| This research has studied the isolation,biochemical identification and molecular identification of lactic acid bacteria in the traditional koumiss.We also detected the cholesterol lowering effect of the dominant bacteria in vivo and in vitro,thus providing a theoretical basis for the development and application of sour mare milk as a health product.This study was based on 4 portion koumiss collected from Xilinguole Meng,Inner Mongolia.The isolation and biochemical identification of lactic acid bacteria were carried out.30 Lactobacillus rhamnosus、 14 Lactobacillus fuchuensis 、11 Lactobacillus acetotolerance and 8 Lactobacillus plantarum were isolated from 63 lactic acid bacteria.12 strains were selected randomly from the dominant bacteria L.rhamnosus,and the acid resistance test,and the cholesterol reducing effect was determined by PS-Fe colorimetric method and single reagent method(GPO-PAP)respectively.The test results showed that 12 Plant L.rhamnosus had good acid resistance,and L.rhamnosus D-3,D-12 and A-5 had the best cholesterol lowering effect in vitro,and their cholesterol degradation rates were 43.94±0.06%,47.58±0.53% and 45.82±1.10% respectively.The degradation rates of triglyceride were 22.40±1.05%,17.19±0.84% and 16.64±0.61%,respectively.The D-3,D-12 and A-5 were identified by 16 S rDNA molecular identification.The results showed that 3 Lactobacillus strains were all L.rhamnosus and the results of biochemical identification.The 3 L.rhamnosus were administered to Wistar rats to determine their cholesterol lowering effects.64 Wistar rats were fed to the normal feed for 7 d and were randomly divided into 8 groups and each group had 8 rats,each group was a blank control group,ordinary one group,ordinary two group,ordinary three group,high-energy control group,high-energy one group,high-energy two group and high-energy three group.The ordinary test group(ordinary one or two and three groups)and the blank control group were fed with ordinary feed,and the highenergy test group(high-energy one or two,three group)and the high-energy control group were fed high energy feed.After the high energy model was established,the blank control group and the high energy control group were continuously intragastric saline,and the other 6 groups were continuously intragastric D-3,D-12 and A-5.The serum total cholesterol(TC),triglyceride(TG)and High-density lipoprotein cholesterol(HDL-C)were measured by the single reagent method and direct method in the tail vein of Wistar rats of each group of 7 d and 21 d respectively.At the end of the gavage,the organs of the Wistar rats were dissected and the Viscera index was measured.The Viscera index of Wistar rats was measured.The results showed that the high-energy test group compared with the high energy control group and the blank control group,the liver index of the high energy test group was significantly lower than the high energy control group,and the difference was significant.The liver index of high energy one and three groups was higher than that of the blank control group,and the difference was significant(P<0.05),but the two groups of high energy were not significant(P>0.05),indicating that 3 strains of L.rhamnosus have good effects on lowering the liver index,among which L.rhamnosus D-12 is the best.There was no significant difference in the index of kidney and spleen in each group(P>0.05),indicating that high energy feed and 3 L.rhamnosus had no significant influence on the kidney and spleen index.The content of TC,TG and HDL-C in serum of Wistar rats was measured.The results showed that the content of TC and TG in the serum of Wistar rats of 7 d and 21 d high-energy group were all lower than those of high-energy control group,and the difference was significant(P<0.05),but the HDL-C content was not obvious.The content of TC and TG in the serum of high-energy group was significantly higher than the blank control group,and the difference was significant(P<0.05),and the content of HDL-C was significantly lower than that of the blank control group(P<0.05),and the content of TC in the 21 d high-energy group was significantly higher than that in the blank control group,and the difference of the serum TC content in the 21 d high-energy group was significantly higher than that in the blank control group,and the difference was significantly higher than that in the blank control group.The difference was significantly higher than that in the blank control group,and the difference between the 7 d high-energy group was significantly higher than that of the blank control group,and the difference was significantly higher than that in the blank control group.Significant(P<0.05),high-energy two or three groups of serum TC content is slightly higher than the blank control group,but the difference is not significant(P>0.05),the level of TG in the high-energy group is significantly higher than the blank control group,and the difference was significant(P<0.05),HDL-C content was significantly lower than the blank control group,and the difference was significant(P<0.05).There was no significant difference in the content of TC,TG and HDL-C in the serum 7 d between the high energy test groups,and the difference was not significant(P>0.05).In the two groups of high energy group 21 d,the content of TC in the high energy group was the lowest,and the relative ratio of the high energy group was significant(P<0.05),and the relative ratio of the high energy three groups was not significant(P>0.05),and the high energy group was two groups.There was no significant difference in the serum TG content between the three groups and the high energy groups(P>0.05),but all were significantly lower than the high energy group,and the difference was significant(P<0.05),and there was no significant difference in the content of HDL-C in each group.The results of cholesterol lowering test in Wistar rats showed that 3 L.rhamnosus could reduce the liver finger of high fat Wistar rats.The contents of TC and TG in serum and serum had no significant effect on HDL-C,and L.rhamnosus D-12 had the best cholesterol lowering effect. |
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