VIABILITY AND METABOLIC ACTIVITY OF PROPIONIBACTERIA ISOLATED FROM HENS ON CECAL WATER

ELOY ARGAÑARAZ MARTÍNEZC; JAIME DANIEL BABOT; MARIA CRISTINA APELLA; ADRIANA PEREZ CHAIA

San Miguel de Tucumán

Congreso; VII CONGRESO ARGENTINO DE MICROBIOLOGÍA GENERAL SAMIGE DEL BICENTENARIO; 2011

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 theory) have propionic and acetic acids as main products of fermentation. These organic compounds may affect the short-chain fatty acids (SCFA) balance in the intestine, which stimulate proliferation and differentiation of intestinal epithelial cells and the absorption of electrolytes and water, improving mucus production and thus leading to a decrease of patogens colonization. For all this, the aim was to evaluate the viability, growth capacity and production of SCFA by propionibacteria in an experimental model that simulated the cecal environment of hen. In the present study, nine strains of propionibacteria isolated from hen¡¯s gastrointestinal tract were used. These strains were inoculated individually at a level of 108 cells in cecal water (5% w/v cecal content slurry sterilized by filtration) and incubated for 10 h at 42 ¨¬C in anaerobic atmosphere (95% N2, 5% CO2). 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 final time of fermentation (¥ìmol/g of cecal content). 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 at 6 and 10 h for most strains. This confirmed their growth which was mainly supported by the consumption of nondigestible carbohydrates and polipeptides present in the cecal water. Slight pH variations were observed as the experiment progressed, showing the lowest values at 6 h of incubation. According to the low pH reduction, due to the shortage of nutrients in the cecal water, fementation products (SCFA) were in small quantities. However, SCFA release was observed for all strains, in quantities that variated according to the strain and type of acid (cecal water control: acetic 51.56 ¡¾ 2.9, propionic 16.64 ¡¾ 0.83, butiric 9.04 ¡¾ 0.63; samples inoculated with propionibacteria: acetic 63.46 ¡¾ 8.09, propionic 27.33 ¡¾ 4.11, butiric 8.7 ¡¾ 1.41). These results suggest that potencial probiotic propionibacteria can remain viable and functionally active in cecal water. As a consequence of this, selected strains of propionibacteria could interact with the cecal microbiota and influence the balance of SCFA with positive impact on the health of host. Supported by ANPCyT PICT 2168, CONICET PIP 0996 and CIUNT D429.