Fig. 1

Schematic diagram of the experimental design. Two basal diets were formulated during 1 to 60 d and 61 d to the end of the experiment. Gilts were fed a basal diet, or a basal diet with three levels of extra dietary fiber (DF) during each phase. DF 1.0, basal diet without DF supplement, and DF 1.5, DF 1.75, and DF 2.0 were basal diets with an additional 50%, 75% and 100% DF, respectively. The DF mixture comprised inulin and cellulose at a ratio of 1:4