This paper will deal with the effects of the oral application of a probiotic preparation (Bifidobacterium animalis) and of the provision of forage (maize and grass silage) to growing-finishing pigs on the composition of the intestinal microbial population and faecal microflora as an important determining factor for pork safety. 76 pigs were reared in 4 different dietary treatments. Clinical health and immune status plus faeces samples and samples of the gut content from the duodenum, ileum, caecum and colon were collected from each animal. Since the second round of the feeding experiment was only finished in March, the datasets are still incomplete because analyses are ongoing, but preliminary results are already available. Microbial analysis showed that CFU (per g DM of faeces) of bifidobacteria ranged from 2.6*10^8 (maize silage treatment) to 8.7*10^8 (probiotic treatment). CFU counts of E.coli showed a significantly lower amount for the control treatment (4.4*10^5) compared with the grass silage- group (3.0*10^6). Blood analysis did not show significant differences between treatments. Both the high level of animal performance (ADG between 902 and 929 g/d) and the negative clinical findings confirm the good health status of the animals. Statistical analysis with the complete data set will soon show whether the trends from these preliminary results will be confirmed for the overall experiment
