Viability and metabolic activity of Propionibacteria isolated from hens on cecal water

ARGAÑARAZ MARTÍNEZ E.; BABOT J.D.; APELLA M. C.; PEREZ CHAIA A.

Tucumán

Congreso; VII Congreso Argentino de Microbiología General ?SAMIGE del BICENTENARIO?; 2011

SAMIGE

Recently, our working group has isolated potencial probiotic propionibacteria from hen?s gastrointestinal tract. These anaerobic microorganisms present in Nurmi Culture (products based on competitive exclusion concept) have propionic and acetic acids as main fermentation products. These organic compounds may affect the short-chain fatty acids (SCFA) balance in the intestine, which stimulate intestinal epithelial cells proliferation and differentiation, electrolytes and water absorption and improve mucus production leading to a decrease in the colonization of potential pathogens. The aim of this work was to evaluate the viability, growth capacity and production of SCFA by propionibacteria in an experimental model that simulated the cecal environment of hens. Nine strains of propionibacteria isolated from hen?s gastrointestinal tract were used. These bacteria were inoculated individually at a level of 108 cells in cecal water (obtained from a 5% w/v cecal content slurry sterilized by filtration) and incubated for 10 h at 42 ºC in anaerobic atmosphere (95% N2 2, 5% CO2). The samples were collected at 0, 2, 6 and 10 h, pH was measured, microbial growth was monitored spectrometrically at 560 nm and viable counts were performed. SCFA were detected by HPLC at the end of the experiment. According to OD values all strains showed absence of lag phase, but they did not reach the stationary phase of growth during the time of incubation of this trial (10 h). Viable counts increased after 6 h for most strains. Slight pH variations were observed as the experiment progressed, the lowest values being obtained at 6 h of incubation. According to the shortage of nutrients and the low pH reduction in the cecal water, fermentation products were present in small quantities. However, all strains produced SCFA in amounts and proportions that were strain dependent. Mean values of acetic, propionic and butyric acids were 51.56 &plusmm 2.9, 16.64 &plusmm 0.83 and 9.04 &plusmm 0.63 &mumol/g of cecal content respectively in cecal water control, while in samples inoculated with propionibacteria were 63.46 &plusmm 8.09, 27.33 &plusmm 4.11and 8.7 &plusmm 1.41 &mumol/g of cecal content respectively. These results suggest that strains of propionibacteria can remain viable and functionally active in cecal water. The growth is mainly supported by the consumption of nondigestible carbohydrates and polipeptides present in this environment. Selected strains of propionibacteria could interact with the intestinal microbiota and influence the balance of SCFA with positive impact on the health of host. This behavior allows include the genera Propionibacterium among potencial probiotics for hens. Supported by CONICET PIP 0996, ANPCyT PICT 2168 and CIUNT D429.