As the global threat of plastic pollution has grown in scale and urgency, so have efforts to find sustainable and efficient solutions. Research conducted over the past few years has identified gut ...environments within insect larvae, including Tenebrio molitor (yellow mealworms), as microenvironments uniquely suited to rapid plastic biodegradation. However, there is currently limited understanding of how the insect host and its gut microbiome collaborate to create an environment conducive to plastic biodegradation. In this work, we provide evidence that T. molitor secretes one or more emulsifying factor(s) (30–100 kDa) that mediate plastic bioavailability. We also demonstrate that the insect gut microbiome secretes factor(s) (<30 kDa) that enhance respiration on polystyrene (PS). We apply these insights to culture PS-fed gut microbiome enrichments, with elevated rates of respiration and degradation compared to the unenriched gut microbiome. Within the enrichment, we identified eight unique gut microorganisms associated with PS biodegradation including Citrobacter freundii, Serratia marcescens, and Klebsiella aerogenes. Our results demonstrate that both the mealworm itself and its gut microbiome contribute to accelerated plastic biodegradation. This work provides new insights into insect-mediated mechanisms of plastic degradation and potential strategies for cultivation of plastic-degrading microorganisms in future investigations and scale-up.
•Extracts from edible insects Acheta domesticus and Tenebrio molitor.•Ultrasound (UAE) or pressurized liquid (PLE) extraction by ethanol or ethanol:water.•All the extracts are antioxidant, which ...correlates with total phenolic compounds.•All the extracts, mainly T. molitor, show inhibitory activity of pancreatic lipase.•Aqueous ethanol is better for antioxidant activity and PLE for inhibition of lipase.
Extracts from the edible insects Acheta domesticus and Tenebrio molitor were obtained by ultrasound-assisted extraction (UAE) and pressurized-liquid extraction (PLE) using ethanol (E) or ethanol:water (E:W). Characterization by GC–MS was performed and total phenolic compounds (TPC), antioxidant activity (DPPH) and pancreatic lipase inhibitory capacity were assayed.
Most extracts, mainly ethanolic extracts, predominantly presented lipids as free fatty acids, followed by aminoacids, organic acids, carbohydrates, hydrocarbons and sterols. The UAE-E:W extracts were different, being characterized by organic acids for A. domesticus, or aminoacids for T. molitor. All the extracts exhibited antioxidant activity, which correlated with TPC values, being the E:W extracts the most effective. All the extracts showed inhibitory activity of lipase, although those from T. molitor and extracted by PLE were the most effective.
Therefore, bioactive insect extracts can be selectively obtained by advanced methods of extraction, being aqueous ethanol preferred for antioxidant activity and PLE for inhibitory lipase activity.
Insect is an important source of dietary protein, and its application in the food industry has attracted attention. Tenebrio Molitor is rich in water-soluble protein, and the over-hydrophilic nature ...of water-soluble protein generally limits its industrial application. For the above reasons, this study systematically investigated the effect of high-intensity ultrasound (HIUS) on the physicochemical and physical characteristics of Tenebrio Molitor Protein (TMP). The results show that HIUS treatment might break the non-covalent bonds through the cavitation effect generated by the ultrasound probe, inducing the unfolding and disintegration of TMP soluble aggregates, and resulting in hydrophobic exposure and particle size reduction. HIUS optimize the physical characteristics of TMP (solubility, foamability, foam stability, emulsification, etc.) by changing its secondary/tertiary structure. Furthermore, emulsions stabilized by HIUS-treated TMP (UTMPEs) present smaller particle size and denser structure due to the changes in secondary structure, which plays a dominant role in the protein interface adsorption stabilization. The results of this study are expected to provide new guidance for better application of HIUS-treated TMP in the future food industry.
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•Modification of Tenebrio Molitor Protein (TMP) using high-intensity ultrasound (HIUS).•HIUS changes the secondary and tertiary structure of TMP.•HIUS enhances the emulsifying ability of TMP.
•Effects of Tenebrio molitor (TM) larvae meal in diets of female broiler chickens.•Partially positive TM effects on bird performance and blood parameters.•No TM effects on gut morphology and ...histological traits.
