Weaning causes a prolonged but transient change in immune gene expression in the intestine of piglets

Abstract

Controlling gut inflammation is important in managing gut disorders in the piglet after weaning. Establishing patterns of inflammation markers in the time subsequent to weaning is important for future research to determine whether interventions are effective in controlling gut inflammation. The objective of this study was to evaluate the intestinal inflammatory response during the postweaning period in piglets. A 45-d study included 108 piglets (weaned at 22 d, body weight 5.53 ± 1.19 kg), distributed in 12 pens with nine pigs per pen. Histomorphometry, gene expression of pro- and anti-inflammatory cytokines, and the quantity of immunoglobulin (Ig) A producing cells were measured in jejunum, ileum, and colon on days 0, 15, 30, and 45 postweaning. Cytokine gene expression in peripheral blood mononuclear cells and Ig quantities were analyzed in blood from piglets on days 0, 15, 30, and 45 postweaning. Histomorphometrical results showed a lower villus length directly after weaning. Results demonstrated a postweaning intestinal inflammation response for at least 15 d postweaning by upregulation of IgA producing cells and IFN-γ, IL-1α, IL-8, IL-10, IL-12α, and TGF-β in jejunum, ileum, and colon. IgM and IgA were upregulated at day 30 postweaning. IgG was downregulated at day 15 postweaning. The results indicate that weaning in piglets is associated with a prolonged and transient response in gene expression of pro- and anti-inflammatory cytokines and IgA producing cells in the intestine.

Keywords: cytokines; immunoglobulin; inflammation; intestine; piglets; weaning.

Figure 1.

Heatmap of Spearman correlation between IgA production and cytokine gene expression in intestinal tissues jejunum (Y), ileum (I), colon (CO), and in PBMC on different time points, where 0 = day 0, 1 = day 15, 2 = day 30 anday 3 = day 45. Cytokines refer to IL-1α, IL-1β, IL-6, IL-8, IL-10, IL-12α, IL-12β, TNF-α, IFN-α, IFN-γ, and TGF-β.

Figure 2.

CDA of cytokine (Ck) IL-1α, IL-1β, IL-6, IL-8, IL-10, IL-12α, IL-12β, TNF-α, IFN-α, IFN-γ, and TGF-β gene expression in intestinal tissues jejunum (Y), ileum (I), colon (CO), and in PBMC on different time points, where 0 = day 0, 1 = day 15, 2 = day 30 anday 3 = day 45. 95% prediction analysis per timepoint (A) and definition of canonical 1 and canonical 2 (B) as pooled within class standardized canonical coefficients.

Figure 3.

Heatmap of cytokine gene expression in intestinal tissues jejunum (Y), ileum (I), colon (CO), and in PBMC on different time points, where 0 = day 0, 1 = day 15, 2 = day 30 and day 3 = day 45.

Figure 4.

Principal component analysis of cytokine IL-1β, IL-6, IL-8, IL-10, IL-12α, IL-12β, TNF-α, IFN-α, IFN-γ, and TGF-β gene expression in intestinal tissues jejunum (yellow), ileum (blue), colon (green), and in PBMC (orange).