Comparison of cocoon quality and raw silk performance between coccons produced from whole instar artificial diet and mulberry leave reared silkworm
Objective In recent years,China has made substantial progress in the research and development in silkworms artificial diet and the innovation of breeding technology.Many researchers studied on using artificial diet in the young instars and applying mulberry leaves in the last larval instars,focusing on the growth and cocoon quality of silkwormsbut with little attention on the raw silk.Therefore,it is necessary to study the cocoon quality,silk quality and raw silk performance of silkworms reared with artificial diet in whole instar.Method The study was carried out by using different origins of silkworm cocoons(silkworm cocoons reared with mulberry leaves of Chunan and Haian,non-factory silkworm cocoons reared with artificial diet in whole instar,and factory silkworm cocoons reared with artificial diet in whole instar)reared with artificial diet and mulberry leaves in whole instar.We tested cocoon width to observe the appearance and morphology.Through reeling,we calculated the number of rushing upon cocoons per myriameter,reelability percentage.Then,the degumming experiment of raw silk was carried out to calculate the gum content of raw silk as well as mechanical performance evaluation.Fourier transform infrared spectroscopy,scanning electron microscopy and X-ray diffraction were adopted to characterize the microscopic morphology of raw silk and analysis.In addition,the experimental results were compared by one-way analysis of variance.Results In terms of appearance,the cocoons of silkworm reared with artificial diet and mulberry leaves in whole instar are oval,and the cocoons of silkworm reared with artificial diet in whole instar are smaller but more orderly.In terms of cocoon quality and silk quality,silkworm cocoons reared with artificial diet in whole instar have a slightly lower amount of total cocoon weight and cocoon shell weight,which is related to the fact that after the silkworms feed with artificial diet,their ingestion is not as good as that of mulberry leaves-breeding silkworms,but the rate of cocoon layer shows higher.In addition,whether or not the form of factory sericulture also has an impact on the cocoon and silk quality performance of silkworms reared with artificial diet in whole instar was also studied.The total cocoon weight and cocoon shell weight of silkworms reared with non-factory sericulture in whole instar are lower,and the length and the fineness of bave are not as good as those of the other three silkworm cocoons.The cocoons of silkworms reared with mulberry leaves in whole instar has less rushing upon cocoons during reeling,better reelability percentage,reelability silk length,and better reelability performance.For raw silk,the surface morphology of raw silk under different feeding methods is basically the same,raw silk gum content of silkworm reared with artificial diet in whole instar is higher,and raw silk gum content of silkworm reared with factory artificial diet of whole instar is the highest.The breaking strength and the elongation at break of raw silk is not significantly different from that of mulberry leave-reared.In addition,there is no significant difference in the secondary structure of raw silk between the whole instar artificial diet and the whole instar mulberry leaves,which all have β-sheet,random coil,α-helix and β-turn structure.Conclusion There is no significant difference in the secondary structure and performance between the silkworm cocoons reared with artificial diet and mulberry leaves in whole instar,but there are differences in cocoon quality and silk quality,which can provide reference for the related research of artificial diet rearing silkworms.In addition,there is also a certain relationship between the quality of cocoon and silk of silkworms rearing with artificial diet in whole instar and whether it is factory sericulture.Factory sericulture can improve the production technology and growth environment,which will also have an impact on the growth and development of silkworms.
artificial dietfactory rearing of silkwormcocoon qualityperformance of raw silk