【作者】 李先磊；

【导师】 倪学勤；

【作者基本信息】 四川农业大学 ， 微生物学， 2003， 硕士

【摘要】 本试验采集、分离、纯化、鉴定、筛选了4株光合细菌，并研究这4株光合细菌对小鼠免疫功能和鲤鱼生产性能的影响，研究结果如下： 1．从所采集的19个样品中富集、分离到36株光合细菌，经过纯化并鉴定后得到5株光合细菌，分别是：Wst22、Sc21、Sc42、Sx52和Sx51。其中Wst22和Sc42为沼泽红假单胞菌，Sc21和Sx51为万尼氏红微菌，Sx52为荚膜红假单胞菌。Wst22、Sc21、Sc42、Sx51 4株光合细菌生长较快，在培养基中光照培养3天活菌数即可达到10~9个/ml；存活期长，在液体培养基中保存3个月后将其转入新的培养基中仍然能够保持很高的繁殖能力。 2．用牛津杯法测定以上筛选到的8株光合细菌对致病性大肠杆菌和沙门氏菌的抑菌作用，结果表明其中的4株光合细菌在不同程度上对致病性大肠杆菌和沙门氏菌都有抑制作用。其中Wst22对大肠杆菌的抑菌圈直径可达30～32mm，Sc42对沙门氏菌的抑菌圈直径达20mm以上，其余的两株光合细菌也分别在不同程度上对致病菌有拮抗作用。 3．4株光合细菌培养液分别连续灌胃小鼠两周，结果显示均对小鼠没有毒、副作用。解剖结果表明试验组小鼠内脏器官的结构与对照组相比没有明显的变化，说明4株光合细菌作为微生态制剂生产菌种是安全的。 4．免疫功能试验结果表明，4株光合细菌对小鼠免疫器官的发育有很好的促进作用，试验组小鼠脾脏指数和胸腺指数均比对照组高，其中Sc42组小鼠胸腺指数较对照组差异显著(P＜0.05)；Sx51组小鼠脾脏指数较对照组差异显著(P＜0.05)。4株光合细菌对小鼠腹腔巨噬细胞吞噬能力的促进作用非常明显，4个试验组小鼠的腹腔巨噬细胞的吞噬率和对照组相比差异显著(P＜0.05)。说明4株光合细菌对小鼠的免疫能力均有促进作用，尤其是Sc42和Sx51作用更明显。 5．光合细菌复合培养物作为饲料添加剂应用于鲤鱼生产试验，在饲喂35天后试验组总增重分别比某公司鱼饲料组、添加黄霉素组(3ppm)、“益畜宝”组提高9.5％、9.6％、15.4％，料肉比降低了2.6％、6.3％、4.8％，说明光合细菌可以提高鲤鱼的生产性能。更多还原

【Abstract】 Four photosynthetic bacteria (PSB) strains were isolated, purified and identified in the study. The effects of them on mice’s immune function and carp’s growth performance were studied. The results were as follows:1.36 PSB strains enriched from 19 samples. 5 strains were isolated, purified and identified. They were Wst22, Sc21, Sc42, Sx51 and Sx52. Wst22 and Sc42 were identified as Rp. palastris, Sc21 and Sx51 were identified as Rp. vannielii, Sx52 was identified as Rp. capsulate. The four PSB strains, Wst22 Sc21 Sc42 Sx51, grow rapidly and can be conserved for a long time.2. The resistant function to pathogenic E. coli and Salmonella enteritidis of four PSB strains was test that they had different function by Oxford cup test. The diameter of the antimicrobial circle could reach 30~32mm in the test of E. coli by Wst22, and the diameter of the antimicrobial circle could reach 20mm in the test of Salmonella enteritidis by Sc42. The others had the different resistance on the pathogenic bacteria.3. The results of safety check showed that four PSB strains didn’t have toxic and side effect significantly on mice. Anatomic test showed there were no significant difference in the splanchnic organ structure between treatment and control.4. The results of mice immune function test indicated that four PSB strains could promote the development of mice immune function organs. The spleen index and thymus index of the treatment were higher than control. Thymus index of the mice treat with Sc42 was significant from control (p<0.05). Spleen index treated with Sx51 was significant with control (p<0.05). Four PSB strains could enhance the phage index of mice peritoneal macrophages significantly (p<0.05). The results indicated that four strains could enhance mice’s immune function, especially the function of Sc42 and Sc51 were significant.5. The results of carp’s growth performance indicated: The mixed nutrient solution of PSBcould improve the increase of carp’s weight than other three groups (carp’s diet of Juxing, flavomycin, "Yixubao" ), they are 9.5%, 9.6%, 15.4% respectively. And it could decrease the feed consumed/gain of carps than others, they are 2.6%, 6.3%, 4.8% respectively. All those showed that the mixed nutrient solution of PSB could enhance the growth performance of carp.From all the above, it can be concluded that the four PSB strains can accord with the standard of the strain of probiotics not only on the living condition and resistance of the pathogenic bacteria, but on the immune function and growth performance of animals.更多还原