A comparative study of the effects of all-instar mulberry leaf and artificial diet on structure and properties of silkworm silk

Nowadays, traditional mulberry leaf-based sericulture has faced challenges such as low efficiency and environmental dependency. Consequently, artificial-diet based sericulture has been developed and recognized as promising alternative for cocoon production. However, comparative studies on the characteristics of cocoons produced via these two methods are limited. This study aims to investigate the effects of mulberry leaf (Mul) and artificial-diet (Art) rearing on the structural and functional properties of industrially produced silk. The results revealed that Mul silk exhibits higher sericin content, while Art silk demonstrates a greater propensity for crystallization, attributing to its distinct amino acid composition and therefore exhibiting 3.3% higher crystallinity and improved thermal stability. Mechanical property analysis shows a decreasing trend in the breaking strength of cocoon silk from outer to inner layer, and significant difference is exhibited among inner layer silk. Additionally, the higher expression of specific proteins such as cadherins in Mul silk appear to support the filamentation process and overall quality. Both silk have similar antibacterial properties and raw silk reeled from Art-cocoons achieves 5A grade. This study provides valuable insights into how different feeding methods impact silk structure and properties, offering guidance for silkworm rearing practices and contributing to the sustainable development of sericulture.