The aim of the present study was to investigate the precaecal and faecal digestibility of prebiotics and prebiotics combined with probiotics (= synbiotics) in pigs, in order to obtain information about their reactions in the gastrointestinal tract. Furthermore, the effects of these substances on nutrient digestibility and microbial characteristics in chyme and faeces were examined. For the present investigation the ileo-rectal anastomosis in end-to-end technique with preserved ileo-caeco-colic valve was used as surgery method. The pig was chosen as animal model because in previous extensive studies the domestic pig was validated as a proven experimental model for studying aspects of digestive physiology in humans and monogastric animals. Three metabolic trials were carried out with a total of seven pigs prepared with ileo-rectal anastomosis and seven pigs with intact digestibility tract as partners for the surgically fitted pigs. All pigs were treated similarly. As pre- and synbiotic feed additives the following substances were used: lactulose, middle- (DP 10–12) and long-chain (DP ≥ 23) inulin, mannanoligosaccharides and the probiotics Enterococcus faecium DSM 10663 and DSM 7134. Besides the precaecal digestibility of the pre- and synbiotics nutrient digestibility and microbial parameters such as bacterial concentration, daily digesta and nutrient excretion, pH-value, NH₃-concentration, volatile fatty acids/lactic acid and nitrogen balance in chyme and faeces were examined. The following precaecal digestibilities were determined: lactulose 79 %, long-chain inulin 98 %, middle-chain inulin 57 %, and middle-chain inulin combined with Enterococcus faecium (DSM 10663) 55 %. The faecal digestibility of lactulose, middle and long chain inulin and middle-chain inulin + E. faecium (DSM 10663) was determined as 100 %. The addition of pre-, pro- and synbiotics influenced the examined nutrient digestibility and microbial parameters only marginally. It can be concluded that prebiotics are digested and absorbed by pigs to a considerable degree in the ileum. The intention to scientifically prove the positive effects of pre-, pro- and synbiotic carbohydrates in pig nutrition, as they are known from human nutrition, was only partly successful. Due to the fact, that the pigs receive high amounts of prebiotic components with their usual feed anyway, it is questionable whether with this prebiotic concept any additional beneficial effects can be achieved in pig nutrition.