猪源乳酸菌的分离、鉴定及其生物学特性

Isolation, identification and characterization of lactic acid bacteria from swine

摘要:

[目的] 将分离自猪肠道粘膜、食糜和粪便的乳酸菌，通过产乳酸能力、生长性能、耐酸和耐胆盐性能及抑菌能力评价，筛选适应养猪生产的潜在益生特性的菌株。[方法] 共分离获得155株乳酸菌纯菌株，从中筛选出4株产酸能力较强的乳酸菌，结合生理生化试验及细菌16S rRNA测序鉴定其种属，评价候选乳酸菌的生长情况、耐酸、耐胆盐及抑菌特性。[结果] 综合变色时间（8 h）、pH值（<3.9）和乳酸含量（>100 mmol/L），筛选出4株（L45、L47、L63和L79）候选菌株，经鉴定依次为罗伊氏乳杆菌、植物乳杆菌、约氏乳杆菌和粪肠球菌。该4株乳酸菌均可在体外快速生长；L47和L79能够耐受pH 2.5的酸性环境，L47能够耐受0.5%胆盐环境；各乳酸菌上清液与指示菌共培养，发现对E coli K88和沙门氏菌均产生了抑制作用，其中L47上清液对指示菌的抑制作用较强。[结论] L47具有较好的产酸性能与生长性能、可耐受猪胃酸和肠道胆盐环境，对E. coli K88和沙门氏菌具有较好的抑制作用，说明该乳酸菌具有潜在的益生特性。

Abstract:

[Objective] We isolated, identified and characterized lactic acid bacteria (LAB) from the intestinal digesta, mucosa and feces of piglets, to explore the potential probiotic stains for the swine production.[Methods] A total of 155 lactic acid bacteria were isolated. Four isolates with high lactate production were identified by conventional biochemical method and bacterial 16S rRNA sequence, and their potential probiotic properties were assessed.[Results] Four LAB isolates (L45, L47, L63 and L79), Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus johnsonii and Enterococcus facium were identified based on lactate production at 8 h (> 100 mmol/L) and final pH at 90 h (< 3.9). The 4 isolates grew rapidly in vitro. They tolerated low pH and bile salt. Strains L47 and L79 tolerated pH 2.5, and L47 tolerated 0.5% bile salts. When the 4 isolates were co-cultured with E. coli K88 and Salmonella, the growth of E. coli K88 and Salmonella was inhibited. L47 demonstrated stronger inhibition effect than other 3 isolates.[Conclusion] L47 strain presented a higher lactate production, better growth, higher tolerance against pH 2.5 and 0.5% bile salt, and stronger antimicrobial effect on E. coli K88 and Salmonella, indicating that L47 isolate may have the potential probiotic properties for swine production.