Lactiplantibacillus plantarum subsp. plantarum 299v (L. plantarum 299v) is one of the most important probiotic strains in animal health, but the molecular mechanisms of how it exerts health benefits remain unclear. The purpose of this study was to explore the changes in miRNA expression profiles in the intestinal tissues of piglets by L. plantarum 299v and to explore its possible molecular regulatory mechanism in intestinal function. Neonatal piglets were orally administered L. plantarum 299v daily from 1 to 20 days old, and high-throughput sequencing was conducted to analyse the changes in miRNA expression in the jejunum and ileum. The results showed that 370 known porcine miRNAs were identified from eight libraries. Five miRNAs (ssc-miR-21-5p, -143-3p, -194b-5p, -192, and -126-3p) were highly expressed in the intestinal tissues. There were 15 differentially expressed miRNAs between the control group and the L. plantarum group, and only miR-450a was expressed differentially in both intestinal tissues. KEGG analysis revealed that the target genes of the 15 differentially expressed miRNAs were involved in 37 significantly enriched pathways (P < 0.01). Then, quantitative polymerase chain reaction confirmed that the miRNA expression was corresponded well with those from the sequencing. Luciferase reporter assays verified that lipopolysaccharide-induced TNF-α factor is a target of miR-450a. Our results also showed L. plantarum 299v could influence intestinal function by changing the levels of cytokines via miRNA expression. This is the first study to analyse differential expression miRNA profiles in intestinal tissue after L. plantarum 299v treatment and investigate the molecular regulatory mechanism of functional miRNA.

植物乳杆菌植物亚种 plantarum 299v（L. plantarum 299v）是动物健康中最重要的益生菌菌株之一，但其如何发挥健康益处的分子机制仍不清楚。本研究旨在探讨植物乳杆菌299v对仔猪肠道组织中miRNA表达谱的变化，探讨其对肠道功能可能的分子调控机制。给新生仔猪口服植物乳杆菌1~20日龄每天299v，进行高通量测序分析空肠和回肠中miRNA表达的变化。结果显示，从 8 个文库中鉴定出 370 种已知的猪 miRNA。五种 miRNA（ssc-miR-21-5p、-143-3p、-194b-5p、-192 和 -126-3p）在肠道组织中高表达。对照组和植物乳杆菌组之间共有15个差异表达的miRNA，只有miR-450a在两种肠道组织中存在差异表达。KEGG分析显示15个差异表达miRNA的靶基因涉及37条显着富集的通路（P < 0.01）。然后，定量聚合酶链式反应证实miRNA表达与测序结果吻合良好。荧光素酶报告基因检测证实脂多糖诱导的 TNF-α 因子是 miR-450a 的靶标。我们的结果还表明，植物乳杆菌299v 可以通过 miRNA 表达改变细胞因子的水平来影响肠道功能。这是首次分析植物乳杆菌299v处理后肠道组织中差异表达的miRNA谱，并探讨功能性miRNA的分子调控机制。