PSII-18 Effect of L-trp Source and Standard Ileal Digestible (SID) Tryptophan to Lysine Ratio on Growth Performance of Nursery Pigs

Abstract

Abstract To evaluate the different sources of L-Trp on growth performance, a total of 288 weaned pigs (PIC1050 x DNA600) were stratified by gender and BW, and assigned to 1 of 7 dietary treatments. Treatments were control (devoid of feed grade Trp to create SID Trp/Lys = 17), and L-Trp from (Ajinomoto CO., INC., TrpA vs Daesang CO., LTD., TrpD) was added to form SID Trp:Lys ratios of 19, 21, and 23. Chlortetracycline (Zoetis Inc. Parsippany-Troy Hills, NJ) was supplemented in phase 1 (6 d) &2 (9 d), and Mecadox (Philbro Animal Health Corp., Ridgefield Park, NJ) was added in phase 3 (10 d) while antibiotic free diets were fed in phase 4 (17 d). Individual pig BW and pen feed intake was measured at each phase to determine BW, ADG, ADFI and F:G ratio. Data were analyzed as Mixed procedure of SAS as RCBD. Orthogonal contrast was conducted to determine linear and quadratic response with SID Trp/Lys from 17 (control) to 23 for each source of L-Trp. Adding both sources of L-Trp had minimum impact on growth performance in phase 1–3. As in phase 4, a tendency and significant linear increase on ADG with increasing level of TrpA (P = 0.09) and TrpD (P = 0.04) was observed with the highest ADG in pigs fed TrpA19. Pigs fed increasing level of SID Trp/Lys from TrpA had a quadratic reduction on F:G ratio (P = 0.09). The results suggested that a Trp:Lys ratio over 17 may enhance growth performance and source of L-Trp may impact performance.