LIPID COMPOSITION OF THE SILKWORM BOMBYX MORI L

Haemolymph metabolomic differences in silkworms (Bombyx mori L.) under mulberry leaf and two artificial diet rearing methods

The new technology of silkworm (Bombyx mori L.) artificial feed breeding has many characteristics and advantages. This study assessed silkworm rearing with mulberry leaf at all instars (MF) as the control, and used metabolomics to explore the differences in haemolymph metabolism of fifth instar silkworms under two modes of rearing with an artificial diet at all instars (AF) and rearing with an artificial diet during first to third instars and mulberry leaf during the fourth and fifth instars (AMF). The results show that, compared with silkworms of the MF group, the amount and fold change of various metabolites were higher in the haemolymph of AF group silkworms, and the metabolism of amino acids and uric acid, carbohydrates, lipids, and vitamins were changed. These changes may be the reasons for the poor performance of the AF silkworms. However, the amount and fold change of the various metabolites of silkworms in the AMF group were lower, and some metabolic pathways were more active. The amount of material and energy supply were greater. These changes could explain the high efficiency growth of body weight of silkworms after the conversion from artificial diet rearing to mulberry leaf rearing. These findings provide an important theoretical basis for the optimisation of artificial diet rearing technology for silkworms.

Insects: A Potential Source of Protein and Other Nutrients for Feed and Food

Sustainable production of healthy food for a growing global population, in the face of the uncertainties of climate change, represents a major challenge for the coming decade. Livestock provide food with high nutritional value but are frequently fed on human-edible crops and are associated with significant production of greenhouse gases. Recent years have seen increasing interest in the farming of insects as a sustainable source of human food, or as a replacement of ingredients such as soya or fishmeal in the feeds of terrestrial livestock or fish. This review provides an overview of insect physiology and growth regulation, considers the requirements for insect farming and mass production, and summarizes the nutritional value of the 10 most commonly studied insect species, before reviewing the literature on the use of insects as feed and food. We highlight the challenges required to develop a sustainable, safe, and affordable insect farming industry.

A Lipidome Map of the Silkworm Bombyx mori: Influences of Viral Infection

Lipids have been recently proposed as key molecules for virus entry and egress, and lipid biosynthesis and signaling were reported necessary for some viruses during replication and infection. The silkworm Bombyx mori is an important economic insect and a model organism, but its lipid profiles have not been systematically investigated. Most silkworm strains are susceptible to the B. mori nuclear polyhedrovirus (BmNPV), a baculovirus that causes serious loss to the sericulture industry. Previously, our lab has screened a natural mutant of B. mori that is highly resistant to BmNPV. In this study, a comprehensive lipidomic analysis by ultrahigh pressure liquid chromatography-mass spectrometry (UPLC-MS) was carried out on the BmNPV-susceptible strain 306 and resistant strain NB (data deposited in MetaboLight MTBLS2142). Comparisons of the lipid profiles between the two strains reveal that phosphosphingolipids, diacylglycerolipids, ceramides, and quinones were present at notably higher levels in the susceptible strain, while lysophosphocholines were found at a higher level in the resistant strain. BmNPV administration changed the lipid profiles in both strains, revealing key lipids involved in virus infection and immune response. Some key enzymes in the lipid biosynthesis pathway were analyzed for their activities in the two silkworm strains and their virus-administered counterparts, underlining the relation among lipid biosynthesis, viral resistance, and immune response in the host.

Sex-Specific Bioamplification of Halogenated Organic Pollutants during Silkworm (Bombyx mori) Metamorphosis and Their Adverse Effects on Silkworm Development

