Cocoon Shell Ratio Research Articles

The expression of ecdysteroid UDP-glucosyltransferase enhances cocoon shell ratio by reducing ecdysteroid titre in last-instar larvae of silkworm, Bombyx mori

Ecdysteroid UDP glucosyltransferase (EGT) is a baculovirus-encoded protein which can hinder the normal molting of insects by inactivating 20-hydroxyecdysone (20E). Here we expressed EGT in the last-instar silkworm larvae using the GAL4/ UAS system. Compared with the control, for the EGT overexpressed silkworm, the hemolymph 20E content was significantly decreased, the feeding and spinning periods of the last-instar silkworm larvae were extended, the cocoon shell ratio was significantly increased, and the transformation from silkworm larvae to pupa was blocked. Increasing EGT expression resulted in the decrease of 20E content in the hemolymph of silkworm larvae, treating the EGT overexpressed male silkworm with 20E decreased the larval weight and cocoon shell ratio, confirming that the increase in the availability of nutrients to the cocoon and an increase in the cocoon shell weight in the hybrid transgenic silkworms is because of the EGT-induced reduction in active 20E content. Furthermore, though the sericin and flavonoid contents were increased in the cocoon of the EGT overexpressing silkworm, the production of silk fibroin didn’t change.

Preventive effects of N-acetyl-l-cysteine against imidacloprid intoxication on Bombyx mori larvae.

Imidacloprid, a widely used neonicotinoid insecticide, is toxic to silkworm (Bombyx mori). To explore whether N-acetyl-l-cysteine (NAC) has an effect on preventing silkworm (B. mori) from toxification caused by imidacloprid, we fed the fifth-instar larvae with mulberry leaves dipped in 200mg/L NAC solution before exposing in imidacloprid, and investigated the silkworm growth, survival rate, feed efficiency, cocoon quality, and the activities of antioxidant enzymes in midgut. The results showed that addition of NAC could significantly increase body weight, survival rate, and feed efficiency of imidacloprid poisoned silkworm larvae (P<0.05), as well as cocoon mass, cocoon shell mass, and the ratio of cocoon shell (P<0.05). Furthermore, it could significantly promote the activities of the antioxidant enzymes including superoxide dismutase, catalase, and glutathione peroxide in the midgut of fifth-instar larvae under imidacloprid exposure at the late stage of treatment. In addition, it also could downregulate the malondialdehyde content. The results of our findings proved that the added NAC may have some beneficial effects on protection or restoration of antioxidant balance in imidacloprid exposed larvae.

EFFECT OF SOME LACTIC ACID BACTERIA ON SOME PARAMETERS OF THE SILKWORM , BOMBYX MORI L.

Effect of lactic acid bacteria (Lactobacillus rhamnoses,Lactobacillus paracasei and Lactobacillus acidophilus) as food additiveson some parameters of Bombyx mori L. was carried out . Experimentalproduct of Lactic acid bacteria was dissolved in distilled water to prepareone concentration (5mg/ml.) from bacteria in addition to yoghurt andmilk. The obtained results showed that, Lactobacillus acidophilusoccupied the first category for improving the most studied parameters ofB. mori when comparing to control. Where the 5th instar larval weightswere 2.159g compared to 2.002 g in control , effective rate of rearingrecorded 82.00% compared to 78.00% in control and total haemolymphprotein recorded 64.00mg/ml. compared to 60.99mg/ml. in control.Cocoon indices registered 1.101 g, 0.209 g and 18.98% for cocoonweight, cocoon shell weight and cocoon shell ratio comparing to 1.005 g,0.177 g and 17.61% for the control respectively.

EFFECT OF HIBISCUS SABDARIFFA ON REARING PERFORMANCE OF SILKWORM , BOMBYX MORI L.

