VOLATILE FATTY-ACID SENSITIVITY OF VEILLONELLA CF3 FROM A CONTINUOUS-FLOW PROBIOTIC CULTURE

Veillonella CF3 which was isolated from chicken cecum as part of an an ti-Salmonella competitive exclusion culture and produces significant a mounts of propionic acid was used to examine growth and survival respo nse to short-chain volatile fatty acids. Growth rare of Veillonella CF 3 was significantly (p < 0.05) decreased by exposure to propionate and butyrate (20-150 mM), while increased by addition of acetate (20-60 m M) during cultivation in anaerobic Viande Levure broth at pH 7.0. As d etermined by percent survivors of Veillonella CF3 in the presence of a cetate, propionate or butyrate at pH 5.0, butyrate was highest in bact ericidal activity, while acetate was least. Survival patterns during i ncubation at pH 5.0 with propionate, which seems to exert major antiba cterial activity in the cecum, showed that Veillonella CF3 could multi ply and survive during prolonged incubation with propionate lower than 100 mM following an initial decrease in viable cells. However, no via ble cells were recovered after six days at concentrations higher than 200 mM. The results indicate that this probiotic Veillonella CF3 strai n may possess adaptive mechanisms for survival against high concentrat ions of propionate, which are initially bacteriostatic to the Veillone lla strain.