Effects Of Enterococcus Faecium SF68 On Production Performance,Intestinal Morphology And Colonic Microflora Community Of Weaned Piglets

The experiment was carried out to explore the effects of Enterococcus faecium SF68 on the production performance,diarrhea rate,antioxidant activity,intestinal morphology and colonic microflora community of weaned piglets and to discover the potential role of Enterococcus faecium SF68 in substitution for antibiotics.1.Effects of Enterococcus faecium SF68 on production performance,diarrhea situation and antioxidant activity of weaned pigletsNinety 21-day-old crossbred(Duroc x Landrace x Yorkshire)weaned piglets(ratio of male to female was 1:1)with similar body weight)6.58±0.07kg)were randomly assigned to 5 treatments according to live weight with 3 replicates(pens)per treatment and 6 piglets in each pen.The 5 treatments were as follows:CON(a basal diet),ANT(the basal diet+0.02%Colistin with the concentration of 10%,0.0075%Chlortetracycline with the concentration of 15%),ALEF(the basal diet+1%Colistin at 0.02%.15%Chlortetracycline at 0.0075%+0.01%Enterococcus faecium SF68 with the concentration of 1.0×1010 CFU/g),LEF(the basal diet+0.01%Enterococcus faecium SF68),HEF(the basal diet+0.01%Enterococcus faecium SF68).The duration of the experimental was 21 d.The average daily gain(ADG),average daily feed intake(ADFI),the ratio of feed/gain(F/G),diarrhea rate and diarrhea score were recorded and calculated during the experiment.The blood sample was taken from precaval vein.The antioxidant activity index of serum,liver,jejunum and ileum was determined.The results were as follows:ADG,ADFI and F/G had no significant difference among the 5 treatments(P>0.05).The diarrhea rate of ALEF was significantly lower than that of CON(P<0.05);The diarrhea rate of LEF had a tendency to be lower than that of CON(P<0.1);The diarrhea score of ALEF and LEF tended to be lower than CON(P<0.1).(2)Serum H2O2 levels of ALEF and LEF were significantly higher than that of CON(P<0.05);Liver H2O2 level of LEF was significantly lower than that of CON(P<0.05).Liver SOD.T-AOC levels of ALEF and HEF were significantly higher than that of CON(P<0.05).Jejunum H2O2 levels of ALEF,LEF and HEF were significantly lower than that of CON(P<0.05).Jejunum SOD activity was significantly higher than that of CON(P<0.05).Compared with CON,ileum SOD activity of other group were significantly increased(P<0.05),and ileum MDA level were significantly decreased(P<0.05).2.Effects of Enterococcus faecium SF68 on intestinal histology of weaned pigletsDuodenum,jejunum and ileum segments were sampled to make into paraffin sections to observe histologic indexes.Small intestinal were sampled to make into electron microscopic section to observe ultrastructure.The results indicated:Compared with CON,the villus height of duodenum in LEF was significantly increased(P<0.05),the ratio of villus height to crypt depth of duodenum in ALEF was significantly increased(P<0.05).Compared with CON,the villus height of jejunum in ALEF,HEF were significantly increased(P<0.05).The microvillus exfoliated in CON and ANT.The striated border in CON,ANT were thinner than those of other groups.Microvillus in ALEF,LEF were more inerratic and tidier than those in CON.3.Effects of Enterococcus faecium SF68 on colonic microflora community of weaned pigletsColonic content of piglet was sampled for this experiment at 42 days at age.Highthroughput 16S rRNA sequencing technology was applied to evaluate effects of Enterococcus faecium SF68 on intestinal microflora community of weaned piglets.The results manifested:(1)Chaol index of LEF,HEF were significantly higher than CON(P<0.05).(2)The relative proportion of Firmicutes,Tenericutes were significantly higher than CON(P<0.05).The relative proportion of Fibrobacteres tended to increase compared with CON(P<0.1).(3)Community structures of LEF and HEF was similar which formed distinct cluster in hierarchical dendrogram and far away from CON in Unifrac distance.The abundance of Lactobacillus was significantly different among groups.Based on the results above,Enterococcus faecium SF68 could improve growth performance while reduce diarrhea of weaned piglets.Its mechanism might be related with the effects on reducing antioxidant stress and the effects of protecting the mucosal barrier.Appropriate dosage of Enterococcus faecium SF68 in diet was 0.01%.