Department of Biological Science and Technology, National Pingtung University of Science and Technology, Pingtung, 912, Taiwan.
Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung, 912, Taiwan; Research Center for Animal Biologics, National Pingtung University of Science and Technology, Pingtung, 912, Taiwan.
Fish Shellfish Immunol. 2019 Oct;93:124-134. doi: 10.1016/j.fsi.2019.07.042. Epub 2019 Jul 16.
The use of probiotics as alternatives to antibiotics for disease control is a relatively eco-friendly approach in aquaculture; hence, studies isolating and assessing the benefit of potential probiotics to fish farming are common. The zebrafish is an excellent model system for validating beneficial functions of potential probiotics before their practical application in aquaculture. Here, a potentially probiotic Chromobacterium aquaticum was isolated from lake water samples and characterized by biochemical analysis and 16S rDNA sequencing. The probiotic produced extracellular enzymes (protease and xylanase) and a bacteriocin-like substance, which exhibited tolerance to extreme pH and high-temperature conditions and broad-spectrum bactericidal activity against diverse pathogens, including aquatic, foodborne, clinical and plant pathogens. The effects of C. aquaticum on zebrafish nutrient metabolism, growth performance and innate immunity were evaluated by measuring the expression of indicator genes after C. aquaticum feeding for 8 weeks. Fish administered the probiotic exhibited significantly increased hepatic mRNA expression of carbohydrate metabolism-related genes, including glucokinase (GK), hexokinase (HK), glucose-6-phosphatase (G6Pase), and pyruvate kinase (PK-L), and growth-related genes, including the growth hormone receptor (GHR) and insulin-like growth factor-1 (IGF-1). Innate immune-related genes (IL-1β, IL-6, TNF-α, IL-10, IL-21, NF-κb, lysozyme and complement C3b) were induced in fish with probiotic supplementation. Probiotic-treated fish exhibited a higher survival rate than control fish after challenge with Aeromonas hydrophila and Streptococcus iniae. Together, these data suggest that C. aquaticum, as a probiotic feed supplement, could enhance nutrient metabolism and growth performance and could modulate innate immunity against A. hydrophila and S. iniae in zebrafish.
将益生菌用作控制疾病的抗生素替代品在水产养殖中是一种相对环保的方法；因此，研究分离和评估潜在益生菌对鱼类养殖的益处是很常见的。斑马鱼是验证潜在益生菌有益功能的极好模型系统，然后再将其实际应用于水产养殖。在这里，从湖水样本中分离出一种潜在的益生菌——水生色杆菌，并通过生化分析和 16S rDNA 测序进行了表征。该益生菌产生了胞外酶（蛋白酶和木聚糖酶）和一种细菌素样物质，对极端 pH 值和高温条件具有耐受性，并对多种病原体具有广谱杀菌活性，包括水生、食源、临床和植物病原体。通过测量 8 周后 C. aquaticum 喂养对斑马鱼营养代谢、生长性能和先天免疫的指示基因表达，评估 C. aquaticum 对斑马鱼的影响。给予益生菌的鱼表现出肝内与碳水化合物代谢相关的基因（包括葡糖激酶（GK）、己糖激酶（HK）、葡萄糖-6-磷酸酶（G6Pase）和丙酮酸激酶（PK-L））和生长相关基因（包括生长激素受体（GHR）和胰岛素样生长因子-1（IGF-1））的 mRNA 表达显著增加。先天免疫相关基因（IL-1β、IL-6、TNF-α、IL-10、IL-21、NF-κb、溶菌酶和补体 C3b）在添加益生菌的鱼中被诱导。与对照组相比，益生菌处理的鱼在受到嗜水气单胞菌和链球菌感染后具有更高的存活率。总之，这些数据表明，作为一种益生菌饲料添加剂，C. aquaticum 可以增强营养代谢和生长性能，并可以调节斑马鱼对嗜水气单胞菌和链球菌的先天免疫。
