M. Panayotov*

Department of Animal Science – Non-ruminants and other animals, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
(Manuscript received 11 April 2016; accepted for publication 26 May 2016)

Abstract. The goal of the present study was to determine the influence of the ultraviolet fluorescence of cocoons, the hybrid, the sex and the interaction among them on the sericin content in silk threads. The study was performed with 3 di- and 2 tetra-cross silkmoth (Bombyx mori L.) hybrids, differentiated in three groups – with violet, intermediate and yellow fluorescence of the cocoons. The examined factors had a significant effect (p≤0.001) on the sericin content. The highest sericin content was detected in the silk threads of the violet-fluorescent and the lowest – in the yellow-fluorescent group. The analysed di-hybrids were distinguished by better characteristics in terms of sericin content, compared to the tetra-hybrids, most obvious for the yellow-fluorescent fraction.