Effect of Hibiscus sabdariffa as food additives on rearingperformance of silkworm, Bombyx mori L. was studied. Dried flowersof H. sabdariffa were crushed and soaked in distilled water to preparedifferent concentrations (20, 40, 60, 80 and 100 mg/ml.). The obtainedresults showed that, the concentration 60 mg/ml. of H. sabdariffaoccupied the first category. Where effective rate of rearing recorded84.00% compared to 76.00% in control, total haemolymph proteinmg/ml. recorded 70.54mg/ml. compared to 64.52mg/ml. in control andnumber of eggs / female recorded 284.00 compared to 262.00 incontrol. Cocoon indices were 1.165 g, 0.229 g and 19.66% for cocoon,cocoon shell weights and cocoon shell ratio comparing to 1.067 g,0.169 g and 17.71% for the control, respectively.

English

This study was conducted in the Sericulture Research Laboratory of Melkassa Research Center. Four bivoltine and one polyvoltine silkworm were involved in the crossing experiment and laid out in complete randomized design with four replications. Data was collected on fecundity, pupation rate (%), number of diseased larvae, survival rate (%), cocoon weight (g), cocoon shell weight (g), cocoon shell ratio (%) and filament length (m). Uniform and non-significant numbers of eggs produced by adults and cocooning percentages were recorded for both hybrid and parents in all the generations. Average larval weight significantly (P&lt;0.01) reduced for F1, F2, F3 and F4 generations hybrids than parents but increased in F5, F6 and F7 generations hybrids. Silk ratios and survival rates significantly (P&lt;0.01) increased for all hybrids than parent bivoltine in all hybrid generations. Larval period significantly (P&lt;0.01) reduced in F5, F6 and F7 generations hybrid than parent bivoltines. Filament length significantly (P&lt;0.01) reduced in F1, F2, F3 and F4 generations hybrids than parent bivoltine but significantly increased in F5, F6 and F7 generations hybrids than parent bivoltines. It can be concluded that instead of using parent polyvoltine and bivoltine mulberry silkworms separately for silk production, the farmers can use F5 and above generations hybrids of multivoltine x bivoltine for relatively higher disease resistance and maximum silk productions. &nbsp; Key words: Polyvoltine silkworm, bivoltine silkworm, hybrids.

Analysis of bulked segregants to identify molecular markers linked with cocoon weight and cocoon shell weight in the silkworm Bombyx mori L

Two silkworm strains viz, B20 Λ (high cocoon shell ratio) and C. Nichi (low cocoon shell ratio) were sib mated for 10 generations to determine the homozygosis. Both bulked segregant analysis (BSA) and near isogenic lines (NIL) studies were done to identify the RFLP markers closely linked to cocoon shell parameters. Three hundred and fifty-two random clones were identified as the low copy number sequence and used for identification of Restriction Fragment Length Polymorphic (RFLP) marker linked to cocoon weight and cocoon shell character. In the bulk segregant analysis>DNA from the parents (B20 Λ C. Nichi), F1 and F2 progeny of high shell ratio (HSR) and low shell ratio (LSR) were screened for hybridization with the random clones. Polymorphic banding pattern achieved through southern hybridization with different probes indicated the probable correlation of polymorphism with high and low cocoon shell character which are possible landmarks in identifying the putative marker(s) for the cocoon shell character. Out of the 100 probes tried with parents, F1, F2 and their bulks, 10 probes were found to be closely linked to cocoon shell characters.

Stifling Cocoons Silkworms Using Butane Gas Mechanical Dryer

Silk is an important economic fiber, its producing not related only to the method of producing but also preparing processes after productions such as stifling cocoons silkworms. The mechanical performance of dryer locally fabricated using butane gas was tested for stifling cocoons silkworms. The study parameters were the heating air temperature 60, 65, 70 and 75 °C; air velocity through the cocoons 1.5, 2.0 and 2.5 m/sec. and treatment times of 20, 25, 30 and 35 min. These parameters were examined and evaluated on cocoons moisture contents;; cocoon weight; shell weight; shell ratio; stifling pupae's and determination of some quality parameters of silk filament like (length of silk filament; reel-ability of cocoons; tenacity and elongation of silk filaments; and cocoon drying). The obtaned results indicated that, the minimum value of cocoons moisture content was 30, maximum value of cocoons weight, cocoon shell weight and cocoon shell ratio were 2.42g, 1.55g and 68.8% respectively. Stifling pupae's was 100% at decreasing cocoons moisture content to a level less than 45%. Also for quality evaluation tests of silk filament, the maximum value of length of silk filament; reel-ability of cocoons; tenacity and elongation of silk filaments; were 955m, 78.9%, 4.89 g/denier, and 15.78%, respectively.

