Studies On Modulating Effects Of Bacterial Genomic DNAs On The Immune Function Of Chinese Mitten Crab Eriocheir Sinensis

Many studies indicate that unmethylated CpG motifs of bacterial genomic DNA and synthetic CpG ODN were a powerful activator of human and animal immune. However, the bacterial genomic DNA on the immune function of Chinese mitten crab reports was not yet seen to date.In order to determine the immunomodulatory effects of bacterial genomic DNA in the Chinese mitten crab (Eriocheir sinensis), the experiment one was processed. Crab were coelom injected with 5, 20, 80μg genomic DNA of Bacillus substilis and genomic DNA of Aeromonas hydrophila kg?1 crab weight. A series of immunology parameters were examined at 1, 3, 5, and 7 days after administration of bacterial genomic DNA. At the same time, one group injected with 0.1mLTE was set as control. Crab were challenged at 1.2×107 colony forming units (cfu)/kg crab weight with a virulent strain of Aeromonas hydrophila (CL99920) of E. sinensis at the sencond sampling time (3d), and mortalities were recorded over a 7-day period. The results demonstrated that the groups injected with genomic DNA of Bacillus substilis and genomic DNA of Aeromonas hydrophila showed a remarkble higher number of THC than controls; while the respiratory burst (release of superoxide anion) increased significantly; also the serum parameters, including phenoloxidase (PO), superoxide dismutase (SOD), acid phosphatase (ACP), lysozyme (LSZ), Nitric oxide synthase (NOS), SOD of Hepatopancreas and Na+-K+-ATPase of muscle were assayed to be significantly increased than the controls(P<0.05). But alkaline phosphatase (ALP) was not significantly changed(P>0.05). At the same time, two kinds of bacteria genomic DNA treated crab's ability of anti-infected by Aeromonas hydrophila were remarkably enhanced. Under this experimental condition, dose of 20μg / kg of two bacterial genomic DNA were best stimuluded in immunity and disease resistance of the Chinese mitten crab, while immune protection rate of the DNA of Bacillus substilis and genomic DNA of Aeromonas hydrophila on Chinese mitten crab was 100% and 71.43% respectively. The results showed that two bacterial genome DNAs were a new potential for mitten crab immunopotentiator. They were worth further developing and utilizing.