Cocoon Shell Weight Research Articles

Selenium Treatment Ameliorates the Adverse Effects Caused by Dynamin Gene Knockdown in Bombyx mori.

Our previous research reported the influence of 50 μM selenium (Se) on the cytosolization (endocytosis) pathway, which in turn stimulates the growth and development of Bombyx mori. Lately, dynamin is recognized as one of the key proteins in endocytosis. To explore the underlying mechanisms of Se impact, the dynamin gene was knocked down by injecting siRNAs (Dynamin-1, Dynamin-2, and Dynamin-3). This was followed by an analysis of the target gene and levels of silk protein genes, as well as growth and developmental indices, Se-enrichment capacity, degree of oxidative damage, and antioxidant capacity of B. mori. Our findings showed a considerable decrease in the relative expression of the dynamin gene in all tissues 24 h after the interference and a dramatic decrease in the silkworm body after 48 h. RNAi dynamin gene decreased the silkworm body weight, cocoon shell weight, and the ratio of cocoon. In the meantime, malondialdehyde level increased and glutathione level and superoxide dismutase/catalase activities decreased. 50 μM Se markedly ameliorated these growth and physiological deficits as well as decreases in dynamin gene expression. On the other hand, there were no significant effects on fertility (including produced eggs and laid eggs) between the interference and Se treatments. Additionally, the Se content in the B. mori increased after the dynamin gene interference. The dynamin gene was highly expressed in the silk gland and declined significantly after interference. Among the three siRNAs (Dynamin-1, Dynamin-2, and Dynamin-3), the dynamin-2 displayed the highest interference effects to target gene expression. Our results demonstrated that 50 μM Se was effective to prevent any adverse effects caused by dynamin knockdown in silkworms. This provides practical implications for B. mori breeding industry.

Effects of mulberry leaf enrichment with Lepidium sativum L. seed powder suspension on the economic parameters of Bombyx mori L

The phytochemicals of high nutritional and functional properties in Lepidium sativum L. (garden cress) seeds have nominated their seed powder (regardless of the concentration used) for enrichment of mulberry leaves in order to enhance Bombyx mori L. larval feeding, and consequently to gain ground in sericulture industry. As expected, B. mori larval feeding on L. sativum-enriched mulberry leaves showed not only a remarkable increase in mean values of certain economic parameters of B. mori, such as cocoon weight, cocoon shell weight, pupal weight, and egg yield, compared with the control group, but also showed a phenomenal increase in egg counts (on average, ca. 958–1256 eggs laid per female moth) and a significant increase in egg size (measured as egg surface area and egg volume). Male or female moth larval diet has significantly influenced the reproductive performance or fitness of both sexes of B. mori in terms of large-sized moths (measured as forewing, hind femur, and hind tibia lengths) and highly fecund moths (i.e., increased fecundity and spermatophore counts per female moth, and large-sized eggs). On the basis of B. mori female moth reproductive index, the female moths from L. sativum-fed larvae proved to have a lower reproductive index compared to their corresponding value for females of the control group, indicating more efficient utilization of larval resources for B. mori reproduction. Quantification of the three main physiological resources viz., protein, lipid and carbohydrate in the internal reproductive tract of B. mori female moths at death has nominated the female moth abdomens, or simply their bodies, as being a reasonable natural source of protein, lipid, and carbohydrate, to be involved in certain manufactures (e.g., pet feed formulations) instead of discarding them as a source of environmental pollution. Evidently, the L. sativum seed powder is of considerable interest because it remarkably improves the performance of such an economically important insect, B. mori. This is the first study for evaluating the efficacy of L. sativum seed powder in sericulture field to enhance B. mori productivity parameters.

