College of Animal Science and Technology, Jilin Provincial Key Laboratory of Animal Nutrition and Feed Science, Jilin Agricultural University, Changchun, 130118, China; Department of Fish Production, Faculty of Agriculture, Al-Azhar University, Cairo, 11884, Egypt.
College of Animal Science and Technology, Jilin Provincial Key Laboratory of Animal Nutrition and Feed Science, Jilin Agricultural University, Changchun, 130118, China.
Microb Pathog. 2023 Jul;180:106163. doi: 10.1016/j.micpath.2023.106163. Epub 2023 May 18.
Probiotics sourced from fish intestinal microbiota have a merit over other bacterial sources due to colonization ability and effective time. This study aimed to evaluate the bacilli isolated from the Rhynchocypris lagowskii intestines and their validity as a probiotic. Three isolates were selected (LSG 2-5, LSG 3-7, and LSG 3-8) and defined by morphological and 16S rRNA analysis as Bacillus velezensis, Bacillus aryabhattai, and Bacillus mojavensis, respectively. Results showed the strain tolerant abilities to gastrointestinal fluid, bile salt, pH, and temperature expotures. Additionally, all bacterial strains showed anti-pathogenic activity against at least four strains out of six tested pathogen strains (Staphylococcus aureus, Aeromonas hydrophila, Escherichia coli, Aeromonas veronii, Edwardsiella, and Aeromonas sobria). The bacterial strains also showed a high percentage of co-aggregation activity, more than 70%, with Aer. hydrophile, Staph. epidermidis, and Klebsiella aerogenes. At the same time, the results of competition, rejection, and substitution activity with Aer. hydrophila and Aer. veronii indicated the ability of the isolated strains to reduce the adhesion of pathogens to mucin. All strains showed safety properties, non-hemolytic, and sensitivity characteristics for most of tested antibiotics. In vivo test after injecting these strains into fish at various concentrations showed no side effects in the internal or external organs of fish compared to controls, proving that this is safe for these fish. Furthermore, the three strains produced lipase, amylase, and protease enzymes. The strains also showed bile salt hydrolase activity and biofilm formation, allowing them to tolerate stressful conditions. Conclusion: Based on these strains characteristics and features, they could be considered a promising candidate probiotic and can be used as an anti-pathogenic, especially in aquaculture.
从鱼类肠道微生物群中提取的益生菌由于其定植能力和有效时间长，优于其他细菌来源。本研究旨在评估从瓦氏黄颡鱼肠道中分离出的芽孢杆菌及其作为益生菌的有效性。选择了三个分离株（LSG2-5、LSG3-7 和 LSG3-8），并通过形态学和 16S rRNA 分析分别将其定义为解淀粉芽孢杆菌、地衣芽孢杆菌和莫哈韦沙漠芽孢杆菌。结果表明，该菌株能够耐受胃肠道液、胆盐、pH 值和温度暴露。此外，所有细菌菌株均对至少 6 种测试致病菌菌株（金黄色葡萄球菌、嗜水气单胞菌、大肠杆菌、维氏气单胞菌、爱德华氏菌和温和气单胞菌）中的至少 4 种具有抗致病性。这些细菌菌株还与嗜水气单胞菌、表皮葡萄球菌和肺炎克雷伯菌表现出高比例的共聚集活性，超过 70%。同时，与嗜水气单胞菌和维氏气单胞菌的竞争、排斥和替代活性的结果表明，分离株具有降低病原体对粘蛋白粘附的能力。所有菌株均表现出安全性、非溶血和对大多数测试抗生素的敏感性特征。将这些菌株以不同浓度注入鱼类后进行体内试验，与对照组相比，鱼类的内部或外部器官均未出现副作用，证明这对这些鱼类是安全的。此外，这三个菌株产生了脂肪酶、淀粉酶和蛋白酶。这些菌株还表现出胆盐水解酶活性和生物膜形成，使它们能够耐受应激条件。结论：基于这些菌株的特性和特点，它们可以被认为是一种有前途的候选益生菌，并可用于抗致病性，特别是在水产养殖中。
