| The study combined traditional bacteriological identification with molecular biology to identify a probiotic bacillus strain which isolated and preserved by the laboratory. And then, it studied the best fermentation, the feeding protein degradation in vitro and the feeding effects on weaned pig of the strain.The probiotic strain H6-3 was identified by using 16SrDNA sequence analysis method. The conserved general primers of bacteria 16SrDNA were designed according to the literature. The genomic DNA of H6-3 was extracted and amplified the target 16SrDNA sequence. Meanwhile, the sequence was compared with the BLAST database of NCBI. Then, it used the biology software clustalx1.81 and mega4.0 to construct the phylogentic tree. At last, combined the bacteriological identification; H6-3 strain was identified as Bacillus subtilis.On the basis of single factor optimization result, the best liquid fermentation conditions were confirmed. The conditions were:temperature39℃, pH7.2 and shaker speed was 120r/min. When seed solution concentration was 105cfu/mL and inoculums was 1%(v/v), culture H6-3 strain with the above qualification, the viable count was 6.4×107cfu/mL after 48h.The feeding protein degradation in vitro was studied by using orthogonal design text. The text showed that the best temperature which H6-3 strain degraded? the corn flour, rapeseed dregs and bean pulp were 42℃,39℃and 37℃. The best water ratios were 1:0.9,1:1.5 and 1:1.3. The best degradation time was 60h; bets loading were 20g and inoculums were 5%,5% and 7%. In the orthogonal design text, the DH of the corn flour, rapeseed dregs and bean pulp text group were higher than the control group. They increased 10.49%,12.73% and 6.80%. And the ALPC were 8.40,8.74 and 79.52, lower than the control group about 65.63%,13.11% and 66.13%.From the result of feeding weaned pig, it could concluded that added H6-3 strain to the weaned pig daily diet could increased average daily gain(21,67%)and dropped the feed conversion(7.50%). |
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