EFFECT OF ZINGIBER OFFICINALE ON MORTALITY PERCENTAGE AND COCOON SHELL RATIO OF THE SILKWORM, BOMBYX MORI L.

The effect of Zingiber officinale was studied on mortalitypercentages and cocoon shell ratio of silkworm, Bombyx mori duringspring season of 2015 at Plant Protec. Dept. Fac. of Agric., El FayoumUniv. The powder of Z. officinale was dissolved in distilled water toprepare different concentrations (10, 20, 30, 40 and 50 mg/ml.). In thepresent study, results showed that, the concentration 20 mg/ml. of Z.officinale occupied the first category to reduce 1st , 2nd and 3rd instarsmortality percentages. While 40 mg/ml. of Z. officinale occupied thefirst category for reducing 4th & 5th instars mortality percentages andimproving cocoon shell ratio.

Effect of biofertilizers on mulberry silkworm

Nutrition of mulberry has a vital role in sericulture as it improves the growth, development, health, feed consumption and conversion, thereby improving the commercial traits of mulberry silkworm Bombyx mori L., as it influences its growth and cocoon production. Hence, the effect of three biofertilizers viz., vermicompost, Phosphobacteria, Azotobacter and their mixture was studied on weight of larvae, disease incidence, coccon weight, single shell weight, coccon shell ratio, effective rate of rearing, cocoon yield, cocoon filament length and weight, and denier of silkworm. The results revealed that significantly high weight of ten matured larvae (35.26 g), single cocoon weight (1.72 g), single shell weight (0.34 g), cocoon shell ratio (19.76%), cocoon yield/10, 000 larvae brushed (17.00 kg), cocoon filament length (928 m), cocoon filament weight (0.275 g), denier (2.66), lower disease incidence (1.33%) and highest effective rate of rearing (98.66%) were obtained in larvae fed with leaves of variety V-1 applied with vermicompost, Azotobacter and Phosphobacteria in equal proportions.

TEST OF Morus khunpai AND M.indica HYBRID TOWARDS SILKWORM FEED

The sustainability of silkworm rearing depends on the availability of qualified mulberry plants. The research is aimed to observe the compatibility of hybrid Morus khunpai and M.indica (KI hybrid) for silkworm's feeding. It is related to the cocoon and filament quality. KI hybrids are a result of pollination control male parent M.khunpai and female parent M.indica S-54. The research applied a Randomized Complete Design by measuring variables, i.e.: the percentage of cocoon, number of normal cocoon, cocoon weight, cocoon shell weight, cocoon shell ratio and filament length. The result showed that cocoon and filament quality of silkworm fed by mulberry hybrid M.khunpai and M.indica (KI) have shown non-significant differences compared with silkworm fed by mulberry parents ( M.khunpai and M.indica and the control ( M.nigra ). This situation showed that there has not been recognised yet as the compatibility of hybrid M.khunpai and M.indica (KI) hybrid for silkworm feeding.

Effects of TiO2 NPs on Silkworm Growth and Feed Efficiency

Silkworm (Bombyx mori) (B. mori) is an economically important insect and a model species for Lepidoptera. It has been reported that feeding of low concentrations of titanium dioxide nanoparticles (TiO2 NPs) can improve feed efficiency and increase cocoon mass, cocoon shell mass, and the ratio of cocoonshell. However, high concentrations of TiO2 NPs are toxic. In this study, we fed B. mori with different concentrations of TiO2 NPs (5, 10, 20, 40, 80, and 160mg/L) and investigated B. mori growth, feed efficiency, and cocoon quality. We found that low concentrations of TiO2 NPs (5 and 10mg/L) were more effective for weight gains, with significant weight gain being obtained at 72h (P<0.05). TiO2 NPs at 20mg/L or higher had certain inhibitory effects, with significant inhibition to B. mori growth being observed at 48h. The feed efficiency was significantly improved at low concentrations of 5 and 10mg/L for 14.6 and 13.1%, respectively (P<0.05). All B. mori fed with TiO2 NPs showed increased cocoon mass and cocoon shell mass; at 5 and 10mg/L TiO2 NPs, cocoon mass was significantly increased by 8.29 and 9.39%, respectively (P<0.05). We also found that low concentrations (5 and 10mg/L) of TiO2 NPs promoted B. mori growth and development, improved feed efficiency, and increased cocoon production, while high concentrations (20mg/L or higher) of TiO2 NPs showed inhibitory effect to the B. mori. Consecutive feeding of high concentrations of TiO2 NPs led to some degrees of adaptability. This study provides a reference for the research on TiO2 NPs toxicity and the basis for the development of TiO2 NPs as a feed additive for B. mori.

