The quantitative degradation of inositol phosphates (InsP6 to InsP2) in the stomach and small intestine as influenced by microbial phytase and fermented liquid feeding was compared by combining the results from two experiments. Six pigs (49 kg) were fitted with gastric cannulas (Exp. 1) and 3 pigs (42 kg) were fitted with special ileal cannulas (Exp. 2) for total collection of digesta. The pigs were castrated males, and both experiments were 3×3 Latin squares. A basal wheat/barley diet was pelleted at 90 °C (P 4 and Ca 7 g/kg DM). Diet 1, basal diet fed dry; diet 2, diet 1 with microbial phytase (750 FTU/kg) fed dry; diet 3, diet 2 fed in liquid form (fermented 17.5 h, 20 °C, 50% residual in the tank). InsP6-P was not present in gastric or ileal digesta in pigs fed diet 3 due to complete InsP6 degradation before feeding. In pigs fed diet 2 the amount of gastric InsP6-P was considerably smaller compared with pigs fed diet 1 due to phytase addition. On the other hand, the amount of ileal InsP6-P was only slightly less in pigs fed diet 2 compared with diet 1 indicating that InsP6 is greatly degraded in the small intestine. Furthermore, the amounts of gastric or ileal InsP5–InsP2-P were very small for all diets showing that degradation of these compounds is rapid and nearly complete.

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