas the impacts of conventional protein sources remain partially defined, evidence is even more limited for alternative sources, such as insects, algae, and fungi. This commentary highlights the critical knowledge gaps in the context of the impact of alternative protein sources on gut microbiota, which need future investigation. This understanding becomes even more critical when considering that many of these sources are regarded as novel foods by large segments of the global population. Emerging findings suggest that differences in protein structure and digestibility may increase the protein content in the lumen, which in turn could enhance microbial protein fermentation and the production of poorly characterized metabolites. Moreover, the gut microbiota may be less adapted to metabolizing and managing such novel substrates if they were not previously part of the habitual diet. Therefore, well-designed clinical trials are urgently needed to understand the real potential effects of the alternative proteins on gut microbiota. Full article

Honey bees (Apis mellifera L.) are considered highly significant economic insects. It is a source of valuable food and medicinal products such as honey, bee pollen, royal jelly, bee brood, and beeswax, which possess excellent nutritional and pharmacological properties. Nevertheless, honey bee health and productivity were often challenged by various environmental factors. Therefore, bee colony management is of the utmost importance. In this light, bee supplements and gut microbiota are crucial to ensure that bees receive sufficient nutritional value to maintain their health and productivity. In this study, we isolate and characterize lactic acid bacteria from the hindgut of the worker bee. 16S rRNA sequencing revealed that three isolated bacteria were Apilactobacillus kunkeei (AK), Lactiplantibacillus sp. (LP), and Lactobacillus brevis (LB). Three species of lactic acid bacteria were investigated for potential probiotic properties by supplementing 50% (w/w) sucrose syrup in the form of a direct-fed microorganism (DFM). The supplement with DFM had no negative effect on average lifespan. Examination took place of the impact of probiotics on the development of the hypopharyngeal glands (HPGs) in the bee’s head at days 3, 6, and 9 post-treatments. The cage-bees fed by pollen and DFM syrup exhibited acini surface areas ranging from 0.020 to 0.023 mm². The L. brevis (LB) group exhibited enhanced HPG development, with an average acini size of 0.027 ± 0.007 mm² at day 6, while the non-treatment control had an average acini size of 0.023 ± 0.006 mm². The significant size differences were maintained throughout the 9-day period. In addition, the DFM syrup enhanced microbial protein content in the bee head, digestibility, and community complexity compared with the negative control groups. Therefore, the DFM syrup with a potential strain of probiotic may enhance overall honey bee health status. Full article

The lemur tree frog (Agalychnis lemur), a critically endangered species, can benefit from ex situ conservation programs; however, managing amphibians under human care presents challenges, including the provision of appropriate nutrition. House crickets (Acheta domesticus), a common feeder insect, have an inverse calcium to phosphorus ratio (Ca:P; 0.15:1) and low calcium content (<0.3%). While gut-loading crickets with an 8% calcium diet can improve their calcium concentrations, no study has assessed the effects of dietary calcium on bone development in Agalychnis spp. Moreover, no study has examined how diet impacts the gut–skin axis and skin microbiome of these frogs. This study examined how crickets gut-loaded with either a 1.3% or 8% calcium diet affected lemur tree frog bone density and skin microbiome. We hypothesized that frogs consuming the 8% calcium diet would exhibit significantly higher Hounsfield units (HU; bone density) over time, as measured by micro-computed tomography (mCT), and that dietary calcium concentration would have no effect on skin bacterial and fungi microbiomes. Eleven juvenile lemur tree frogs underwent mCT scans at baseline and 90 and 180 days. Total body volume of interest analysis showed a significant increase in HU in the 8% calcium group compared to the 1.3% group (F = 9.9, p = 0.01). There was no significant difference noted in the alpha or beta diversities for the bacterial and fungal microbiomes between dietary groups. This study provides the first evidence of dietary calcium’s impact on bone density in lemur tree frogs, offering valuable insights for improving ex situ management of this species. Full article

