Subclinical necrotic enteritis (SNE) is one of the serious threats to the poultry industry. Probiotics have been proven to exert beneficial effects in controlling SNE. However, their exact mechanisms have not been fully elucidated. Moreover, few studies have focused on their impact on microRNAs (miRNAs). Therefore, the present study aimed to explore the miRNA expression profiles in the ileum of broiler chickens during probiotic supplementation for controlling SNE. A total of 180 newly hatched male broilers were randomly allocated into three groups, including a negative control group, an SNE infection group, and a Bacillus licheniformis H2 pretreatment group. Illumina high-throughput sequencing was conducted to identify the miRNA expression of the three groups. Results showed that 628 miRNAs, including 582 known miRNAs and 46 novel miRNAs, were detected in the miRNA libraries. The target genes of 57 significantly differentially expressed miRNAs were predicted and annotated. Moreover, they were found to be partly enriched in pathways related to immunity and inflammation such as tumor necrosis factor receptor binding, immune response-regulating signaling pathway, Toll-like receptor 2 signaling pathway, interleukin-15 production, activation of NF-κB-inducing kinase activity, and MAP kinase tyrosine/serine/threonine phosphatase activity. Some of the target genes of 57 miRNAs were related to the MAPK signaling pathway. Furthermore, the expression of several miRNAs, which may be involved in the MAPK signaling pathway, was significantly affected by SNE induction and showed no significant difference in the presence of H2. All these findings provide comprehensive miRNA expression profiles of three different treatment groups. They further suggest that H2 could exert beneficial effects in controlling SNE through immune and inflammatory response associated with altered miRNA expression, such as the MAPK signaling pathway.

亚临床坏死性肠炎 (SNE) 是对家禽业的严重威胁之一。益生菌已被证明在控制 SNE 方面发挥有益作用。然而，它们的确切机制尚未完全阐明。此外，很少有研究关注它们对 microRNA (miRNA) 的影响。因此，本研究旨在探索在补充益生菌以控制 SNE 期间肉鸡回肠中的 miRNA 表达谱。将180只新孵出的雄性肉鸡随机分为三组，包括阴性对照组、SNE感染组和地衣芽孢杆菌H2预处理组。进行Illumina高通量测序以鉴定三组的miRNA表达。结果表明，在miRNA文库中检测到628个miRNA，包括582个已知miRNA和46个新miRNA。预测并注释了57个显着差异表达的miRNA的靶基因。此外，发现它们在与免疫和炎症相关的通路中部分富集，例如肿瘤坏死因子受体结合、免疫反应调节信号通路、Toll 样受体 2 信号通路、白细胞介素 15 的产生、NF-κB 的激活。诱导激酶活性和 MAP 激酶酪氨酸/丝氨酸/苏氨酸磷酸酶活性。57个miRNA的部分靶基因与MAPK信号通路相关。此外，几种miRNA的表达，可能参与 MAPK 信号通路，受 SNE 诱导显着影响，在 H2 存在下无显着差异。所有这些发现提供了三个不同治疗组的综合 miRNA 表达谱。他们进一步表明，H2 可以通过与改变的 miRNA 表达（例如 MAPK 信号通路）相关的免疫和炎症反应，在控制 SNE 方面发挥有益作用。