The aim of the present study was to evaluate the animal performance, haematochemical parameters, intestinal morphology and histological features of broiler chickens fed diets including Tenebrio molitor (TM) larvae meal. A total of 160 female broiler chicks (Ross 708) at one-day of age were randomly allotted to four dietary treatments: a control (C) group and three TM groups, in which TM meal was included at 50 (TM50), 100 (TM100) and 150 (TM150) g/kg, respectively. Each group consisted of five pens as replicates, with eight chicks per pen. After the evaluation of growth performance and haematochemical parameters, two birds per pen were slaughtered at 40days and carcass traits were recorded. Morphometric investigations were performed on duodenum, jejunum and ileum and histopathological alterations were assessed for liver, spleen, thymus, bursa of Fabricius, kidney and heart. The live weight (LW) showed a linear (12days, P<0.05, maximum with TM150) and quadratic response (40days, P<0.05, maximum with TM50) to dietary TM meal inclusion. The average daily gain (ADG) showed a linear increase (1-12days, P<0.05, maximum with TM150) in response to TM meal utilization. A linear effect (1–12 and 12–25days, P<0.01 and P<0.05, maximum with TM150 and TM50) was observed for the daily feed intake (DFI). The feed conversion ratio (FCR) showed a linear response to TM utilization in the period 12–25days (P<0.01, maximum with TM150). A quadratic effect (P<0.05, maximum with TM50) was observed for the carcass weight. The abdominal fat weight and percentage showed a linear response to dietary TM meal inclusion (P<0.05 and P<0.01, maximum with TM150 and TM100). A quadratic increase (P<0.05, maximum with TM100) was observed for the erythrocytes, while the albumin and GGT showed a linear and quadratic decrease (P<0.05, minimum with TM100) in relation to TM utilization. Gut morphology and histopathological findings were not significantly influenced (P>0.05) by dietary TM meal inclusion. The present study suggests that increasing levels of dietary TM meal inclusion in female broiler chickens diets may improve body weight and feed intake, but can partially worsen feed efficiency. However, positive effects on carcass traits and haematochemical parameters related to TM meal utilization are observed, along with no negative influence on gut morphology and histological findings.
Findings of viable Salmonella spp., which are important foodborne pathogens, are seemingly not reported in mealworms (Tenebrio molitor) for feed and food. Still, the bacterial load of mealworms is ...naturally high and includes members of the Enterobacteriaceae family to which Salmonella belong. This indicates that Salmonella may be able to thrive in mealworms if introduced into the production. Therefore, this study aimed to assess the quantitative level of Salmonella enterica serovar Typhimurium (ST) in mealworms over a 14-day course after exposure to substrate contaminated with ST levels from 1.7 to 7.4 log CFU/g at start (i.e., day 0). The level of ST found in larvae was below the quantitative detection level (1 or 2 log CFU/g) on day 1 in larvae exposed to contamination levels of 1.7, 3.4, and 3.6 log CFU/g opposed to contamination levels of 5.4, 5.6, and 7.4 log CFU/g, respectively. The maximum level of ST detected in individual 1-g larvae samples was 5.8 log CFU/g, but the level varied among the triplicate samples from each sampling, and the highest average value was 5.3 ± 0.3. Beyond day 7, only larvae exposed to the contamination level of 7.4 log CFU/g were >1.0 log CFU/g in the triplicate samples. However, qualitative testing (10 g) showed the presence of ST in larvae until the end of the experiment on day 14 except for the lowest contamination level of 1.7 log CFU/g. Parallel testing of surface disinfected larvae indicated that some larvae may be ST-positive due to Salmonella residing on the surface only. Still, any detection of Salmonella is of concern from a food safety perspective. In substrate with contamination levels below 3.6 log CFU/g, the level of ST was below the quantitative detection limit within a few days. Still, ST was detected until the end of experiment on day 14 except for the lowest contamination level of 1.7 log CFU/g. This study indicates the importance of avoiding introduction of Salmonella into the production, e.g., via contaminated substrate in order to avoid Salmonella-positive larvae as they remained positive for at least 14 days (except at the lowest contamination level).
This study was conducted to evaluate the effects of dietary Tenebrio molitor larvae meal (TM meal) inclusion on the performance, carcass traits, caecum microbiota and blood parameters of broiler ...chickens. A total of 180‐day‐old chickens were allocated to three dietary groups with five replicate pens (12 birds/pen). Experimental diets were included a corn‐soybean basal diet, and two diets with 2.5% and 5% TM. TM‐included diets have been administered for periods of starter (1–10 days) and grower (11–25 days). A regular finisher diet was given to all groups during the 26–42 days of age. Diets containing TM meal did not influence feed intake and mortality percentage. Feed conversion ratio was lower with the 2.5% TM meal diet compared with the control group at starter period (p < .05). Besides, broiler chickens fed TM meal included diet had a higher body weight gain than the control group during 1–10 days of age (p < .05). The carcass characteristics and length and weight of different parts of small and large intestines were not influenced by diets. TM meal inclusion decreased the albumin‐to‐globulin ratio compared with the control group (p < .05). Additionally, lower total count of aerobic and Escherichia coli bacteria was observed in response to diet inclusion of 5% TM meal. Overall, the inclusion of TM meal in broilers' diet improved body weight gain and feed conversion ratio in the starting period, decreased albumin‐to‐globulin ratio and E. coli bacteria content.
