PS1-16. Apparent Total Tract Digestibility of Nutrients and Energy of Diets with Fiber Sources for Pigs in the Initial Phase

Fiber-rich feed ingredients have always had restricted use in pigs feeding due to low digestibility and to negatively impact the utilization of other dietary nutrients. However, these effects are dependent on the type of fiber and the inclusion level of the fibrous feedstuff in diets. The objective of this study was to evaluate the apparent total tract digestibility (ATTD) of nutrients and energy of diets for pigs in the initial phase, with two sources of fibers: wheat middlings (WM) and a processed fiber ingredient (PFI). The PFI was a thermically processed feedstuff, composed of corn, soyhulls and soybean oil coproduct (4,4 Mcal/kg GE, 45% NDF and 8.9% CP). A total of 40 piglets (20.48 ± 5.08 kg) were housed in metabolic cages for 12 days (8 days for adaptation and 4 days for total collection of feces and urine). The diets were corn and soybean meal based, and contained 4% WM or 3.0, 6.0, and 9.0%. of PFI in replacement of corn. Piglets were fed 2.8 times the DE requirement for maintenance (110 kcal DE/kg of BW0.75) with free access to water. Samples of feces and diets were analyzed for dry matter (DM), ash, calcium (Ca), phosphorus (P), nitrogen (N) for crude protein (CP) calculation, ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), and gross energy (GE). Urine samples were analyzed for DM, N, and GE content. The ATTD of DM, ash, organic matter (OM), Ca, P, CP, EE, NDF, ADF, GE, digestible energy (DE), and metabolizable energy (ME) of the diets, and estimated net energy (NE) were determined. A randomized block design was used, with 4 treatments and 10 replicates, with the animal as the experimental unit. The data were submitted to ANOVA and comparison of means by the t-test, using the Mixed procedure of SAS. It was observed that the ATTD of DM, OM, ash, CP, ADF, Ca, and GE, as well as the metabolizability of energy and the contents of DE, ME and estimated NE did not differ among the experimental diets. The EE digestibility of diets PFI_6.0 and PFI_9.0 were similar, but higher (P < 0.05) than that of PFI_3.0, which in turn was higher (P < 0.05) than WM. The ATTD of NDF of diet PFI_9.0 was greater (P < 0.05) than of the other diets, with the digestibility of NDF of diet PFI_6.0 being higher (P < 0.05) than that of PFI_3.0, but both did not differ from diet WM. The ATTD of phosphorus of diet PFI_6.0 was higher (P < 0.05) than of diets PFI_3.0 and WM, which did not differ. The inclusion of PFI up to 9.0% or WM at 4% did not impair the digestibility of most nutrients and energy in the diets.