The main objective of this study was to find out if fermentation plays an important role in the effects of a fermentable non-starch polysaccharides (fNSP) rich diet on the stability of glucose and insulin levels and physical activity in sows several hours after feeding. Ten empty sows were either fed a low- (L-sows) or a high-fNSP diet (H-sows), twice daily. In three successive periods, sows received first no infusion and then, in different sequences, continuous fNSP infusion in the cecum or glucose infusion in the blood for 8 days each (GLU; energetic control). The fNSP infusion was as effective, or even somewhat more effective than the GLU infusion in stabilising blood glucose levels in L-sows and reducing physical activity in both L- and H-sows. Insulin stability was less affected by the infusions. Both the GLU and the fNSP infusions prevented the 15% interprandial decline of glucose below basal
levels, which was observed in L-sows with NO infusion. Basal levels themselves, however, in L-sows with a fNSP infusion were reduced by 7% in comparison with NO infusion. This lower level did not seem to cause a higher pre-prandial feeding motivation. As no differences were found in physical activity and stability of glucose levels between L-sows receiving a fNSP infusion and H-sows receiving a GLU infusion, it can be concluded that fermentation
(intracecally received fNSP) can achieve the same effect as fermentation plus gut fill (orally ingested fNSP).