仿刺参(Apostichopus japonicus)肠道源植物乳杆菌(Lactobacillus plantarum) HY21的生长及益生特性分析

Growth and probiotic properties of Lactobacillus plantarum HY21 from intestinal tract of Apostichopus japonicus

摘要:

【目的】在仿刺参(Apostichopus japonicus)健康养殖中为了寻找具有良好耐受性、益生性、安全性的益生菌,本研究从仿刺参肠道内容物中分离获得一株植物乳杆菌(Lactobacillus plantarum) HY21,对其益生潜能进行评价。【方法】利用摇瓶发酵培养、应用环境因子模拟试验、抗生素药敏测试等方法,分析L. plantarum HY21的生长特性、产酸性能、发酵液的抗氧化性质和对水产致病菌的抑制作用;检测菌体的疏水性、自聚性和共聚性、黏附力和药物敏感性,以及对应用环境因子的耐受性。【结果】L. plantarum HY21摇瓶发酵培养温度30℃、初始pH 8.0,于2-10 h为对数生长期,发酵18 h后pH达到最低3.6;发酵液对溶藻弧菌的抑菌直径达到(13.96±0.30) mm,对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-trinitrophenylhydrazine, DPPH)自由基清除率达到95.45%±1.56%;L. plantarum HY21的疏水率为60.42%±2.78%、自聚率为22.69%±1.36%,与溶藻弧菌共聚率为27.98%±1.45%;对体表和肠道黏液蛋白的黏附量分别达到(1.66±0.01)×10⁶ CFU/mL和(1.23±0.15)×10⁶ CFU/mL;对13种常见的抗菌药物均表现敏感;菌体在模拟胃肠液(pH 3.0, pH 6.8)中孵育3 h存活率均可达99%以上,在10%鱼胆汁溶液中孵育3 h存活率达到68.11%±7.98%,在3%海盐溶液中孵育16 h存活率达到97.58%±7.14%。【结论】L. plantarum HY21具有良好的定殖作用、抑菌作用、抗氧化作用等益生特性,而且在应用环境中具有高存活率和高安全性,可以作为一株新的水产益生菌,为开发水产益生菌制剂提供科学理论依据。

Abstract:

【Objective】 To search for the strains with improved tolerance, probiotic properties, and safety, we isolated Lactobacillus plantarum HY21 from the intestinal contents of Apostichopus japonicus and evaluated the probiotic potential of the strain. 【Methods】 The shake flask fermentation, environmental factor simulation test, and antibiotic susceptibility test were carried out to study the growth characteristics and acid production of the strain, as well as the antioxidant capacity and aquatic pathogen-inhibiting effects of the fermentation broth. In addition, L. plantarum HY21 was characterized in terms of the tolerance to environmental factors, hydrophobicity, auto-agglutination and co-aggregation, antibiotic susceptibility, and intestinal adhesion ability. 【Results】 L. plantarum HY21 in shake flask culture with the initial pH 8.0 entered the logarithmic growth during the period of 2–10 h. The culture showed a strong acid-producing ability with the minimum pH 3.6 at the time point of 18 h. The fermentation broth of the strain showed an inhibition zone diameter of (13.96±0.30) mm against Vibrio alginolyticus and a 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical scavenging rate of 95.45%±1.56%. L. plantarum HY21 had a hydrophobicity rate of 60.42%±2.78%, an auto-agglutination rate of 22.69%±1.36% and a co-aggregation rate of 27.98%±1.45% with V. alginolyticus. Furthermore, the strain showed the adhesion number of (1.66±0.01)×10⁶ CFU/mL and (1.23±0.15)×10⁶ CFU/mL to fish body surface and intestinal mucus protein, respectively. L. plantarum HY21 was susceptible to 13 common antibiotics. The survival rate of L. plantarum HY21 reached 99% and above in simulated gastrointestinal fluid (pH 3.0, pH 6.8) within 3 h, 68.11%±7.98% in 10% fish bile fluid within 3 h, and 97.58%±7.14% in 3% sea salt solutions within 16 h. 【Conclusion】 L. plantarum HY21 is a probiotic strain with strong colonization potential, antimicrobial activity, and antioxidant capacity, demonstrating a high survival rate and high safety in the applied environment. The findings provide a theoretical basis for the development of new probiotic strains as probiotic additives for aquaculture.