Effect of Dietary Stevia on Immune Response of Growing Pigs Challenged with Escherichia coli Lipopolysaccharide

This experiment was conducted to investigate the effect of Stevia (R.bertoni) on growing pigs’ blood immune responses after an E.coli lipopolysaccharide (LPS) challenge. Twenty four growing pigs (22.1± 0.5 kg of BW) were used to determine the effect of Stevia on Red Blood Cells (RBC), White blood Cells (WBC), Lymphocyte, Cortisol, tumor necrosis factor-? (TNF-?) concentration and body temperature. Animals were randomly allotted to 1 of 4 treatments: 1) CON (basal diet+ saline), 2) ADD (CON+ 0.30% Stevia+ saline), 3) CON-LPS (CON+LPS), and 4) ADD-LPS (ADD+ LPS). At the end of the feeding period, 24 pigs were selected from the CON and ADD-LPS treatments, and 6 pigs received LPS and the other 6 pigs received an equivalent amount of saline. The data of blood immune system and rectal temperature were collected at 0, 2, 4, 6, 8, and 12 h after challenge. LPS challenge depressed lymphocyte concentration at 4 and 12 h (P < 0.05) in CON-LPS and ADD-LPS group. LPS injection increased rectal temperature at 2 and 4 h post-challenge (P < 0.05). TNF-? concentration increased significantly at 2 and 12 h post-challenge (P < 0.05). In conclusion, supplementation of Stevia in growing pigs improves blood immunity and alleviates the inflammatory responses in LPS challenge.