Silk Percentage Research Articles

Effects of different cocoon-stifling methods on the reeling and quality characteristics of raw silk

In this study, we evaluated the effects of five stifling methods on the reeling parameters and raw silk characteristics of double hybrid cocoons. The methods were open sun drying, sun drying under a black cloth, drying in the SKUAST-K-fabricated solar cocoon dryer, multifuel hot air drying, and hot air drying. Our findings showed that hot air drying produced the best results in terms of reeling parameters, i.e. average filament length (805.750 m), average non-breakable filament length (800.750 m), average denier (2.777), renditta (2.805), silk waste percentage (15.17), raw silk percentage (30.382), reelability percentage (80.982), and degumming loss percentage (16.285). The method also yielded superior results for raw silk characteristics, such as winding (0.000 breaks), evenness first (1.000 count), evenness second (0.000 count), neatness percentage (95.000), cleanness percentage (96.500), tenacity (4.032 g/denier), elongation percentage (23.000), and cohesion (68.250 strokes). The SKUAST-K-fabricated solar cocoon dryer produced the second-best results.

Silkworm (Bombyx mori L.) fed with mulberry (Morus alba L.) leaves and cow’s milk

Objective: To evaluate the effect of cow’s milk as a protein supplement to improve growth and expression of productive parameters in the silkworm (Bombyx mori L.). Design/Methodology/Approach: Four treatments with mulberry foliage supplemented with milk were used, plus a control (which was fed with fresh leaf). Feeding was determined for the last two larval instars, resulting in the following groups: Treatment 1: V instar-TD, Treatment 2: V instar-DI, Treatment 3: IV and V instar-TD, and Treatment 4: IV and V instar-DI. Results: Larvae fed with foliage supplemented with milk obtained an increase in growth rate and larval weight and formed their cocoons faster than the control. Additionally, there were differences in cocoon weight, silk percentage, and pupal weight, relevant traits for silk production. Study Limitations/Implications: Very few works have been published about silkworms fed with mulberry foliage supplemented with milk. Findings/Conclusions: Supplementation has a positive effect on growth and the evaluated traits, improving the yield of silk production.

Studies of the silkworm enzyme activity and their correlations with economic variables

The experiment was conducted to analyse the larval performance and economic traits of bivoltine silkworm breeds of silkworm (SK-1, SK-6, SK-22, SK-28, SK-33, CSR4, CSR2, NB4D2, DUN6 and APS4) during spring season. The haemolymph total protein, succinate and gultamate dehydrogenase activities were estimated and their correlation with economic traits were also worked out. The results of the study confirmed that among ten bivoltine silkworm breeds, highest haemolymph SDH activity of 3.47 µmoles/ml/mgprotein/min was recorded in the silkworm breed SK1 and least SDH activity of 1.58 µmoles/ml/mg protein/min was recorded in the breed APS4. The highest peak of succinate dehydrogenase activity of 2.65 µmoles/ml/mg protein/min was observed on 7th day of the 5th instar and lowest peak of succinate dehydrogenase activity of 2.39 µmoles/ml/mg protein/min was observed on 4th day of the 5th instar. GDH activity of 0.46 µmoles/ml/mg protein/min was recorded highest in the silkworm breed SK1 and lowest of 0.15 µmoles/ml/mg protein/min was recorded in silkworm breed APS4. The highest peak of haemolymph GDH of 0.36 µmoles/ml/mg protein/min was recorded on 7th day of 5th instar and lowest peak of 0.26 µmoles/ml/mg protein/min was recorded on 4th day of 5th instar. The correlational studies revealed that haemolymph total protein, SDH and GDH were found to be positively corelated with yield by weight and number (cocoon), weight of mature larvae, shell weight ,cocoon weight, shell ratio percent, silk productivity, rate of pupation, fecundity, raw silk percentage and length of filament. Thus, the study revealed that silkworm breeds like SK1, SK6, SK22 and SK28 as productive breeds and hence may be used for future breeding programmes for evolution of new robust silkworm breeds

Performance of some newly produced multivoltine strains of Bombyx mori (Linnaeus) for commercially vibrant qualitative and quantitative traits