Poultry production faces considerable challenges in terms of feed costs and sustainability, particularly regarding conventional protein sources such as fish meal (FM). Insect-based proteins, such as housefly larvae (HL) meal, offer sustainable alternatives. Therefore, this study aimed to investigate the effects of HL on growth, gut health, metabolizable energy, and gut microbiota of broilers to clarify the availability of HL meal for broiler diet. Experiment 1 was performed to investigate the effects of replacing FM with HL on growth performance, intestinal morphology, cecal short-chain fatty acids, and gut microbiota composition and diversity in male broilers. Experiment 2 was performed to assess the digestibility of broiler diets containing HL. HL addition effectively maintained growth and improved intestinal morphology. Blood analysis revealed that HL addition reduced TNF-α levels and improved protein utilization. Additionally, HL substitution induced significant changes in the gut microbiota community and metabolic pathways. In conclusion, HL are a viable alternative to FM with adequate energy content and beneficial effects on gut health, supporting their use as a sustainable protein source. Full article

Pollution from synthetic polymers, particularly low-density polyethylene (LDPE), poses a significant environmental challenge due to its chemical stability and resistance to degradation. This study investigates an eco-biotechnological approach involving bacterial strains isolated from insect guts—Bacillus cereus LDPE-DB2 (from Achroia grisella) and Pseudomonas aeruginosa LDPE-DB26 (from Coptotermes formosanus)—which demonstrate the ability to degrade LDPE, potentially through the action of lignin-modifying enzymes. These strains exhibited notable biofilm formation, enzymatic activity, and mechanical destabilization of LDPE. LDPE-DB2 exhibited higher LDPE degradation efficiency than LDPE-DB26, achieving a greater weight loss of 19.8% compared with 11.6% after 45 days. LDPE-DB2 also formed denser biofilms (maximum protein content: 68.3 ± 2.3 µg/cm²) compared with LDPE-DB26 (55.2 ± 3.1 µg/cm²), indicating stronger surface adhesion. Additionally, LDPE-DB2 reduced LDPE tensile strength (TS) by 58.3% (from 15.3 MPa to 6.4 ± 0.4 MPa), whereas LDPE-DB26 induced a 43.1% reduction (to 8.7 ± 0.23 MPa). Molecular weight analysis revealed that LDPE-DB2 caused a 14.8% decrease in weight-averaged molecular weight (Mw) and a 59.1% reduction in number-averaged molecular weight (Mn), compared with 5.8% and 32.7%, respectively, for LDPE-DB26. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and gel permeation chromatography (GPC) analyses revealed substantial polymer chain scission and crystallinity disruption. Gas chromatography–mass spectrometry (GC-MS) identified environmentally benign degradation products, including alkanes, alcohols, and carboxylic acids. This study demonstrates a sustainable route to polyethylene biotransformation using insect symbionts and provides insights for scalable, green plastic waste management strategies in line with circular economy goals. Full article

The scarab species Protaetia brevitarsis, an edible insect, has been used in traditional medicine, as animal feed, and for converting agricultural organic wastes into biofertilizer. The intestinal tract, which contains a diverse array of microbiota, including viruses, plays a critical role in animal health and homeostasis. We previously conducted a comparative analysis of the gut microbiota of third-instar larvae of P. brevitarsis obtained from five different farms and found significant differences in the composition of the gut bacterial microbiota between farms. To better understand the gut microbiota, the composition of DNA viruses in the hindgut contents of P. brevitarsis larvae obtained from five farms was investigated using metagenomic sequencing in this study. The β-diversity was significantly different between metagenomic data obtained from the five farms (PERMANOVA, pseudo-F = 46.95, p = 0.002). Family-based taxonomic analysis indicated that the relative abundance of viruses in the gut overall metagenome varied significantly between farms, with viral reads comprising approximately 41.2%, 15.0%, 4.3%, 4.0%, and 1.6% of metagenomic sequences from the farms Tohamsan gumbengi farm (TO), Secomnalagum gumbengi (IS), Gumbengi brothers (BR), Kyungpook farm (KB), and Jhbio (JH), respectively. More than 98% of the DNA viruses in the hindgut were bacteriophages, mainly belonging to the Siphoviridae family. At the species level, Phage Min1, infecting the genus Microbacterium, was detected in all farms, and it was the most abundant bacteriophage in intestinal microbiota, with a prevalence of 0.9% to 29.09%. The detected eukaryotic DNA viruses accounted for 0.01% to 0.06% of the intestinal microbiota and showed little or no relationship with insect viruses. Therefore, they most likely originated from contaminated feed or soil. These results suggest that the condition of substrates used as feed is more important than genetic factors in shaping the intestinal viral microbiota of P. brevitarsis larvae. These results can be used as reference data for understanding the hindgut microbiota of P. brevitarsis larvae and, more generally, the gut virome of insects. Full article

