Effects Of Different Types Of Probiotics On Intestinal Absorption And Barrier Function Of Piglets Challenged With Lipopolysaccharide

For a long time, the use of antibiotics makes significant contributions to thedevelopment of the animal husbandry while reducing many negative effects such astoxicity, drug residuces, bacterial resistance to drugs, therefore the safe and highlyeffective green feed additives instead of antibiotics is bcoming an importantdirection of the development in animal husbandry. The this study, firstly, weresearched biological characteristics of the bacillus subtilis, bacillus licheniformisand lactobacilli from many different sources and using bacteriostasis experiment ofprobiotics to E. coli (K88) in vitro, it was to determine the best compositeproportion of probiotics; And then it was to study the effects of different types ofprobiotic on growth performance and intestinal contents of weaned piglet and theeffects on intestinal absorption and barrier function of piglets challenged withlipopolysaccharide. The main contents were as follows:Experiment1: Comparative analysis of probiotic strains on the biologicalcharacteristicsStrains were isolated respectively from5kinds of bacillus subtilis products,6kinds of bacillus licheniformis and3kinds of lactobacilli products and identifiedthrough physiological and biochemical method. The experiment of hightemperature resistance test, acid resistance test, bile salts resistance test andbacteriostatic test were carried out and then the best strains were screened throughcomprehensive comparative analysis for fermentation production of probiotic. Theresults fouond that bacillus subtilis ZJ2had stronger high temperature resistancecharacteristic, strain ZJ4had stronger acid resistance and antibacterialcharacteristics, they were not significant differences in bile salt resistantcharacteristi expect for poor strain ZJ3; Strain D2of bacillus licheniformis hadstronger resistance characteristic to high temperature and bile salts, Strain D3wasbetter in acid properties, strain D4had better antibacterial characteristic whilestrain D2was poorer; Lactobacillus strain R2had stronger resistance characteristic to acidity, bile salts and bacteriostasis. The results showed that bacillus subtilis ZJ4,bacillus licheniformis D2and lactobacillus R2having relatively strong biologicalcharacteristics, could be used as excellent strains for fermentation experiment.Experiment2: The research on antibacterial test of different combinations ofprobiotics on E.coli K88in vitroThe different proportions of Bacillus subtilis and Bacillus licheniformis wereused to study their antimicrobial effects on inhibiting E. coli growth. And then thebest composite bacillus was mixed with Lactobacillus and yeast in differentproportions. The inhibitory effcts of composite strains on E. coli were determinedby the number of E.coli. The results showed that the optimal ratio of Bacillussubtilis and Bacillus licheniformis for inhibiting E.coli prolification was1:1, andoptimal ratios of Bacillus composite, Lactic acid bacteria and Yeast was2:3:1toinhibit the growth of E.coli, this can get the best strongest inhibitory effect onE.coli(K88), and determine the best composite ratio of probiotics.Experiment3: Effects of different types of probiotics on growing performanceand blood biochemical indices of weaned pigletsA total40weaned piglets (duroc×large white×landrace) were randomlyassigned to five treatments at28days, each treatment included8piglets that weresubdivided equally to4pens, each pen have2piglets. The five treatments were thatcontrol, treatment1(Bacillus), treatment2(Lactobacillus), treatment3(CompoundProbiotics), treatment4(Colistin sulfate), the experiment was carried out for30days. After that, the growth permance and blood biochemical indicators weredetermined. The results found that①there was no significantly effect in theaverage daily gain (ADG) of weaned piglets feeded by Bacillus, Lactobacillus andCompound Probiotics (P>0.05). Bacillus and Compound Probiotics could improveremarkably the rates of feed intake and ADG (F/G) of piglets (P<0.05), there wasno significantly effect on F/G of weaned piglets feeded by Lactobacillus (P>0.05).While Bacillus, Lactobacillus and Compound Probiotics could decrease remarkablythe diarrhea ratio (DR) of piglet (P<0.05);②Lactobacillus and Compound Probiotics could effectively