In this study investigations were conducted with a clear cut intention of producing a best suited strain which suits exactly to the climatic, rearing and maximum productivity conditions of South Tamilnadu, India silkworm rearing areas. Using the parental stock breeds of CSR2 pure, CSR2 × CSR4, Tamilnadu local pure and CSR2 × TN, eight new strains were crossed and its quantitative and qualitative parameters of egg, larva, pupa, cocoon and silk were studied in this analysis. Concerning the qualitative and quantitative parameters of egg, the breeds of (CSR2 × TNL) ♀ x (CSR2 × TNL) ♂ and TNL ♀ x (CSR2 × TNL) ♂ were identified best for rearing similar to that of available commercial breed. Silk parameters such as colour, texture, preciseness, single filament length, silk percentage, and percentage of reelability were also observed. The maximum percentage of silk was recorded in (CSR2 × TNL) ♀ x (CSR 2 × TNL) ♂ and (CSR2 × TNL) ♂ x TNL ♀. Percentage of reelability was recorded and the highest was recorded in TNL ♀ x (CSR 2 × TNL) ♂. Maximum silk filament length (m) was measured in (CSR 2 × TNL) ♀ x (CSR 2 × TNL) ♂, and TNL ♀ x (CSR 2 × TNL) ♂ strains. The overall study clearly shows that, if proper selection of breeds were found and breed, new productive strains can be produced with an immense success and this also help the establishment of good quality silk in world silk market and will surely increase silk yield and productivity.

Vigor híbrido en cruzamientos de líneas endocriadas de gusanos de seda (Bombyx mori L)

Productive characteristics of hybrids, from the crossing of a FA-UBA line and other one of a European origin, have been assessed. Three quantitative variables have been measured: length and weight of the entire cocoon and of the cocoons without pupa. Weight and silk weight of 20000 cocoons and raw silk percentage were also determined. This data was analyzed through ANOVA and several comparisons were performed for each variable analyzed. For all the variables tested, highly significant differences were found between genotype media (breeds and hybrids). For the three features tested, the heterosis effect was very strong. For the cocoon length (mm) the differences were de following: 30.2 parental average vs. 36.05 the direct hybrid and 34.53 the reciprocal hybrid. For the entire cocoon weight (g): 1.17 parental average vs. 1.57 the direct hybrid and 1.54 the reciprocal hybrid. For the bark weight: 0.21 parental hybrid vs. 0.30 the direct hybrid and 0.29 the reciprocal hybrid. The raw silk percentage was between the species ranges (16 to 24%) but the hybrid average turned to be higher than the parents average. The hybrids silk production was 39% higher than the parents production media. In conclusion, the crossing of the two lines used showed strong heterosis effect for all the variables analyzed.

E-spun composite fibers of collagen and dragline silk protein: fiber mechanics, biocompatibility, and application in stem cell differentiation.

Biocomposite matrices with high mechanical strength, high stability, and the ability to direct matrix-specific stem cell differentiation are essential for the reconstruction of lesioned tissues in tissue engineering and cell therapeutics. Toward this end, we used the electrospinning technique to fabricate well-aligned composite fibers from collagen and spider dragline silk protein, obtained from the milk of transgenic goats, mimicking the native extracellular matrix (ECM) on a similar scale. Collagen and the dragline silk proteins were found to mix homogeneously at all ratios in the electrospun (E-spun) fibers. As a result, the ultimate tensile strength and elasticity of the fibers increased monotonically with silk percentage, whereas the stretchability was slightly reduced. Strikingly, we found that the incorporation of silk proteins to collagen dramatically increased the matrix stability against excessive fiber swelling and shape deformation in cell culture medium. When human decidua parietalis placental stem cells (hdpPSCs) were seeded on the collagen–silk matrices, the matrices were found to support cell proliferation at a similar rate as that of the pure collagen matrix, but they provided cell adhesion with reduced strengths and induced cell polarization at varied levels. Matrices containing 15 and 30 wt % silk in collagen (CS15, CS30) were found to induce a level of neural differentiation comparable to that of pure collagen. In particular, CS15 matrix induced the highest extent of cell polarization and promoted the development of extended 1D neural filaments strictly in-line with the aligned fibers. Taking the increased mechanical strength and fiber stability into consideration, CS15 and CS30 E-spun fibers offer better alternatives to pure collagen fibers as scaffolds that can be potentially utilized in neural tissue repair and the development of future nanobiodevices.

