The ATTD and STTD of phosphorus were greater in fermented soybean meal than in conventional soybean meal if no phytase was included in the diets. But if phytase was used, the difference between the two sources of soybean meal was less, meaning that fermentation releases some of the phosphorus bound in the phytate in soybean meal, which increases the digestibility of phosphorus in fermented soybean meal vs. conventional soybean meal.