Phosphorus Availability in Soybean Meal

Two studies with growing pigs were conducted using the regression analysis technique to estimate the true digestibility of phosphorus in canola and soybean meals and quantify the effect of microbial phytase on total phosphorus digestibilities for these meals. Forty-eight barrows weighing 17-kg were assigned to six dietary treatments arranged in a 3 x 2 factorial with three graded levels of canola or soybean meal (132, 264, or 396 g/kg) and two levels of phytase (0 or 1,000 units/kg). The total collection method was used to calculate phosphorus digestibilities. Results indicated that phytase supplementation improved (P < 0.05) the apparent total tract phosphorus digestibility for soybean meal treatments with values ranging from 34.3 to 38.6% without phytase and from 68 to 71.2% with supplemental phytase. True phosphorus digestibility estimates for SBM without phytase was 40.9% and was increased to 70.8 % (P < 0.05) with added phytase. These two studies indicate a total phosphorus digestibility of 34 or 41% in growing pigs fed canola meal or soybean meal and demonstrate that the addition of microbial phytase at 1,000 units/kg improves true digestibility of phosphorus in canola and soybean meals by 78 and 73%, respectively.

A. S. Akinmusire, A.S. and O. Adeola. 2009. True digestibility of phosphorus in canola and soybean meals for growing pigs: Influence of microbial phytase. J. Animal Sci. 87:977-983.