A study on the establishment of bacterial microbiota in the gut of silkworm bombyx mori

A study was carried out to assess the colonization of bacterial strains adherent to the upper and lower sides of the mulberry leaves, in the intestinal zones of the silkworm Bombyx mori. Upper and lower sides of one week, two week and three week old mulberry leaves were scraped aseptically and cultured in nutrient agar medium. Morphological, physiological and fermentation characteristics of the bacterial isolates were studied to identify the strains. The bacterial strains isolated were: Bacillus cereus, Bacillus subtilis, Lactococcus lactis, Staphylococcus lactis, Enterobacter aerogenes, Escherichia coli and Klebsiella pneumoniae. Second instar larvae of Bombyx mori were segregated into three sets and each set was maintained on mulberry leaves of selected age( one, two or three week old) for 15 days and the regionwise abundance of gut bacteria was assessed. Among the intestinal zones of Bombyx mori foregut harboured more bacteria ( 5.2 to 6.2 cfu x 108 ). Identity and distribution of intestinal bacteria could establish that gut microbiota of B. mori has its origin from the phyllosphere microbes of mulberry and that the gut microbes may have definite role in the nutrition of silkworm.