UTILIZATION OF THE TOPICAL APPLICATION OF LIMONENE TO THE FIFTH INSTAR LARVAE OF THE SILKWORM,BOMBYX MORI (L.) (RACE: PM X CSR2) FOR THE PARAMETERS OF LARVAE, COCOON AND SILK FILAMENT

The attempt is concerned with topical application of the limonene on the fifth instar larvae of multivoltine silkworm, Bombyx mori (L.). The ten microliters of one milligram per liter strength acetone solution of limonene was topically applied to the individual fifth instar larvae of multi voltine cross breed race of silkworm, Bombyx mori (L.) (PM x CSR2) variously at 48, 54, 60 and 66 hours after the fourth moult. Topical application of acetone solution of limonene was found variously reflected into prolongation of larval age (23.129-38.775%); improvement in the tissue somatic index (TSI) of silk glands (3.041-7.761); cocoon shell ratio (2.828-4.497); Tex of silk filament (0.038-0.107) and denier scale of silk filament (0.343- 0.962). Topical application of acetone solution of limonene, thus chiefly lengthen the larval age in silkworm, Bombyx mori (L.). Time required for eating and amount of mulberry leaves eaten had both been increased and they were practically reflected into the improvement in the quality of cocoon and the silk filament. The terpenoid nature of limonene and delay in the spinning among the larvae, recipient of this limonene in the attempt indicate the possibility of it’s insect juvenoid activity in silkworm, Bombyx mori (L.). Efficient utilization of limonene, the terpene compound through acetone solvent for topical application to the fifth instared larvae of silkworm, Bombyx mori (L.) may open a biotechnological avenue in the sericulture industries.

UTILIZATION OF THE TOPICAL APPLICATION OF LIMONENE TO THE FIFTH INSTAR LARVAE OF THE SILKWORM,BOMBYX MORI (L.) (RACE: PM X CSR2) FOR THE PARAMETERS OF LARVAE, COCOON AND SILK FILAMENT

The attempt is concerned with topical application of the limonene on the fifth instar larvae of multivoltine silkworm, Bombyx mori (L.). The ten microliters of one milligram per liter strength acetone solution of limonene was topically applied to the individual fifth instar larvae of multi voltine cross breed race of silkworm, Bombyx mori (L.) (PM x CSR2) variously at 48, 54, 60 and 66 hours after the fourth moult. Topical application of acetone solution of limonene was found variously reflected into prolongation of larval age (23.129-38.775%); improvement in the tissue somatic index (TSI) of silk glands (3.041-7.761); cocoon shell ratio (2.828-4.497); Tex of silk filament (0.038-0.107) and denier scale of silk filament (0.343- 0.962). Topical application of acetone solution of limonene, thus chiefly lengthen the larval age in silkworm, Bombyx mori (L.). Time required for eating and amount of mulberry leaves eaten had both been increased and they were practically reflected into the improvement in the quality of cocoon and the silk filament. The terpenoid nature of limonene and delay in the spinning among the larvae, recipient of this limonene in the attempt indicate the possibility of it’s insect juvenoid activity in silkworm, Bombyx mori (L.). Efficient utilization of limonene, the terpene compound through acetone solvent for topical application to the fifth instared larvae of silkworm, Bombyx mori (L.) may open a biotechnological avenue in the sericulture industries.

