PS2-17. Effects of Dietary L-glutamate, L-aspartate, and Their Combination on Amino Acid Digestibility and Red Blood Cell Profiles of Weaned Piglets Challenged with Enterotoxigenic Escherichia coli F18

L-glutamate and L-aspartate are functional amino acids essential for intestinal epithelial functions and physiological metabolism. This study aimed to investigate the effects of L-glutamate, L-aspartate, and their combination on red blood cell (RBC) profiles and amino acid (AA) digestibility of weaned piglets challenged with enterotoxigenic Escherichia coli (ETEC). Sixty-five weaned pigs (7.59 ± 1.11 kg BW) were randomly assigned to one of five treatments, with thirteen replications per treatment. The treatments included a control (CON), CON with 1% glutamate (GLU), CON with 1% aspartate (ASP), CON with 1% glutamate and 1% aspartate combination (GAC), and CON with 50 mg/kg carbadox (ABX) supplementation. All pigs were orally challenged with F18 ETEC for three consecutive days at the dose of 1010 CFU/dose/day. The study period lasted for four weeks, with a 7-day adaptation period and 21 days post-inoculation (PI). Blood samples were collected on d 0, 2, 4, 14, and 21 PI, and ileal digesta samples were collected on d 21 PI for RBC profiling and AA digestibility analysis, respectively. Data were analyzed using ANOVA in PROC MIXED of SAS with the individual pig as the experimental unit. On d 14 PI, pigs fed GLU or ASP increased (P < 0.05) hemoglobin, hematocrit, mean corpuscular volume (MCV), and mean corpuscular hemoglobin compared with CON. Interestingly, pigs fed GLU showed lower (P < 0.05) red cell distribution width (RDW) than CON on d 14 PI, but higher (P < 0.05) RDW on d 21 PI. In addition, pigs fed ASP showed lower (P < 0.05) RDW and tended to have higher (P < 0.1) MCV compared with CON on d 21 PI. Apparent ileal digestibility (AID) of dry matter differed among treatments on d 21 PI, with pigs fed ASP showing greatest (P < 0.05) digestibility value compared with the other groups. AID of crude protein, total AA, and the mean of indispensable AA tended to be higher (P < 0.1) in pigs fed GAC and ABX compared with CON. The mean AID of dispensable AA tended to increase (P < 0.1) in pigs fed ASP and GAC compared with CON. Additionally, pigs fed GAC had greater (P < 0.05) AID of lysine, aspartate, and glutamate than CON. In contrast, standardized ileal digestibility (SID) of crude protein was not affected by treatments on d 21 PI. However, pigs fed GAC showed greater (P < 0.05) SID of lysine, aspartate, and glutamate compared with CON. Pigs fed ASP also had higher (P < 0.05) SID of aspartate compared with CON and ABX. In conclusion, dietary supplementation of glutamate and/or aspartate enhanced ileal digestibility of specific amino acids and modulated RBC parameters, indicating potential benefits for nutrient utilization and hematological status in ETEC-challenged weaned pigs.