Comparison of Intestine Microbiota Between Wild and Farmed Korean Rockfish, Sebastes schlegelii

The Korean rockfish, Sebastes schlegeli , is most commonly farmed in sea cages along the coast of Korea; however, detailed information on intestinal microbiota regarding this fish is not readily available. In this study, comparison of the seasonal changes of microbial communities in the intestine between farmed and wild through the amplicon sequencing approach was conducted. The composition of major species in the intestine of this fish was very simple compared to that of other marine fish species, with members affiliated with the family Vibrionaceae hyper-dominating and comprising on average 97.6% of microbiota. However, the composition at the genus or species level and the pattern of seasonal changes of diversity indices showed significant differences between farmed and wild fish. In the farmed fish, Photobacterium phophoreum was most dominant throughout the year, accounting for 58.8% of the total. Aliivibrio fisherii and/or Aliivibrio finisterrensis also were dominant in the fall to winter but substituted by Photobacterium damselae during spring to summer. In the wild fish, on the other hand, opportunistic pathogens in the genera Aliivibrio or Vibrio were dominant in most of the samples. The analysis of shared species between gut microbiome, feed microbiota, and seawater microbiota indicated that the intestinal microbial diversity of farmed fish was affected more by microbiota of seawater than that of feed in spring and winter seasons. Additionally, the proportion of potential pathogenic Vibrio spp. in the gut showed a negative correlation with plasma glucose levels of the host. This study and following studies will be helpful in understanding the interaction between microbiome hosts and the development of techniques to enhance production of healthy Korean rockfish.