The Gut Microbiota of Silkworm Are Altered by Antibiotic Exposure

In recent years, antibiotics have frequently been detected in soil, lakes, and rivers. Antibiotic residues in the environment may alter microbial structure and cause bacterial resistance, but their effect on interactions among host microbiota is still poorly understood. To investigate this issue, here we used silkworm (Bombyx mori) fed on antibiotic-treated mulberry leaf as a model to explore the effects of antibiotic exposure on gut bacteria and fungi. We observed that elimination of fungi significantly reduced bacterial richness and diversity in silkworm intestine after exposure to the antifungal amphotericin B, while the elimination of bacteria dramatically increased the richness and diversity of fungi after exposure to the antibacterial ampicillin-streptomycin. Thus, antibiotic-treated mulberry leaf significantly altered the community structure of microbiota in the gut of silkworm. Clearance of gut bacteria enhanced the correlation between gut fungi and leaf-derived fungi, while clearance of gut fungi promoted abnormal proliferation of gut bacteria. These data provide a simple model to explore the comprehensive effect of diet-derived bacteria, fungi, and antibiotics on gut microbiota.