That level of exposure corresponds to a probability of at least one new BSE infection of 3.6 × 10⁻⁶ — in other words, fewer than one out of every 100,000 slaughtered BSE-infected cows would give rise to a new infection through the insect-rearing pathway. The assessment addresses a narrow but consequential question: what the BSE risk would be if insects were reared on residual streams containing animal proteins. The researchers parameterized their model for three such streams — former food from supermarkets, kitchen food scraps from consumer households, and category 2 meat meal from rendering — and evaluated two insect species, the yellow mealworm (Tenebrio molitor) and the black soldier fly (Hermetia illucens).

The model produces two linked estimates: the expected exposure of cattle to BSE infectivity, expressed in cattle oral ID50 units, and the corresponding probability that this exposure results in at least one new BSE infection. The calculations are anchored to a specific scenario in which a single BSE-infected cow escapes detection at slaughter and enters the residual stream used as insect substrate. From the substrate, the model traces infectivity along three routes that could return it to the cattle population.

The first is cross-contamination of ruminant feed, in which infectivity carried by the insects or their processing residues reaches feed intended for cattle. The second runs through grassland fertilized with pig or poultry manure or with insect frass, where material derived from the rearing process could be deposited on pasture grazed by cattle. The third is calf milk replacer, a feed product for young calves through which contaminating material could also be distributed.

For each combination of residual stream, insect species and exposure route, the model combines the amount of infectivity entering the substrate, the fraction carried over into the insects and their processed products, and the pathways by which those products can reach cattle. The authors identify the carry-over of prions from substrate to insects as the main uncertainty in the assessment. Direct measurements of this transfer are limited, and the magnitude of prion survival through insect rearing and processing is therefore not precisely known.

To account for this, the team adopted a worst-case approach, choosing assumptions at the pessimistic end of the plausible range so that the calculated risks should overstate rather than understate the true exposure. Even against this deliberately cautious backdrop, the estimated exposures remained very low for every combination of residual stream and insect species assessed. The results did vary with both substrate and species, with kitchen food scraps fed to yellow mealworm producing the highest median exposure among the scenarios examined.

On the basis of these results, the researchers conclude that rearing insects on residual streams containing animal proteins is unlikely to result in BSE transmission. The findings are model-based estimates rather than direct measurements, and they apply to the specific scenario of a single BSE-infected cow escaping slaughter detection under the worst-case assumptions described. Within those boundaries, the study quantifies how small the residual risk would be: a median exposure of at most 5.2 × 10⁻⁶ cattle oral ID50, and a corresponding probability of new infection below one in 100,000 per infected cow.

Subject of Research: Quantitative risk assessment of BSE transmission through insects reared on residual streams containing animal proteins

Article Title: Quantitative risk assessment of BSE transmission if insects are reared on residual streams containing animal proteins

Article References: de Vos, C. J., Antonis, A. F. G., Appel, M. J., & Hoek-van den Hil, E. F. (2026). Quantitative risk assessment of BSE transmission if insects are reared on residual streams containing animal proteins. Frontiers in Microbiology, 17, Article 1943428. https://doi.org/10.3389/fmicb.2026.1943428

Image Credits: AI Generated

DOI: 10.3389/fmicb.2026.1943428

Keywords: BSE, prions, insect rearing, yellow mealworm, black soldier fly, residual streams, risk assessment, cattle, food safety, quantitative model, animal proteins, Wageningen

The nutritional case for insects is straightforward. Depending on species and processing, insect meals typically contain roughly 40 to 70 percent crude protein on a dry matter basis, placing them alongside soybean meal and fishmeal as viable protein sources for monogastric animals. House cricket meal sits at the high end, at 63 to 70 percent protein, while black soldier fly larvae meal ranges from 37 to 63 percent and yellow mealworm larvae from 47 to 60 percent. Essential amino acids such as lysine, methionine, threonine, and valine are present at concentrations compatible with the requirements of livestock and farmed fish. Yet the review stresses that crude protein figures can be misleading, because nitrogen-based estimates count non-protein nitrogen in the chitinous exoskeleton, and the chitin matrix may physically limit enzyme access to proteins.

