Abstract
A total of 80 piglets ($5.18{\pm}0.61kg$ of BW; 16 d of age) were fed experimental diets to evaluate the effect of extruded full-fat soybean (EFS) on the growth of eatly weaned pigs. Pigs were allotted into five treatments based on body weight, in a completely randomized block design. Each treatment has 4 replicates of 4 animals each. Treatments consisted of diets representing substitutional ratios of EFS for soybean meal. 1) 100:0 (SBM), 2) 75:25 (EFS 25), 3) 50:50 (EFS 50), 4) 25:75 (EFS 75) and 5) 0:100 (EFS 100). During phase I (d 0 to 7), piglets were fed diets containing 3,340 kcal ME, 26% crude protein, 1.85% lysine, 1.0% Ca and 0.9% P. For phase II (d 8 to 21), piglets were fed diets supplying 3,340 kcal ME, 23% crude protein, 1.65% lysine, 0.9% Ca and 0.8% P. Urease activity (pH rise) of EFS (0.18) was three times higher than that of SBM (0.06) indicating that processing conditions were not efficient enough to inactivate urease activity. During the first week postweaning, pigs fed SBM had significantly greater average daily gain (ADG), average daily feed intake (ADFI) and better feed conversion ratio (FCR) compared to pigs fed FFS diets. Linear negative effect on growth rate was found as the inclusion rate of FFS increased. During d 8 - 21 postweaning, piglets fed EFS 50 diet showed the best ADG and FCR despite no significant difference between treatment SBM and EFS 25 have been observed. Overall, piglets fed diets up to 50% FFS inclusion rate exhibited similar weight gain. Only piglets fed EFS 100 diet showed a significantly decreased growth rate. No other significant effect was found in feed intake and feed conversion ratio. At d 7, dry matter digestibility was higher in pigs fed SBM diet than piglets fed EFS 75 diet (p<0.05) and crude protein digestibility was higher in piglets fed SBM diet than piglets fed EFS 50, EFS 75 and EFS 100 (p<0.05). At d 21, no difference other than in phosphorus digestibility was detected. This indicates that piglets at 21 d postweaning are capable of utilizing nutrients from FFS. No treatment effects were detected in blood metabolites. The data suggests that piglets at 16 d of age are not sufficiently mature to use extruded FFS in their diets. Nevertheless, FFS seemed to be able to replace upto 50% of SBM in weaned piglet diet.