Effects Of Co-Administration Of Bacillus Subtilis And Porcine Lactobacillus Salivarius On Innate Immunity In Newborn Piglets

Probiotics, defined as’live microbial food supplements which improve the health of the host’, have obtained increasing medical relevance. In the intestine they may not only prevent the overgrowth of pathogenic bacteria, increase the resistance of the gut to invasion by pathogens and ameliorate disease processes, but also stimulate the immune cells to produce cytokines, regulate the specific and non-specific immune response. Therefore, probiotics have been used for the prevention and treatment of gastrointestinal diseases. At present, there are many researches related to probiotics enhance the host mucosal protection against gastrointestinal infections, and most researches are based on Lactic acid bacteria or Bacillus bacteria. However, very few studies have contemplated the mechanisms of action for probiotics impact on host immune function, especially in the host intestine, whether or not have the interaction between probiotics is not yet reported. Therefore, this study assess the possible modulation to newborn piglets innate immunity by administration of live B.subtilis and L.salivarius to determine any effect due to their interaction in the gut microenvironment. The possible use of such bacterial species as probiotics for swine breeding is discussed.1Impacts of B.subtilis and L.salivarius on the gene expressions of cytokine/pBD-2of small intestine in piglets40newborn piglets were divided into five groups (n=8). After breastfeeding a week, four groups were fed with antibiotic-free feed, and treatments consisted of basal diet containing B.subtilis (1.0×109cfu/mL), L.salivarius (1.0×109cfu/mL), B.subtilis and L.salivarius (volume ratio1:1), and the same amount of sucrose mixed solution at0,7,14,26days, the remaining fed commonly to the end of the trial. Free access to water and feed. All the piglets were sacrificed at28days of age, duodenum and ileum were collected. Interleukin-1β (IL-1β), Interleukin-6(IL-6), tumor necrosis factor-α (TNF-α) and porcine (3-defensin-2(pBD-2)gene expression of the small intestinal were examined dy Real-time PCR. The results showed that the gene expression of IL-1β and IL-6of the small intestine were significantly increased with co-administration of the B.subtilis and L.salivarius. These results indicated that the co-administration of the B.subtilis and L.salivarius could enhance the gene expression of some functional gene and cytokines in the intestinal epithelial cells, and had positive effect to the intestinal mucosal immune, which enhanced the host defense.2Impacts of B.subtilis and L.salivarius on the expressions of TLRs of small intestine in pigletsThe experimental design is same as above. All the piglets were sacrificed at28days of age, duodenum and ileum were collected. The expression of the Toll-like receptors-2(TLR-2), TLR-9of the small intestinal were examined dy Real-time PCR and Western-blot, respectively. The results showed that the gene and protein expression of TLR-2and TLR-9of the duodenum were significantly increased with co-administration of the B.subtilis and L.salivarius. These results indicated that the co-administration of the B.subtilis and L.salivarius could enhance the expression of TLR-2and TLR-9of the intestinal epithelial cells, which activated the immunocyte and restrained the infection of pathogenic microorganism.3Impacts of B.subtilis and L.salivarius on the amount and distribution of IgA producing cells of intestine in pigletsThe experimental design is same as above. All the piglets were sacrificed at28days of age, duodenum、jejunum、ileum and colon were collected. Tissue samples were studied by immunohistochemistry methods for detection of the IgA producing cells in gastrointestinal mucosa. The results showed that fed with B.subtilis, L.salivarius, or the mixture of the two probiotics didn’t change the distribution characteristics of mucosal immunocompetent cells in different part of intestine. But along the intestinal tract from duodenum to colon, IgA producing cells showed a downward trend in the number. In addition, compared with the control group, the number of IgA producing cells of the ileum had no significant changes in the remaining treatments. These results indicated that the colonization of the B.subtilis or L.salivarius did not change the distribution of the IgA producing cells in testinal tract. But could induce antibody-producing cells migrate from the GALT to the proximal small intestine, preferably. Thereby, improved the local humoral immunity of the proximal small intestine.4Impacts of B. subtilis and L. salivarius against Escherichia coli on intestine epithelium in pigletsTo further discuss the anti-inflammatory effects of B. subtilis RJGP16and L. salivarius B1on intestinal in piglets. Based on the previous study, this part of the test, after fed with B. subtilis and L. salivarius, the E. coli K88were inoculated on32、34、36days to piglets, and were killed and sampling on38days. The results of HE staining showed that, while pigs fed with B. subtilis and L. salivarius, the intestinal epithelial cells lined up in order, normal morphology, and no inflammatory cell infiltration. These results suggest that B. subtilis and L. salivarius could inhibit the destruction of intestinal epithelia induced by enterotoxic Escherichia coil in piglets, prevent and treatment the piglet diarrhea.