Yellow mealworm (Tenebrio molitor) larvae meal (TM), one of the seven insect species approved for use in aquafeed in Europe, is a frequently investigated candidate for fish diets. This study aimed to ...investigate the effects of dietary defatted TM on production performance, serum biochemistry, nutrient digestibility, fillet traits, intestinal microbiota, and environmental impacts of perch (Perca fluviatilis). Four experimental diets, characterized by defatted TM inclusion levels of 0, 6.8, 13.5 and 20.3%, respectively, or 0, 25, 50, and 75% replacement for fishmeal on a w/w basis (TM0, TM25, TM50, and TM75, respectively), were fed to juvenile perch (bodyweight 20.81 ± 3.36 g, total length 117.7 ± 7.2 mm) (quadruplicated per diet) for 105 days. Inclusion levels of 6.8% or 25% fishmeal replacement by defatted TM did not show a significant effect on specific growth rate and feed conversion ratio, while further levels of 13.5 and 20.3%, or 50 and 75% fishmeal replaced by defatted TM, respectively, displayed a significant delay in the former (P = 0.01), but increase in the latter indice (P = 0.04) compared to TM0 diet. The aspartate aminotransferase activities in perch's serum increased with increasing dietary TM (P = 0.02). Protein digestibility of perch exhibited a negative correlation with dietary TM (P = 0.03). Dietary defatted TM did not, alter fillet composition of perch (P > 0.05) and modify diversity of fish gut microbiota (Chao1 index, P = 0.742; Shannon index, P = 0.557; and observed species, P = 0.522), but significantly reduced abundance of Lactobacillus (P = 0.04) and Streptococcus (P = 0.01). Diets containing more than 6.8% TM generated a comparable amount of total solid waste and solid phosphorus waste as the TM0, whereas solid nitrogen waste significantly increased with elevated TM levels (P < 0.001). The estimated environmental impacts of perch fed TM25 were comparable to TM0 for global warming potential, acidification, and land use (P > 0.05), whereas TM50 and TM75 exerted heavier burdens on energy use, eutrophication, and water use than TM0 (P < 0.001). Fishmeal replacement by TM significantly reduced the economic fish-in fish-out ratio (P < 0.001). Results of this multidisciplinary study revealed important considerations for formulating diets with insect meals and their potential effects on fish performance and environmental impacts.
•Inclusion of 6.8% of defatted Tenebrio molitor (TM) showed comparable growth indices with an insect-free diet.•Dietary TM did not alter the fillet composition of perch.•Insect-based diets produced less solid waste, but comparable solid phosphorus waste with the control.•Dietary TM significantly increased solid nitrogenous waste and environmental impacts (energy use, water use, eutrophication).•The inclusion of TM significantly reduced economic fish-in fish-out.
Polystyrene (PS) is a plastic polymer extensively used for food packaging. PS is difficult to decompose and has low recycling rates, resulting in its accumulation in the environment, in the form of ...microplastic particles causing pollution and harming oceans and wildlife. Degradation of PS by mealworms (
) has been suggested as a possible biological strategy for plastic contamination; however, the biodegradation mechanism of PS by mealworms is poorly understood. It is hypothesized that the gut microbiome plays an important role in the degradation of PS by mealworms. This study carried out a comparative analysis of the gut microbiome of
larvae under different feeding strategies, and of the formation of degradation compounds (monomers, oligomers). A diet of bran:PS at 4:1 and 20:1 ratios was tested. The diet with the low ratio of bran:PS led to the presence of higher amounts of these compounds, compared to that with the high ratio. In addition, it was demonstrated that the addition of H
O significantly improved the biodegradation of PS monomer and oligomer residues, which could be identified only in the frass. The protein and nitrogen contents in insects' biomass and frass varied amongst treatments. The diets resulted in differences in the gut microbiota, and three potential bacterial strains were identified as candidates involved in the biodegradation of PS.
The use of alternative fertilizers instead of conventional mineral fertilizers, such as the insect excreta (frass) is a new sustainable agronomic practice. Rearing insects for mass consumption has a ...small ecological footprint, but produces high quantities of frass. The aim of this work was to verify the potentials of frass from Tenebrio molitor L. as fertilizer. Two experiments were performed: firstly a germination test to observe the effects of frass on sunflower, tomato, lettuce and cress at four levels of frass added to a potting mix, and; secondly, a pot experiment to compare frass as organic fertilizer against NPK-mineral fertilization on sunflower. We provided 120 kg ha−1 N, 43 kg ha−1 P and 47 kg ha−1 K via the application of frass or NPK mineral fertilizer or the combination of the two. From the germination test, all species show a reduction in the germination rate. Considering the seedlings biomass, sunflower performs better than the other species especially at the lowest frass dose. In the pot experiment, sunflower plants from soil amended with frass or NPK mineral fertilizer had a similar biomass, demonstrating that frass from T. molitor can be used as organic fertilizer being capable of meeting the crop requirements.
•Tenebrio molitor frass affects germination of cress, lettuce, tomato and sunflower and the of effect is species dependant.•Soil amended with T. molitor frass stimulated the growth of sunflower in the same extent as mineral NPK fertilization.•NPK accumulation in plants from T. molitor frass amended substrate was not lower than plants from NPK fertilizer substrate.•T. molitor frass application shortened the vegetative growth phases.•Application of T. molitor frass can sustain sunflower growth throughout its entire life cycle.
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