| The influence of the probiotic bacterium B.subtilis and L.johnsonii on the immunesystem, intestinal microbial population, average daily liveweight gain and diarrhea scorewere determined in a feeding experiment with piglets. Capture enzyme-linkedimmunosorbent assays were used to quantify the total concentrations of IgA in faecesof different groups. Blood of piglets was sampled by means of vena cava anterior, and flowcytometry detected influence of different probiotics on T-cell subpopulation. Quantitativechange of CD3+CD4+, CD3+CD8+, CD3+CD4+/CD3+CD8+, CD4+CD8+ andCD4-CD8- reflected effect of probiotics. Fresh faeces of different ages'piglets werecollected to detect intestinal microbial population and secretory IgA. Diarrhea condition ofpiglets was recorded to find effect of probiotics in controlling dearrhea. At the beginning.and the end of the experiment, weigh to calculate average daily liveweight gain.Total IgA of piglets in different groups appeared to be unaffected. Piglets of differentgroups showed similar SIgA levels up to 5 weeks after birth with a slight low tendency. Atan age of 35 days, percentage of CD3+CD8+ of B.subtilis group was significantlyhigher than control and L.johnsonii groups (P＜0.05). At the age of 29 days and 35 days, Asto percentage of CD3+CD4+ and proportion of CD3+CD4+/CD3+CD8+, L.johnsoniigroup was significantly higher than control and B.subtilis groups (P＜0.05), suggestingL.johnsonii can improve piglets'immunity and enhance disease resistance,and difference ofB.subtilis and control groups was not obvious. But CD3+CD8+ was obviously higher thananother two groups, suggesting B. subtilis can not enhance piglets'immune obviously, andthen change percentage of CD3+CD8+ in peripheral blood as an extrinsic bacteria. Pigletsthat was supplemented B.subtilis group displayed higher levels of CD4+CD8+ thanL.johnsonii group at the age of 35 days, just then percentage of CD3+CD4+ andCD3+CD4+/CD3+CD8+ of L.johnsonii group was obviously higher than control and B.subtilis groups, suggesting that CD4+CD8+ can not evaluate piglet'health here, at thesame time can not predicate role of CD4+CD8+. Percentage of CD4-CD8- in peripheralblood of different groups was not obviously different, and took on a slight low tendencywhen piglets got older from birth to 5 weeks.With regard to influence ofprobiotics on intestinal microbial population, at an age of 35days, E. coli of control group was obviously higher than L.johnsonii group, but differentgroups were not obvious difference in the remaining time; As to Clostridium, when pigletswere 7,14 and 29 days, B.subtilis and L.johnsonii groups were obviously higher thancontrol group (P＜0.05); At the age of piglets'7 days and 21 days, Peptococcus ofL.johnsonii group was obviously higher than control group (P＜0.05); When piglets wereweaned, Enterococcus of L.johnsonii group was obviously higher than control; At theage of 7 days, L.johnsonii of probiotics groups was obviously higher than control group;Bifidobacterium of different groups appeared to be unaffected. These analysis suggestedprobiotics can increase anaerobian in the intestinal tract to some extent. When piglets wereweaned, enterococcus of probiotics groups increased, which could suggest probiotics couldbalanced the minute ecology of intestinal tract that was proportion of anaerobian andaerobe.Influence of probiotics on piglets' average daily liveweight gain was obvious, especiallyend-weight and day-weight of L.johnsonii group were obviously higher than controlgroup. Probiotics could effectively control piglets' diarrhea, and diarrhea index wasobviously lower than control group (P＜0.05). In conclusion, probiotics could controldiarrhea and elevate average daily liveweight gain effectively.
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