Sublethal effects of nitenpyram on the development of silkworm

The utilization of nitenpyram for aphid and whitefly control may induce environmental contamination and negative repercussions on non-target organisms. Formerly, we found that nitenpyram would pollute the peripheral and sub-peripheral areas of the adjacent mulberry orchard. Under acute toxicity conditions, nitenpyram induced oxidative damage in silkworms, affected biological metabolism, synthesis, immunity, and signal transduction. Considering the impact of nitenpyram mist drift on mulberry leaves, we investigated the effects of low concentrations of nitenpyram on silkworms. The results showed that silkworms exposed to 0.17 mg/L, 0.35 mg/L and 0.70 mg/L of nitenpyram (1/40 LC50, 1/20 LC50 and 1/10 LC50) showed obvious poisoning symptoms. The cocoon weight and cocoon shell weight decreased gradually with increases in the concentration, and these decreases prolonged the growth and development time of silkworms and induced the detoxification enzymes carboxylesterase (CarE) and glutathione-S-transferase (GST) to cope with the stress damage caused by nitenpyram. Exposure to low concentrations of nitenpyram downregulates genes involved in the drug metabolism-other enzymes and peroxisome pathway in silkworms. Additionally, through injection of miRNA mimics and inhibitors, we discovered that detoxifying enzyme pathway genes are influenced by bmo-miR-3382-3P, bmo-miR-3213-5P and bmo-miR-133, regulating the immune response of silkworms. This study provides an overall view of the toxicity and detoxification metabolism of nitenpyram in silkworm, and provides a reference for environmental assessment.

Selenium Treatment Alleviates the Inhibition Caused by Nep-L Gene Knockdown in Silkworm (Bombyx mori).

Recent studies have emphasized the beneficial effects of 50 μM selenium (Se) on the growth and development of the silkworm, Bombyx mori; however, less is known about its underlying mechanism. To unravel the effect of 50 μM Se on the silkworms with neutral endopeptidase 24.11-like gene (NEP-L) knockdown, we injected small interfering RNA (siRNA) into the body cavity of silkworms. Phenotypic characteristics, mRNA expression of the Nep-L gene, and enriched Se content were evaluated in silkworms from each treatment group. After injecting Nep-L siRNA, the body weight, cocoon quality (cocoon weight, cocoon shell weight, and cocoon shell ratio), and egg production of silkworms were significantly reduced, without any significant effect on egg laying number. However, Se treatment could significantly alleviate the inhibition of body weight, and cocoon quality, without significant effects on egg laying number and production. In addition, the gene knockdown increased Se content in the B. mori. On the molecular level, the targeted Nep-L gene was inhibited significantly by siRNA interference, essentially with the strongest effect at 24 h after RNAi, followed by steady recovery. Among the three fragments, the siRNA of Nep-L-3 was the most effective in interfering with target gene expression. Nep-L gene showed the highest expression in Malpighian tubules (MTs). Both at the phenotypic and genotypic levels, our results show that Nep-L knockdown can exert a significant inhibitory effect on silkworms, and 50 μM Se can reverse the negative effect, which provides a practical prospect for strengthening the silkworm food industry.

Selected Thermotolerant Bivoltine Hybrids of Bombyx mori L. Exhibit Desirable Heterosis for Quantitative Traits under Beauveria bassiana Infection

Four thermotolerant bivoltine silkworm parents viz., B1, B4, B6 and B8 and their 12 hybrids viz., B1×B4, B1×B6, B1×B8, B4×B1, B4×B6, B4×B8, B6×B1, B6×B4, B6×B8, B8×B1, B8×B4 and B8×B6 were used in the experiments. One set of the parents and their hybrids were inoculated with Beauveria bassiana spore suspension (9.04 × 104 spores / ml), on the first day of the fifth instar before first feed and another set were exposed to high temperature (36 ± 1o C temp. & 85 ± 5 % RH) and their responses were studied in terms of heterotic expression of quantitative traits. Significantly highest positive relative heterosis under normal condition was recorded in B1×B4 hybrid for five characters (fifth instar larval weight, cocoon yield by weight, single cocoon weight, shell weight and filament length) and under muscardine inoculation significantly highest positive relative heterosis was recorded in the hybrid B4×B6 for ten characters (ERR, cocoon yield by number, fifth instar larval weight, cocoon yield by weight, single cocoon weight, shell weight, shell ratio, pupal weight, filament length and filament weight). Heterosis scoring over all the traits under muscardine inoculation revealed that the hybrid B4 × B6 scored high overall status of heterotic effects across the characters. Thus, B1 and B8 among parents and B1 × B8 and B4 × B6 among hybrids could be selected for dual stress tolerance against high temperature and muscardine disease.

