Nutritional Value of Silkworm Pupae (Bombyx mori) with Emphases on Fatty Acids Profile and Their Potential Applications for Humans and Animals

Effects of chemical modifications on allergenicity and functional properties of silkworm pupae proteins

Silkworm pupae proteins (SPP) have been exploited as a new functional protein, but there are still some people who are allergic to it. This study investigated the effects of different chemical modifications (phosphorylation, succinylation, deamidation, glycosylation) on SPP's allergenicity and its structural and functional impact. Spectroscopic analysis showed that all three modifications except glycosylation loosened the three-dimensional structure of SPP. Enzymatic hydrolysis studies have shown that the succinylated group can significantly enhance the hydrolysis resistance of SPP at 30 kDa, and the ability to bind IgE was maintained. Most proteins were hydrolyzed into small peptides within 30 min after combined digestion. A functional study of chemically modified SPP demonstrated that succinylation had a strong water-holding capacity. Further deamidation and phosphorylation have stupendous foaming ability and foaming stability, respectively. This discovery collectively will provide the experimental basis for developing and using silkworm pupae protein in the food industry.

Proteomic Analysis of Midgut of Silkworm Reared on Artificial Diet and Mulberry Leaves and Functional Study of Three UGT Genes

There remains a significant gap in production performance and disease resistance between silkworms reared on artificial diets and those reared on mulberry leaves. This study aims to identify key differential proteins through proteomic analysis of the midgut of silkworms fed artificial diets compared to those fed mulberry leaves. Utilizing molecular docking technology, three anti-nutritional factors that consistently bind to the UGT40B4, UGT340C2, and UGT40A1 proteins were selected, and the differential expression of these UGT genes in response to various anti-nutritional factors was examined. The findings indicate that variations in feed significantly influence the expression of digestive, metabolic, and immune-related proteins within the silkworm midgut. Notably, the expression levels of the UGT40B4, UGT340C2, and UGT40A1 genes vary across different silkworm organs and developmental stages, reflecting their respective physiological roles. Furthermore, the effects of soybean isoflavone, tannic acid, and arabinoxylan on silkworm growth and cocoon quality were found to differ when these substances were incorporated into semi-synthetic feed. This research is anticipated to provide valuable insights for future studies on the role of UGT genes in the silkworm midgut and the formulation of artificial diets for silkworms.

Edible Insects as an Alternative Source of Nutrients: Benefits, Risks, and the Future of Entomophagy in Europe-A Narrative Review

According to projections by the Food and Agriculture Organization of the United Nations, the global population will reach 9 billion by 2050. This raises concerns about the ability to feed such a population. In view of the above, it is necessary to search for alternative food sources. Edible insects are rich in complete protein, essential fatty acids, vitamins and micronutrients. Despite this, entomophagy is not common in Europe. In 2021, the European Union approved Acheta domesticus, Tenebrio molitor, Locusta migratoria, and Alphitobius diaperinus for consumption. However, their consumption may also be associated with certain hazards, e.g., food allergies. The purpose of this review is to present existing knowledge, discuss the possible dangers of consuming insects, and identify areas for further research. Studies in Asian populations indicate that edible insects may be responsible for 4.2-19.4% of food allergies and 18% of fatal food-induced anaphylaxis. There are also increasing reports from Europe of food allergies to edible insects. A thorough understanding of allergens, their properties, and the mechanisms of food allergies associated with edible insects' consumption is essential for ensuring consumers' safety. In the future, it would be worthwhile to investigate the effects of heat treatment on the allergenicity of insect proteins.

We are what we eat: Implications of host plant suitability on sustainable production of silkworm pupae as novel ingredient with dietary and health benefits

Although, the impact of mulberry leaves on mortality of Bombyx mori [silkworm] and cocooning rates has been investigated, limited research has exploited the influence on the quality of B. mori pupae. This study evaluated the effects of four mulberry cultivars (Ichinose, Noi-EX-Thailand, Ex-Thika and Victory1) on the nutritional quality of B. mori pupae. The proximate composition, amino acids, vitamins, and minerals of different mulberry cultivars and silkworm pupae were analyzed using standard methods. Silkworms fed on Noi-EX-Thailand and Ex-Thika cultivars exhibited the highest crude protein (57.9%) and fat content (44.3%), respectively. Eight essential amino acids were identified in silkworm pupae, with histidine (6.02-7.12 μg/100mg) being the most abundant, followed by significant amounts of lysine (1.40-5.03 μg/100 mg), leucine (1.96-2.47μg/100 mg), and valine (0.89-2.03 μg/100 mg). Pupae raised on Noi-Ex-Thailand leaves had the highest total amino acid content (23.01 μg/100 mg). Potassium was the major mineral in pupae (505.62-665.30 mg/100 mg), with the highest levels observed in those fed on Noi-EX-Thailand. Vitamin C levels ranged from 28.84 to 61.88 mg/100 g, with pupae fed on Victory1 showing the highest concentration. There was a strong positive correlation between magnesium, crude protein and nitrogen-free extracts of mulberry leaves that mirrored the corresponding levels in silkworm pupae. These results underscore the importance of mulberry leaf composition in determining silkworm pupae quality, especially when considering their use as sustainable ingredient for the food, feed and pharmaceutical industry.

