Correlation Analysis of Flora in the Habitat Environment and in the Gut Contents of Sea Cucumber (Apostichopus japonicus)

Abstract:

Here we studied the properties of flora in the gut content and attachments of sea cucumber (Apostichopus japonicus) as well as in the sediments of pond where sea cucumber were cultured. 16S rDNA PCR denaturing gradient gel electrophoresis (PCR-DGGE) was employed as the major method. The DGGE band numbers were 30.00±1.00, 15.33±1.70, and 21.67±2.62 for gut content, attachments, and pond sediments respectively. This indicated that the gut content had the highest diversity of bacterial species. UPGMA cluster analysis showed that flora from three gut content samples could be categorized into one branch with a similarity value of 0.785, and that flora from attachments and pond sediment samples were clustered into another branch with a similarity value of 0.532. Twenty specific DGGE bands from the three kinds of samples were cut and sequenced. The results showed that Synechococcus sp., Desulfobacterium, Desulfosarcina sp., Polaribacter, Algibacter sp. were the dominant bacterial species in the gut content; Robiginitalea sp., Silicibacter sp. were dominant in attachments; and Proteobacterium, Cytophaga, Desulfosarcina sp. were dominant in the sediment. The specific bacteria in the gut content could be candidates of probiotics in the sea cucumber culture.