The effects of the inclusion in the diet of a regular soybean meal (44% CP) or a high protein SBM (HP-SBM, 49% CP), and the degree of grinding of the HP-SBM, on apparent total tract digestibility and growth performance of piglets from 27 to 56 d of age were studied. The experiment compared six different soybean meal treatments where the soy protein provided 6.5% of the dietary crude protein.

The treatments consisted of a soybean meal diet; a diet that included 10% soy protein concentrate (SPC) that replaced the soybean meal and two high-pro soybean meal treatments that were ground or micronized (geometric mean diameter of 881 or 60 ?m). Each treatment was fed to eight pens of six pigs each. Results indicated that from 28 to 56 d of age, treatment did not affect growth performance, but pigs fed the micronized soybean meal had better G:F (P <= 0.05) from 28 to 35 days of age and ADFI (P = 0.06) from 35 to 42 days of age compared to pigs fed the ground soybean meal. In general, nutrient digestibility was higher for the soy protein concentrate treatment than for the soybean meal treatment with the high-pro soybean meal treatment being intermediate. Micronization of the SBM did not affect nutrient digestibility. It was concluded that the inclusion of soy protein concentrate in the diet in substitution for 44% protein soybean meal improved nitrogen digestibility, but did not affect growth performance. Micronization of SBM did not affect nutrient digestibility, but seemed to improve G: F during the first week post-weaning.