On the other hand, B. longum subsp. infantis 14390 decreased rapidly at the beginning of simulation but after the addition of pancreatic juice and bile salts and a change to an anaerobic environment, the reduction rate decreased. Our study suggests that this strain is well adapted to the conditions in the intestine

but needs to be ingested in high numbers to survive the conditions in the stomach (oxygen, low pH). As mentioned above, B. longum subsp. infantis strains belong to the first group of bacteria populating the intestine of infants [26]. In contrast to B. longum subsp. infantis, B. adolescentis this website decreased almost linearly during the 7 h simulation. There was no detectable interruption when the conditions in the fermenter changed. Based on the experiments for the acid tolerance screening, this result was unexpected. However, this might be related to the testing conditions where the bile salt and gastric juice concentrations remained at the initial level and were not diluted as they would be in vivo. In a future experiment, it should be evaluated whether the dilution method developed by Sumeri et al.

[9] would stabilize the cell counts of B. adolescentis during the 6 h simulation period in the intestine. In our study, we also evaluated the stomach-intestine passage of Lactobacillus gasseri K7. The strain has already been evaluated for survival in vivo in piglets [14]. Therefore, it was possible to GF120918 mouse compare our in-vitro results with data from in vivo experiments. Bogovic Protein Tyrosine Kinase inhibitor et al. [14] fed piglets

over a period of 14 days with 5*1010 cfu day-1 of L. gasseri K7. This resulted in approx. 7*104 cfu g-1 in the faeces during the feeding period. It has to be taken into account that the concentration of bacteria was diluted before it finally arrived at the stomach-intestine passage. In a rough approximation, we estimated that about 1% arrived at the passage. This allowed us to compare the results of this piglet study with the end of our simulation. As shown in Figure 5, L. gasseri K7 had a cell concentration of approximately 5*104 tetracosactide cfu ml-1 after the 7 h simulation period (with a pre-culture of 250 ml) which is similar to the concentration in the faeces of the piglets. This suggests that the simulation model used in this study could be a helpful tool to estimate the effects of the passage in an in-vitro model prior using expensive in vivo models. The model could be further optimized by diluting the bile salts and pancreatic juice as described by Sumeri et al. [9]. To simulate the activation and deactivation of enzymes a suitable method has still to be found. When only 100 ml medium was used for the inoculum of L. gasseri K7, the culture survived the simulation better (Figure 7). Both volumes had a similar initial cell count. Both volumes were inoculated by 1 ml.