Domestication Gene Mlx and Its Partner Mondo Are Involved in Controlling the Larval Body Size and Cocoon Shell Weight of Bombyx mori.

Bombyx mori was domesticated from Bombyx mandarina. The long-term domestication of the silkworm has brought about many remarkable changes to its body size and cocoon shell weight. However, the molecular mechanism underlying the improvement in the economic characteristics of this species during domestication remains unclear. In this study, we found that a transposable element (TE)-Bm1-was present in the upstream regulatory region of the Mlx (Max-like protein X) gene in wild silkworms but not in all domesticated silkworms. The absence of Bm1 caused an increase in the promoter activity and mRNA content of Mlx. Mlx and its partner Mondo belong to the bHLHZ transcription factors family and regulate nutrient metabolism. RNAi of Mlx and Mondo decreased the expression and promoter activity of glucose metabolism-related genes (trehalose transport (Tret), phosphofructokinase (PFK), and pyruvate kinase (PK)), lipogenic genes (Acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS)), and glutamine synthesis gene (Glutamine synthase 2, (GS2)). Furthermore, the transgenic overexpression of Mlx and Mondo in the fat body of silkworms increased the larval body size, cocoon shell weight, and egg number, but the silencing of the two genes resulted in the opposite phenotypes. Our results reveal the molecular mechanism of Mlx selection during domestication and its successful use in the molecular breeding of Bombyx mori.

TAR: A Highly Accurate Machine-Learning Model to Predict the Cocoon Shell Weight of Tasar Silkworm Antheraea Mylitta

TAR: A Highly Accurate Machine-Learning Model to Predict the Cocoon Shell Weight of Tasar Silkworm Antheraea Mylitta

Low concentration of indoxacarb interferes with the growth and development of silkworm by damaging the structure of midgut cells

As an important economic insect, Bombyx mori plays an essential role in the development of the agricultural economy. Indoxacarb, a novel sodium channel blocker insecticide, has been widely used for the control of various pests in agriculture and forestry, and its environmental pollution caused by flight control operations has seriously affected the safe production of sericulture in recent years. However, the lethal toxicity and adverse effects of indoxacarb on silkworm remain largely unknown. In this study, the toxicity of indoxacarb on the 5th instar larvae of silkworm was determined, with an LC50 (72 h) of 2.07 mg/L. Short-term exposure (24 h) to a low concentration of indoxacarb (1/2 LC50) showed significantly reduced body weight and survival rate of silkworm larvae. In addition, indoxacarb also led to decreased cocoon weight and cocoon shell weight, but had no significant effects on pupation, adult eclosion, and oviposition. Histopathological and ultrastructural analysis indicated that indoxacarb could severely damage the structure of the midgut epithelial cells, and lead to physiological impairment of the midgut. A total of 3883 differentially expressed genes (DEGs) were identified by midgut transcriptome sequencing and functionally annotated using GO and KEGG. Furthermore, the transcription level and enzyme activity of the detoxification related genes were determined, and our results suggested that esterases (ESTs) might play a major role in metabolism of indoxacarb in the midgut of B. mori. Future studies to examine the detoxification or biotransformation function of candidate genes will greatly enhance our understanding of indoxacarb metabolism in B. mori. The results of this study provide a theoretical basis for elucidating the mechanism of toxic effects of indoxacarb on silkworm by interfering with the normal physiological functions of the midgut.

Effects of Population Density on Survival, Development Time, Fecundity and Hatchability of <i>Samia cynthia ricini</i> Boisduval

Samia cynthia ricini Boisduval Lepidoptera:Saturniidae is a lepidopteran insect that has a gregarious behaviour during their larval stage. This research aimed to determine the minimum population limit of larvae that can support the survival of S. c. ricini by observing the development time, fecundity, and hatchability of eggs produced by adult moths under different larval densities rearing conditions. The research was conducted by observing the lifecycle and development of S. c. ricini at different population densities. The results showed that density had effect on the development time of S. c. ricini egg only. Population density also affects the survival and adult fecundity of S. c. ricini. A density of 30 is the minimum population required to support the success of S. c. ricini’slife. Samia cynthia ricini reared at this density had the highest survival rate, faster egg development time, heavier cocoon shell weight and highest fecundity.

