The Cheese Matrix Modulates the Immunomodulatory Properties of Propionibacterium freudenreichii CIRM-BIA 129 in Healthy Piglets

Propionibacterium freudenreichii is a beneficial bacterium, used as a cheese starter, which presents versatile probiotic properties. These properties are strain-dependent. We hypothesized they may also be delivery vehicle-dependent. In this study, we thus explored in healthy piglets how the cheese matrix affects the immunomodulatory properties of P freudenreichii. During 2 weeks, three groups of weaned piglets consumed, respectively, P freudenreichii as a liquid culture (PF-culture), P freudenreichii under the form of a cheese (PF-cheese), or a control sterile cheese matrix (Cheesematrix). The in vivo metabolic activity of P freudenreichii was assessed by determining short chain fatty acids (SCFA) concentration and bifidobacteria population in feces. Whatever the delivery vehicle, P freudenreichii was metabolically active in piglets' colon and enhanced both bifidobacteria and SCFA in feces. P freudenreichii consumption decreased the secretion of TNFa and of IL-10 by peripheral blood mononuclear cells (PBMC). It did not alter IL-10, IFN gamma, IL-17, and TNF alpha secretion in mesenteric lymph node immune cells (MLNC). PF-cheese enhanced significantly Treg phenotype, while PF-culture decreased significantly Th17 phenotype in PBMC and MLNC. Remarkably, only PF-cheese induced an increase of Th2 phenotype in PBMC and MLNC. Ex vivo stimulation of PBMC and MLNC by Lipopolysaccharides and Concanavalin A emphasized the difference in the immunomodulatory responses between PF-culture and PF-cheese group, as well as between PBMC and MLNC. This study shows the importance to consider the delivery vehicle for probiotic administration. It confirms the anti-inflammatory potential of P freudenreichii. It opens new perspectives for the use propionibacteria-fermented products as preventive agents for inflammatory bowel diseases and intestinal infectious diseases.