Effect of an Insoluble Fiber Source on Energy and Nitrogen Digestibility, and on Basal Intestinal Endogenous Losses of Nitrogen and Acid Hydrolyzed Ether Extract, in Growing Pigs.

The overall objective of this study was to determine the effect of an insoluble fiber source (IF; purified cellulose: Solka-Floc, International Fiber Corp., North Tonawanda, NY) on energy and nitrogen digestibility and on basal intestinal endogenous losses (BIEL) of N and acid hydrolyzed ether extract (AEE). Seventeen gilts (76.9 ± 0.7 kg BW) were fitted with T-cannulae at the terminal ileum and randomly allocated to one of two dietary treatments: 1) a control AEE-nitrogen free diet with 3% cellulose and 2) the same diet but with 10% cellulose replacing an equal amount of corn starch. Seven d of adaptation to dietary treatments preceded 3 d of fecal collection and 3 d of ileal digesta collection. Chromic oxide was used as an indigestible marker so that the apparent ileal digestibility (AID), the apparent total tract digestibility (ATTD) and hindgut disappearance of DM and GE were determined along with BIEL of N and AEE. Data were analyzed using the T-TEST procedure (SAS 9.4); pig was the experimental unit. Addition of 10% IF decreased the AID of DM and GE compared to the control diet (80.6 vs. 86.0% and 81.3 vs. 86.9%; P < 0.001 and P = 0.001, respectively). Addition of 10% IF did not affect BIEL of N and AEE at the terminal ileum compared to the control diet (3.1 vs. 3.2 g N and 3.1 vs. 3.9 g AEE/kg of DMI; P = 0.717 and P = 0.172, respectively). The ATTD of DM and GE decreased with the addition of 10% IF compared to the control diet (88.1 vs. 92.7% and 88.2 vs. 93.3%; P < 0.001 and P < 0.001, for DM and GE, respectively). Total tract BIEL of N increased with the addition of 10% IF compared to the control diet (2.4 vs. 2.0 g/kg DMI; P = 0.037). However, the addition of 10% IF did not affect total tract BIEL of AEE (4.7 vs. 5.3 g/kg DMI; P = 0.411). Addition of 10% IF did not affect hindgut disappearance of DM or GE (7.5 vs. 6.7 % and 6.9 vs. 6.5 %; P = 0.429 and P = 0.705, respectively). In conclusion, increasing the concentration of an insoluble fiber source decreased digestibility of GE and DM, did not affect BIEL of AEE at either the ileum or rectum, and increased BIEL of N across the total tract.