Synbiosis between Enterococcus faecium DSM 3530 and Fructan Compounds of Different Degree of Polymerization: a Preliminary In vitro Assay in a Condition Simulated Chicken Caecum

This experiment was conducted to determine the potential synergistic relationship between Enterococcus faecium and fructans with different average Degree of Polymerization (DPav) including OligoFructose (OF, DPav 4), Standard-inulin (ST-inulin, DPav 10), Synergy1-Inulin (SYN1-inulin, DPav 15) and High-Polymer inulin (HP-inulin, DPav 25). A sterilized minimal MRS broth media was prepared by omission of glucose. The media pH was adjusted to a constant initial value of 5.8±0.1 and the temperature was maintained at 41°C. Sterilized fructans were added (1% wt⁄vol) to the broths, as experimental treatments with 3 replications each, and the medium with no added prebiotic was considered as the control. The same starting density of 108 E. faecium cells per ml was introduced to all media. The media pH, viable cells count, as well as growth of the latter were determined during 24 hours of incubation. The lowest pH and best growth rates were observed in the media enriched with OF and ST-inulin. Unlike aerobic, the anaerobic conditions produced no significant differences in growth of the bacteria among SYN1-inulin and HP-inulin treatments compared to the control. The viable cells count in the media containing OF was significantly higher than in the control and other treatments. The significant differences were also found among the control and treatments supplemented with ST-inulin and SYN1-inulin. In conclusion, the fructans with lower DP were preferentially metabolized by E. faecium, and hence it follows that a synbiotic blend of E. faecium and OF has the potential to be used in poultry nutrition.