Effects of artificial diet rearing during all instars on silk secretion and gene transcription in Bombyx mori (Lepidoptera: Bombycidae).

Silkworms (Bombyx mori) reared on artificial diets during all instars have the advantages of simplicity and efficiency, year-round production, and reduced risk of poisoning. However, low silk yield remains a challenge, limiting its industrial application. To address this issue, the spinning behavior, nutrient absorption, and transcriptomics of silkworms were investigated. Compared with silkworms reared on mulberry leaves during all instars, those fed with artificial diets showed significantly lower cocoon weight, cocoon shell weight, cocoon shell rate, and silk gland tissue somatic index at the end of the fifth instar (P < 0.01). The spinning duration and crawling distance of silkworms reared on artificial diets were also significantly lower than those reared on mulberry leaves (P < 0.01). Regarding nutrient absorption, the dietary efficiency indexes of silkworms fed with artificial diets were significantly lower than those fed with mulberry leaves, except for the efficiency conversion of digesta to cocoon (P < 0.01). Further RNA-Seq analysis revealed 386 differentially transcribed genes between the 2 groups, with 242 upregulated and 144 downregulated genes. GO enrichment analysis showed that differential transcriptional genes were mainly enriched in organic acid metabolism, oxidation-reduction, and drug catabolism. KEGG enrichment analysis showed that differential transcriptional genes were mainly enriched in genetic information processing and metabolism pathways. Our findings provide new insights into the silk secretion and can serve as a reference for future research and application of silkworms fed with artificial diets.

Creation of heat-resistant, high-product breeds and hybrids of mulberry silkworm (Bombyx mori l.)

In the current era of highly developed science, technology and technology, the demand for natural fabrics is increasing year by year in the world market, and the world silk industry and science are led to the cultivation of mulberry varieties with high nutritional value and the creation of breeds and hybrids suitable for different seasons of the changing external environment. In recent years, in the Republic of Uzbekistan, the practice of rearing mulberry silkworms several times a year has been used. However, there are no breeds and hybrids suitable for the hot summer conditions of our country, based on this, scientific research has been started in the direction of creating heat-resistant breeds at the Silk Research Institute. In this article, the results of the breeding of 6 breeds and 4 different industrial hybrids of mulberry silkworm under hot conditions are described. Based on preliminary data, Line 1 and Line 2 systems were found to have high embryonic and post-embryonic viability under hot summer conditions. However, the average cocoon weight of these systems was 1.68-1.73 g, cocoon shell weight was 339 mg, and cocoon silkiness was 19.6-20.2%. Based on the obtained results, it was concluded that Line 1 and Line 2 systems can be used as initial selection material for creating heat resistant breeds.

EFFECT OF THRIPS (PSUDODENDROTHRIPS MORI NIWA) INFESTED MULBERRY LEAVES ON BIOCHEMICAL AND ECONOMIC PARAMETERS OF SILKWORM, Bombyx mori L.

Mulberry, (Morus alba L.) leaves are the predominant food source for silkworm, Bombyx mori L. that has been attacked by number of insect pests and pathogens. Among the sucking pests, thrips, (Pseudodendrothrips mori Niva) is a dominant pest causing enormous damages to mulberry leaves. Rearing of silkworm with thrips infected mulberry leaves affects growth, development and causes to reduce silk production. The present study deals with silkworm larvae fed with thrips infested mulberry leaves on biochemical and economic parameters. The biochemical parameters such as protein, lipid, carbohydrate and glycogen content, were studied in tissues of larvae like haemolymph, silkgland and fatbodies. The result showed that there was decreased in protein, lipid, carbohydrate, glycogen contents, when the larvae fed with thrips infested mulberry leaves than control. Maximum decrease (-53.80%) was noticed in the lipid content. There was also decreased in the economic characters such as cocoon weight (-20.26%), shell weight (-43.75%), shell ratio (-7.48%), filament length (- 30.19%), reliability (-29.28%) and denier (-25.22%)due to feeding of thrips infested mulberry leaves when compared to control.

