Impact of systemic immune system stimulation on intestinal integrity and function in pigs

Abstract

Immune system stimulation (ISS) can cause physiological changes in the intestine and impact nutrient utilization in pigs. Our previous work showed that ISS reduced the apparent ileal digestibility of dietary protein and amino acids, increased ex vivo active nutrient transport, but had no effect on transepithelial resistance. A gene expression study was conducted to further investigate the impact of ISS on small intestinal function and integrity. Sixteen of 28 gilts (BW 63 ±4 kg) were injected (i.m.) every 48 h, for 7 d, with increasing amounts of E.coli lipopolysaccharide. Remaining pigs were injected with saline. Pigs were euthanized to collect ileal tissue. Total RNA was extracted and reverse transcribed, and gene expression was determined by qPCR. Immune system stimulation increased expression of MUC2 and SGLT1 by 1.6 and 2.0 folds, respectively (P < 0.05), but had no effect on MUC5AC and GLUT2 (P >; 0.10). No effect of ISS was observed on the expression of genes that control tight junctions, i.e. claudin‐3 and 4, occludin, ZO‐1 and MLCK (P >; 0.10). Collectively, these results suggest that systemic ISS does not affect intestinal integrity and barrier function, but alters absorptive capacity of the small intestine. Reduced apparent ileal digestibility of protein and amino acids in ISS pigs may be associated with increased gut endogenous protein loss, since mucin is the main component of such loss. USDA 2011–68004‐30336