College of Fisheries, Guangdong Ocean University, Huguang Yan East, Zhanjiang, 524088, Guangdong, China.
Shenzhen Institute of Guangdong Ocean University, Shenzhen, 518120, Guangdong, China.
Probiotics Antimicrob Proteins. 2020 Jun;12(2):412-424. doi: 10.1007/s12602-019-09562-5.
Probiotics used in aquaculture are mostly from non-fish sources, as a result ineffective in eliciting the desired effects in aquatic animals. In this study, three Bacillus species were isolated from the digestive tract of freshwater fish Oreochromis niloticus and characterised based on their morphological, biochemical and evolutionary relationships. Their probiotic potentials were evaluated based on their ability to tolerate low pH, bile salt concentration, high temperatures, adhesion ability (auto-aggregation and hydrophobicity), haemolytic activity and antimicrobial activity including biosafety assay. Three Bacillus strains identified as Bacillus velezensis TPS3N (MK130897), Bacillus subtilis TPS4 (MK130899) and Bacillus amyloliquefaciens TPS17 (MK130898) were designated as TPS3N, TPS4 and TPS17, respectively. TPS3N and TPS17 were α-haemolytic, while TPS4 was γ-haemolytic. The three isolates had higher viability ability after exposure to higher temperatures (80 °C, 90 °C and 100 °C) and were resistant to low pH (1) and bile salt concentration (0.5%) as well as high cell surface hydrophobicity and auto-aggregation. The three isolates were compatible with one another and thus can be used in consortia. These strains were susceptible to gentamicin, cephalexin, ampicillin, ceftriaxone, kanamycin, amikacin, penicillin, cefoperazone, chloramphenicol, erythromycin, tetracycline, doxycycline, ciprofloxacin, clindamycin (except TPS4) and furazolidone (except TPS17). The antimicrobial assessment showed that among the three isolates, TPS3N and TPS17 exhibited good antimicrobial activity against the three fish pathogens (Streptococcus agalactiae, Aeromonas hydrophila, Vibrio harveyi), while TPS4 was effective against Streptococcus agalactiae only. The results of this work suggest that Bacillus strains TPS3N, TPS4 and TPS17 could be considered as potential probiotics in tilapia aquaculture.
水产养殖中使用的益生菌大多来自非鱼类来源，因此在水生动物中无法产生预期的效果。在这项研究中，从淡水鱼奥利亚罗非鱼的消化道中分离出三种芽孢杆菌，并根据它们的形态、生化和进化关系进行了特征描述。根据它们耐受低 pH 值、胆汁盐浓度、高温、粘附能力（自聚集和疏水性）、溶血活性和抗菌活性（包括生物安全性测定）的能力，评估了它们的益生菌潜力。三种芽孢杆菌菌株被鉴定为芽孢杆菌 velezensis TPS3N（MK130897）、枯草芽孢杆菌 TPS4（MK130899）和解淀粉芽孢杆菌 TPS17（MK130898），分别命名为 TPS3N、TPS4 和 TPS17。TPS3N 和 TPS17 为α-溶血，而 TPS4 为γ-溶血。三种分离株在暴露于较高温度（80°C、90°C 和 100°C）后具有更高的生存能力，并且能够耐受低 pH 值（1）和胆汁盐浓度（0.5%）以及高细胞表面疏水性和自聚集。三种分离株彼此相容，因此可以用于联合体。这些菌株对庆大霉素、头孢氨苄、氨苄西林、头孢曲松、卡那霉素、阿米卡星、青霉素、头孢哌酮、氯霉素、红霉素、四环素、强力霉素、环丙沙星、克林霉素（除 TPS4 外）和呋喃唑酮（除 TPS17 外）敏感。抗菌评估表明，在三种分离株中，TPS3N 和 TPS17 对三种鱼类病原体（无乳链球菌、嗜水气单胞菌、哈维氏弧菌）表现出良好的抗菌活性，而 TPS4 仅对无乳链球菌有效。这项工作的结果表明，芽孢杆菌菌株 TPS3N、TPS4 和 TPS17 可以被认为是罗非鱼养殖中的潜在益生菌。
