Lactobacillus rhamnosus RC007 with immune-modulatory properties in an experimental model of TNBS-induced colitis in mice. Potential use as a feed additive for pig production.

G. GARCIA; C. DOGI; A. DE MORENO DE LEBLANC; L. CAVAGLIERI; C. GRECO

Congreso; IMMUNOCOLOMBIA 2015 - 11th Congress of the Latin American Association of Immunology - 10o. Congreso de la Asociación Colombiana de Alergia, Asma e Inmunología; 2015

ALAI

In piglets, the inflammatory processes that take place at intestinal level, are associated with the physiological consequences produced by weaning, this induce significant changes that affect gut anatomy, the immune function and consequently, the productivity indexes. In addition, an up-regulation of proinflammatory cytokines, mainly TNF-alpha was reported at weaning. Antibiotics have been banned as growth promoters in animal feed. Different alternatives, such as probiotics have been explored and represent a potentially significant therapeutic or preventive safe advance in animal production. In previous study we found that the lactic acid bacteria (LAB) L. rhamnosus RC007 isolated from maize silage was able to inhibit toxicogenic fungus and to improve silage fermentation in laboratory scale-silos, also proved to have no genes for resistance to antibiotics of veterinary medicine importance. The aim of this work was to evaluate the immunomodulatory effect of Lactobacillus rhamnosus RC007 in an experimental model of TNBS-induced colitis in mice. The trial was conducted to test the ability of LAB to attenuate the inflammatory effects that occur in the post weaning period and use it as a food additive in pig production.Lactobacillus rhamnosus RC007 was previously isolated form maize silage.  Colitis was induced in BALB/c mice by intrarectal inoculation of TNBS solution. Control mice (Mock group) received only PBS mixed with ethanol. TNBS-treated mice were subdivided into 2 groups (n=10): (i) inflammation control group (or TNBS group), (ii) mice receiving the LAB (L. rhamnosus RC007-TNBS group). The strain were orally administered to mice during 10 days before TNBS injection and continued until the end of the experiment. After 14 days, 5 mice per group were sacrificed. Large intestine was taken for macroscopic/microscopic evaluation of inflammation and intestinal contents were collected. Level of both pro-and anti-inflammatory molecules IL-12p70, IL-10, tumor necrosis factor alfa (TNF-alpha) and monocyte chemo attractant protein-1 (MCP-1/CCL2), were measured by using Cytometric Bead Array (CBA) mouse inflammation kit (BD Bioscience, San Diego, EE.UU), values were expressed in relation to the protein concentration in the sample. Cytokine ratios for each mouse were also determined. The experimental protocol was performed two times. Our results showed less macroscopic and histologic damages in the large intestine of mice from L. rhamnosus-TNBS group compared to TNBS group. Some animals presented score similar to the control mice without inflammation. In TNBS group, the concentration of MCP-1 increased significantly compared to the Mock group. This increase was not observed in mice that received the lactic acid bacteria. The pro-inflammatory cytokines IL-12p70 and TNFα also increased significantly in the intestinal fluids of mice from TNBS group compared to the Mock group. However, the administration of L. rhamnosus to TNBS inoculated mice decreased significantly the concentrations of these cytokines in the intestinal fluids, maintaining similar levels to those observed in the mock group. IL-10 concentrations were also increased significantly in the intestinal fluids from TNBS group compared to Mock group; however, no significant differences were observed for this cytokine when compared L. rhamnosus-TNBS group with TNBS and mock groups. The analysis of anti- / pro-inflammatory cytokine ratios showed that these relations were higher in mice that received the lactic bacteria than in inflamed control mice (TNBS group), being IL-10 / TNF-alpha significantly increased. Considering the importance of maintain the health of the animals without the excessive use of antibiotics, in the present work we evaluated the probiotic potential of L. rhamnosus RC007, a lactic acid bacteria that has interesting properties to be used as supplement for animal feeds. Mice that received LAB decreased the severity of the inflammation. They showed less intestinal damage and gut immune modulation. This result is due to the decrease of pro-inflammatory cytokines, however it is important to note that LAB administration conserved an important release of IL-10 to the intestinal fluid demonstrating its anti-inflammatory properties by maintaining increased ratio of anti- / pro-inflammatory cytokines. We can conclude that L. rhamnosus RC007 is a potential probiotic bacterium that can exert beneficial effect as supplement for animal feed in pig production and has the potential to be used in infected/inflamed animals at the weaning period.