The Protective Effects Of Bacillus Coagulans,Puerarin And Zinc Oxide On Intestinal Function Of Piglets Infected With Escherichia Coli

In order to provide a theoretical basis for the development and application of BC and PR,this study was conducted to investigate the protective effects of bacillus coagulans（BC）,puerarin（PR）and zinc oxide（ZnO）on intestinal function of piglets infected with Escherichia coli（ETCT）.Forty healthy 7-day-old piglets（Duroc×Landrace×Yorkshire）were randomly allocated to one of five treatments:control group,ETEC group,BC+ETEC group,RR+ETEC group,ZnO+ETEC group.Each treatment group contained 8piglets.The trial period lasted for 10 days.During day 4-9 of the trial,the BC+ETEC group was administered orally with BC（1×10⁸ CFU/kg body weight）,the PR+ETEC group was administered orally with PR（5 mg/kg body weight）,the ZnO+ETEC group was administered orally with ZnO（100 mg/kg BW）,and the control group and ETEC group were administered orally with the same volume of phosphate buffer saline（PBS）.On the day 8 of the trial,the ETEC group,BC+ETEC group,PR+ETEC group and ZnO+ETEC group were administered orally with ETEC K88(1×10¹⁰ CFU per piglet),and the control group were administered orally with the same volume of PBS.On the day 10 of the trial,D-xylose was orally administrated to all piglets.At 1 h after the administration of D-xylose,blood samples were collected to detect plasma biochemistry,blood cell count and other blood indicators,and then all pigs were killed under sodium pentobarbital anesthesia（50 mg/kg BW）to obtain the small intestine.The small intestine was used to detect the intestinal flora and the expression of the related genes and proteins.1.Effects of BC,PR and ZnO on growth performance and blood index of ETEC infected pigletsThe results show that:（1）Compared with the control group,the ETEC group increased the fecal score of piglets（P<0.05）and decreased the average daily feed intake（ADFI）of piglets（P<0.05）.Compared with the ETEC group,the ZnO+ETEC group decreased the fecal scores of ETEC infected piglets（P<0.05）,the BC+ETEC group increased the ADFI of ETEC infected piglets（P<0.05）,the PR+ETEC group had a tendency to increase the ADFI of ETEC infected piglets（P<0.10）.（2）Compared with the control group,the ETEC group decreased the activities of plasma aspartame transaminase（AST）and creatine kinase（CK）（P<0.05）and had a tendency to decrease the blood urea nitrogen（BUN）and the triglyceride（TG）level（P<0.10）.Compared with the ETEC group,the BC+ETEC group had a tendency to decrease the plasma TG and increase the plasma BUN levels of piglets（P<0.10）;the PR+ETEC group increased the plasma AST and CK activities of piglets（P<0.05）,and had a tendency to increase the plasma BUN levels（P<0.10）.Compared with the ETEC group,the ZnO+ETEC group increased the plasma AST activity of piglets（P<0.05）,and had a tendency to increase the plasma CK activities and decrease the plasma TG levels（P<0.10）.（3）Compared with the control group,the ETEC group increased the percentage of basophils（BASOR）,the number of basophils（BASO）,the mean corpuscular hemoglobin contentration（MCHC）,the measured value of mean hemoglobin concentration（CHCM）,and the width of hemoglobin distribution（HDW）in blood of piglets（P<0.05）.Compared with the ETEC group,BC+ETEC group decreased the blood BASO and BASOR of ETEC-infected piglets（P<0.05）,PR+ETEC group decreased the blood BASOR,CHCM and increased the blood WBC of ETEC-infected piglets（P<0.05）,and ZnO+ETEC group decreased the blood BASOR and increased the blood WBC of ETEC-infected piglets（P<0.05）.The results showed that ETEC infection caused diarrhea of piglets,increased fecal scores,decreased food intake and increased the number of basophils.BC administration can improve feed intake and reduce the number of basophils in ETEC infected-piglets;PR administration improved feed intake of ETEC-infected piglets and decreased the number of basophils;ZnO administration decreased the fecal scores of ETEC-infected piglets,decreased the diarrhea rate and the number of basophils in blood of piglets.2.Effects of BC,PR and ZnO on intestinal morphology and microflora structure of ETEC infected pigletsThe results show that:（1）Compared with the control group,the ETEC group decreased（P<0.05）the villus height in duodenum,jejunum and ileum the villus height/crypt depth and villus surface area in duodenum and jejunum of piglets.Compared with the ETEC group,BC+ETEC group increased（P<0.05）the villus height/crypt depth in duodenum and jejunum,and villus surface area in jejunum of ETEC-infected piglets;Both the PR+ETEC group and the ZnO+ETEC group increased the villus height in jejunum and ileum,villus height/crypt depth in jejunum and villus surface area in jejunum of ETEC infected-piglets（P<0.05）.