Selection And Application Of Probiotics From Intestinal Tract Of Abalone，Haliotis Discus Hannaiino

It is universly accepted that probiotics as an alternative mean of antibiotics. Themicroflora of intestinal tract of animals play an important role in health and disease resistence,and become important secletion source of probiotics. This research based on the preliminaryanalysis on the microflora of the intestinal tract of abalone (Haliotis discus hannai Ino),probiotics strains screening experiments were conducted both in vitro and in vivo, and thesafety of probiotics were also evaluated. For application of probiotics in farming of abalone,effects on the immune function and disease resistance were investigated in this work.The achievements of this research are as fellows:1. Microflora in the intestinal tract of cultured and wild abalones (Haliotis discus hannaiIno) individuals was studied and PCR-DGGE fingerprint explored to analyzing thedifferences. Results showed that: The total aerobe and facultative anaerobe in the intestinaltract of cultured and wild abalone reached3.50±0.85×106cfu/g,3.03±1.10×106cfu/grespectively; The dominant species in the intestinal tract of two groups was similar, Vibriowas the dominant species and Shewanella, Roseobacter were the secondary dominant species,Bacillus was detected in the cultured group only, which indicated that environment factorcould influence the intestinal microflora of abalone. Futhermore, The PCR-DGGE fingerprinthad high similarity between the two groups which indicated that abalone have specificselective of microflora in the intestinal tract.2. Experiment was conducted to select potential probiotics isolated from124non-hemolysis strains of the GI of abalone by antagonistic against Vibrio harveyi, Vibriosplendidus and enzyme producing capabilities in vitro. Potential probiotics showed nopathogenicity to abalone under107cfu/ml. Then, the identified potential probioticsShewanella colwelliana WA64and Shewanella olleyana WA65had significantly improvedweigh gain ratio and survival rate in a120d feeding experiment (P<0.05). Furthermore, theeffects of WA64and WA65in pilot scale trials showed Mortality no. of juvenile smallabalone was decreased obviously. The antibiotic sensitive test results revealed that only strainWA65was resistant to Gentamicin and Streptomycin, but sensitive or medium sensitive to theother13kinds of antibiotics. 3. Experiment was conducted to investgate the effects of feeding probiotics WA64andWA65to abalone (Haliotis discus hannai Ino) on immune function and diseaseresistance.Thus, abalone were fed WA64and WA65supplemented diets at concentrations atof~109cfu g-1feed for four weeks, and then challenged intraperitoneally with vibrio harveyiat weekly intervals. Result shows: Compared with the control, cellular immune parametersand humoral immune parameters were higher. Each treatments significantly increased the no.(p<0.05); Inhanced respiratory burst activity and notably greater serum lysozyme wereobseverd (p<0.05). Total protein levels were significantly increased (p<0.05); Futhermore,each treatments led to significantly reduction in mortalities at different feeding regime(p<0.05).