Soluble wheat pentosans exhibit different anti-nutritive activities in intact and cecectomized broiler chickens

The role of the ceca in the anti-nutritive effect of wheat pentosans was studied in intact and cectomized broiler chickens. Addition of wheat pentosans (equivalent to 30 g pure arabinoxylans/kg diet) depressed the digestibilities of starch, protein and fatty acids in both types of birds. Cecectomized birds were less efficient (P < 0.01) in dry matter and energy utilization, but starch digestion was not influenced by cecectomy. Inclusion of isolated wheat pentosans decreased the fecal protein digestibility by 18% in intact birds and by 7% in cecectomized chickens, with the bird type x pentosan interaction being significant (P < 0.05). The ileal pentosan digestibility was not affected either by addition of isolated pentosans or by cecectomy; however, the fecal pentosan digestibility was significantly (P < 0.001) influenced. Thus, in intact birds the fecal pentosan digestibility coefficient was 0.216 in birds fed the control diet and 0.646 in those fed the diet with wheat pentosans; in cecectomized chickens the corresponding values were 0.193 and 0.399, indicating a significant influence of the hindgut microflora on pentosan digestion. The ileal and fecal digestibilities of fatty acids were also determined. There was no interaction between bird type and pentosan addition in the ileal digestibilities of fatty acids. Depressions in the fecal digestibilities of fatty acids 14:0 and 18:0 were significantly (P < 0.05) greater in intact birds. Our results indicate that anti-nutritive effects of wheat pentosans in poultry are partially due to an increased activity of hindgut microflora.