Effect of ectoparasiteon the histopathology and gill and gut microbiota of goldfish ().

Abstract

INTRODUCTION: The ectoparasite, is the pathogen of white spot disease in freshwater fish, which parasitizes on gills, fins, and skins of fish, causing tissue damage and death of host. However, whether it influences gill and gut microbiota is still unknow. METHODS: In this study, H&E staining was used to show the gill and gut histopathological characteristics of-infected and uninfected goldfish (). Meanwhile, 16S rRNA gene amplicon sequencing was conducted to analyze the difference of gill and gut microbiota between-infected and uninfected goldfish. RESULTS: Histopathological examination revealed thathas induced significant damage to the gills of goldfish, characterized by lamellae fusion, cell hyperplasia, cell hyperaemia, inflammatory infiltration, necrosis and desquamation. 16S rRNA gene sequencing result showed that alpha and beta diversity of gill microbiota was significantly reduced in the-infected group, while no significant changes were observed in gut microbiota. Genusexhibited the highest relative abundance in the-infected group. Meanwhile, the abundance of opportunistic pathogensandwere increased in the intestines of-infected goldfish. DISCUSSION: The increased presence ofmay originate from within the cells of. The increase of opportunistic pathogensandmay pose a threat to the health of goldfish. In summary, this study laid a foundation for further research on the interaction betweenand host microbiota.