Department of Fish Diseases and Management, Faculty of Veterinary Medicine, Zagazig University, Sharqia, Zagazig, 44511, Egypt.
Probiotics Antimicrob Proteins. 2018 Dec;10(4):692-703. doi: 10.1007/s12602-017-9314-6.
Fish gut bacteria can be used as probiotics for aquaculture. The aim of this study is to screen and identify beneficial probiotic bacteria from the gut of Nile tilapia, Oreochromis niloticus. Nine out of one hundred thirty-five isolates were non-pathogenic through intraperitoneal injection and had antibacterial activities with at least a strain from the five isolated fish pathogens, Aeromonas sobria, Aeromonas hydrophila, Pseudomonas aeruginosa, Pseudomonas putida, and Staphylococcus aureus. Further tests showed that such isolates can survive in the presence of high bile concentration (10%) and at different acidic pH values. A strains (14HT) was sensitive to all selected antibiotics, two strains were (9HT and 11HT) resistant to streptomycin and three strains (9HT, 11HT and 38HT) had resistance to two antibiotics. Four isolates (11HT, 33HT, 38HT and 41HT) had an amylase and a protease activities and one strain (47HT) showed only amylase activity. Based on 16S rRNA gene analysis, the isolated strains were identified as follows: Lactococcus lactis (8HT, 9HT, 11HT and 33HT); Enterococcus faecalis (14HT), Lysinibacillus sp. (38HT) and Citrobacter freundii (39HT, 41HT and 47HT).
鱼肠道细菌可用作水产养殖的益生菌。本研究旨在从尼罗罗非鱼（Oreochromis niloticus）肠道中筛选和鉴定有益的益生菌。通过腹腔注射，从 135 个分离株中筛选出 9 株非致病性菌株，对 5 种分离的鱼类病原菌（嗜水气单胞菌、温和气单胞菌、铜绿假单胞菌、恶臭假单胞菌和金黄色葡萄球菌）均具有抗菌活性，至少有一株。进一步的测试表明，这些分离株可以在高胆汁浓度（10%）和不同的酸性 pH 值下存活。一株（14HT）对所有选定的抗生素均敏感，两株（9HT 和 11HT）对链霉素耐药，三株（9HT、11HT 和 38HT）对两种抗生素耐药。四株（11HT、33HT、38HT 和 41HT）具有淀粉酶和蛋白酶活性，一株（47HT）仅具有淀粉酶活性。基于 16S rRNA 基因分析，鉴定分离株分别为：乳酸乳球菌（8HT、9HT、11HT 和 33HT）；粪肠球菌（14HT）、解淀粉芽孢杆菌（38HT）和弗氏柠檬酸杆菌（39HT、41HT 和 47HT）。
