Abstract: 【Aim】 Research the influence of fluoride on the retained enzyme-producing bacteria in the intestine of the silkworm, Bombyx mori so as to contribute to understanding the difference of the enduring fluoride between fluoride-resistant and sensitive varieties. 【Methods】 Fluoride-resistant variety T6 and fluoride-sensitive variety 734 of the silkworm were fed with fresh mulberry leaves soaked in NaF solution until the 3rd day of the 5th instar for experiment. Protease-, cellulase-, lipase- and amylase-producing strains were screened on selection medium, and the taxonomic composition of the intestinal bacterial community was identified according to phylogenetic relationship based on 16S rDNA sequences. 【Results】 Genera producing digestive enzymes in the silkworm intestine included Bacillus, Staphylococcus, Enterobacter, Acinetobacter, and Exiguobacterium, among which Bacillus sp., Staphylococcus sp. and Acinetobacter sp. bacteria produced four kinds of enzymes at the same time. The species of enzyme-producing bacteria in the intestine of T6 and 734 varieties reduced from 5 to 4 and 2 to 1, respectively after fluorosis. 【Conclusion】 The retained enzyme-producing bacteria in silkworm intestine are related to the ability of enduring fluoride of silkworm.  

Key words: Bombyx mori, intestinal bacterial community, enzyme-producing bacteria, fluoride, fluoride poisoning, fluoride-resistant variety