Altered Intestinal Microbiota Composition Associated with Enteritis in Yellow Seahorses Hippocampus kuda (Bleeker, 1852)

Enteritis comprises one of the most common diseases affecting the survival of farmed yellow seahorse (Hippocampus kuda), an important economic fish species cultured worldwide. Although there are several studies describing bacteria associated with seahorse, the microbial alternations associated with enteritis in seahorse has not been extensively investigated. In the present study, high-throughput 16S rRNA gene sequencing was used to explore the changes in the intestinal microbiota of seahorse suffering from enteritis. The results showed that the diversity, structure, and function of intestinal microbiota were significantly different between healthy and diseased seahorse. Particularly, significant increase was observed in Brevinema, Mycobacterium, and Vibrio, as well as significant decrease in Psychrobacter, Bacillus, and Shewanella in diseased seahorse (P < 0.05). In addition, PICRUSt predictions revealed that the intestinal microbiota significantly changed the specific metabolic pathways (related to metabolic diseases, replication and repair, transport and catabolism, infectious diseases and immune system) in diseased seahorse (P < 0.05). Altogether, our findings point out the association between changes of the intestinal microbiota and enteritis in seahorse, which provide basic information useful for optimization of breeding regimes and improvements in the health of this endangered species in captivity.