A partial life cycle test was performed with silkworms (Bombyx mori) exposed to different levels of halogenated organic pollutants (HOPs). The aims were to investigate the fate of HOPs during metamorphosis and the adverse effects of HOP exposures on silkworm development. Contaminant exposures resulted in decreased body weights, increased development times, and reductions of fecundity in silkworms. Assimilation efficiencies of HOPs decreased with an increasing octanol-water partition coefficient (log K_OW). From the larvae to the pupae stage, bioamplification factors (BAmFs) exhibited concentration-dependent results, in which there was a positive correlation with the log K_OW at the high concentrations but no correlation at the low concentrations. From the pupae to the moth stage, BAmFs were linearly negatively correlated with the log K_OW for males, but a parabolic correlation with the log K_OW was more suitable for females. Regarding reproductive activities, female moths selectively transferred low log K_OW HOPs to eggs by the oviposition except for highly halogenated lipophilic pollutants. However, BAmFs of male moths during mating showed no correlation with the log K_OW, although highly halogenated lipophilic pollutants had the highest BAmF values. The sex-specific bioamplification processes and special behaviors of highly halogenated lipophilic pollutants deserve further research.

Protective effect of silkworm pupa oil on hydrochloric acid/ethanol-induced gastric ulcers

BACKGROUND

Silkworm pupae are a traditional Chinese food, rich in various saturated and unsaturated fatty acids. Unsaturated fatty acids have a certain protective effect against oxidative damage. The present study used an animal model to determine the protective effect of silkworm pupa oil on hydrochloric acid / ethanol-induced gastric ulcer.

RESULTS

Silkworm pupa oil is rich in unsaturated fatty acids, including palmitoleic acid 63.4 g kg^-1 , oleic acid 249.1 g kg^-1 , linoleic acid 47.0 g kg^-1 , and linolenic acid 337.8 g kg^-1 , whereas its unsaturated fatty acid content is 700 g kg^-1 . Compared to a gastric ulcer control group, high and low doses of pupa oil reduced gastric ulcer area and gastric secretion, whereas gastric pH increased. It also increased serum antioxidant superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) levels, somatostatin (SST), and vasoactive intestinal peptide (VIP) levels, and reduced serum interleukin-6 (IL-6), interleukin-12 (IL-12), tumor necrosis factor (TNF-α), and interferon-γ (IFN-γ), motilin (MTL), and gastrin (GT) levels. RT-qPCR and western blot analyses indicated that silkworm pupa oil significantly increased CAT, GSH-Px, epidermal growth factor (EGF), Epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), Cu/Zn-SOD, Mn-SOD, and NF-kappa-B inhibitor-α (IκB-α) expression and lowered nuclear factor-kappa B (NF-κB), B-cell lymphoma-2 (Bcl-2), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) expression.

CONCLUSION

Silkworm pupa oil treatment reduced oxidative damage and inflammation in mice, and high-dose silkworm pupa oil was superior to low-dose silkworm pupa oil, following ranitidine. © 2018 Society of Chemical Industry.

Efficacy of silkworm (Bombyx mori L.) chrysalis oil as a lipid source in adult Wistar rats

The effects of silkworm chrysalis oil, rich in n-3 α-linolenic acid (ALA), on lipid metabolism in Wistar rats were investigated. The rats were fed diets containing 7% soybean oil (control), silkworm chrysalis oil (SWO), or fish oil (FO) for 8weeks. Plasma triglyceride and glucose levels were significantly lower in the SWO group after 8weeks compared to the control and FO groups. The total cholesterol and blood urea nitrogen levels were higher in the control group than in the SWO and FO groups at 8weeks post-consumption. However, aspartate amino transferase and alanine amino transferase levels were not significantly different among all groups. A higher arachidonic acid (AA) content was detected in the control group, while lower AA levels were observed with the increase in EPA and DHA in the SWO and FO groups. These results suggest that n-3 α-linolenic acid-rich silkworm chrysalis oil can improve hyperlipidaemia and hyperglycaemia.

Quantitative data on the Bombyx mori L. silkworm: a review

This paper summarizes a variety of quantitative data on the silkworm Bombyx mori, collected in the literature, to help building models on silk gland differentiation. The properites of the silk gland and their changes especially during the last larval instar have been reviewed (size, DNA, RNA amino acids, enzymes). The components of the silk (fibroin and sericin) are also studied (molecular weight, composition). Thus translation and transcription rates have been estimated. The relevant data on the fat body and the haemolymph are also given, as well as some characteristics of the oocyte/egg system.