The Preliminary Study On Mechanism Of Several Probiotics In Breeding Sea Cucumber(Apostichopus Japonicus)

At present, sea cucumber farming leads a rapid development, and has been one of the most important cultured seawater animals in North China. But with the development of sea cucumber aquaculture, the various diseases have been come frequently and tempestuously. It has inflicted considerable loss to sea cucumber culture. Antibiotics and chemical disinfectants have good effects, but may lead to bacterial resistance and sulfonamide residues. So antibiotics and chemical disinfectants are severely restricted in aquaculture. Probiotics can inhibit pathogenic bacteria, improve intestinal microecological balance, increase the capacity of the immunity, and be friendly to environment. This paper connected with application of the probiotics in breeding sea cucumber and provided some help for the development of probiotics in aquaculture.3strains which could inhibit bacteria from Atlantic Flounder's intestine and sea cucumber's intestine were selected by vitro antibacterial experiment. These strains were identified by identification of biochemical properties and16s rDNA sequence genotyping. A30-days feeding trial was conducted to investigate the effects of lactic acid bacteria on aquaculture environment, intestinal flora and the growth performance of juvenile A. japonicus. The effects of probiotics on aquaculture were not notable. Contrasting to control, the number of lactic acid bacteria in cultured water in experimental group didn't significantly increase. A60-days feeding trial was conducted to investigate the effect of several probiotics on juvenile A. japonicus (average weight2.74±0.17g) based on specific growth, microflora of intestine, nonspecific immunity and anti-stress reaction. The results indicated that experimental groups showed higher SGR than the control. These probiotics improved the nonspecific immunity of sea cucumber. The stress reaction was improved by these probiotics. It could be included that metabolites in lactobacillus fermentation liquor played a more important role to sea cucumber than thalli. Bacillus natto showed good effects on nonspecific immunity and intestinal bacteria of sea cucumber.10%(m/m) fermented soybean meal was added to basic feed,and it was found that the fermented soybean meal could improve the SGR of sea cucumber. The number of Vibrio spp. and Escherichia coli in intestine of A. japonicus in experimental group prominently decreased. And the immune response and stress resistance still proved that fermented soybean meal brought benign influence on sea cucumber.In conclusion,3potential probiotics in aquaculture were selected. It could rich aquaculture beneficial bacteria library. Application of lactic acid bacteria, lactic acid bacteria metabolites, bacillus natto, yeast, and fermented soybean meal could promote healthy growth and anti-stress of sea cucumber. We initially explored the mechanism of probiotics through analysis of water quality indicators, the intestinal flora, and some immune indicators. It would provide theoretical reference for the development.