Three structural components dominate the mechanistic discussion. The first is chitin, a beta-linked polymer of N-acetyl-D-glucosamine that makes up roughly 5 to 17 percent of dry matter in common insect meals. Once dismissed as an anti-nutritional factor because monogastric animals digest it poorly, chitin is increasingly viewed as a fermentable substrate for microbes with chitinolytic capacity, potentially acting in a prebiotic-like manner. The second is the lipid fraction, particularly lauric acid in black soldier fly larvae, a medium-chain fatty acid with recognized antimicrobial activity against Gram-positive bacteria. The third is a family of antimicrobial peptides, including defensins, cecropins, attacins, and diptericins, which insects deploy as part of innate immunity and which show inhibitory activity against bacterial and fungal targets in purified form.

The antimicrobial evidence for insect lipids is among the most concrete in the review. In vitro, black soldier fly fat containing 0.58 grams of lauric acid per 100 milliliters inhibited D-streptococci, and raising the concentration to 0.87 grams per 100 milliliters produced roughly a 2-log reduction in bacterial counts. When piglets were fed black soldier fly-based diets, the reduction in intestinal D-streptococci was smaller, about 0.5 log, a gap the authors highlight as a warning against extrapolating laboratory potency to the gastrointestinal environment. Separately, black soldier fly larvae lipid fractions showed dose-dependent inhibition of multidrug-resistant Aeromonas hydrophila and A. salmonicida, with minimum inhibitory concentrations of 0.09 and 0.38 milligrams per milliliter respectively, evidence obtained outside a feeding model but relevant to aquaculture pathogens.

In poultry, dietary insect inclusion appears to shift microbial ecology without wholesale restructuring it. In layer pullets fed black soldier fly larvae meal in place of fishmeal, the community remained broadly comparable to controls, dominated by Firmicutes with Lactobacillus accounting for about 93 percent of genus-level sequences, but potentially beneficial taxa including Lactobacillus, Bacteroides, Blautia, and Enterococcus increased with higher inclusion, and complete fishmeal replacement produced the highest alpha diversity. A study of free-range chickens given 7.5 percent yellow mealworm meal reported significantly greater cecal microbial alpha and beta diversity, a higher Firmicutes to Bacteroidetes ratio, and enrichment of genera such as Clostridium, Oscillospira, Ruminococcus, Coprococcus, and Sutterella, all without changes in villus height, crypt depth, or mucin composition.

Swine studies tell a similar story with a focus on the vulnerable post-weaning period. Piglets fed diets containing 5 or 10 percent black soldier fly larvae meal showed increased cecal microbial beta diversity and greater abundance of genera associated with fiber fermentation, including Blautia, Coprococcus, Eubacterium, Prevotella, Roseburia, and Ruminococcus, together with a higher proportion of neutral mucins in the small intestine and no signs of inflammation. In growing pigs, replacing soybean meal with 5 or 10 percent yellow mealworm meal reduced Bacteroidetes and significantly increased branched-chain fatty acids, even though total short-chain fatty acid concentrations stayed flat. The authors note this distinction matters: taxonomic shifts do not necessarily predict changes in the metabolites conventionally linked to gut health.

Aquaculture results are arguably the most striking. Rainbow trout fed diets replacing 10 to 30 percent of fishmeal with black soldier fly larvae meal showed increased bacterial richness and diversity, with enrichment of lactic acid- and butyrate-producing bacteria attributed mainly to the fermentable chitin fraction. Juvenile Nile tilapia receiving defatted larvae meal replacing 60 percent of soybean meal survived Aeromonas veronii infection at significantly higher rates, with less intestinal inflammation, more goblet cells, and enhanced mucin 2 expression, accompanied by increased intestinal L-tyrosine that upregulated barrier-related genes in epithelial cells. In Pacific white shrimp, replacing 10 to 20 percent of fishmeal protein reduced opportunistic genera such as Vibrio and improved survival after Vibrio parahaemolyticus challenge, but pushing replacement to 30 percent damaged intestinal morphology, a clear dose limit.

