PSXVI-4 Supplemental effects of increasing levels of soy protein concentrate replacing animal protein supplements on growth performance and intestinal health of nursery pigs

This study evaluated supplemental effects of increasing levels of soy protein concentrate (SPC) replacing animal protein supplements on growth performance and intestinal health of nursery pigs. Thirty-two newly weaned pigs (6.4 ± 0.4 kg BW) were allotted to 4 treatments in a RCBD with initial BW and sex as blocks and fed for 35 d in 3 phases (P1/2/3 for 10/12/13 d, respectively) following NRC (2012). Dietary treatments were SPC-0 (diet with fish meal 4/2/1%, poultry meal 10/8/4%, and blood plasma 4/2/1% for P1/2/3, respectively); SPC-1, SPC-2, and SPC-3 (SPC-0 with SPC replacing 1/3, 2/3, and 3/3 of animal protein supplements). Titanium dioxide (0.4%) was added to the diets as indigestible marker from d 30. Growth performance was recorded for each phase. Pigs were euthanized on d 35 to collect jejunal tissue to measure intestinal health, and ileal digesta to measure apparent ileal digestibility (AID) of nutrients. Data were analyzed using the MIXED procedure of SAS. Overall, increasing levels of SPC replacing animal proteins reduced linearly (P < 0.05) the BW (21.4 to 17.3 kg), ADG (431 to 312 g/d), and ADFI (551 to 390 g/d) of pigs. The G:F decreased linearly (P < 0.05) on P1 (0.72 to 0.52). Increasing levels of SPC replacing animal proteins did not affect the AID of nutrients. Immunoglobulin A tended to increase (P = 0.099, 3.39 to 5.55 mg/mg of protein) when SPC supplemental levels were compared with the control group. Increasing levels of SPC replacing animal proteins did not affect the concentration of MDA, TNF-a, IL-8, protein carbonyl, and IgG and villus height, villus width, and crypt cells proliferation among treatments. Collectively, increasing level of SPC supplement did not negatively affect the intestinal health and digestibility of nutrients, whereas linearly reduced the growth performance.