ARS | Publication request: Effects of dietary inorganic sulfate levels on growth performance and markers of intestinal inflammation in growing pigs

Submitted to: Journal of Animal Science
Publication Type: Abstract
Publication Acceptance Date: July 7, 2008
Publication Date: July 11, 2008
Citation: Weber, T.E., Spence, C., Whitehead, T.R., Kerr, B.J. 2008. Effects of dietary inorganic sulfate levels on growth performance and markers of intestinal inflammation in growing pigs. Journal of Animal Science. 86(E-Suppl. 2):444.

Technical Abstract: Co-products from the ethanol industry may contain moderate amounts of inorganic sulfur. In the digestive tract, inorganic sulfate can be reduced to hydrogen sulfide by sulfate-reducing bacteria. Hydrogen sulfide has been found to alter the inflammatory response in cell culture and rodent models, but the impact of dietary inorganic sulfate levels on inflammation in pigs has not been reported. In a 35-d experiment, growing pigs (n = 64; 13.3 ± 1.7 kg) were fed diets containing 0, 0.625, 1.25, 2.5, or 5.0% calcium sulfate. In addition, two control diets containing reduced levels of calcium and sulfur were fed. On d 35, all pigs were weighed and samples of ileal tissue, ileal mucosa, and colon tissue were harvested from pigs fed 0 and 5% calcium sulfate for the analysis of cytokine, intracellular adhesion molecule 1 (ICAM1), and suppressor of cytokine signaling 3 (SOCS3) mRNA. The activity of mucosal alkaline phosphatase and sucrase, and the abundance of IkB, and phosphorylated p22/p44 MAP kinase (MAPK) in intestinal tissue were also determined. Increasing dietary inorganic sulfate levels had no impact on ADG or ADFI, but there was a cubic effect (P < 0.05) for G:F as dietary sulfate levels increased. There was no difference in growth performance found in pigs fed reduced calcium or sulfate levels when compared to pigs fed the diet containing added inorganic sulfate. Real-time RT-PCR analysis revealed that feeding 5% inorganic sulfate increased (P < 0.05) the relative abundance of ICAM1, tumor necrosis factor alpha (TNF-alpha), and SOCS3 mRNA and tended (P < 0.09) to increase the relative abundance of IL-6 mRNA in ileal tissue compared to pigs fed 0% added inorganic sulfate. In pigs fed diets containing 5% inorganic sulfate there tended (P < 0.10) to be a decrease in IL-6 and TNF-alpha mRNA. Pigs fed 5% inorganic sulfate had a reduced (P < 0.05) abundance of IkB, and an increase (P < 0.05) in phosphorylated MAPK in ileal tissue, but there was no effect in colon tissue. Addition of 5% inorganic sulfate had no impact on mucosal alkaline phosphatase or sucrase activity. These data suggest that growing pigs can tolerate relatively high levels of dietary inorganic sulfate and that high dietary sulfate levels alter inflammatory mediators in the intestine.