Immune responses appear modulatory rather than simply stimulatory. In gilthead seabream, dietary chitin increased respiratory burst and complement activity without affecting phagocytosis or lysozyme levels, and similar selective effects appear in carp and grouper studies, though most used purified chitin not derived from edible insects. Under experimental Eimeria and Clostridium perfringens challenge, broilers given 5 percent black soldier fly larvae meal showed higher cecal acetate and butyrate and reduced IL-6 expression, while laying hens fed low levels of expanded larvae meal showed reduced TNF-α expression. The review interprets such findings as evidence of immune equilibrium rather than generalized immunosuppression, while acknowledging that inflammatory markers do not respond uniformly across studies, and that improved homeostasis sometimes occurs without major changes in classical cytokines.

The authors are emphatic that these benefits should be understood as properties of the whole insect matrix rather than of any single compound. Antioxidant effects illustrate the point: yellow mealworm supplementation reduced hepatic malondialdehyde in heat-stressed broilers without changing total antioxidant capacity, and black soldier fly pulp improved catalase activity in mirror carp at moderate inclusion, while the highest level impaired intestinal morphology and higher insect meal inclusion in rainbow trout was associated with reduced glutathione peroxidase activity. Because whole meals deliver chitin, fatty acids, peptides, minerals, and micronutrients simultaneously, no in vivo study to date can isolate the contribution of individual constituents.

The review closes with a research agenda shaped by frustration with heterogeneity. Studies vary in insect species, developmental stage, rearing substrate, processing, inclusion level, host age, and trial duration, making comparisons difficult and preventing standardized recommendations. Most trials run for weeks rather than production cycles, leaving questions of microbial resilience and long-term adaptation open, and most involve healthy animals rather than the pathogen, heat, and transport stressors of commercial farms. The authors call for minimum reporting standards, ingredient fractionation experiments, and integrated metagenomic, metatranscriptomic, and metabolomic approaches to identify which insect-derived compounds drive which physiological responses. Until then, they argue, insect feeds should be treated as promising multifunctional matrices whose gut-health potential is real, measurable, and still awaiting mechanistic precision.

Subject of Research: Effects of edible insect-based feed ingredients on gut microbiota and gastrointestinal physiology in monogastric livestock and aquaculture species

Article Title: Edible insect-based feed ingredients as modulators of gastrointestinal physiology in monogastric livestock and aquaculture species

Article References: Sánchez-Velázquez, O. A., & Hernández-Álvarez, A. J. (2026). Edible insect-based feed ingredients as modulators of gastrointestinal physiology in monogastric livestock and aquaculture species. Frontiers in Physiology, 17, Article 1945787. https://doi.org/10.3389/fphys.2026.1945787

Image Credits: AI Generated

DOI: 10.3389/fphys.2026.1945787

Keywords: insect meal, black soldier fly, yellow mealworm, gut microbiota, chitin, lauric acid, antimicrobial peptides, poultry, swine, aquaculture, animal nutrition, intestinal barrier

The yellow mealworm, Tenebrio molitor, occupies a peculiar dual role in human affairs. It is a notorious pest that infests stored cereal products, yet it is simultaneously one of the most valuable and nutritionally rich insects used in both animal and human food industries. Researchers describe it as a beneficial pest precisely because of this contradiction. Beyond its agricultural significance, the species can degrade polystyrene and plastic waste, making it an object of interest for waste management research, and it serves as a model organism in laboratories worldwide.