Effects of 4-week Eri silkworm cornflakes supplementation on oxidative stress and antioxidant status in male university athletes: A preliminary crossover study

Aim: This study among moderately fit male athletes investigated changes in oxidative stress and antioxidant levels after supplementation with Eri silkworm cornflakes. Method: Male university athletes (n = 18, age 19-21 years) were enrolled in a randomized crossover trial. They participated in either the supplementation period (consuming 0.20 g protein/kg body weight Eri silkworm daily) or the control period (no supplementation). Each period lasted 4 weeks, with a washout period of 4 weeks in between. Results: Compared to the control period, reduced glutathione concentration (p = 0.019) and reduced/oxidized glutathione ratio (p < 0.001) were significantly higher, and oxidized glutathione (p = 0.018) and malondialdehyde (p = 0.002) concentrations were significantly lower in the supplementation period. Conclusion: Eri silkworm supplementation as cornflakes for 4 weeks improved oxidative stress and antioxidant status in male university athletes. This supplement may be an alternative to support optimal antioxidant status for athletic individuals. Thai Clinical Trials Registry (TCTR): TCTR20180303003.

Comparison of lipid profiles of male and female silkworm (Bombyx mori) pupae through high-resolution mass spectrometry-based lipidomics and chemometrics

Silkworm (Bombyx mori) pupae lipid profiles were analyzed using high-resolution mass spectrometry-based lipidomics. A total of 241 lipid molecular species were annotated with high confidence in male and female silkworm pupae. Triacylglycerol (TG), phosphoethanolamine (PE) and phosphocholine (PC) were the main lipid subclasses of silkworm pupae, accounting for 63, 41 and 38 lipid molecular species, respectively. No unique lipid molecular species were identified, but there were differences in the abundance of lipid molecular species between male and female silkworm pupae. Therefore, the differences in the lipid abundance of male and female silkworm pupae were analyzed by chemometrics. As a result, 8 lipid molecular species were screened for differential lipids. Hierarchical clustering analysis (HCA) showed that male and female silkworm pupae samples formed two distinct branches, indicating that these differential lipids could potentially be used as biomarkers to distinguish between male and female silkworm pupae.

Toxicological Evaluation Verifies the Safety of Oral Administration of Steamed Mature Silkworm Powder in Rats

Globally, the edible insect industry is emerging due to its potential contributions to food security and environmental sustainability. Edible insects are rapidly being integrated into the development of alternative foods and new pharmaceuticals. Silkworms, known for their high protein content, are not only a potential new source of human food and animal feed but have also been traditionally used for medicinal purposes. However, conventional silkworms are difficult to ingest. To address this, we have developed a steamed and freeze-dried mature silkworm larva powder (SMSP), and it is essential to investigate its potential toxicity and food safety for further studies and applications. Therefore, this study aimed to evaluate the toxicity of SMSP. A toxicity assessment of SMSP was conducted according to OECD guidelines. An oral repeat-administration study was performed on male and female SD rats at doses of 625, 1250, and 2500 mg/kg/day for 4 and 13 weeks. No toxicological changes were observed in clinical signs, body weight, water and food intake, urine tests, hematology, clinical biochemistry, gross findings, or histopathological examination. In conclusion, the no observed adverse effect level (NOAEL) of SMSP was 2500 mg/kg/day, with no target organs identified in either sex of the rats. These results suggest that SMSP is safe, is without side effects and has potential for use as an edible ingredient and in health functional food applications.

