Li Lijie, Zhao Kuan, Lei Baishi, Zhang Wuchao, Wang Junli, Liu Mandi, Wang Weizhu, Yuan Wanzhe
College of Animal Medicine, Hebei Agricultural University, Lianchi District, No. 2596, Lekai South Street, Baoding, 071001, Hebei, China.
Hebei Veterinary Biotechnology Innovation Center, Hebei Agricultural University, Lianchi District, No. 2596, Lekai South Street, Baoding, China.
Probiotics Antimicrob Proteins. 2025 Jul 29. doi: 10.1007/s12602-025-10682-4.
The novel duck reovirus (NDRV) poses a significant threat to the poultry industry, with limited effective treatment options and no effective vaccine available. As the dominant genus of Bacillus in the duck intestine, its antiviral effects, particularly in a heat-inactivated form, have been previously reported. In our study, we used the NDRV-infected duck embryo fibroblast (DEF) cells and a Cherry Valley duck model to evaluate the antiviral properties of heat-inactivated Bacillus. Four strains of probiotics were isolated from healthy duck feces, namely Bacillus subtilis (B. subtilis) Bac28, Bacillus tequilensis (B. tequilensis) Bac41, Bacillus subtilis (B. subtilis) Bac45, and Bacillus licheniformis (B. licheniformis) Bac55, all exhibiting probiotic properties. In an in vitro assay, the cytotoxic effectsi of heat-inactivated isolates on DEF cytotoxicity were assessed using the CCK-8 assay. Furthermore, the anti-NDRV activities of heat-inactivated solutions of these four strains were evaluated through RT-qPCR. Additionally, the mRNA relative expression levels of inflammatory factors such as TNF-α, IL-1β, and IL-6, as well as ZO-1 and occluding, were examined using RT-qPCR. The results demonstrated that the heat-inactivated solution exhibited no cytotoxicity and displayed inhibitory effects against NDRV in DEF cell cultures. Treatment with the heat-inactivated solution significantly down-regulated inflammatory cytokine levels and up-regulated mRNA expression levels of intestinal barrier factors. In the in vivo tests, the heat-inactivated Bacillus mixture effectively alleviated clinical symptoms and intestinal damage of ducks infected by NDRV. These findings suggest that the four probiotic strains could provide some levels of protective effects against NDRV infections.
新型鸭呼肠孤病毒（NDRV）对家禽业构成重大威胁，目前有效的治疗选择有限且尚无有效疫苗。作为鸭肠道中芽孢杆菌的优势属，其抗病毒作用，尤其是热灭活形式的抗病毒作用，此前已有报道。在我们的研究中，我们使用感染NDRV的鸭胚成纤维细胞（DEF）和樱桃谷鸭模型来评估热灭活芽孢杆菌的抗病毒特性。从健康鸭粪便中分离出四株益生菌，分别为枯草芽孢杆菌（B. subtilis）Bac28、特基拉芽孢杆菌（B. tequilensis）Bac41、枯草芽孢杆菌（B. subtilis）Bac45和地衣芽孢杆菌（B. licheniformis）Bac55，它们均表现出益生菌特性。在体外试验中，使用CCK-8法评估热灭活菌株对DEF细胞毒性的细胞毒性作用。此外，通过RT-qPCR评估这四株菌株热灭活溶液的抗NDRV活性。另外，使用RT-qPCR检测TNF-α、IL-1β和IL-6等炎症因子以及ZO-1和闭合蛋白的mRNA相对表达水平。结果表明，热灭活溶液在DEF细胞培养物中无细胞毒性且对NDRV具有抑制作用。用热灭活溶液处理可显著下调炎症细胞因子水平并上调肠道屏障因子的mRNA表达水平。在体内试验中，热灭活芽孢杆菌混合物有效减轻了感染NDRV的鸭的临床症状和肠道损伤。这些发现表明，这四株益生菌菌株可为抵抗NDRV感染提供一定程度的保护作用。
