Two experiments were conducted to determine phosphorus digestibility, digestible energy and metabolizable energy content of two enzyme-treated soybean meals and in a conventional soybean meal (SBM). In the first experiment, phosphorus digestibilities of two enzyme-treated SBM and a conventional SBM were measured using 36 barrows with an average body weight of 21.9 kg housed in metabolism cages and randomly allotted to six diets with six replicates per diet. The treatments were: 1) A SBM treated with an enzyme mixture containing no phytase; 2) A SBM treated with an enzyme mixture that contained exogenous phytase; and 3) A conventional SBM. Three diets were formulated so that the SBM was the sole source of phosphorus and three diets were fortified with 500 units of microbial phytase. The apparent total tract digestibility of phosphorus was increased (P < 0.05) as phytase was included in the diet (from 59.8 to 77.7% for enzyme-treated SBM and from 65.5 to 79.5% for conventional SBM), but the digestibility of phosphorus in the phytate-treated SBM was not significantly improved with additional phytase in the diet (83.8 and 87.7%, respectively). Adding phytate to the enzyme treatment significantly improved (P>0.05) the digestibility of phosphorus in the SBM.

The digestible and metabolizable energy content of corn, two enzyme-treated meals and conventional SBM were measured in the second experiment using 28 barrows housed in metabolism cages weighing an average of 16.8 kg. A corn-diet consisting of 96.45% corn, vitamins and minerals was formulated. Three additional diets were formulated by mixing corn and each source of SBM with vitamins and minerals. Pigs were randomly allotted to the four diets with seven replicate pigs per diet. Urine and feces were collected quantitatively during the last five days of a 14-day feeding period. The concentration of digestible energy in the two enzyme-treated SBMs and conventional SBM was 4,333, 4,316, and 4,347 kcal/kg of DM, respectively. These values were not different (P > 0.05), but they were greater (P < 0.05) than the DE in corn (3,891 kcal/kg of DM). The concentration of metabolize energy was 3,780, 3,926, 3,914, and 3,980 kcal/kg of DM in corn, the two enzyme-treated SBMs and conventional SBM, respectively. These values were not different (P > 0.05). The researchers concluded that enzyme treatment of SBM without phytase in the mixture does not influence the digestibility of phosphorus or the concentration of DE and ME in the meals.