（2）Compared with the control group,the ETEC group increased the plasma DAO activities（P<0.05）and decreased the relative expression of ileal i-FABP protein（P<0.05）in piglets.Compared with the ETEC group,BC+ETEC group increased the plasma d-xylose levels of ETEC-infected piglets（P<0.05）,ZnO+ETEC group decreased the plasma DAO activities in ETEC infected-piglets（P<0.05）.Additionally,BC+ETEC group,PR+ETEC group and ZnO+ETEC group increased the relative expression of i-FABP protein in ileum of ETEC-infected piglets（P<0.05）.（3）Compared with the control group,the ETEC group increased the number of E.coli in cecum of piglets（P<0.05）,decreased the number of lactobacillus in cecum of piglets（P<0.05）,and decreased the number of bifidobacteria and lactobacillus in colon（P<0.05）.Compared with the ETEC group,the BC+ETEC group increased the number of lactobacillus in cecum（P<0.05）,increased the number of bifidobacteria and lactobacillus in colon of ETEC-infected piglets（P<0.05）;Both the PR+ETEC group and ZnO+ETEC group increased the number of lactobacillus in cecum and colon of ETEC-infected piglets（P<0.05）.The above results showed that ETEC infection caused intestinal morphological damage in piglets,increased the number of harmful bacteria（E.coli）in cecum,and decreased the number of beneficial bacteria（lactobacillus）in cecum and colon.BC administration increased the number of beneficial bacteria in cecum（lactobacillus）and colon（bifidobacterium,lactobacillus）,improved the intestinal absorption function of piglets,and alleviated the damage of morphology of duodenum and jejunum in piglets.Oral administration of PR or ZnO increased the number of beneficial bacteria（lactobacillus）in the cecum and colon and alleviated the intestinal morphological damage of jejunum and ileum.3.Effects of BC,PR and ZnO on intestinal immunity and antioxidant indexes in ETEC-infected pigletsThe results show that:（1）Compared with the control group,ETEC group increased（P<0.05）plasma IL-6 level and had a tendency to increase the plasma TNF-αlevel（P<0.10）.Compared with the ETEC group,the BC+ETEC group decreased（P<0.05）the plasma TNF-αlevel in ETEC-infected piglets;the PR+ETEC group decreased（P<0.05）the plasma levels of IL-6 and TNF-αin ETEC-infected piglets;the ZnO+ETEC group decreased（P<0.05）the plasma TNF-αlevel,and had a tendency to decrease the plasma IL-6 levels（P<0.10）in ETEC-infected piglets.（2）Compared with the control group,ETEC group decreased（P<0.05）the CAT activities in jejunum and ileum,had a tendency to decrease the activities of T-SOD and GSH-Px in jejunum of piglets（P<0.10）.Compared with ETEC group,BC+ETEC group increased（P<0.05）the CAT activities in jejunum and ileum of ETEC-infected piglets;the PR+ETEC group decreased（P<0.05）the levels of H₂O₂ in jejunum,and increased（P<0.05）the T-SOD activities in jejunum and ileum,CAT in ileum of ETEC-infected piglets;the ZnO+ETEC group decreased（P<0.05）the levels of H₂O₂ in jejunum,and increased（P<0.05）the activities of CAT and T-SOD in jejunum and ileum of ETEC-infected piglets.（3）Compared with the control group,ETEC group increased（P<0.05）the relative expressions of IL-1β,IL-4 genes in the jejunum and ileum,decreased（P<0.05）the relative expressions of ICAM1,VCAM1,MX2,GBP1 and GBP2 genes in jejunum,and decreased（P<0.05）the relative expressions of ICAM1,MX1 and MX2 genes in the ileum of piglets.Compared with the ETEC group,BC+ETEC group decreased（P<0.05）the relative expression of IL-4 in jejunum,the IL-1βand IL-4 in ileum,increased（P<0.05）the relative expression of VCAM1,MX1 and MX2 genes in jejunum of ETEC-infected piglets;PR+ETEC group decreased（P<0.05）the relative expression of IL-4 in jejunum and IL-1βand IL-4 in ileum,increased（P<0.05）the relative expression of IL-1β,ICAM1,VCAM1,MX1,MX2and GBP1 in jejunum and the GBP1 in ileum of ETEC-infected piglets;ZnO+ETEC group decreased（P<0.05）the relative expression of IL-4 in the jejunum and IL-1βin the ileum,increased（P<0.05）the relative expression of IL-1β,VCAM1,MX1 and MX2 in jejunum and the MX2 in ileum of ETEC-infected piglets.In conclusion,the above results show that ETEC infection can increase the plasma inflammatory cytokines,decrease the antioxidant capacity of the intestine,promote the expression of some intestinal inflammatory related genes,inhibit the expression of some inflammatory and immune-related genes in the intestine,and damage the intestinal function of piglets.Oral administration of BC,PR or ZnO reduced the levels of plasma inflammatory cytokines,regulate the expression of intestinal inflammatory and immune-related genes,improve the antioxidant capacity of the intestine,and thus alleviate the intestinal function damage caused by ETEC infection.