Inulin or plant materials containing this polysaccharide are deemed interesting additives to feed mixtures for pigs. The experiment was conducted with 120 weaners, hybrids of (PLW × PL) × Duroc breeds with the initial body weight of 30.0±0.5 kg, which were divided into 5 feeding groups. Inulin was added to feed mixtures in the following forms: 2% inulin obtained from chicory roots with two extraction methods: water (group II) and water-alcohol (group III), and 4% powder from Jerusalem artichoke tubers (group IV) or from chicory roots (group V). Body weight of the animals and feed intake were controlled at two-week intervals, and carcasses were analysed postslaughter. Determinations were carried out for physicochemical properties of longissimus dorsi muscle of fatteners. Additional measurements were made for pH value, electrical conductivity and colour (CIE L*a*b* system) of fresh and thermally-treated meat samples. The highest body weight gains were recorded in group IV (powder from Jerusalem artichoke tubers) and group II (water additive of inulin). Dietary inclusion of both types of powders contributed to decreased thickness of backfat. The study showed also the effect of adding inulin or inulin-producing materials on the quality of raw and cooked pork. Significant differences between the control and experimental groups were demonstrated for hardness, chewiness and gumminess of cooked meat. The highest colour saturation (L* and b*) and hue value were noted in raw loin of the fatteners administered feed mixtures with inulin from water-alcohol extraction. Inclusion of 2% inulin preparation with differing degrees of polymerization (water or water-alcohol extraction) or inulin-producing materials (topinambur or chicory powder) in fattener diets is likely to improve animal performance, but the application of Jerusalem artichoke appears to be more justified.