SPINNING STIMULATION OF SILKWORM , BOMBYX MORI L. BY PIMPINELLA ANISUM

The present work has been carried out at Plant Protec. Dept. Fac.of Agric., El Fayoum Univ. during spring season of 2014 to study theeffect of Pimpinella anisum as food additives on spinning of silkworm,Bombyx mori L. Dried seeds of P. anisum were crushed and dissolvedin distilled water to prepare different concentrations (5, 10, 15, 20 and 25mg/ml.). In the present study, results showed that, the concentration 10mg/ml. of P. anisum occupied the first category to improve the moststudied parameters of B. mori L. when comparing to control. Where 5thinstar mortality percentage recorded 5% compared to 10% in control. 5thinstar larval duration were 10.40 days compared to 10.44 days in control.Cocooning percentage were 96.82% compared to 92.22% in control andcocoon indices were 1.192 g, 0.253 g and 21.23% for cocoon, cocoonshell weights and cocoon shell ratio comparing to 1.088 g, 0.194 g and17.90% for the control respectively. Total haemolymph proteinregistered 75.90 mg/ml compared to 67.52 mg/ml in control. Proteaseenzyme were 64.33 µg alanine/min/ml compared to 57.21 µgalanine/min/ml. in control and silk productivity were 2.434 cg/daycompared to 1.866 cg/day in control.

ANTIFUNGAL EFFECT OF OCIMUM SANCTUM L. AGAINST WHITE MUSCARDINE DISEASE OF SILKWORM, BOMBYX MORI L.

ABSTRACT The “Queen of Herb”, Tulsi is an important herb with greater medicinal value used in Ayurveda, Siddha, Unani, Greek and Roman medicine for prevention and cure of many illness. Fifth instar larvae inoculated with Beauveria bassiana were fed with mulberry leaves enriched with different concentrations (1 %, 2%, 3% and 4% ) of ethanolic extract of Ocimum sanctum leaves and its effect on cocoon weight, pupal weight, shell weight, shell ratio and silk characteristics were studied. Among the different concentrations, 3%ethanolic extract of O. sanctum has been found to be most effective against B. bassiana infection as compared to others. Inoculated control group recorded very low economic values as compared to normal control and other treated groups.

Effects of feeding silkworm with nanoparticulate anatase TiO2 (TiO2 NPs) on its feed efficiency.

This study aimed to investigate the effects of titanium dioxide nanoparticles (TiO2 NPs) on feed efficiency of silkworm (Bombyx mori) (B. mori). The results showed that the amount of ingested food was increased by 3.31%, the percentage of ingested food was increased by 16.36%, the instar was prolonged by 6.77 h, the body mass of mature silkworm was increased by 11.41%, the cocoon mass was increased by 5.47%, the cocoon shell mass was increased by 9.80%, and the ratio of cocoon shell was increased by 3.54%. Average cocoon filament length, reelability, and neatness were increased by 3.15, 17.57, and 1.72%, respectively, whereas the cocoon filament size was decreased by 0.19%. The gene expression profiles were also examined with digital gene expression (DGE). The results showed that among 4,011 genes detected, 127 genes were differentially expressed including 57 genes whose expression was upregulated and 70 genes whose expression was downregulated. The expression levels of five genes related to metabolism were verified with quantitative real-time PCR, and the results were consistent with the DGE data. The activities of three major digestive enzymes in the midgut were also assayed; the results showed that the activities of trehalase, protease, and lipase in TiO2 NP-fed group were increased by 42.55, 78.13, and 33.33%, respectively. These results indicate that feeding B. mori with TiO2 NPs can stimulate the transcriptional level of genes related to digestion and absorption of nutrients in the midgut and increase the activities of trehalase, protease, and lipase and, thus, increase the feed efficiency of B. mori.

Structure and properties of silk from the African wild silkmoth Gonometa postica reared indoors.

