PS3-9. Effects of Replacing Plasma Protein with Egg Protein on Growth Performance, Fecal Score, Antioxidant Status, Inflammation, and Gut Barrier Functions in Weaning Pigs.

Abstract This study evaluated the effects of egg protein replacing plasma protein on growth performance, fecal score, antioxidant status, inflammation, and gut barrier functions in weaning pigs. A total of 54 pigs (initial body weight: 5.83 ± 1.08 kg weaned at 19.0 ± 2.0 d of age) were allotted to 3 treatments in 6 replicates with 3 pigs per pen for a 42-d feeding trial. Treatments were: 1) Plasma protein (2.5%); 2) Plasma protein (1.25%) + egg protein (2.5%); 3) Plasma protein (0%) + egg protein (5%). All pigs were fed experimental diets in Phase 1 and 2 (d 0-14 and 14-28 postweaning, respectively), followed by a common nursery diet in Phase 3 (d 28-42 postweaning). Growth performance and fecal score (1=normal, 4=severe diarrhea) were measured in each phase and overall period and fecal and blood samples were collected from 1 pig per pen at d 28 postweaning for serum antioxidant capacity, inflammatory cytokines, d-lactate and diamine oxidase level analysis. Linear and quadratic effects were analyzed for increasing egg protein supplementation levels. There were quadratic increases observed in body weight from d 14 to 42 postweaning (25.54, 24.39, and 25.78 kg, respectively at d 42 postweaning) and in average daily gain in d 0-14, 14-28 postweaning and overall period (p < 0.09; 0.469, 0.442, and 0.475 kg/d, respectively in overall period) with increasing egg protein supplementation levels, while no difference was observed in average daily feed intake. Gain-to-feed ratio had quadratic decreases in d 0-14, 14-28 and 0-28 postweaning with increasing egg protein supplementation levels (P < 0.05; 0.695, 0.626, and 0.665, respectively in d 0-28 postweaning). Although there was no fecal score difference, fecal butyrate concentrations linearly decreased (P < 0.05; 19.67, 13.96, and 13.60 mM, respectively) with increasing egg protein supplementation levels. Serum superoxide dismutase activity tended to have a quadratic decrease with increasing egg protein supplementation levels (P = 0.09; 9.66, 7.31, and 9.28 U/mL, respectively), while serum urea nitrogen levels increased quadratically (P < 0.05; 6.33, 5.36, and 8.17 mg/dl, respectively). Increasing egg protein supplementation levels tended to decrease serum IL-1β levels linearly (P = 0.06; 452.51, 351.47, and 366.92 pg/mL, respectively). There were no differences in serum diamine oxidase, d-lactate, malondialdehyde, protein carbonyl, or catalase activity levels. Feed cost per gain had a quadratic response in d 0-28 postweaning (P < 0.05) with relative values (baseline=100) of 100.0, 106.4, and 94.3, respectively. In conclusion, 5% egg protein supplementation replacing plasma protein could result in comparable growth performance and antioxidant capacity to the 2.5% plasma protein supplementation, while reducing proinflammatory cytokine levels and feed cost per gain, but increasing serum urea nitrogen levels and decreasing fecal butyrate concentrations. However, 2.5% egg protein supplementation replacing plasma protein appears insufficient to enhance growth performance and antioxidant capacity.