Phytic acid is the primary storage of phosphorus in plants, typically in the form of phytate and contributing to 60 to 80% of phosphorus in feedstuffs of plant origin (Eeckhout and De Paepe, 1994). Phytate consists of an inositol bound to six phosphates and contains approximately 28% phosphorus. Corn-soybean meal-based swine diets typically contain 1% phytate or 0.28% phytate-bound phosphorus, but the level varies with the ingredients in the diet.
Phytate is considered an antinutritional factor for swine because it reduces digestibility of phosphorus, energy, and other nutrients in pigs. The antinutritional effect of phytate on phosphorus availability is a consequence of pigs not being able to effectively release phosphorus from phytate. Phytate becomes negatively charged in the digestive tract of pigs, which confers phytate the capacity to form stable complexes with protein and minerals like calcium, zinc, and iron in the digestive tract, preventing nutrient absorption (Woyengo and Nyachoti, 2013). Therefore, the degradation of phytate in the upper part of the digestive tract is essential to improve phosphorus availability and eliminate the antinutritional effects of phytate.