A study including two experiments was carried out to evaluate partial substitution of soybean meal (SM) by full-fat extruded soybean (ES) in the pre-starter diet, for piglets weaned at 21 days of age. In each experiment four levels (0, 20, 40 and 60%) of substitution of SM by ES were compared. In the first experiment, daily feed intake (DFI) and feed:gain ratio linearly increased for the total nursery period, due to substitution of SM by ES. Daily gain (DG) was not affected. Average height of the intestinal mucousa (HIM) in the low jejunum was linearly reduced, and in the duodenum had a quadratic effect, when ES was increased. In the experiment 2, DG, DFI and body weight at the end of the nursery phase (BW35) had a quadratic response, in consequence of substitution of SM by ES. It was concluded that partial substitution of SM by ES in the pre-starter diet for piglets weaned at 21 days of age provide an improvement for performance of piglets in the initial period after weaning. In the experiment 1, it was not possible to determine the maximum value for substitution of SM by ES, because DG showed a linear response until 60% of substitution. However, in the experiment 2, the best result for DG, estimated through the derivatization of the quadratic equation, was obtained at 26.82% of substitution, from 0 to 14 days post weaning.
diarrhea; intestinal morphology; performance; soybean byproducts
