Silver effects on silkworm, Bombyx mori

Abstract

Silver nanoparticles (Ag-NPs) are known as a noble metal, and owing to their exclusive properties, their use is widespread in consumer products and they are mostly incorporated into food packaging and food contact products. The aim of this work was to evaluate the effects of direct ingestion of Ag-NPs through food to assess their toxicity effects on the growth and development of silkworms at different concentrations (1 mg·L^-1 to 100 mg·L^-1), in addition to the examination of the distribution of Ag-NPs in the silkworm body and midgut histopathological analysis. RNA sequencing was performed to investigate the transcriptomic responses to Ag-NPs exposure. Our results show that the highest Ag-NPs’ concentrations induced a significant increase in the silkworm body weight with histopathological changes in the midgut compared to the control group. The gene ontology (GO) and pathway enrichment analysis for differentially expressed genes showed that Ag-NPs altered the gene expressions and that they were significantly involved in carbohydrate metabolism, digestive system, and energy metabolism. These findings indicate that the Ag-NPs may induce harmful effects on the primary target organs (alimentary system) with energy deregulation and nutrition digestion and absorption imbalance. This study is an important step in understanding the molecular mechanisms of Ag-NPs’ toxicity in vivo.