PHOTOSENSITIVE EFFECT OF THE BIOCHEMICAL AND ECONOMIC TRAITS OF Bombyx mori L.

The silkworm is by nature very delicate and sensitive to environmental conditions. The ecological factors, chiefly temperature, humidity and light during rearing show significant effect on growth larvae and finally cocoon crop quality. Silkworms are photosensitive and they have a tendency to crawl towards dim light. They do not like either strong light or complete darkness. In this way, based on various exposures of light on the effect of biochemical content and economic traits of silkworm were recorded. Biochemical content such as protein is highly essential for insects. The intracellular transport of the silk protein is dependent on hydrophobicity or hydrophilicity of the amino acid residues of the heavy and light chain of the silk protein and the haemolymph is the only extracellular fluid of insects with diverse functions and serves as reservoir for the products required for every physiological activity of the insect body, thus changes in the composition of haemolymph reflect the physiological and biochemical transformations taking place in the insect tissue. In this way of study, effect of light on biochemical content such as protein and carbohydrate of haemolyph and silk gland are significantly increased. The protein content was high in the haemolymph (17.48%) when the larvae exposed to 5 watt light and silk gland (66.67%) in 3 watt exposure group but fat body (44.33 %) when the larvae exposed to 8 watt. The carbohydrate content of haemolymph (35.54 %), silk gland (12.85%) and fat body (57.26 %) were significantly increased in 3 watt exposure group. In this findings, biochemical content had direct relation to economic traits of B. mori. The cocoon characters such as cocoon weight (28.42 per cent), pupal weight (20.9 per cent), shell weight (71 per cent) and shell ratio (33.48 per cent) were significantly increased in the 3 watt exposed group.

Effect of Mulberry Irrigated with Treated Sewage Water on Silkworms and Cocoon Production

Aim: The experiment was aimed at evaluating the effect of mulberry irrigated with treated sewage water on silkworms and cocoon production.&#x0D; Study Design: The experiment was laid out in a Randomized Complete Block Design (RCBD) with six treatments and four replications.&#x0D; Place and Duration of Study: The study was conducted during Rabi 2019 in pre-established irrigated V-1 mulberry garden at Department of Sericulture, University of Agricultural Sciences, Gandhi Krishi Vigyana Kendra, Bengaluru, Karnataka, India.&#x0D; Methodology: A field experiment was conducted in a V1 mulberry garden established under paired row system to study the influence of raw and treated sewage water irrigation on growth of mulberry and subsequent effect on silkworm (PM × CSR2) growth and cocoon parameters. The raw and treated sewage water was collected from GKVK sewage treatment plant and irrigated to mulberry garden. Silkworms fed with mulberry leaves raised on recommended dose of NPK kg/ha/year + FYM along with raw and treated sewage water irrigation showed positive influence on late age silkworms.&#x0D; Results: Observations recorded on silkworm growth and cocoon parameters revealed that significant higher fifth instar larval weight (32.02 g/10 larvae), ERR (99.0 %), single cocoon weight (1.706 g), pupal weight (1.385 g), shell weight (0.321 g), shell ratio (18.65%) and shorter fifth instar larval duration (181.91 hrs). Similarly, reeling parameters of cocoons showed significantly longer filament length (853.00 m) and higher filament weight (0.28 g) in silkworms fed with mulberry leaves from the plots irrigated with raw sewage water.

Seasonal Rearing Performance of Multivoltine Pure Mysore Silkworm in Southern dry Zone of Karnataka, India

