Effects of blend of organic acids and monoglycerides on immune responses of weaned pigs experimentally infected with enterotoxigenic Escherichia coli F18

Abstract Our previous research implies that dietary supplementation of organic acids blend, monoglycerides blend, and the combination of both can mitigate diarrhea of weaned pigs infected with Escherichia coli (E. coli) F18. The objective of this study was to investigate the effects of dietary supplementation with a blend of organic acids, a blend of monoglycerides, or the combination of both on immune responses of weaned pigs experimentally infected with E. coli F18. Forty pigs [average body weight (BW) = 7.81 ± 0.84 kg] were individually housed and randomly assigned to one of four treatment groups with 10 replicate pigs per treatment. The four dietary treatments were: () Control: nursery basal diet, 2) Acids: basal diet supplemented with a blend of organic acids (formic acid, lactic acid, and sodium formate) at 0.3%, 3) Monoglycerides: basal diet supplemented with a blend of monoglycerides of fatty acids at 0.3%, or 4) Combination of acids and monoglycerides: basal diet added with the acids blend at 0.2% and the monoglycerides blend at 0.2%. The experiment lasted 28 d, with 7 d before and 21 d after the first inoculation (d 0). All pigs were orally inoculated with E. coli F18 (1010 CFU/3 mL) for 3 consecutive days from d 0. Serum samples were collected on d 0, 2, 5, and 14 post-inoculation (PI) to measure the concentration of C-reactive protein (CRP) and haptoglobin using ELISA. Porcine Cytokine/Chemokine13-Plex Discovery Assay (Eve Technology, Canada) was also conducted with serum samples from d 0, 5, and 14 PI. Data were analyzed by ANOVA using PROC MIXED of SAS with a randomized complete block design. The concentrations of serum CRP and haptoglobin were increased (P < 0.0001) on d 2 PI and then gradually decreased on d 5 and 14 PI. However, no differences were observed in serum CRP and haptoglobin concentrations among all treatment groups throughout the experiment. Pigs fed with monoglycerides tended (P < 0.10) to have decreased serum granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin 1-alpha (IL-1α), and tumor necrosis factor-alpha (TNF-α) concentrations on d 0 PI compared with other treatments. Pigs supplemented with monoglycerides also tended (P < 0.10) to have decreased GM-CSF on d 5 PI and less IL-1α on d 14 PI among all treatments. Supplementation of the combination tended (P < 0.10) to have greater GM-CSF concentration on d 5 PI compared with other treatments. In conclusion, dietary supplementation of monoglycerides blend or the combination of organic acids and monoglycerides alleviates systemic inflammation of weaned pigs during E. coli F18 infection by modulating related cytokines. However, additional research is needed to understand the modulation mechanisms.