Bacteria community in the intestine and culture environment of Apostichopus japonicus in winter
冬季刺参养殖环境与肠道内细菌菌群的研究

Studies on the bacteria community in the intestine and culture environment of Apostichopus japonicus in winter were conducted using tranditional bacterial cultivation method combined with molecular biology techniques during the period between November 2008 to January 2009. The total numbers of bacteria in the pond water, the sediment, the cultch and A. japonicus intestine, estimated by the tranditional bacterial cultivation method, ranged from 0.75×102 to 1.4×104 cfu/mL, 8.7×104 to 8.1×105 cfu/g, 3.8×105 to 2.8×106 cfu/g and 7.1×105 to 1.5×107 cfu/g, respectively. Twenty-two strains were isolated judged by the morphological characteristics of bacteria cultured on the plates. ARADA analysis with restriction enzymes Rsa I and Msp I revealed that the 22 strains were divided into 8 Operational Taxonomic Units (OTUs), which were dominated by OTU2 and OTU3 that accounted for 30% and 20% of the total isolated strains, respectively. Molecular identification was employed to identify the dominant bacteria in different environments. It was shown that the dominant bacteria were Pseudomonas stutzeri, P. mendocina, and Bacillus megaterium in the pond water; B. megaterium, P. stutzeri, and Bacillus thuringiensis in the sediment; B. megaterium, B. thuringiensis, and Vibrio splendidus on the cultch; B. megaterium, B. thuringiensis, V. splendidus, and P. stutzeri in the sea cucumber intestine. The result of this experiment may be helpful for hypothermia probiotics isolation and disease prevention in sea cucumber culture.