The differences in the seasons and environmental components considerably affect the quality of the multivoltine silk worm seed crop such as cocoon weight, shell weight, and cocoon shell ratio. Frequent fluctuations in the environmental conditions day to day and season to season point up the importance of management of temperature and relative humidity for sustainable seed cocoon production in the basic seed farms. Hence to know the role of seasonal temperature and humidity on growth and development of Multivoltine silkworm, present study conducted at P2 Basic Seed Farm Nagenahalli, Central Silk Board, Karnataka to assess the seasonal performance of the multivoltine silkworm using various parameters. In the study all the data were recoreded were subjected to the correlation and the correlation results revealed significantly higher hatching per cent yield (number and weight)/ 100 dfls (Kg),single cocoon weight(gm) and single cell weight (gm) were 95.67, 43414.45 ( by number) and 57.70 kg (by weight), 1.233 and 0.180, respectively) during the winter season, whereas significantly higher weight of 10 matured larvae (28.01g) and shell weight (0.180) were recorded during rainy season. Further, significantly lower fecundity (480), hatching% (94.98), larval duration (28 days), weight of 10 matured larvae (25.80g), cocoon yield/100dfl (43.29 kg), single cocoon weight (1.146g), single cell weight (0.169g), pupation (95.22%) and cocoon leaf ratio (21.95) were recorded during summer.among the seasons. In all, winter season was more ideal for the rearing of multivoltine silkworm in the southern dry zone seed area of Karnataka with superior cocoon and egg characters due to lower temperature and humidity fluctuations.

Growth and Productivity of Silkworm Bombyx mori L. (Lepidoptera: Bombicidae) Given Mulberry (Morus sp.) It Contains Vitamin B1

The effect of mulberry leaves that contain vitamin B1on the growth and productivity of silkworms (Bombyx mori L.) was studied. This research used Completely Randomized Design (CRD) with the treatments were 10 silkworm feed with an untreated control leaves and an addition 0.1, 0.2, 0.3 and 0.4 mg/100ml of vitamin B1. Every treatment consisted of 3 replications. The results showed that an addition of vitamin B1 inhibited the growth, morphological structure of instars III, and IV such as head length, head diameter, body length, and body diameter, the weight of instars III, V, and the percentage of cocoon shell. Vitamin B1 has no effect on the morphological structures of instars V, the weight of instars IV, the pupae weight, the fiber length, the fiber percentage, the cocoon weight, and the cocoon shell weight. However, the frontal and posterior glands were decreased at the concentration 0.4 mg/100ml

Evaluation of Castor (Ricinus communis L.) Genotypes and Their Feeding Values on Rearing Performance of Eri Silkworm (Samia cynthia ricini Boisduval) (Lepidoptera: Saturniidae) in Southwest Ethiopia

The quality of feed plays an important role in the growth and development of silkworms and eventually in the economic traits of cocoons. This study was conducted to evaluate ten castors (Ricinus communis L.) genotypes and their feeding values on the rearing performance of Eri Silkworm (Samia cynthia ricini Boisduval) (Lepidoptera: Saturniidae) at Tepi, southwest Ethiopia. A total of ten castor genotypes were evaluated in a randomized complete block design (RCBD), and the suitability of castor genotypes as feed for a mixed strain of Eri-silkworm was also evaluated in a completely randomized design (CRD) under laboratory conditions. A hundred worms were used in each replication. Castor genotypes showed significant differences in fresh leaf yield. Among the castor genotypes tested, genotype 219645 recorded 439 g of ten fresh leaf yields. Results of Eri-silkworm rearing performance depict that a shorter larval period (22 days), a higher effective rate of rearing (94.54%), and a shorter life cycle (58 days) were observed in Eri-silkworm fed on leaves of the 200390 genotype, while a higher larval weight (6.16 g) was recorded in the Abaro genotype. However, higher cocoon weight (3.26 g), pupal weight (2.46 g), shell weight (0.45 g), and silk ratio (13.80%) were found in Eri-silkworms fed on leaves of genotype 219645. Hence, based on silkworm rearing performance, genotype 219645 showed relatively superior results and is recommended for future development work. Further studies should continue giving more emphasis to the multilocation study of genotype 219645 to understand its performance in the diverse growing environment.

Multi-tissue metabolomic profiling reveals potential mechanisms of cocoon yield in silkworms (Bombyx mori) fed formula feed versus mulberry leaves.