Gregarines are parasitic protozoans belonging to the phylum Apicomplexa, a group that includes some of the most notorious parasites of invertebrates. These single-celled organisms colonize the digestive tracts of many different insect species, and their effects on hosts have proven remarkably complex. Numerous experimental studies have documented both detrimental and beneficial outcomes. On the harmful side, gregarines can arrest host development, cause mortality, and inhibit reproduction. On the beneficial side, some studies have shown they can increase host growth, fitness, and longevity, complicating any simple assessment of their ecological role.

The research team dissected forty larval and forty adult mealworms from each location, examining their intestines under microscopes at magnifications ranging from 10x to 1000x. When parasitic infections were observed, the scientists prepared Giemsa-stained smears to visualize the parasites in greater detail. The slides were air-dried, fixed with methanol, and stained with a freshly prepared 5 percent Giemsa solution before re-examination. The team then measured key anatomical structures of the parasites, including the length of the epimerite, deutomerite, and protomerite, along with total body length and various width ratios that help distinguish between gregarine species.

The results revealed a dramatic contrast between the two populations. In the Tbilisi samples, gregarine infection was present in both life stages, with several life stages of the parasite found in the midgut lumens of larvae and adults alike. Each trophozoite was elongate with a bud-type epimerite measuring 5.5 micrometers, and the largest trophozoite observed reached 67.9 micrometers in length. The sporadins found in the midgut lumen were solitary, with a clearly distinct septum separating the protomerite from the deutomerite, and the deutomerite was ovoid to ellipsoid with a spherical nucleus averaging 10.3 micrometers in diameter.

Infection rates differed sharply between life stages. Twenty-nine of the forty examined larvae were infected, representing a 72.5 percent infection rate, while only seven of the forty examined adults carried the parasite, corresponding to just 17.5 percent. This substantial difference suggests that mealworm larvae are considerably more susceptible to gregarine infection than adults, a finding that carries practical weight for insect farmers who rear larvae as the primary product for food and feed applications.

In stark contrast, the Antalya population from Türkiye showed no gregarine infection whatsoever, neither in larvae nor in adults. This complete absence of the parasite in one geographic population while another shows high infection rates raises intriguing questions about how gregarines spread within and between insect colonies, and what environmental or management factors might explain such divergent outcomes between facilities located in different countries.

To identify the parasites, the researchers compared their morphological measurements and ratios against a well-documented comparative study by Clopton and colleagues from 1991, which described the morphology and general appearance of gregarine species infecting T. molitor. According to a recent review of harmful and beneficial symbionts of the mealworm, four eugregarine species are known to infect this insect: Gregarina cuneata, G. polymorpha, G. niphandrodes, and G. steini, with G. cuneata considered the most impressive and complex among them. The parasites found in the Georgian population resembled both G. cuneata and G. niphandrodes in body morphology and general appearance, yet they differed from published descriptions in their morphological measurements and ratios.

This discrepancy becomes particularly interesting when considering host stage specificity. Clopton and colleagues reported that G. polymorpha and G. steini are found only in mealworm larvae, whereas G. niphandrodes was reported only from adults. Gregarina cuneata, by contrast, infects both larvae and adults. Because the Georgian parasites were detected in both life stages, the researchers suggest that more than one gregarine species might be infecting the Georgian population, or that multiple species could coexist within the same individual host. The possibility even remains that a previously unknown gregarine species could be identified from Georgian mealworm populations.

The findings arrive at a critical moment for the edible insect industry. High-density rearing conditions associated with mass production may increase the risk of disease and infections by parasitic symbionts, promoting their spread within insect colonies. These pathogens could potentially be passed to humans and animals consuming mealworms as food, making parasite surveillance a food safety concern as well as a production issue. The researchers call for further characterization of the gregarines in Georgian mealworm populations, including molecular phylogeny studies, and recommend documenting the presence and distribution of these parasites across other Georgian populations. Such work will be essential for understanding whether the parasites represent a threat to commercial production or simply another facet of the complex biology of an insect that humanity increasingly relies upon for sustainable protein.

