大菱鲆肠道乳杆菌Lactobacillus sp.N5的筛选鉴定及其抑制水产病原菌的研究

Screening,Identification and Inhibitory Effect on Aquaculture Pathogens of Lactobacillus sp.N5 From Intestine of Turbot Scophthalmus maximus

从大菱鲆(Scophthalmus maximus)肠道内分离出8株乳酸菌,经16S rDNA鉴定为Lactobacillus sp.,以对水产病原菌的抑制和对抗生素的敏感性为指标,研究乳酸菌的特性。其中,菌株N5对鳗弧菌(Vibrio anguillarum)、哈维氏弧菌(V.harveyi)、副溶血弧菌(V.parahaemolyticus)和金黄色葡萄球菌(Staphylococcus aureus)均具有较强的抑制作用,对氨苄青霉素、庆大霉素和罗红霉素敏感。菌株N5发酵上清液经加热、排酸和过氧化氢酶处理后,仍有抑菌作用;经蛋白酶处理后失去抑菌能力,推测菌株N5分泌的抑菌物质为耐热的乳酸菌素,其可以抑制病原菌生物膜的形成。菌株N5在凡纳对虾(Litopenaeus vannamei)肠道定植5 d后,加入鳗弧菌和哈维氏弧菌,继续养殖7 d,死亡率显著降低。本研究结果可为菌株N5制备水产养殖益生菌剂提供实验依据。

Eight strains of lactic acid bacteria were isolated from intestine of turbot Scophthalmus maximus and identified as Lactobacillus sp.by 16S rDNA.The characteristics of lactic acid bacteria were investigated based on the inhibition of aquaculture pathogens and the sensitivity to antibiotics,with strong inhibitory effects on pathogens Vibrio anguillarum,V.harveyi,V.parahaemolyticus,and Staphylococcus aureus in strain N5.The strain N5 had sensitive to ampicillin,gentamicin and roxithromycin,and the supernatant of fermented strain N5 still had antibacterial effect after heating,acid excretion and catalase treatment.It was speculated that the antibacterial substance secreted by strain N5 was heat-resistant lactobacillin.Moreover,strain N5 could inhibit the formation of pathogen biofilm.After the colonization of strain N5 in the intestine of Pacific white leg shrimp Litopenaeus vannamei,it can improve the ability of anti-pathogenic bacteria and reduce the mortality of shrimp.The findings provide an experimental basis for the preparation of aquaculture probiotics by strain N5.