Silkworm pupae protein co-degradation by magnetic nanoparticles immobilized proteinase K and Mucor circinelloides aspartic protease for further utilization of sericulture by-products

Silkworm pupae, by-product of sericulture industry, is massively discarded. The degradation rate of silkworm pupae protein is critical to further employment, which reduces the impact of waste on the environment. Herein, magnetic Janus mesoporous silica nanoparticles immobilized proteinase K mutant T206M and Mucor circinelloides aspartic protease were employed in the co-degradation. The thermostability of T206M improved by enhancing structural rigidity (t1/2 by 30 min and T50 by 5 °C), prompting the degradation efficiency. At 65 °C and pH 7, degradation rate reached the highest of 61.7%, which improved by 26% compared with single free protease degradation. Besides, the immobilized protease is easy to separate and reuse, which maintains 50% activity after 10 recycles. Therefore, immobilized protease co-degradation was first applied to the development and utilization of silkworm pupae resulting in the release of promising antioxidant properties and reduces the environmental impact by utilizing a natural and renewable resource.

An In-Depth Insight into the Profile, Mechanisms, Functions, and Transfer of Essential Amino Acids from Mulberry Leaves to Silkworm Bombyx mori L. Pupae and Fish

The silkworm Bombyx mori, the second most varied group of insects, is a fascinating insect that belongs to the Lepidoptera species. We aimed to deepen our knowledge about the composition and significance of amino acids (AA) from the sericulture chain to fish. AAs are the most prevalent molecules throughout the growth process of silkworms. We described AAs classification, occurrence, metabolism, and functions. Online datasets revealed that the essential AAs (EAA) level in fish meal and silkworm pupae (SWP) is comparable. SWP have a high content of methionine and lysine, which are the principal limiting AAs in fish diets, indicating that SWP have nutritional potential to be added to fish diets. Additionally, an overview of the data analyzed displays that SWP have a higher protein efficiency ratio than fish meal, the classical protein-rich source (>1.19 times), and compared to soybean meal, the second-most preferred source of protein in aquaculture (>2.08 times), indicating that SWP can be considered effective for animal feeding. In this study, we provide an overview of the current knowledge concerning AAs, paying special emphasis to EAAs and explaining, to some extent, certain mechanisms and functions of these compounds, from mulberry leaves to larvae-pupae and fish diets.

Purification, Immunological Identification, and Characterization of the Novel Silkworm Pupae Allergen Bombyx mori Lipoprotein 3 (Bomb m 6)

Allergic reactions caused by silkworm pupae greatly limit their utilization, and studies suggest that silkworm pupae proteins of 25-30 kDa may be the principal allergens. To further understand these allergens, we attempted to purify a protein of about 30 kDa by ammonium sulfate salting, pH-graded precipitation, and ion-exchange chromatography. The protein was identified by mass spectrometry and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), western blot, enzyme-linked immunosorbent assays, circular dichroism, and fluorescence spectroscopy analyses. We identified the purified protein as Bombyx mori lipoprotein 3 (Bmlp3), which has high IgE reactivity and is a novel uncharacterized allergen that we named Bomb m 6 according to the WHO/IUIS Allergen Nomenclature Sub-Committee. This allergen is stable against heat, acids, bases, and digestion. In conclusion, we successfully purified and characterized a novel silkworm pupa allergen, which may inform the diagnosis and treatment of silkworm pupa allergies.

Potential of Full-Fat Silkworm-Based Diets for Laying Quails: Performance and Egg Physical Quality

The present research was conducted to determine the optimal inclusion level of full-fat silkworm chrysalis meal (SWM) into laying quails' diets, focusing on performance traits and egg physical quality. A total of 240 31-day-old female Japanese quails were randomly assigned to four dietary groups (12 replicates/treatment; 5 quails/replicate); quails were initially fed a standard commercial diet for pullets until 63 days of age. When oviposition started, the experimental groups received the following diets: a conventional corn and soybean-based diet (control diet-C) and three other diets, including 4%, 8%, or 12% of full-fat SWM (SWM4, SWM8, SWM12, respectively). Experimental diets were provided until quails reached 119 days of age. Birds displayed satisfactory productive performance throughout the trial. SWM12 and SWM8 had higher (p < 0.001) egg production but also a higher feed conversion ratio compared to C. At the end of the trial, the eggs edible portion increased, and shell weight decreased with increasing the SWM dietary inclusion level (p < 0.001). At the same time, SWM12 displayed an increase in albumen pH (p < 0.05), even though in the normal range for quail egg. Overall, full-fat SWM (up to 12%) can be considered a promising feed ingredient for laying quails, although higher inclusion levels (>8%) require special attention because SWM also contains anti-nutritional factors.