Subject of Research: Gregarine parasite infection in yellow mealworm populations in Georgia and Türkiye

Article Title: Occurrence of gregarine parasites of Tenebrio molitor ( Coleoptera : Tenebrionidae ) in Georgia and Türkiye

Article References: Yaman, M., Kereselidze, M., & Güvendik, T. S. (2025). Occurrence of gregarine parasites of Tenebrio molitor (Coleoptera: Tenebrionidae) in Georgia and Türkiye. Caucasiana, 4, 119-124. https://doi.org/10.3897/caucasiana.4.e164996

Image Credits: AI Generated

DOI: 10.3897/caucasiana.4.e164996

Keywords: gregarine parasites, Tenebrio molitor, yellow mealworm, Apicomplexa, insect farming, edible insects, Georgia, Türkiye, parasitology, food safety, entomology, sustainable protein

The timing is not accidental. Conventional edible lipids face mounting constraints: unsaturated plant oils often lack the solid-fat functionality demanded by bakery fats and spreads, animal fats carry saturated fatty acids and cholesterol, and fish oil, the main source of long-chain omega-3 fatty acids, is both oxidation-prone and increasingly scarce, with global output falling by roughly 21 percent in 2023 according to the FAO. Meanwhile, insects are already being processed at scale into protein concentrates and defatted meals, leaving behind an oil-rich stream that is frequently underused. Recovering that fraction could yield an additional ingredient while preserving a protein-rich co-product for further valorization.

What makes insect oils genuinely interesting, the review contends, is not their fatty-acid composition alone but their triacylglycerol architecture, the specific way fatty acids are assembled onto the glycerol backbone. Three recurring compositional archetypes emerge from the literature. Black soldier fly larvae oil is lauric-rich, containing roughly 28 to 62 percent lauric acid depending on diet and processing, placing it closer to coconut and palm-kernel fats than to typical animal fats. Mealworm, cricket, and locust oils are dominated by oleic and linoleic acids, resembling liquid vegetable oils. Silkworm pupal oil stands apart as an alpha-linolenic-acid-rich oil, with the omega-3 fatty acid accounting for roughly 35 to 38 percent of total fatty acids in representative samples, a profile more comparable to flaxseed or perilla oil than to fish oil, since it delivers ALA rather than the longer-chain EPA and DHA.

These labels, the authors stress, are descriptive rather than a formal classification system, because composition shifts with species, developmental stage, rearing substrate, and extraction method. Diet is the most accessible pre-harvest lever: rye bran raised the lipid content of yellow mealworm larvae to about 30 percent, while rapeseed oil cake reduced it to around 15 percent. Yet the final oil never simply mirrors the feed, because insect digestion, selective deposition, and de novo fatty-acid synthesis impose species-specific limits. Enriching feed with polyunsaturated fats can improve the target profile while simultaneously raising oxidation susceptibility, a trade-off that feed designers must manage as an integrated system.

The review’s central technical argument is that fatty-acid surveys alone cannot predict how an insect oil will behave in food. Intact triacylglycerol species, their positional distribution, and minor constituents such as tocopherols, sterols, and phospholipids jointly determine crystallization, melting, interfacial behavior, and digestion. Cold-pressed black soldier fly larvae oil, for example, contains trilaurin, dilauroyl-myristoyl, and lauroyl-dimyristoyl triacylglycerols as major species, producing a thermal profile similar to palm-kernel and coconut fats. Yet processing can overturn expectations: larvae killed by freezing, freeze-dried, and defatted with supercritical carbon dioxide yielded an oil with a melting peak at 14.51 degrees Celsius and less than 10 percent solid fat at room temperature, while seven other combinations of killing, drying, and extraction retained more than 40 percent solid fat. Species identity and fatty-acid composition, in other words, do not constitute a thermal specification.

