Dietary supplementation with dihydroartemisinin improves intestinal barrier function in weaned piglets with intrauterine growth retardation by modulating the gut microbiota.

The aim of this study was to investigate whether dietary dihydroartemisinin (DHA) supplementation could improve the intestinal barrier function and microbiota composition in intrauterine growth restriction (IUGR) weaned piglets. Twelve normal birth weight (NBW) piglets and 24 IUGR piglets at 21 days of age were divided into 3 groups, which were fed a basal diet (NBW-CON and IUCR-CON groups) and an 80 mg/kg DHA diet (IUGR-DHA group). At 49 days of age, 8 piglets of each group with similar body weights within groups were slaughtered, and serum and small intestine samples were collected. The results showed that IUGR piglets reduced growth performance, impaired the markers of intestinal permeability, induced intestinal inflammation, decreased intestinal immunity and disturbed the intestinal microflora. Dietary DHA supplementation increased average daily gain, average daily feed intake and body weight at 49 days of age in IUGR weaned piglets (P < 0.05). DHA treatment decreased serum diamine oxidase activity and increased the numbers of intestinal goblet cells and intraepithelial lymphocytes, concentrations of jejunal mucin-2 and ileal trefoil factor 3, and intestinal secretory immunoglobin A and immunoglobin G (IgG) concentrations of IUGR piglets (P < 0.05). Diet supplemented with DHA also up-regulated mRNA abundances of jejunal IgG, cluster of differentiation 8 (CD8), major histocompatibility complex-I (MHC-I) and interleukin 6 (IL-6) and ileal IgG, Fc receptor for IgG (FcRn), cluster of differentiation 8 (CD4), CD8, MHC-I, IL-6 and tumor necrosis factor α (TNF-α), and enhanced mRNA abundance and protein expression of intestinal occludin and ileal claudin-1 in IUGR piglets (P < 0.05). In addition, DHA supplementation in the diet improved the microbial diversity of the small intestine of IUGR piglets and significantly increased the relative abundance of Actinobacteriota, Streptococcus, Blautia and Streptococcus in the jejunum, and Clostridium sensu_ stricto_in the ileum (P < 0.05). The intestinal microbiota was correlated with the mRNA abundance of tight junction proteins and inflammatory response related genes. These data suggested that DHA could improve the markers of intestinal barrier function in IUGR weaned piglets by modulating gut microbiota. DHA may be a novel nutritional candidate for preventing intestinal dysfunction in IUGR pigs.