Intestinal Microbiota in Large Yellow Croaker, Larimichthys crocea, at Different Ages

The polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) of 16S ribosomal RNA gene was used to investigate bacterial communities in the intestines of large yellow croaker at six different ages (12d, 18d, 26d, 40d, 3mo, and 1yr old) as well as within the corresponding feed and culture water. In addition, Illumina Miseq sequencing was utilized to compare intestinal microbiota between 12-d-old and 1-yr-old individuals. PCR-DGGE results revealed that the culture water had the highest bacterial diversity, followed by the feed, while the intestines had the lowest diversity. The intestinal microbiota at six ages changed severely; however, the change did not follow any trend. The large yellow croaker intestines harbored specific bacterial communities that differed from those in both feed and water. Illumina Miseq sequencing results revealed that the diversity of intestinal bacteria in 12-d-old fish was higher than that in 1-yr-old fish, and the bacterial composition differed significantly between them. -Proteobacteria and Pseudoalteromonas supplied the most abundant phylum and genus in the 12-d-old fish intestine. However, in the 1-yr-old fish intestine, Firmicutes and Clostridium were the most dominant, respectively. The study may contribute to a better understanding of gut microbiota and dynamics of the large yellow croaker and the relationship with their surrounding environment.