Dissertation
Dissertation > Agricultural Sciences > Aquaculture, fisheries > Fisheries Protection > Fisheries pharmacology, pharmacology

Evaluation of Inhibitory Effect of Biocontrol Agents Bacillus Isolates on Aquaculture-Conditional Pathogenic Bacteria and Protective Roles in the Culture of Eirocheir Sinensis, Macrobrachium Nipponnensic and Trionyx Sinensis

Author WuHuiXian
Tutor FengMingGuang
School Zhejiang University
Course Microbiology
Keywords Bacillus Probiotics Antagonistic bacteria Aeromonas hydrophila Mild Aeromonas Aquatic pathogens Chinese mitten crab Japanese prawn Soft-shelled Turtle Bioassay Time - dose - mortality modeling Aquaculture protection Microbial Control
CLC S948
Type PhD thesis
Year 2005
Downloads 749
Quotes 5
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From Bacillus as an important class of biocontrol bacteria in the biological control of livestock has been widely studied and applied in aquaculture, especially in freshwater fishing is just getting started, its screening, the utility evaluation are lacking specification standards. In this study, widely found in fresh water conditions the pathogens - Aeromonas targeted seven antagonistic Bacillus screening test, culture and fermentation conditions optimized elected Bs01 strains and Bacillus bacteria culture on the Chinese mitten Eirocheir sinensis megalopa, Japan Macrobrachium the Macrobrachium nipponnensic, soft-shelled turtle Trionyx sinensis and other aquatic animals were more in-depth evaluation of bioassay and farmed the protective effect, in order to promote China biocontrol agents in 淡水养殖业Application Based on the seven Bacillus isolated laboratory Determination of the antagonistic strain selection and optimization of culture conditions commonly found in the aquaculture water three conditions pathogenic Aeromonas flat antagonistic tests showed significant antimicrobial effect . Bs01 strains tested the inhibitory effect of the three pathogens Best, 24 h inhibition zone average diameter of 14.6f10.7 21.3) mm: of Bs03 strain followed, inhibition zone of 12.9 (10.7 to 17.2) mm; Bs04 and Bs05 strains of antibacterial effect was slightly lower than the Bs03; while the remaining three Bacillus average inhibition zone diameter of only 8.5 ~ 9.5 mm, significantly lower than the other strains. Sensitivity of Aeromonas strains of Bacillus differentially expressed hydrophila Aeromonas Aeromonashydrophila CL99817 strain is most sensitive to the tested Bacillus (inhibition zone average of 14.9 mm), and mild Aeromonas A sobria the TL97424 strains and hydrophila of Aeromonas QXS the-1 strain sensitivity is relatively weak (bacteriostatic ring mean is less than 5.0 mm). Bs01 of Bacillus bacteria antagonistic effect does not depend entirely on flora concentration the fermentation broth metabolites also have significant antagonistic effect, removal of viable cells in the Bs01 broth, the supernatant was CL99817 strains inhibition with a strong performance at room temperature under neutral conditions, the fermentation the supernatant inhibitory effect of up to 85% or more of the bacteria. Trial optimization of of Bs01 strain culture conditions, pH, quantity of contents, temperature and nutrients can affect the concentration of the fermentation broth flora growth to pH 7.0 the most suitable strain cultured viable cells after 24 h amounted to 21.6 × 1 O ~~ 8CFU/ml, pH 4.5 under the conditions of growth increment to (O.58 × 10 ~ 8CFU/ml) of more than 40 times, three times higher than the amount of growth in the pH 5.5 and 8.5: optimum loading amount and incubation temperature. 40% and 35 ° C: the basic broth supplemented with 0.5% glucose is suitable medium Bacillus Bs01 strain. Bacillus protective effects were evaluated using the Chinese mitten crab megalopa farming waters inoculation method, setting the three-dose treatment, a biocontrol dealt with separately, a hydrophila Aeromonas CL998 17 separate vaccination treatment and a water blank control, inoculation dose specification for the unit volume of water contained in the colony-forming units, the number of viable cells (CFLUml), 4 repeats, each including 20 repeat megalopa. The results show that the pure pathogen treatment and water

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