采用不同培养基和泥样加热方法,从红岛仿刺参养殖区泥样中分离出27株可培养细菌,对其进行16SrRNA基因序列分析。发现海泥中可培养细菌多分布于γ-变形菌纲(γ-proteobacteria)(占总菌数的71.4%),其中包括假交替单胞菌属(Pseudoalteromonas)、弧菌属(Vibrio)和希瓦氏菌属(Shewanella)等;80℃加热处理20min,海泥中可培养细菌多属于芽孢杆菌属(Bacillus)。人工浸泡感染实验发现,泥样中灿烂弧菌LJ08(Vibrio splendidus)对仿刺参幼参具有致病性。泥样中分离获得的可培养细菌经安全性、抑菌活性和毒性检测,筛选出对灿烂弧菌LJ08有明显抑菌作用的LJ03、LJ04和LJ06并用其进行人工拮抗实验。统计分析显示,添加LJ03和LJ06拮抗组的累计排脏率分别为(36.11±4.81)%和(2.78±4.81)%,与仅添加灿烂弧菌LJ08的阳性对照组差异显著(P〈0.05)。结果表明,LJ03和LJ06具有很好保护仿刺参幼参的作用,尤其LJ06对仿刺参幼参的排脏保护率达104.7%。作为拮抗灿烂弧菌的潜在有益菌,LJ06在仿刺参养殖中将有良好的应用前景。
Twenty-seven culturable bacterial strains were isolated from the mud of sea cucumber (Apostichopus japonicus) culture area in Hongdao with different cultural media and heating treatments. The 16S rRNA gene sequencing showed that 7- Proteobacteria were predominant (71.4% of the total), which included species in genus Pseudoalteromonas, Vibrio, Shewanella and among others. Bacillus strains dominated the isolates when the heating treatment was carried out at 80℃ for 20 min. V. splen- didus LJ08 was found to be virulent to sea cucumber when it was challenged with immersion method. Three strains, namely LJ03, LJ04 and LJ06, showed antagonistic effects on V. splendidus LJ08 in vitro, which were investigated for their protection efficiency to infected sea cucumber larvae. LJ03 and LJ06 displayed significant protective effect against V. splendidus LJ08 (P〈0.05). Especially, LJ06 of genus Agarivorans showed a higher level of protection rate (104.7%) against viscera ejection than LJ03 (34. 9%). As a probiotical candidate against V. splendidus, LJ06 has enormous potential of being used in the culture of A. japonicus.