Use of formula feed (FF) for silkworms for all instars, has promoted transformation and progress in traditional sericulture. However, the cocoon yield of FF silkworms has failed to reach that of silkworms fed mulberry leaves (ML). The biological mechanisms underlying this phenomenon have not been well described. This study aimed to identify metabolic mechanisms and potential biomarkers relating to the poor cocoon yield of FF silkworms. In this study, silkworms received treatments of either ML (ML group) or FF (FF group) for all instars. At the 3rd day of the 5th instar, the midgut (MG), hemolymph (HL) and posterior silk gland (PSG) were collected for the metabolome profiles detection. The remaining silkworms were fed ML or FF until cocooning for investigation. The whole cocoon yield (WCY) was significantly higher in the FF group than the ML group (p < 0.05), whereas the cocoon shell weight (CSW) and cocoon shell rate (CSR) were significantly lower in the FF group (p < 0.05). A total of 845, 867 and 831 metabolites were qualified and quantified in the MG, HL and PSG of the FF silkworms, respectively. Correspondingly, 789, 833 and 730 metabolites were quantified in above three tissues of the ML group. Further, 230, 249 and 304 significantly different metabolites (SDMs) were identified in the MG, HL and PSG between the FF and ML group, respectively. Eleven metabolic pathways enriched by the SDMs were mutual among the three tissues. Among them, cysteine and methionine metabolism, arginine biosynthesis, and arginine and proline metabolism were the top three pathways with the highest impact value in the PSG. Six biomarkers were obtained through biomarker analysis and Pearson correlation calculation. Among them, homocitrulline, glycitein, valyl-threonine, propyl gallate and 3-amino-2,3-dihydrobenzoic acid were positively correlated with WCY, but negatively correlated with CSW and CSR (p < 0.05). An opposite correlation pattern was observed between 3-dimethylallyl-4-hydroxyphenylpyruvate and the three cocoon performance traits. Overall, three key metabolic pathways and six biomarkers associated with cocoon yield were interpreted, and should provide directions for formula feed optimization in factory-raised silkworms.

Hydrogen sulphide treatment improves the inhibition byvps4 gene knockdown in silkworm (Bombyx mori)

Bombyx mori is considered an alternative source of protein food due to its rich nutritional value. There has been a new upsurge of interest in the utilisation of insects as food during the last few years. Vacuolar protein sorting 4 (vps4) is known for its multifaceted role in biological processes such as lysosomal degradation, intracellular protein transport, and vesicle formation. It is known that H2S can promote the growth and development of silkworms. Here, we used body cavity injection of siRNA to interfere withvps4 genes in H2S-treated silkworms. The interference via injection ofvps4 siRNA significantly decreased the body weight, cocoon weight, cocoon shell weight, egg laying and production in silkworms, without much effect on the cocoon shell ratio. H2S treatment could significantly improve the inhibition of body weight, cocoon weight, cocoon shell weight and cocoon shell ratio by knocking down thevps4 gene in silkworms, without significant effects on egg laying and production. The interference of siRNA significantly decreased the expression of targetedvps4 gene and was concentrated in 24 h followed by gradual recovery. Three interference fragments also showed different interference effects, and siRNA ofvps4-2 exerted the highest interference effect to the target gene expression. Fat body had the highest mRNA expression ofvps4 gene, and the best interference effect was observed after siRNA injection. Our results suggest that there are significant phenotypic and genotypic effects ofvps4 gene knockdown in silkworms, which is of great significance for future research on silkworms.

Impact of certain plant extracts on different larval and cocoon characters of silkworm bombyx mori linn

Silkworm Bombyx mori L. feeds on the leaves of mulberry tree which is only the host plant for silkworm. The improvement of larval feeding is enrichment of mulberry leaves with supplementary nutrients. The present study has been aimed at investigating various economic traits of the silkworm cocoon, when fed on mulberry leaves fortified with the effect of leaf extract of Ocimum sanctum (“Queen of Herb” Tulsi), Azadirachta indica (Neem or Nim tree) and Vitex negunda (Nirgundi or Sindvar) medicinal leaf extract at different concentration viz., 0.1%, 1.0%, 2.5% and 5.0% on silkworm was studied. There was significant improvement in silk ratio % and filament length at 2.5% concentration of different medicinal plant leaf extract but the cocoon and shell weight decreased in comparison to control. In was significantly increased the larvae, economic traits like cocoon weight, shell weight, pupa weight, shell percentage, filament length, fibroin, sericin and denier of silk filament. Extract has growth promoting effect on silkworm, which helps to enhance the commercial qualities of silk and can be used in sericulture for yield improvement.