Association between Capillaria hepatica infection-induced alterations in gut microbiota and estrogen expression in Brandt's voles (Lasiopodomys brandtii)

Abstract

Abstract Background Capillaria hepatica, a zoonotic parasite, is present in the population of Brandt's voles (Lasiopodomys brandtii) and has been a central issue in ecological studies regarding its impact on host populations. Brandt's voles are known for their extremely high reproductive capacity, and outbreaks of Brandt's voles have occurred multiple times in the grasslands of Inner Mongolia over the past few decades. However, the mechanisms underlying the population dynamics of Brandt's voles, particularly in response to C. hepatica infection, remain poorly understood. The gut microbiota plays a crucial role in regulating hormones in the reproductive endocrine system. In this study, we investigate the role of gut microbiota in the regulation of host population dynamics in response to C. hepatica infection. Methods Female Brandt's voles were inoculated with eggs of infected C. hepatica, and BALB/C mice were used as a control. At the end of the experimental period, cecal contents were collected for 16S rRNA amplicon sequencing, and the expression levels of reproductive-related hormones were determined using enzyme-linked immunosorbent assay (ELISA). Results C. hepatica infection leads to an increased diversity of gut microbiota in Brandt's voles, with significant changes in microbial composition. The relative abundance of Muribaculaceae and Eubacteriaceae increased significantly, while that of Rikenellaceae and Lachnospiraceae decreased significantly. The expression level of estradiol in the serum of infected Brandt's voles shows a slight decrease without statistical significance. However, the expression of equol is significantly higher in the infected group compared to the uninfected group, and the expression of enterolactone is significantly lower in the infected group than in the uninfected group. Conclusions This study demonstrates that infection with C. hepatica indirectly affect the abundance of gut microbiota in Brandt's voles, which are associated with reproductive hormones. This indirect effect on hormone expression can subsequently impact the reproductive function of the host. By investigating the changes in gut microbiota, this study sheds light on the mechanisms through which parasites regulate population fluctuations in Brandt's voles.