213 Increasing Growth Performance by Attenuating the Transportation Stress Response in Nursery Pigs Through L-Tryptophan Supplementation

Abstract

Abstract Weaning and transport stress impairs intestinal function and reduces nutrient absorption leading to reduced growth performance and feed efficiency. The objective of this study was to eliminate or reduce short- and long-term, transport-induced reductions in feed efficiency and growth by providing supplemental Tryptophan (Trp) above NRC (2012) pre- and/or post-weaning. A total of 480 pigs were blocked by sex, ancestry, and body weight (BW) and used in a RCB design with a 2x2x2 factorial arrangement of pre-weaning treatment (oral gavage of Trp at 0.35, 0.45, and 0.55 g/d (increasing every 5d) pre-weaning or control), transport (transported or not at weaning), post-weaning nursery treatment (1X or 2X NRC Trp). At farrowing pigs were blocked by sex, within litter, and randomly assigned to either a pre-wean Trp or control treatment, where Trp supplementation began on d 5 post-farrowing and stopped at weaning. Post-weaning Trp supplementation included a 3 d oral gavage of Trp and 2X Trp in the diet for the entire 42 d nursery period. At weaning, all pigs were blocked by sex, weaning weight and pre-wean treatment and randomly assigned to transport and post-wean treatments. Pigs were fed four nursery phases with diets containing 1X or 2X NRC recommended concentrations of Trp. There were 10 pens/trt with 6 pigs/pen (equal barrows and gilts). Individual BW were determined every 5 d pre-weaning and every 7 d post-weaning along with pen feed intakes. Data were analyzed as a RCB using GLM procedure in SAS 9.4 with fixed effects of pre-wean dietary treatment, transport treatment, and post-wean dietary treatment, the interactions, and random effect of replicate. Pre-weaning Trp supplementation had no effect on pre-weaning growth performance. A 3-way interaction of pre-wean treatment x transportation x post-wean treatment was observed for overall nursery BW (P = 0.0148) and ADG (P = 0.0175). This interaction was the result of post-weaning Trp supplementation increasing BW and ADG in all pigs, except for transported pigs that did not receive Trp pre-weaning. While there were 2-way interactions of pre-wean treatment x post-wean treatment on ADFI at week 1 ( P= 0.0123) and week 6 (P = 0.0297) and a 3-way interaction of pre-weaning treatment x transportation x post-weaning treatment at week 2 (P = 0.0092), there were no consistent or overall effects on overall ADFI or G:F. Tryptophan improves transported pigs BW and ADG when supplemented pre- and post-weaning but does not benefit transported pigs when only supplemented post-weaning, suggesting transportation induced reductions in BW and ADG can be mitigated by supplementing Trp prior to and following transportation.