Department of Animal Science – Ruminant and Other Animals, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
Abstract. Sericin content of raw silk has a significant effect on the economic efficiency of the silkreeling process and the qualities of raw silk. The objective of the present study was to analyze sericin content in raw silk from Bombyx mori L. cocoons with different fluorescent characteristics. The subject of study were 1998 skeins distinguished by sex and fluorescence of double and tetra-cross silkworm hybrids. The results obtained show that the ultraviolet fluorescence of cocoons influences the phenotypic expression of sericin content. Reliably lowest is the content of skeins from yellow fluorescent cocoons and the highest is that from violet fluorescent ones. Higher is the sericin content of skeins from the tetra-cross hybrids compared to double-cross hybrids. Given that the high sericin content is undesirable, economically more viable for the silkreeling industry is the creation and use of breeds and hybrids in which cocoon of yellow fluorescence dominate.