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目的:从羊新鲜粪便中分离筛选具有降胆固醇能力的乳酸杆菌,探讨其对小鼠血清胆固醇含量的影响。方法:以碳酸钙-MRS培养基和胆固醇-MRS培养基筛选具有高效降胆固醇能力的乳酸杆菌;利用形态特征、生理生化特性和16SrDNA序列分析鉴定分离菌株L-3。为了验证其效果,将40只8周龄雄性BALB/c小鼠随机分为基础饲料组(A)、高脂模型组(B)、高脂模型+生理盐水组(C)、高脂模型+菌株L-3组(D)。分别饲喂第15、30天,采血,测定总胆固醇(totalcholesterol,TC)、总甘油三酯(triglyceride,TG)和高密度脂蛋白胆固醇(highdensitylipoprotein-cholesterol,HDL-C)的含量。结果:筛选得到一株能够高效降解胆固醇的菌株L-3,胆固醇降解率达到(35.93±0.43)%,经鉴定为植物乳杆菌。饲喂第15天,成功构建出高脂血症小鼠模型。灌胃第30天,与B组相比,D组TC、TG、动脉硬化指数水平均极显著降低(P<0.01),HDL-C水平显著升高(P<0.05),HDL-C/TC水平极显著升高(P<0.01),而对照组几乎无降胆固醇效果(P>0.05)。结论:实验获得了1株在体内外均具有高效降胆固醇能力的植物乳杆菌LactobacillusplantarumL-3,为进一步开发其为功能性微生态制剂提供了可能。
OBJECTIVE: To isolate and screen Lactobacillus with cholesterol-lowering ability from fresh feces of sheep and investigate its effect on serum cholesterol. Methods: Lactobacillus with high cholesterol-reducing ability was screened by calcium carbonate-MRS medium and cholesterol-MRS medium. The strain L-3 was identified by morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis. In order to verify its effect, 40 8-week-old male BALB / c mice were randomly divided into basal diet group (A), hyperlipidemic model group (B), hyperlipidemic model group + saline group (C) Strain L-3 group (D). The rats were fed on the 15th and 30th day respectively for blood sampling. The contents of total cholesterol (TC), total triglyceride (TG) and high density lipoprotein cholesterol (HDL-C) were measured. Results: A strain of L-3 that was able to degrade cholesterol was obtained. The cholesterol degradation rate was (35.93 ± 0.43)%, which was identified as Lactobacillus plantarum. On the 15th day after feeding, the mouse model of hyperlipidemia was successfully constructed. Compared with group B, the levels of TC, TG and atherosclerosis index in group D were significantly decreased (P <0.01), HDL-C was significantly increased (P <0.05) (P <0.01), while the control group had almost no hypocholesterolemic effect (P> 0.05). CONCLUSION: Lactobacillus plantarum L-3, an Lactobacillus plantarum L-3 with high cholesterol-lowering activity both in vitro and in vivo, was obtained experimentally, which made it possible to further develop it as a functional microecological preparation.