| Mixing lactic acid bacteria on blood lipids and promote the absorption characteristics of the body’s digestive function has a certain theoretical and practical value.In this study,four lactic acid bacteria with auxiliary hypolipidemic function were selected as the research object,and the fermentation conditions of single and mixed lactic acid bacteria were optimized.The effects of mixed hypolipidemic and digestion and absorption of nutrient were discussed.The main findings are as follows:(1)Single and mixed lactic acid fermentation conditions optimization.The single factor experiments investigated medium carbon and nitrogen sources,the pH initial medium,culture temperature and time as well as single and mixed inoculum of lactic acid bacteria functional properties.The results showed that the mixed strains could grow in all the carbon sources,and the best carbon source was lactose.The optimum nitrogen source was tryptone.The results showed that the mixed strain had a significant effect on the cholesterol degradation rate and viable count.The factors were lactose,tiyptone,culture temperature and inoculation amount.And the response surface optimization analysis of each factor was carried out to obtain the optimal culture conditions of single and mixed strains.L.rhamnosus grx10 optimum fermentation conditions were:lactose 21.3g/L,soya peptone 11.4g/L,initial pH 6.5,culture temperature of 36.2 ℃;25h incubation time,5.9%of inoculum.L.casei g9 optimum fermentation conditions were:lactose 20.1g/L,soy peptone 9.6g/L,initial pH 7.0,culture temperature of 32.5 ℃,35h incubation time.4.0%of inoculum.Optimum fermentation conditions of L.Fermentum f5 were:Sucrose 18.7g/L,soya peptone 10.8g/L,initial pH 6.0,culture temperature of 36.7 ℃,25h incubation time,7.1%of inoculum.The optimum fermentation conditions B.longum w10:glucose 22.1g/L,tryptone 11.2g/L,initial pH 5.5,culture temperature 39.6 ℃,incubation time 45h,7.3%of inoculum.Optimal conditions for the fermentation of mixed strain:Lactose 24.2g/L,tryptone 8.4g/L,initial pH 6.5,culture temperature of 28.3 ℃,incubation time 30h,5.2%of inoculum.The results showed that the strain strain was cultured under the optimal fermentation conditions,and the cholesterol degradation rate of the strain was 35.06%higher than that of the control strain.Viable bacteria increased significantly,bile salt hydrolase enzyme activity was significantly improved,comprehensive evaluation is better than the single strain.(2)The effects of single and mixed lactic acid bacteria on blood lipids in experimental animals.To establish rat model of hyperlipidemia,Single and mixed using a fermentation broth of lactic acid bacteria intervene in hyperlipidemic rats,we found lactobacillus can significantly reduce the serum TC and hyperlipidemic rats,the content of TG,LDL-C and of ApoB(P<0.05),and possibly by reducing TC liver.,TG content,increasing fecal TC,TG and TBA as to assist the hypolipidemic effect;antioxidant capacity,can significantly reduce lactobacillus hyperlipidemic rats serum ALT,AST content(P<0.05);vivo experiments confirmed lactobacillus which was helpful to reduce the blood lipid level of rats and improve the antioxidant capacity of rats,and to achieve the effect of hypolipidemic effect.The effect was more significant than that of strains grx10 and f5(P<0.05).(3)To research the effects of single and mixed lactic acid bacteria on digestion and absorption of high fat model rats.It was found that the effects of high fat diet on the apparent digestibility of crude protein,crude fat and crude fiber were not significant.The single and mixed lactic acid bacteria could significantly increase the apparent digestibility of crude fiber,crude fat and total calcium(P<0.05).Among them,the mixed lactic acid bacteria could significantly increase the apparent digestibility of total calcium in rats(P<0.05).Single and mixed lactic acid bacteria can significantly improve the serum TP,GLB content,mixed lactic acid bacteria more advantages(P<0.05),Gavage each group can significantly reduce serum BUN content,but had no significant effect between serum ALB and GLU(P>0.05);Single and lactobacillus can significantly reduce the pancreatic amylase activity in rats,there was no significant effect on pancreatic lipase and trypsin,f5 and mixed lactic acid bacteria can effectively improve the intestinal amylase and lipase activity in rats for 28 days,and the effect of mixed lactic acid bacteria is more significant than that of single strain.The vivo experiments confirmed lactobacillus helps promote digestion and absorption in rats crude fiber,crude fat total calcium nutrients and improve the nutritional index of serum,promote the synthesis of protein metabolism and deposition of proteins,improvement of rat intestinal starch Enzyme and lipase activity.The results showed that the fermentation of mixed lactic acid bacteria could enhance the nutrient metabolism and digestion and absorption of rats.(4)To research the effects of single and mixed lactic acid bacteria on intestinal metabolites in rats.The results showed that,compared with normal control group,model group were fecal metabolites butyric acid,succinic acid,creatine phosphate reduced,a-glucose,[beta]glucose,uracil component content;and acetic acid,valine,isoleucine,TMA,choline and other ingredients increased.Mixed lactic acid bacteria fermentation broth for 4 weeks after the intervention,increased succinic acid and other organic acids content,inhibit the growth of pathogens in the intestine;Increased the α-glucose,β-glucose and other components of the content,improve the body’s intestinal flora metabolism. |
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