Dietary fiber is made of non-starch polysaccharides and lignin. It is resistant to degradation by endogenic digestive enzymes in the stomach and small intestine of pigs, but it may be mostly fermented by hindgut microbial. The objectives of this study were to determine the effects of the two functional properties of purified fiber in corn-soybean meal diets on nutrient and energy digestibility, digesta characteristics, and VFA concentration in ileal-cannulated finishing pigs. Six crossbred barrows (Large White×Landrace; initial BW=21.3±1.0 kg) were surgically fitted with an ileal T-cannula and were allotted to 3 treatments in a replicated 3×3 Latin square. 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). Chromic oxide was included in all diets as an indigestible marker. 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.
It was concluded that the inclusion of 5% inulin into a corn-soybean meal diet may increase the hindgut fermentation, but the inulin inclusion in the diet reduce the AID of most nutrients and energy. In contrast, the inclusion of 5% carboxymethylcellulose into a diet increased the AID of CP and NDF.
Gao, L., Chen, L., Huang, Q., Meng, L., Zhong, R., Liu, C., Tang, X., Zhang, H. 2015. Effect of dietary fiber type on intestinal nutrient digestibility and hindgut fermentation of diets fed to finishing pigs. Livestock production science, 174, 53-58. doi:10.1016/j.livsci.2015.01.002