Effects of Dietary Wheat Bran on Ileal and Hindgut Digestibility of Nutrient in Pigs and Influences of Ileal Digesta Collection on Proceeding Fecal Nutrient Digestibility

Simple Summary The effects of dietary fiber on nutrient digestibility are relatively well-known in pigs. However, information on the influence of dietary fiber on hindgut nutrient digestibility is lacking, and ileal digesta collection before fecal collection may affect the proceeding fecal digestibility of nutrients. We determined the influences of wheat bran, a fiber-rich ingredient, on ileal digestibility, fecal digestibility, and hindgut digestibility of nutrients in pigs. Additionally, we tested the influence of ileal digesta collection on proceeding fecal nutrient digestibility. Experimental diets contained 0, 20, or 40% of wheat bran. The ileal digestibility and fecal digestibility of energy and nutrients decreased with increasing dietary wheat bran from 0 to 40%. Hindgut digestibility of dry matter and organic matter increased with increasing dietary fiber. The fecal nutrient digestibility did not differ whether fecal samples were collected before or after ileal digesta collection. Overall, the inclusion of wheat bran, a fiber-rich ingredient, reduced ileal and fecal digestibility of most nutrients but increased hindgut digestibility of some nutrients, and ileal digesta collection before fecal collection did not affect fecal nutrient digestibility. Abstract The objectives were to determine the effects of graded inclusion rates of wheat bran (WB) on apparent ileal (AID), apparent total tract (ATTD), and hindgut digestibility of nutrients and tested the influence of ileal digesta collection on proceeding fecal nutrient digestibility in pigs. Six barrows with an initial mean body weight of 70.7 ± 5.7 kg fitted with an ileal T-cannula were used. The animals were assigned to a replicated 3 × 3 Latin square design with three diets and three periods. A basal diet was based mainly on wheat, soybean meal, and cornstarch. Two additional diets were formulated to contain 20 or 40% of WB at the expense of cornstarch. Each experimental period consisted of a seven-day adaptation period and a four-day collection period. After the adaptation period, fecal samples were collected on day 8, and ileal digesta were collected on days 9 and 10. Another set of fecal samples was collected on day 11 to determine the influence of ileal digesta collection on proceeding total tract nutrient digestibility. The AID of energy, dry matter (DM), organic matter (OM), crude protein, and phosphorus linearly decreased (p < 0.05) with an increasing inclusion rate of WB from 0 to 40%. The ATTD of energy, DM, OM, crude protein, ether extract, and phosphorus linearly decreased (p < 0.01) as the inclusion rate of WB increased. Hindgut digestibility of DM, OM, and ether extract linearly increased (p < 0.05) with an increasing inclusion rate of WB. The ATTD of GE and most nutrients did not differ between the two fecal collection periods of before and after ileal digesta collection. Taken together, the inclusion of a fiber-rich ingredient reduced ileal and fecal digestibility of nutrients but increased hindgut digestibility of some nutrients, and total tract digestibility of nutrients did not differ whether the fecal samples were collected before or after two days of ileal digesta collection in pigs.