Expression of toll-like receptors and inflammatory cytokines in gut-associated lymphoid tissues in pigs subjected to cross-fostering

Gastrointestinal (GI) disease is the leading cause of preweaning mortality and thus of great economic loss for the swine industry. Newborn pigs must receive colostrum during the first 3 d of life to receive a proper maternal immune protection. This study sought to establish a baseline for mucosal immune gene expression in young pigs reared in cross-fostering model given high quality colostrum from birth dam or foster dam upon birth. Thirteen piglets were euthanized at d 21 (a common weaning time in the pig industry) to characterize the mucosal inflammatory gene expression profiles at different biogeographical locations. Tissues from intestinal mucosa in jejunum, colon, ileum, peyer’s patches and associated lymph nodes were utilized. Piglets were randomly assigned to 1 of 3 treatments, according to colostrum source and postcolostral milk feeding for 21 d, as follow: treatment 1 (n = 8), received colostrum and post-colostral milk feeding from their own dam; treatment 2 (n = 8), received colostrum from foster dam and returned to their own dam for post-colostral milk feeding; and treatment 3 (n = 8), received colostrum and post-colostral milk feeding from foster dam. Quantitative real time PCR analysis was performed to quantify the expression of toll-like receptors (TLR) 2, 4, and 10, tumor necrosis factor-α (TNFα), interleukin (IL) 4, 10 and interferon gamma (IFNγ). Results show that all mrNAs were detected in all tissues. Transcript levels of the toll-like receptors and cytokines were higher (P < 0.01) in ileum lymph nodes and peyer’s patches tissues. Transcripts of TLR2 and 4 were equally expressed in colon. Furthermore, TRL10 and inflammatory cytokines were also expressed in jejunum peyer’s patches. Overall, our data suggests that expression of toll-like receptors and cytokines were more consistent in the peyer’s patches and lymph nodes tissues. Thus, revealing novel information about the distribution and expression patterns of these in the GI tract of the piglet.

Key words: piglet, gene expression, cytokines.

Presented at the Symposium on Gut Health in Production of Food Animals, St. Louis, 2016.