Background
Parasitic protozoans, helminths, alter the gut microbiota in mammals, yet little is known about the influence of intestinal cestodes on gut microbiota in fish. In the present study, the composition and diversity of the hindgut microbiota were determined in the intestine of common carp (
Cyprinus carpio
) infected with two tapeworm species,
Khawia japonensis
and
Atractolytocestus tenuicollis
.
Results
The intestine contained a core microbiota composed of Proteobacteria, Fusobacteria and Tenericutes. Infection with the two cestode species had no significant effect on the microbial diversity and richness, but it altered the microbial composition at the genus level. PCoA analysis indicated that microbial communities in the infected and uninfected common carp could not be distinguished from each other. However, a Mantel test indicated that the abundance of
K. japonensis
was significantly correlated with the microbial composition (
P
= 0.015), while the abundance of
A. tenuicollis
was not (
P
= 0.954). According to Pearsonʼs correlation analysis, the abundance of
K. japonensis
exhibited an extremely significant (
P
< 0.001) positive correlation with the following gut microbiota taxa:
Epulopiscium
,
U114
,
Bacteroides
,
Clostridium
and
Peptostreptococcaceae
(0.8<
r
< 0.9); and a significant (
P
< 0.05) correlation with
Enterobacteriaceae
,
Micrococcaceae
,
Rummeliibacillus
,
Lysinibacillus
boronitolerans
,
Veillonellaceae
,
Oxalobacteraceae
,
Aeromonadaceae
(negative),
Marinibacillus
and
Chitinilyticum
(0.4<
r
< 0.7).
Conclusions
These results suggest that the composition of gut microbiota was somewhat affected by the
K. japonensis
infection. Additionally, increased ratios of pathogenic bacteria (
Lawsonia
and
Plesiomonas
) were also associated with the
K. japonensis
infection, which may therefore increase the likelihood of disease.
Electronic supplementary material
The online version of this article (10.1186/s13071-019-3510-z) contains supplementary material, which is available to authorized users.