166 Fate of pentoses in the small intestine and hindgut of growing pigs

Abstract

Abstract Two experiments were conducted to test the hypotheses that pentoses absorbed from the small intestine of pigs reduce energy utilization and that pentoses that reach the hindgut are fermented. In Exp. 1, 24 barrows (9.95 ± 0.51 kg) with a T-cannula in the distal ileum were allotted to a completely randomized design with 3 diets that contained 15% glucose, 15% xylose, or 15% arabinose. Ileal digesta, feces, and urine were collected from all pigs. Data were analyzed via ANOVA using the Proc Mixed Procedure of SAS. No differences among diets were observed for apparent total tract digestibility of GE or for DE, but ME in xylose and arabinose diets was reduced (P < 0.01) compared with the glucose diet (Table 1) indicating that xylose and arabinose that are absorbed from the small intestine are excreted in the urine. In Exp. 2, 21 barrows (18.02 ± 1.1 kg) were allotted to a completely randomized design with 3 treatments and 7 pigs per treatment. A diet based on corn starch, casein, and 15% glucose was fed for 11 d. On d 4 through 11, saline, xylose, or arabinose (3% of the daily feed) was infused into the cecum of pigs via an ileal cannula, and feces and urine were collected. Data were analyzed as in Exp. 1. Infused xylose or arabinose was not detected in feces of the pigs infused with pentoses indicating that pentoses are fully fermented in the hindgut (Table 1). In conclusion, dietary free pentoses are absorbed prior to the end of the small intestine, but partially excreted in the urine, and therefore may reduce energy utilization. If pentoses are liberated in the hindgut, they may contribute to the energy status of the pig by being fermented with a subsequent absorption of short chained fatty acids.