Changes in the Intestinal Microbiota of Gibel Carp (Carassius gibelio) Associated with Cyprinid herpesvirus 2 (CyHV-2) Infection

Abstract

Gut microbiota are integral to the host, and have received increased attention in recent years. However, information regarding the intestinal microbiota of many aquaculture animals is insufficient; elucidating the dynamics of the intestinal microbiota can be beneficial for nutrition, immunity, and disease control. In this study, we used 16S rRNA sequencing to observe changes in the intestinal microbiota of gibel carp (Carassius auratus gibelio) associated with cyprinid herpesvirus 2 (CyHV-2) infection. Our results indicate that the diversity of the intestinal microbiota was strongly reduced, and the composition was dramatically altered following CyHV-2 infection. The most dominant species in healthy fish were Cetobacterium, Rhodobacter, and Crenothrix; meanwhile, Cetobacterium, Plesiomonas, Bacteroides, and Flavobacterium were the most abundant species in sick fish. Plesiomonas was highly abundant in infected samples, and could be used as a microbial biomarker for CyHV-2 infection. Chemical properties of the aquaculture water were significantly correlated with the microbial community structure; however, it is difficult to determine whether these changes are a cause or consequence of infection. However, it may be possible to use probiotics or prebiotics to restore the richness of the host intestinal microbiota in infected animals to maintain host health.

Analysis of the tonsillar microbiome in young adults with sore throat reveals a high relative abundance of Fusobacterium necrophorum with low diversity

“…Regardless, similar changes have been documented in a wide range of infections and hosts ranging from pulmonary tuberculosis in humans [ 31 ], to Cryptosporidium intestinal infection in lower primates [ 32 ], to herpesvirus infection in fish. [ 33 ]…”

Host–microbiota interactions and responses to grass carp reovirus infection in Ctenopharyngodon idellus

“…Grass carp infected by GCRV always show damaged endothelial and blood cells, resulting in platelet activation and aggregation, haemolysis, and inflammatory responses (Meri, 2013). We found that the alpha‐diversity of gut microbiota in the diseased grass carp was significantly lower than that of controls, which is consistent with virus diseases in gibel carp challenged by Cyprinid herpesvirus (She et al ., 2017). A viral infection may promote extensive immune reaction against viruses, a failure of properly calibrate immune responses will further result in confrontations to commensal bacteria, thus decrease the alpha‐diversity.…”

“…We have much less understanding of fish immune responses to a dysbiosis of gut microbiota initiated by virus invasion (Nie et al ., 2017; Xiong et al ., 2019). Although the infection of cyprinid herpesvirus 2 (CyHV‐2) in gibel carp could decrease the diversity of intestinal microbiota (She et al ., 2017), and fish gut microbiota are also found to be closely correlated with host immunity (Stagaman et al ., 2017; Murdoch and Rawls, 2019), how microbial disturbances influence fish immune response remains unknown (Gómez and Balcázar, 2008; Nie et al ., 2017). Understanding and manipulating gut microbiota may be a new direction to improve fish health and production (Dimitroglou et al ., 2011).…”

Use of probiotics in aquaculture of China—a review of the past decade

“…Genus Flavobacterium is Gram-negative, rod-shaped, non-motile and motile bacteria, and they have been reported in the GI tract of several fish species [34,35,[41][42][43], but several species are known to cause disease in fish [44,45]. Flavobacterium sasangense BA-3, an autochthonous intestinal strain isolated from common carp (Cyprinus carpio), has been suggested as probiotics [21].…”