Cocoon Filament Quality of a Special Silkworm Variety, GoldenSilk

The effect of cultivation season on the cocoon filament quality of authorized silkworm variety, GoldenSilk was examined with cocoon filament character, reeling character, and fiber character during 3 years. In cocoon filament character, filament length of spring and autumn cocoon was 979 and 879 m, respectively. Cocoon filament weight of spring and autumn cocoon was 33.1 and 26.5 cg, which is lower than that of general bivoltine strain, BaeGokJam. Raw silk percentage of spring and autumn cocoon was 15.65 and 13.77%, respectively. In reeling character, reelability showed similar trend regardless of cultivation season and strain. However, the length and weight of non-broken filament of spring season were slightly higher than those of autumn cocoon. Cultivation season did not affect on the fiber characteristics such as clearness and neatness, lousiness, and degumming loss. In cocoon character, filament length, size, and weight, spring cocoon filament showed higher value than autumn cocoon, but lower than authorized general silkworm varieties. In reeling characteristics, non-broken length and weight showed the similar trends with the cocoon filament character. However, the reelability of GoldenSilk cocoon was not affected by cultivation season. The reelability of GoldenSilk cocoon was also similar with that of authorized general one. Fiber character including clearness and neatness, lousiness, and degumming loss was also similar regardless of the rearing season and different strain.

Impact of varietal feeding of eight Mulberry varieties on Bombyx mori L.

The eight improved mulberry varieties i.e. S146, K2, S1635, AR14, TR10, BR2, S1 & AR12 were introduced in mulberry garden of Department of Applied Animal Sciences and theses varieties were evaluated for nutritional potential by feeding experiments. Weighted quantities of leaves of each variety were fed to mulberry silkworms and data were collected and evaluted. The larvae feeding on BR2 leaves were observed the higher weight of mature larvae and showed improved economic traits i.e. cocoon weight, shell weights and silk percentage in comparision to other varieties.

Evaluation of economically important traits from sixteen parental strains of the silkworm Bombyx mori L (Lepidoptera: Bombycidae)

The classification and characterization of silkworm strains are important for sericulture, which is supported by the constant development of new hybrids. In this study, 16 parental strains of Bombyx mori L from the germplasm banks of the Universidade Estadual de Maringá--UEM, and Associação dos Criadores de Bicho-da-Seda de Nova Esperança e Regiões Sericícolas do Paraná--ACESP, were evaluated regarding biological and productive traits economically important. The Chinese C122-B and C121-A, and the Japanese HA-A and HA-B strains yielded the highest cocoon weight, which is related to the raw silk percentage. Our data will be useful in breeding programs for the production of superior silkworm strains and hybrids.

Efecto de la propagación asexual y prolongación del período vegetativo de Morus alba en la producción de capullos de seda

A. Pelicano, M. Divo de Sesar, N. Zamuner, J. L. Danelon, and M. Yoshida. 2007. The effect of asexual propagation and persistence of the vegetative growth of Morus alba on silk cocoon production. Cien. Inv. Agr. 34 (2):81-89. The goal of this work was to establish an effi cient protocol for vegetative propagation of Morus alba. At the same time this study aimed to evaluate the infl uence of this propagation protocol on the feeding of the larvae of Bombyx f mori and crude silk production. Vegetatively propagated mulberry plants were transplanted to 4 L containers and treated with 15 g of fertilizer, N:P:K (15:15:15,), and/or 6-benzyladenine (5 mg·L -1 ) (Ck). In autumn and spring, leaves were used for the feeding of one cohort of third stage larvae. It was observed that 60% of the plants treated with Ck sprouted before the others, in July, and the rest in August. Although the fertilized plants (TF) and those fertilized and treated with 6-benzyladenine (TFCk) sprouted shortly before the control (T), the Ck treated plants were notably uniform and had more and larger leaves. In the TFCk treatment, the percentage of fi ber, insoluble in neutral detergent (FIND) free from ash, was minor (29.73%). The quality of the food was refl ected in the weight gain and in crude silk percentage. Although interaction between TF and Ck was not signifi cant, there were signifi cant differences between control plants (T) and those treated with TF, TCk and TFCk. In the autumn test, the TCk treatment negatively affected the larvae of B. mori. These larvae twisted, assiduously inducing intestine evacuation. This caused reduced food consumption, and it was a transitory effect, but that meant a lower fi nal weight. The results of this work are very promising and useful for massive production since a longer vegetative cycle for M. alba would allow a greater number of B. mori generations per year.

Avaliação da idade de corte de dois cultivares de amoreira nos desempenhos biológico e produtivo do bicho-da-seda (Bombyx mori L.)

