| The purpose of the study is to test the effect of Bacillus subtilis of engineered bacteria fermentation product on rat growth performance, the index of immune organs and immune function. And, it would lay a foundation for further application in livestock, and provide certain theoretical and practical value through analysis of the performance and useage. In this experiment, a total of 200 rats were chosen.Firstly,40 rats of 18 to 21 age were randomly divided into four groups according to weight, sex ratio, T group, T15(4.5×106CFU/g), T30(9×106CFU/g) and T50(1.5×107CFU/g) which were fed for a total of 40 days, five days adaption. At the end of the trial, average daily feed intake(ADFI), average daily gain(ADG)and feed to gain ratio(F:G) were tested, and the characterization of rats(including signs and hair color), liver, thymus and spleen indices were also checked. Secondly, 160 SD rats with similar age(18~21), similar weight, half male and half female were randomly divided into 5groups, group A(contrast), group B(1×105CFU/g Bacillus subtilis WB800 N the empty vector),group C(1×105CFU/g Bacillus subtilis), group D(2×105CFU/g Bacillus coli) and group E(3×105CFU/g Bacillus subtilis), there were four replicates in each treatment.Research WB800N-CC31 engineering bacteria fermentation products on rat growth performance,apparent nutrient digestibility and intestinal microflora, and detection of rat serum biochemical indices, immune globulin protein and immune organ index, to investigate the WB800N-CC31 engineering bacteria fermentation product effect and biological activity, in order to obtain the optimal and safe dose. Test results show that:(1) A high dose of Bacillus coli engineering bacteria fermentation product had no effect on rat growth performance, immune organ index and survival rate, there was no any visible change of signs and hair color, so it is safe for rats to eat fermentation product WB800N-CC31 engineering bacteria.(2) WB800N-CC31 engineering bacteria fermentation product can increase average daily weight gain and feed weight ratio after feeding 20~30 and 30~40 days(P<0.05), and average daily gain of was significantly higher than those with D and E diet, group E was 19.3% higher and 20.1% higher than group A and B respectively. At 10~20, 20~30 and 30~40 days, the feed weight ratio of group D and E were significantly higher than that in the other groups(P<0.05),and the E group was 17.7% lower than that of A group, and the feed intake was not significantly different(P>0.05).(3)After feeding 1~10, 10~20, 20~30 and 30~40 days, dry matter, crude ash, calcium,phosphorus and apparent nutrient digestibility rate had no significant difference(P>0.05), crude fat and crude protein apparent digestibility were significantly higher in Group E than that in group A(P< 0.05), group E was 4.4% and 3.6% higher than group A and B respectively.(4) Feeding Bacillus subtilis fermentation product can reduce the number of harmful bacteria and increase the number of beneficial bacteria, especially,compared with the control group(group A and group B), group E significantly reduced the number of rat cecal contents of Escherichia coli and Staphylococcus aureus about 4.4%, 1% and 3.4%, 3% respectively(P<0.05), group E compared with group A and group B,the number of lactobacilli and bifidobacteriawere increased by 3%, 2.2% and 4.1%, 3%(P<0.05).(5) When 20~30 and 30~40 days, thymus index and spleen indices in group E were significantly increased(P<0.05) compared group A, 31%, 32% and 42.3%, 22% respectively,difference of immune organ indices to liver were not obvious. The Ig G, Ig A and Ig M indices of the group E the ratserum were significantly higher than those ofgroup A about, 64%, 27.3% and19%(P<0.05), respectively.(6) The total protein, albumin, globulin, blood glucose levels in the serum were not significant amng groups(P>0.05), but there showed an increasing trend, in the group C, D, E,B and A in turn, the maximum value appeared in the E group. The urea nitrogen content in the serum of group D and E were significantly lower than the group A and B(P<0.05), and compared with the group A, group E decreased by 40%.In conclusion, add 3×105CFU/g engineering bacteria fermentation product can improve growth performance,nutrient digestibility, promote the growth of beneficial intestinal bacteria,inhibit harmful bacteria, enhance immunity, reduce the content of serum urea nitrogen. |
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