424 Effects of level of soybean meal and Yucca schidigeraaddition to diets on growth performance of nursery pigs

A total of 180 crossbred pigs (average BW = 6.1 kg) were used to determine the effects of addition of Yucca schidigera(Micro-Aid; Porterville, CA) to a soybean meal-based diet on growth performance of nursery pigs in a 43-d experiment. Pigs were weaned at 20 d of age and allotted to 1 of 3 treatments in a completely randomized design (5 barrows, 5 gilts/pen; 6 pens/trt). The 3 dietary treatments consisted of: 1) control diet (CNT) containing animal protein sources (plasma, fish meal), 2) a high soybean meal-based diet without animal protein sources (HSBM), and 3) the HSBM-based diet plus 125 ppm of Micro-Aid (MA). Pigs were fed in 4 dietary phases. During d 0–21, animal plasma and fish meal were replaced in the CNT diet with soybean meal. Soybean meal was included at 30% in phases 1 (d 0–7), 2 (d 7–14), and 3 (d 14–21) for the HSBM and MA diets. Soy protein concentrate, soybean oil, L-lysine HCl, DL-methionine, L-threonine, dicalcium phosphate, and limestone were added to the HSBM and MA diets to equalize ME, amino acid, Ca, and P concentrations. During phase 4 (d 21–43), due to decreasing use of animal protein sources, the concentration of soybean meal was similar across the 3 dietary treatments. Feed disappearance and BW were recorded to calculate ADG, ADFI, and G:F for d 0–14, 0–21, 21–43, and 0–43. For d 0–14, pigs fed CNT had greater (P< 0.02) ADG (222 vs. 186 g/d), ADFI (281 vs. 254 g/d), and G:F (0.79 vs. 0.73) compared with pigs fed the HSBM diet. There was no difference (P> 0.10) in growth performance between pigs fed CNT and MA diets during d 0–14. Pigs fed MA tended to have greater (P< 0.10) ADG (209 vs. 186 g/d) and greater (P< 0.04) G:F (0.78 vs. 0.73) compared with pigs fed the HSBM diet during d 0–14. However, for d 0–21, 21–43, and 0–43, there were no differences (P> 0.10) among treatments. These results suggest pigs fed the HSBM diet from d 0–14 have decreased performance, but recover in the following phases, such that no differences in performance were noted at the end of the nursery phase. Addition of Micro-Aid tended to partially alleviate the negative effects of high soybean meal on growth performance during d 0–14 in the nursery. This work was partially supported by NPB SREE.