Objetivo: Avaliar o desempenho do bicho-da-seda quando alimentado com cultivares de amoreira em diferentes idades de corte. Material e Método: Desenvolvido na Unidade de Pesquisa e Desenvolvimento de Gália, SP, da Agência Paulista de Tecnologia dos Agronegócios da Secretaria de Agricultura e Abastecimento do Estado de São Paulo, no período de 31/12/1997 a 06/05/1998. O experimento foi iniciado com lagartas do Bombyx mori L., no 3° instar, alimentadas com dois cultivares de amoreira (lZ 56/4 e Korin) em quatro idades de corte (7, 10, 13 e 16 'semanas), sendo analisados, no 5° instar, caracteres biológicos e de produção de casulo. Resultados: Quando foi analisado cada cultivar de amoreira nas diferentes idades de corte, observaram-se, para os caracteres biológicos, variações somente para peso vivo (PV) e ganho de peso (GP) das lagartas. Dos caracteres produtivos estudados, variou apenas o peso de casca sérica (PCS), quando proveniente de lagartas alimentadas com o cultivar Korin. Quando se compararam os cultivares em cada idade de corte, apenas foram observadas variações para os caracteres biológicos PV e peso de crisálida (PCr) e para os caracteres produtivos peso de casulo (PC), PCS e número de casulos formados (NC). Conclusões: As lagartas apresentaram bom PV, no 5° instar, quando receberam no 3° e 4° instares folhas de ambos os cultivares de amoreira com idade de corte próxima a dez semanas, embora tenham apresentado melhor GP quando alimentadas com folhas de plantas em idade de corte mais avançada (acima de dez semanas). A variável porcentagem de seda líquida (PSL) pouco foi influenciada pelos tratamentos, assim como o NC em relação à idade de corte da planta. O cultivar Korin, no geral, propiciou ao bicho-da-seda melhores desempenhos biológico e produtivo.

The relation between reelabirity percentage and raw silk percentage of cocoons

The relation between reelabirity percentage and raw silk percentage of cocoons

Combining ability of seven silk technological characters in mulberry silkworm,Bombyx mori

Abstract The combining ability (abbreviated, CA) effects of five races (KA, CC1, CA2, NB4D2 and NB18) of mulberry silkworm Bombyx mori and their 20 F1’s, including reciprocals, were analyzed in a 5x5 diallelic crossing system for the following seven silk technological characters: cocoon weight, shell weight, cocoon shell ratio, raw silk percentage, silk filament length, silk reelability and silk neatness. The parental race CA2 did not show the best general CA for any of these seven characters, whereas the other parental races did for different characters as follows: race KA for raw silk percentage, silk filament length, silk reelability and silk neatness; race CCI for cocoon weight, shell weight, and cocoon shell ratio; race NB4D2 for cocoon weight, raw silk percentage; race NB18 for cocoon shell ratio. Values of race CA2 for general CA were negative for cocoon weight, shell weight, cocoon shell ratio and raw silk percentage, and were low for silk filament length, silk reelability and silk neatness. This ...

Genetic Analysis of Growth Rate, Puapation Rate and Some Quantitative Characters by Diallel Cross in the Silkworm, Bombyx mori L.

蚕の日本種及び中国種の改良種8品種を用い，二面交雑により，発育速度(5齢期)，化蛹歩合，繭重，繭層重，生糸量歩合，繭糸長，繭糸繊度及び解舒率の8形質について遺伝分析を行った。発育速度，生糸量歩合，繭糸長，繭糸繊度，解舒率は不完全優性を示したが，繭層重は完全優性，化蛹歩合と繭重は超優性を示した。エピスタシス効果は化蛹歩合，繭重，繭糸繊度及び解舒率において認められた。細胞質効果は化蛹歩合と繭糸繊度において認められた。また，発育速度では細胞質効果によらない正逆交雑間の差異が認められたが，これは伴性の成熟遺伝子(LmとLm+)に起因するものと判断した。有効遺伝子数は，発育速度，解舒率，繭糸繊度で少なく，化蛹歩合，繭層重，生糸量歩合，繭重で多いものと推定された。また，遺伝率(狭義)は生糸量歩合，繭糸長で高かったが，化蛹歩合と解舒率では極めて低かった。これらの結果から，繭重，化蛹歩合及び収繭量はF1における雑種効果の利用により改良の行える形質であるが他の形質は選抜による改良の方が適した形質であり，とくに解舒率は環境条件を制御し，優性遺伝子を集積することにより，改良は可能なものと推察された。

Relationships of Actual Performance of Double Cross Hybrids and Predicted Value based on the Mean Value of the Single Crosses concerned in the Silkworm, Bombyx Mori L.

The correlation between actual performances of double cross hybnds and mean values of corresponding measurements obtained for single crosses produced among parenta, 1 four strains were examined in the silkworm, in order to evaluate the possibility of prediction of double cross performance frorn the single cross data. It was found that the correlations were high for some traits such as cocoon shell percentage, raw silk percentage, Iength of cocoon filarnent and size of cocoon filament, but they were low for others such as pupation rate, cocoon yield and reelability.