COMPARATIVE ANALYSIS OF THE INTESTINAL MICROBIOTA IN PACIFIC ABALONE Haliotis discus hannai

To study the relationship between the internal microbial population and the grow rate of the host animal,  microbial populations in the intestine of Pacific abalone Haliotis discus hannai o f different sizes were analyzed by  using next generation sequencing of 16S rDNA by Illumina MiSeq. Microbiota groups  belonging to the phyla Tenericutes, Fusobacteria and Proteobacteria were found to be dominant in the intestine of Pacific abalone. C omparison of the community compositions in the large and small size groups indicated a  more diverse microbial diversity in a smaller size  group.  Detailed analysis in the levels of class and genus of microbiota will be presented.

Microbial communities in the intestine of marine organisms reflect the physiological status affecting the growth. To study the relationship between intestinal microbial population and grow rate of abalone ,  Pacific abalones of 750 days post fertilization  were  collected  and  divided  into small (S) and large (L) size groups.

Intestine of each abalone group s were subject to DNA purification followed by metagenomics analysis. Illumina Mi-Seq  analysis  led to identification of 67146.25 and 73361.13 valid reads from eight small and large individual abalones, respectively .  Bacteria community structure was analyzed up to  the genus level. While a  32.7% of total bacteria were classified into Mycoplasma  _g18, only 8.45% was in small group.  In addition to Vibrio species accounting for 14.96% and 9.93% in  the  small and  the large groups, respectively, Psychrilyobacter was a lso  detected in  the small (8.15%) and large (17.3%) abalones . Relative abundance of the microbial populations in each group was compared by analyses including alpha-diversity indices . Overall, microbial composition in a smaller size abalone group  showed a  higher divers ity than that of the large size group.