Dietary soy isoflavone attenuated growth performance and intestinal barrier functions in weaned piglets challenged with lipopolysaccharide

• Soy isoflavone attenuated growth performance of piglets challenged with LPS.
• Soy isoflavone upregulated mRNA expression of jejunal mucosa after LPS challenge.
• p38 and TLR4 pathways may be involved in improvement of tight junctions by soy isoflavone.

This study was conducted to investigate the protective roles of soy isoflavone in weaned pigs challenged with lipopolysaccharide (LPS). A total of 72 weaned piglets (14 days of age) were randomly allotted into either 0 (control group) or 40 mg/kg soy isoflavone (ISO) supplementation group. On days 7 and 14, half of the pigs in each group were challenged with LPS. Soy isoflavone increased average daily gain (ADG) and average daily feed intake (ADFI) of piglets challenged with LPS at days 7–14 (P < 0.05). The incidence of diarrhea and plasma concentrations of malondialdehyde (MDA) and endotoxin in piglets from LPS group were higher than those in control group (P < 0.05). Soy isoflavone reduced the incidence of diarrhea and plasma concentrations of endotoxin in piglets challenged with LPS (P < 0.05). LPS challenge decreased (P < 0.05) mRNA abundances of β-defensin 2 (pBD-2), mucin (MUC-4), zona occludens 1 (ZO-1), and occludin in jejunal mucosa of piglets, and soy isoflavone upregulated (P < 0.05) mRNA abundances of ZO-1 and occludin in jejunal mucosa of piglets challenged with LPS. The present results demonstrated that both p38 and TLR4 pathways in jejunal mucosa of piglets were activated by LPS challenge (P < 0.05), and soy isoflavone reduced their activations (P < 0.05). Collectively, our results suggested that supplementation of soy isoflavone could partly attenuate the barrier-damaged effects of LPS and improve the intestinal barrier function of weaned piglets, at least partially by inhibiting activations of p38 and TLR4 dependent pathways induced by LPS. This study provides a potential usage of soy isoflavone for alleviating intestinal barrier damages of neonates and piglets.