Ileal and faecal digestibility of nutrients was studied on 8 intact and 4 ileorectostomized 45 kg pigs assigned at random according to a replicated 2 x2 Latin square design to one of two diets containing either refined sucrose or Jerusalem artichoke tubers (fresh, whole) as the only source of energy. The diets were formulated with soyabean meal to be isonitrogenous. Ileal organic mather (OM) digestibility of Jerusalem artichoke diet was significantly lower (P< 0.001) than of the sucrose diet (48.5 vs 89.1%, respectively). This phenomenon was less pronounced (P<0.05) in faecal OM digestibility in both sources of energy (86.0 vs 95.2%, respectively) indicating decisive participation of the large intestine in the digestion of nutrients of Jerusalem artichoke tubers. The sucrose diet led to higher and lower SCFA concentrations in the ileal and faecal sites (117.5 and 41.3 mmol/100 g DM), while the reverse occurred with the Jerusalem artichoke tubers (21.0 and 117.8 mmol/100 g DM). There was a certain dietary influence in the lactate level in the precaecal part of the alimentary tract of the animals. The experimental data indicate a different site of digestion for both sources of fructose studied and, at the same time, a different extent of digestion of nutrients by the pig.