Probiotic Effects Of Three LAB In Vivo On Rats Fed With High Fat Diet

This study analyzed probiotic effects of Enterococcus faecium B21,Lactobacillus plantarum D28 and Lactobacillus caise K17 in vivo on Wistar rats fed by high-fat diet(HFD).The three lactic acid bacteria(LAB)displayed cellular antioxidant and or bile salt hydrolase activities in vitro in our previous studies.Seventy-two male Wistar rats were randomly divided into six groups,including the normal chow diet group(NCD),HFD group,HFD supplemented with ascorbic acid(HFD+Vc),HFD supplemented with E.faecium B21(HFD+B21),HFD supplemented with L.plantarum D28(HFD+D28),and HFD supplemented with L.caise K17(HFD+K17).The group HFD+B21,HFD+D28 and HFD+K17 were individually fed with the corresponding LAB(10~8cfu/ml)each day.After the intragastric administration for 8 weeks,the body weight,body fat mass,serum lipid and liver lipid,oxidative stress-related biomarkers in serum,liver and small intestines,and the expression of obesity-related genes in the perirenal fat and liver of the different rat groups were measured.Meanwhile,bacterial communities in the cecum,colon and feaces of the six rat groups were analyzed by high-throughput sequencing of bacterial 16S rRNA gene.The major results were as below:(1)Obesity index and fasting blood glucose levels of the Wistar rats in different groups.The mean increased body weight of the rats in the groups HFD+B21(203.40 g)and HFD+K17(207.84 g)were significantly increased when compared with the groups HFD(185.86 g,p<0.05)and NCD(152.02 g,p<0.05).The fasting blood glucose levels of the rats in the groups HFD+Vc(6.55 mmol/L),HFD+B21(7.63 mmol/L),HFD+D28(7.10 mmol/L)and HFD+K17(8.18 mmol/L)were significantly reduced compared with the HFD group(8.75 mmol/L,p<0.05),and also no significant different compared with the NCD group(7.08 mmol/L,p>0.05).(2)Lipid levels in blood and liver tissues of the Wistar rats in different groups.The levels of serum total cholesterol(TC,2.04 mmol/L),triglyceride(TG,1.21 mmol/L)and low density lipoprotein cholesterol(LDL-C,0.616 mmol/L)in the HFD+K17 group were significantly lower than the group HFD(2.15 mmol/L,1.71 mmol/L,0.948mmol/L,p<0.05),in contrast the level of serum high density lipoprotein cholesterol(HDL-C,0.886 mmol/L)was significantly higher than the group HFD(0.545 mmol/L,p<0.05).Likewise,the levels of serum TG(1.19 mmol/L)and LDL-C(0.465 mmol/L)were also significantly reduced,but the the level of serum HDL-C(0.807 mmol/L)was significantly increased in the group HFD+D28 when compared to the group HFD(p<0.05).In addition,the liver TC level(0.074 mmol/g protein)in the group HFD+K17was significantly lower than the group HFD(0.086 mmol/g protein,p<0.05).(3)Oxidative stress factor concentrations in serum,liver and small intestine tissues of the Wistar rats in different groups.The serum malonic dialdehyde(MDA),concentration(5.12 mmol/mL)in the group HFD+K17 was significantly lower than the group HFD(6.65 mmol/mL,p<0.05),but the serum superoxide dismutase(SOD,182.26 U/mL)and GSH-Px(3085.7 U/mL)were significantly higher than the group HFD(173.05 U/mL,2771.4 U/mL,p<0.05).Similarly,the serum MDA(4.69 mmol/mL)was significantly decreased,but the serum glutathione peroxidase(GSH-Px,3054 U/mL)was significantly increased in the group HFD+D28 when compared to the group HFD(p<0.05).The liver SOD and GSH-Px levels in the groups HFD+K17(311.74 U/mg protein,402.81 U/mg protein)and HFD+D28(328.06 U/mg protein,531.71 U/mg protein)were significantly higher than the group HFD(292.98 U/mg protein,409.86 U/mg protein,p<0.05).For the group HFD+B21,the liver SOD(329.52 U/mg protein)was also higher than the group HFD(p<0.05).The small intestine MDA concentration(0.62 mmol/mg protein)in the group HFD+D28 was significantly lower than the group HFD(1.46 mmol/mg protein,p<0.05).The small intestine GSH-Px levels in the groups HFD+B21(73.34 U/mg protein),HFD+D28(72.44 U/mg protein)and HFD+K17(73.06 U/mg protein)were significantly increased when compared to the group HFD(53.03 U/mg protein,p<0.05).(4)Cytokine gene expression in perirenal fat and liver tissues of the Wistar rats in different groups.The ucp2 gene relative expression in the group HFD+Vc was significantly decreased when compared to the group HFD(p<0.05).The ppar?relative expression in the group HFD+B21 was significantly higher than the group HFD(p<0.05).The ppar?gene relative expression in the groups HFD+B21,HFD+D28 and HFD+K17 were significantly increased when compared to the group HFD(p<0.05).(5)Bacterial population structure and composition in cecum,colon and feaces of the Wistar rats in different groups.The HFD greatly changed bacterial communities in cecum,colon and feces of the Wistar rats,which resulted in the intestinal bacterial imbalance.The feeding of E.faecium B21,L.plantarum D28 and L.caise K17 all decreased the potential pathogenetic Desulfovibrio in colon and feaces of the HFD rats but increased the probiotic Blautia in feces.In addition,E.faecium B21 was likely colonized in the rectum of the HFD rats.Taken together,the feeding of E.faecium B21 and L.caise K17 for 8 weeks highly increased the body weight of the HFD Wistar rats.E.faecium B21,L.plantarum D28and L.caise K17 decreased fasting blood glucose levels of the rats.L.caise K17 and L.plantarum D28 ameliorated serum lipids but enhanced the serum oxidative stress-related biomarkers of rats,and the latter also decreased small intestine MDA of the rats.All the three LAB significantly incresed small intestine GSH-Px level of the rats.Moreover,E.faecium B21?L.plantarum D28 and L.caise K17 had a hypoglycemic effect and regulated the imbalance of intestinal bacterial population caused by the HFD of the Wistar rats.