Cysteine Attenuates Intestinal Inflammation by Regulating the Gut Microbiota and TLR4-JNK/MAPK-NF-κB Pathway in Piglets

As a nutritionally important amino acid, cysteine (Cys) could attenuate oxidative damage on growth performance and intestinal barrier function in piglets. However, the mechanism of Cys in attenuating intestinal injury remains unclear. The aim of this study was to investigate the mechanism of Cys in defending against intestinal inflammation in piglets. A total of twenty-four piglets were divided into four groups and fed a diet with or without 0.1% BPA or Cys for a 28 d feeding trial. The results showed that Cys supplementation reinstated the jejunal barrier by increasing cell proliferation and the goblet cell number, and decreased cell apoptosis upon BPA exposure. Cys supplementation also decreased serum and jejunal pro-inflammatory cytokine and immunoglobulin levels in BPA-challenged piglets. Furthermore, Cys mitigated inflammation by normalizing the activation of the toll-like receptor 4 (TLR4)-JNK/MAPK-nuclear factor-kappa B (NF-κB) pathway caused by BPA. Additionally, dietary Cys supplementation restored the levels of butyrate, valerate and isovalerate in cecum contents that were decreased by BPA exposure. Meanwhile, Cys supplementation normalized the abundances of <i>Prevotellaceae</i> and <i>Romboutsia</i> upon BPA exposure. In conclusion, Cys is critical to nutrition through attenuating intestinal inflammation by regulating gut microbial balance and suppressing the TLR4-JNK/MAPK-NF-κB pathway.