Quality attributes are equally process-dependent. Acid values reported across studies range from about 1.1 to more than 97 milligrams of potassium hydroxide per gram, reflecting hydrolytic damage that can continue after insect killing unless lipases are inactivated; blanching suppressed post-mortem lipolysis in black soldier fly larvae more effectively than freezing. Oxidation requires paired primary and secondary indices, because oils with moderate peroxide values can already carry high loads of aldehydic breakdown products. Sensory quality presents its own challenge: crude insect oils may carry grassy, fermented, or rancid notes from pyrazines, alcohols, and oxidation-derived aldehydes, but deodorization, while effective, risks stripping tocopherols and generating refining-related contaminants such as trans fatty acids and glycidyl esters if conditions are too severe.

On the application side, direct incorporation into foods currently has the strongest evidence. In a consumer study of 344 participants, replacing 25 percent of butter with black soldier fly larvae fat in cakes, cookies, and waffles did not reduce overall liking, and waffles maintained acceptance even at 50 percent replacement. Deodorized yellow mealworm oil replaced 50 to 100 percent of vegetable oil in crackers and hummus without lowering liking among 253 consumers, and among 90 tasters, potato chips fried in a 50:50 blend of vegetable and deodorized mealworm oil were the most frequently preferred. Roasted insect oils have even been incorporated into bone broth, shifting the fatty-acid profile toward that of beef while modifying meat-like aromas. More experimental routes, including wax-based oleogels that convert liquid mealworm oil into a shortening-like solid, whey-protein-coated emulsions that enhance lipolysis of silkworm oil, and enzymatic restructuring that repositions fatty acids on the glycerol backbone, remain largely at the prototype or in-vitro stage.

Biological evidence, the review cautions, is overwhelmingly preclinical and material-specific. Silkworm pupal oil showed higher apparent free-fatty-acid release during simulated digestion than linseed oil, and enzymatically restructured versions released even more, but such endpoints do not establish superior absorption or bioavailability in humans. Animal studies have reported reduced hepatic triglycerides in obese Zucker rats fed black soldier fly larvae fat compared with palm oil, altered lipid-metabolism gene expression in fish, and antioxidant and anti-inflammatory signals in cell and worm models, yet none of these findings can be generalized across insect oils as a category. Human trials using chemically characterized, food-grade oils and realistic intake conditions remain absent.

The path to industrial translation runs through several bottlenecks the review enumerates candidly. Batch variability is substantial, intact triacylglycerol data are scarce for most species, and consumer research has rarely tested purchase intention, price tolerance, or the effect of disclosing insect origin, leaving a gap between blind liking and real purchasing behavior. Residual allergenic proteins, including tropomyosin and arginine kinase that can cross-react with crustacean allergens, cannot be assumed absent from minimally refined oils. Regulatory identity is product-specific: in the European Union, authorization of whole or defatted insects does not automatically cover separately extracted oils, and comparable product-specific assessments apply in the United States and China. A single pilot-scale study processing 5.5 kilograms of mealworms with supercritical carbon dioxide achieved 84 percent defatting with promising life-cycle indicators, but the authors emphasize that such single-route assessments cannot support broad comparisons. Their prescription is a structure-property-application framework: match a reproducible, well-characterized oil to a defined product function, apply modification only where it delivers demonstrable advantage, and validate performance under realistic processing, storage, and sensory conditions before insect oils earn a permanent place on the ingredient shelf.

Subject of Research: Composition, functionality, and food applications of edible insect lipids

Article Title: Insect lipids as novel food ingredients: Linking molecular structure and quality attributes to food applications and industrial translation

Article References: Huang, Y., Kitts, D. D., Dabbour, M., Chen, X., Mintah, B. K., Dai, C., & He, R. (2026). Insect lipids as novel food ingredients: Linking molecular structure and quality attributes to food applications and industrial translation. Food Chemistry: X, 39, Article 104577. https://doi.org/10.1016/j.fochx.2026.104577

Image Credits: AI Generated

DOI: 10.1016/j.fochx.2026.104577

Keywords: insect oil, edible insects, triacylglycerol, black soldier fly, yellow mealworm, silkworm pupal oil, food chemistry, oleogel, oxidative stability, novel food, food processing, sustainable fats