The Selection And Application Of Denitrifying Bacteria In Litopenaeus Vannamei Biological Floccules Breeding

With the rapid development of aquaculture, in order to seek the benefits of shrimp, aquaculture are often used the high-dens ity factory farming methods. However, the high density of factory farming model have a lot of problems, bait, organic and inorganic nitrogen accumulation of toxic water pollution caused by farming and breeding animals often get sick to death. Bio-floc technology is the way by adding beneficial microbes into the culture water to organic matter and water, protozoa, algae and other after bioflocculation combined to form floc. These beneficial microbes can utilize both metabolites and residual feed farmed animals, to water purification purposes, and can be farmed animals feeding, improve feed conversion. The main findings are as follows:1、The Selection and Identification of heterotrophic nitrification bacteria and their inorganic nitrogen removal detection capabilities.These strains that come from farming water and shrimp intestine have denitrification, By contrast experiment denitrification better ability to filter out two denitrification bacteria, named 20131023A05 and 20131023XS-1-3, After 16 Sr DNA sequencing, 20131023A05 belong false Alteromonas, 20131023XS-1-3 belong alginolyticus. Under laboratory conditions discussed the growth of bacteria, denitrification capacity size. The results show: two strains have the ability to remove ammonia mainly nitrogen, and nitrite nitrogen removal is not obvious, At 28 ° C, p H value of 7.2, while shaking speed 150 r / min bacteria 20131023A05 inorganic nitrogen removal capacity reached 49.9%, 20131023XS-1-3 for inorganic nitrogen removal capacity of 41%. The results showed that two strains have the ability of efficient removal of inorganic nitrogen, so the application of these two strains in biological floc shrimp farming.2、Two strains of heterotrophic nitrification bacteria used in Litopenaeus vannamei biological floccules breedingPseudoalteromonas piscicida and Vibrio alginolyticus separately and equal mixture of two types of bacteria added to the water of Litopenaeus vannamei breeding, organic carbon source provided by the addition of brown sugar and adequate ventilation, generate biological floc, and set the blank group and several control groups. The results showed that these two strains added to aquaculture water, the addition of carbon to the biological floc farming mode, can effectively reduce the ammonia content in water breeding, aquaculture water pollution reduction of ammonia. In these two strains of biological floc formed mainly in farming systems can improve the survival rate of vannamei.3、The strain of Vibrio parahaemolyticus antagonistic selectionBy separating vannamei farming water and vannamei internal bacteria were isolated and screened for laboratory conservation Vibrio parahaemolyticus 20130629002S01 antagonistic bacteria. Through security culture experiments show that the strain of shrimp and no pathogenic lethal effects. These strains were selected for its antagonism by paper disk method against Vibrio parahaemolyticus. With lower concentration of Vibrio parahaemolyticus, gradually increasing the size of the zone of inhibition, screening out five strains of bacteria, Strain 201310232-102 maximum diameter of inhibition zone, the best inhibitory effect on the tablet when Vibrio parahaemolyticus bacteriostatic circle diameter of 1.57 × 103 CFU / cm when the inhibition zone diameter 14.34 ± 0.048 mm, in six bacteria, inhibition zone diameter of the smallest strains 20110727001-9. By adding water to a concentration of shrimp farming experiments strain, the Marsupenaeus japonicus in vivo injection of Vibrio parahaemolyticus, were compared with the control group to verify the added bacteria in shrimp aquaculture effects on Vibrio parahaemolyticus, The blank group of Marsupenaeus japonicus lowest survival rate experiment, the Marsupenaeus japonicus of each group plus bacteria were higher than the control group survival, description Adds fungus improves the survival rate of Japanese shrimp, 20131023A05, 201310232-102 survival rate between the two groups in which the highest, reaching 50%, Add strains 20110727001-9 group survival in these groups the lowest. Water was added to the culture of Vibrio parahaemolyticus antagonistic bacteria can raise shrimp resistance to vibrio parahaemolyticus, improve the survival rate.