Effect of dietary fiber type on intestinal nutrient digestibility and hindgut fermentation of diets fed to finishing pigs

The objective of this experiment was to determine the effects of dietary fiber type on intestinal nutrient and energy digestibility and hindgut fermentation in finishing pigs. Six ileal-cannulated pigs (initial BW=21.4±1.5 kg) were allotted to 3 treatments in a replicated 3×3 Latin square. The pigs were provided a corn-soybean meal control diet or a diet in which corn and soybean meal was partly replaced by 5% inulin (INU) or carboxymethylcellulose sodium (CMC). The apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and energy were measured. The VFA concentration was also determined in the ileal and fecal samples. The AID of DM, carbohydrates (CHO), NDF and GE were less (P<0.01) for pigs fed the INU diet than those fed the control and CMC diets. The ATTD and hindgut fermentation of DM, CHO, ADF, NDF, and GE were less (P<0.01) in the CMC diet than in the control diet or the INU diet, whereas, the AID of CP was greater (P<0.05) in the CMC diet than in the other diets. The ATTD of NDF and hindgut fermentation of EE were greater (P<0.01) in the control diet than in the INU diet or the CMC diet. The hindgut fermentation of CHO and GE were greater (P<0.01) in the INU diet than in the control diet or the CMC diet. The total tract flow of nutrients and energy increased (P<0.01) by inclusion of 5% CMC in the diet. There were no differences in ileal VFA concentrations between the diets. The fecal acetate and total VFA concentrations were greater (P<0.01) in pigs fed the INU diet than fed the control diet or the CMC diet. The fecal pH and concentration of acetate, propionate, isobutyrate, butyrate, isovalerate, and total VFA were less (P<0.01) in pigs fed the CMC diet than those fed the control diet or the INU diet. In conclusion, addition of 5% inulin into a diet had a low digestibility of nutrients and energy in upper gut and high hindgut fermentation. In contract, the CMC increased the AID of CP and reduced other nutrient and energy digestibility and fermentation.