African wild silkmoth, Gonometa postica Walker (Lepidoptera: Lasiocampidae), were reared indoors in order to examine the influence of rearing conditions on the structure and properties of silk cocoon shells and degummed fibers by using a scanning electron microscope, an Instron tensile tester, and a thermogravimetric analyzer. The cocoons reared indoors showed inferior quality in weight, length, width, and cocoon shell ratio compared to cocoons reared outdoors. There were no differences in cocoon shell and fiber surfaces and cross sectional structures. Cocoon shells were covered with calcium oxalate crystals with few visible fibers on their surface. Degummed fibers were smooth with minimum unfractured surfaces and globular to triangular cross sections. Indoor-reared cocoon shells had a significantly higher breaking strain, while the breaking stress was higher for cocoons reared outdoors. Fibers from indoor cocoons had a significantly higher breaking stress while outdoor fibers had higher breaking strain. Thermogravimetric analysis curves showed two main thermal reactions revealing the dehydration of water molecules and ir-reversible decomposition of the crystallites in both cocoons and fibers reared indoors and outdoors. Cocoon shells underwent additional peaks of decomposition with increased temperature. The total weight loss was higher for cocoon shells and degummed fibers from indoors. Rearing conditions (temperature and relative humidity), feeding method used, changes in total life span, days to molting, and spinning might have influenced the variation in the properties observed.The ecological and commercial significances of indoor rearing of G. postica are discussed.

Boil-off Loss Ratio of Cocoon Shell as a Selection Criterion in the Newly Developed Bivoltine Silkworm (Bombyx mori L.) Hybrids

Boil-off loss ratio is one of the most important economic traits to be considered during the course of silkworm breeding. The boil-off loss ratio varies among the breeds and seasons. The present study was undertaken with 5 oval and 5 peanut breeds and twenty five hybrids involving these parents to select the promising hybrids with desired boil-off loss ratio. Accordingly, studies were undertaken to estimate the heterosis and heterobeltiosis. It was observed that majority of the hybrids revealed negative heterosis for boil-off loss ratio which is desirable. Based on the heterosis and heterobeltiosis, among all the hybrids, the hybrid APBRO5 x APBRD5 exhibited highest negative heterosis for boil-off loss ratio and also exhibited highest EI value (64.5) for the quantitative and qualitative traits. Based on the hybrids performance, boil-off loss ratio, heterosis and heterobeltiosis and evaluation index, the hybrids viz. APBRO5 x APBRD5, APBRO1 x APBRD1 and APBRO3 x APBRD4 were identified for commercial exploitation. Abstract

Estimation of Hybrid Vigor of Some Egyptian Single Local Hybrids of Mulberry Silkworm, Bombyx mori L.

Fifteen races resulted from silkworm breeding programat Sericulture Research Department (SRD) were used for hybridization. Fourteen hybrids were obtained and coded as; Giza C, D, R, S, T, U, A, V, W, P, H, L and Qanater 1, 2. The traits of cocoon weight, cocoon shell weight, pupal weight, cocoon shell ratio, silk productivity, fifth instar duration, total larval duration, number of cocoon per liter and pupation ratio were evaluated. Data were analyzed by using three formulae of heterosis over better, mid and checkparent values. Hybrids of Giza V, C, N, Qanater 1 and2 are promising and could be used in commercial cocoon production. Generally, there are some new hybrids can be exploited in commercial scale. Also, the local races can be evolved using the hybridization, inbreeding and selection program.

Antibiotic (Gentamicin) Impact on Bacterial Flacherrie Disease of Silkworm, Bombyx mori L..

There are many factors that influence the success of silk production. Bacterial flacherrie considered the most important factor. Antibiotics showed promising results for controlling of silkworm diseases and to improve the production of silk and harvesting superior crop. The effect of antibiotic (Gentamicin) upon the infection with bacterial flacherrie was discussed. Gentamicin as a cheap antibiotic in Egypt can be used easily by trainees and farmers. It was found that Gentamicin significantly increases the effective rate of rearing (ERR %) and larval weight (97.333% and 2.631gm, respectively). Single female and male cocoon weights (1.400 gm and 1.068 gm, respectively) and male cocoon shell ratio (22.708%) were significantly increased under the effect of antibiotic treatment comparing with control. Polymorphism among the tested haemolymphal samples were investigated using SDS-PAGE electrophoresis. A variation was detected in the protein banding pattern with considerable polymorphism (88.2 %), with the appearance of 2 monomorphic bands, 12 polymorphic and 3 unique bands.