Bacterial community associated with the intestinal tract of P. monodon in commercial farms.

The potentially important roles of intestinal bacteria on immune response, disease resistance, and nutrition for the black tiger shrimp Penaeus monodon have been increasingly investigated. However, so far, little is known about the intestinal bacterial community of the shrimp in the commercial aquaculture settings. In this study, the intestinal bacterial communities of juvenile P. monodon (70 individuals) from eight commercial farms in Thailand were examined using 16S rDNA PCR-DGGE, and seven 16S rDNA clone libraries from representative DGGE profiles were constructed. Bacteria in the γ-Proteobacteria class were the only common bacteria group found in the intestinal tracts of shrimp from all farms. The dominant bacterial genera in the intestinal population of each shrimp varied among different farms, and these genera were Vibrio, Photobacterium, Aeromonas, or Propionigenium (phylum Fusobacteria). Other commonly found genera included Actinomyces, Anaerobaculum, Halospirulina, Pseudomonas, Mycoplasma, and Shewanella. Twelve phyla of bacteria including Proteobacteria, Firmicutes, Fusobacteria, Actinobacteria, Cyanobacteria, Tenericutes, Deinococcus-Thermus, Planctomycetes, Spirochaetes, Synergistetes, Thermotogae, and Verrucomicrobia were represented in the sequences. Additionally, strictly anaerobic bacteria such as Propionigenium and Fusibacter were found. These intestinal bacterial communities varied significantly among different commercial farms and were distinct from their rearing water. The results provide descriptive structures of the intestinal bacterial communities of P. monodon in commercial farms, which can further be applied to areas of research on the immunity, disease resistance, and nutrition of shrimp to improve aquaculture of the black tiger shrimp.