In recent years, edible insects have gained significant attention as a sustainable and innovative source of feed for animal nutrition due to their excellent content of protein, fats, vitamins, and chitin. Among these, chitin is the least studied nutritional component, despite its promising properties and potential benefits. Chitin, an important polysaccharide found in the exoskeleton of arthropods, including insects, presents both negative and positive aspects in animal nutrition. As is known, the main drawback is its digestibility, which varies among livestock animal species depending on their ability to produce chitinase. However, chitin also exhibits benefits, including the enhancement of gut microbiota and immune response, together with the reduction in cholesterol and pathogen levels in animals. This review aims to summarise the current knowledge on the effects of chitin derived from edible insects on animal nutrition by analysing both the negative aspects and benefits for the different farmed animals for which insect feeding is legally permitted (fish, poultry, and pigs), while proposing future research directions. Full article

Due to their nutritional value and sustainability, edible insect-based foods are gaining popularity in Europe. Their use is regulated by EU legislation, which defines authorised species and sets labelling requirements. Molecular tools are being developed to authenticate such products. In this study, yellow mealworm (Tenebrio molitor) larvae authorised for human consumption were fed wheat flour-based diets containing varying proportions of house cricket (Acheta domesticus) flour for 21 days. This was followed by a 48 h starvation period to assess the persistence of insect DNA in the digestive tract. Two novel, species-specific, single-copy markers were designed: ampd gene for the Acheta domesticus and MyD88 gene for the Tenebrio molitor. These were applied using qPCR and ddPCR. Both methods successfully detected cricket DNA in the guts of starved larvae. Linear regression analysis revealed a strong, statistically significant correlation between the proportion of Acheta domesticus flour in the diet and the normalised relative quantity of DNA. ddPCR proved to be more sensitive than qPCR, particularly in the detection of low DNA levels. These results suggest that the presence of DNA from undeclared insect species in edible insects may be indicative of their diet rather than contamination or adulteration. This highlights the importance of contextual interpretation in food authenticity testing. Full article

Trehalose, a disaccharide consisting of two D-glucose molecules, is present in a variety of organisms, including bacteria, yeast, fungi, insects, and plants. In plants, it functions as a source of energy and carbon, and in yeast and plants, it serves as a signaling molecule, influencing metabolic pathways and growth regulation. Additionally, it plays a role in protecting proteins and cell membranes from stress-induced damage. This study aims to assess the optimal level of trehalose supplementation in the diets of layer hens aged 34 to 49 weeks, addressing the limited existing literature on its effects on productivity. Experimental diets, designed in accordance with nutritional recommendations, were formulated to contain six different levels of trehalose (0, 0.05, 0.10, 0.30, 0.60, and 1.00%). The study was conducted over five 21-day periods, during which various performance parameters were evaluated. The results indicated that trehalose supplementation at levels of 0.05%, 0.10%, and 0.30% led to increased feed intake (FI) compared to the 1.00% level (p < 0.05). Furthermore, the highest trehalose level (1.00%) significantly reduced the feed conversion ratio by egg mass (FCRem) compared to both the control group and the other supplementation levels; however, the feed conversion ratio by dry matter (FCRDz) remained consistent across all treatments. The levels of 0.05%, 0.10%, and 0.30% exhibited superior FCREm and FCRDz compared to the 1.00% level. Egg weight (EW) was higher in the trehalose-supplemented groups compared to the control group. Additionally, the 1.00% trehalose treatment was found to be the most effective in terms of relative weights of shells (RWS), and egg mass (EM) was higher at all trehalose levels compared to the control group. The antioxidant status, as measured by malondialdehyde (MDA) levels, indicated that supplementation with 0.30% and 0.60% trehalose had a protective effect against oxidative stress, although the 1.00% level resulted in increased MDA levels. Total weight (TW) was highest in the 0.30% treatment group, and bone strength (BS) improved in the groups supplemented with 0.10% and 1.00% trehalose. Other parameters, including lipid content (L), dry matter (DM), phosphorus (P), and calcium (Ca), did not show any significant differences among the treatment groups. In conclusion, supplementation with 1.00% trehalose enhances feed efficiency, egg weight, and quality, with minimal impact on lipid peroxidation, while potentially providing benefits for gut health and egg quality. Full article