improve the blood glucose levels of weaned piglets(P<0.05), but Bacillus had no significantly effect on the the blood glucose levels(P>0.05). The three probiotics had a tendency to improve the content of serum totalprotein and urea nitrogen (P>0.05). The results showed that three different types ofprobiotic all improved the feed conversion rate, reduced effectively the occurrenceof the diarrhea of piglets.Experiment4: Effect of different types of probiotics on intestinal microflora，pH and Volatile Base Nitrogen of weaned pigletsThe experiment was conducted to stduy the effect of Bacillus, Lactobacillus onintestinal microflora，pH and Volatile Base Nitrogen (VBN) of weaned piglets.24healthy piglets were randomly assigned to three treatments, each treatment included8piglets that were subdivided equally to4pens, each pen have2piglets. The threetreatments were that control, treatment1(Bacillus), treatment2(Lactobacillus), theexperiment was carried out for30days. After the test, all piglets in each group wereslaughtered, the digesta of the cecum and colon was collected to determineintestinal microflora，pH and Volatile Base Nitrogen. The results showed that theBacillus and Lactobacillus had both improve the relative number of lactobacilli inthe cecum and colon, reduced the pH value of cecal digesta, increased the pH valueof colonic contents and also reduced the contents of VBN in the cecum and colon.Experiment5: Effects of different types of probiotics on intestinal absorptionand barrier function of small intestinal mucosal of piglets challenged withlipopolysaccharideThe study was conducted to investigate the effects of of different types ofprobiotics on intestinal absorption and barrier function of small intestinal mucosalof piglets challenged with lipopolysaccharide (LPS). A total32weaned piglets(duroc×large white×landrace) were randomly assigned to four treatments at28days，each treatment included8piglets that were subdivided equally to4pens, eachpen had2piglets. The four treatments were that control group(basal diet), LPSgroup (basal diet), treatment1(Bacillus), treatment2(Lactobacillus), the experiment was carried out30days. On d30, piglets in the LPS and treatmentgroups were injected intraperitoneally with LPS (100μg/kg BW)，whereas pigletsin the control group were injected intraperitoneally with the same volume ofphysiological saline. At2h after LPS challenge, D-xylose was orally administratedat the dose of0.1g/kg·BW, at3h after LPS challenge, blood samples werecollected, and at6h after LPS challenge, all the piglets were slaughtered to collectsmall intestinal tissue samples and scrape intetinal mucosa for analysis.The results found that:①Compared with control group, LPS challengereduced the ratio of villus height to crypt depth in jejunal mucosa (P<0.05), thevillous width and surface area and alkaline phosphatase (AKP) activity in duodenal(P<0.05) and jejunal mucosae (P<0.05). The D-xylose content in plasma wasreduced by33.3%(P<0.05), lactase activity in jejunal mucosa was significantlyreduced (P<0.05), invertase activity in ileum mucosa was increased (P>0.05) andDAO activity of plasma significantly was increased (P<0.05) in LPS group.②Compared with LPS group, Bacillus group and Lactobacillus group increased theratio of villus height to crypt depth in jejunal mucosa (P<0.05), Lactobacillus groupincreased the villous width and surface area in duodenal mucosa (P<0.05) andBacillus group increased the villous width and surface area in jejunal mucosa(P<0.05), while there was no significantly effect in AKP activity in Bacillus andLactobacillus groups. D-xylose content in plasma were increased by15.6%(P>0.05)and18.8%(P>0.05), invertase activity in ileum mucosa was significantly reduced(P<0.05), lactase activity in jejunal mucosa was significantly increased (P<0.05) inBacillus and Lactobacillus groups, lactase activity in ileum mucosa in Lactobacillusgroups was significantly increased (P<0.05); DAO content in jejunum and ileummucosa in Bacillus group were reduced by27.1%(P<0.05) and38.0%(P<0.05),DAO content in jejunum and ileum mucosa in Lactobacillus group were werereduced by33.3%(P<0.05) and17.0%(P>0.05). These results indicated thatDietary supplementation with Bacillus and Lactobacillus can partly alleviate theintestinal damage induced by LPS challenge in piglets, which may protect the integrity of intestinal mucosa to a certain extent.