Replacing dietary antibiotics with L-glutamine and synbiotics following weaning and transport in pigs

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Immediately following weaning, pigs must adapt to multiple stressors such as transportation, handling, litter mixing, crowding, and delayed access to feed and water. Antibiotics have traditionally been used to help combat the negative impacts of weaning and transport in pigs. However, their use has been limited in the United States swine industry due to consumer pressures and concerns regarding antibiotic resistance. Therefore, nutraceutical supplements such as L-glutamine and synbiotics may be beneficial alternatives to improve piglet health and welfare following weaning and transport stress. The results from this study suggest that the provision of dietary antibiotics and 0.20% L-glutamine may improve some biological markers of immune function (e.g., haptoglobin). In addition, adding synbiotics (probiotic and prebiotic mix) may be of benefit to intestinal health through an increase in goblet cells that produce mucin to protect the intestine from pathogenic bacteria. Moreover, withholding dietary antibiotics resulted in an increase in gene expression for pro-inflammatory cytokines in the intestine. Despite the improvements in some metrics of intestinal health for pigs provided either nutraceuticals or antibiotics, an increase in growth performance was not detected, but this may be due to the lack of stress in the research setting relative to previous experiments. Taken together, results from this experiment demonstrate that both nutraceuticals and antibiotics can improve biomarkers of immune function and intestinal health, but growth performance improvements may not be apparent when pigs are transported and housed under non-stressful conditions.