Abstract

To investigate the effect of feeding on hibernatingHirudo nipponia, metagenomic sequencing was performed on the microorganisms collected from the digestive tract ofH. nipponiaindividuals that were fed (FW) or starving (SW) before hibernation. In addition, the salivary gland tissues were obtained from these individuals to conduct transcriptome sequencing. Results showed that feeding before hibernation increased the relative abundance of Bacteroidetes and Proteobacteria at the phylum level and that ofAeromonas,Mucinivorans,Bacteroides, andDesulfovibrioat the genus level. Functional prediction results indicated that feeding before hibernation not only improved metabolic capacity but also increased the susceptibility ofH. nipponiato pathogens. Among the 133,082 unigenes obtained by transcriptome sequencing, a total of 2801 differentially expressed genes (DEGs) were found, of which 355 were up-regulated and 2446 were down-regulated; the expression patterns of 15 selected DEGs were validated by qRT-PCR. Results from the GO and KEGG enrichment analyses showed that a majority of these DEGs were involved in the signal transduction pathways. This study established a basis forH. nipponiabreeding during hibernation through analyses of the abundance of microorganisms in the digestive tract and the gene expression pattern of salivary glands by high-throughput sequencing. The findings also revealed the effect of feeding on the expression of both gastrointestinal microorganisms and salivary gland genes of hibernatingH. nipponia.Keywords:Hirudo nipponia;hibernation;metagenome;transcriptome;microorganisms in the digestive tract;salivary gland