| Clostridium butyricum C2 strain isolated from the chicken intestine was evaluated in the present research. Prior to studying characters of resistance and enzyme-producung, inhibition to bacteria to C2 strain, it was identified by biochemical and molecular biological methods firstly. Manipulation of C. butyricum C2 strain on growth, digestive enzyme, humoral immune response, microecology, cooperation with FOS(Fructooligosaccharide) and approach to mechanism were also investigated in Miichthys miiuy. Results were as following:1 The C2 stain was identified Clostridium butyricum by the colony figure, physical, biochemical and molecular biological methods.2 Tolerance of C. butyricum to temperature, bile salts and antibiotic was evaluated. Results showed that C2 strain could survive at 100℃for 10 min, and co-work with chloromycetin, penicillin, cephalothinⅥand acetylspiramycin. The srain could survive in bile salts at the concentration of 5mg/ml.3 Inhibition of C.butyricun, Bacillus subtilis and streptomycin sulfate on Edwardsiella tarda, Vibro anguillarum and Aeromonas hydrophila was valued by filter paper agar lysoplate assay. Results indicated that C2 strain could inhibit Edwardsiella tarda, Vibro anguillarum and Aeromonas hydrophila and inhibition effect of C.butyricun was better than that of streptomycin sulfate(P<0.05). There was no significant differences between inhibition to Edwardsiella tarda of Clsotridium butyricun,and Bacillus subtilis at 12, 18, 24, 36, 48hours(P>0.05). Inhibition to V. anguillarum of C.butyricun was better than Bacillus subtilis(P<0.05) at 12, 18, 36 and there was no differences between them at 36, 48hours. There was different between C.butyricun, and Bacillus subtilis on inhibition to Aeromonas hydrophila at 12 hours(P<0.05) and no difference from 18 hours.4 Based on establishing intestinal epithelial cell model of Miichthys miiuy, adherence experiment was conducted. Results indicated that adherence rate of C. butyricum to intestinal epithelial cells was 7.39±1.85 and decreased adherence rate of Vibro.anguillarum, further more, the live C. butyricum was better than that heat-killing ones(P<0.05); Cell damage rate of C. butyricum and to intestinal epithetical cells was 1.02±0.35 and significantly lower than that of V. anguillarum(P<0.05); cell viability rate of C. butyricum treatment was not significant different in comparison with the treatment without bacteria; cell adherence rate of V. anguillarum decreased 7.03% when the V. anguillarum and C. butyricum co-culture with the epithelia(P<0.05), while in repulsion and substitution experiment cell adherence rate of V. anguillarum decrease 8.97% and 6.02%, respectively.5 Results in the present study showed that C. butyricum supplemented to the diet could significantly increase the DWG(daily weight gain) and SGR(specific growth rate), and reached 1.62±0.36g/D, 0.58±0.09% in comparison with control in Miichthys miiuy, the FCR(food conversion rate) was significantly lower than that of control at dose of 109 CFU g-1(P<0.05).6 The C2 strain could increase the intestinal digestive enzyme activities in Miichthys miiuy. At dose of 109CFU g-1 C. butyricum, amylases activity of hepatopancreas significantly increased and reached 4200.0±98.75 U/g(P<0.05); amylases activity in pylorus cecum and foregut significantly higher than that in control when C. butyricum supplementation to diet over 105CFU g-1(P<0.05); but for hindgut C. butyricum supplementation to diet over 107CFU g-1. There were not significant different for protease in stomach, pylorus cecum and foregut with C. butyricum supplementation to diet, but increased at dose of 107CFU g-1 in hindgut(P<0.05). There was no significant different for lipase with supplementation amount to the diet.7 Results indicated that C. butyricum could increase lysozyme activity in the serum and skin mucus in Miichthys miiuy at the dose of 109CFU g-1, acid phosphatase and phenoloxidase activities(P<0.05), IgM concentration in serum also(P<0.05).8 The C2 strain could survive in the intestine of Miichthys miiuy. The viable bacteria counting method indicated that it was 6.43±0.32, 6.36±0.22, 7.28±0.28 log CFU g-1 in the foregut, midgut and hindgut when the 108 CFU g-1 C. butyricum was fed.9 Pseudomonas was domain microflora in Miichthys miiuy intestine. Dietary supplementation with C. butyricum C2 strain could regulate the microflora structure of intestine, which promoted the growth of Bifidobacterium, Lactic acid bacteria, and inhibited E.coli, Enterobacter, Brevibacterium and probably cause the growth of Photobacterium. There was no significant different on total number of anaerobic bacteria(P>0.05), and total namber of aerobic bacteria was lower than that of control(P<0.05). 10 The C2 strain could cooperate with fructooligosarccharide(FOS). It could promote the growth in Miichthys miiuy, increase DWG(daily weight gain) and reduce FCR(food conversion rate)(P<0.05), significantly decreased fecal nitrogen excretion(P<0.05), and showed the tendency to reduce ammoniac nitrogen in the culture water, but there was not significant different for the dissolved phosphorus excretion.
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