| 摘要: |
| 乳酸乳球菌（Lactococcus lactis）是一种具有促进宿主生长、增强机体免疫力的益生菌。本研究以仿刺参（Apostichopus japonicus）为研究对象，以仿刺参源肠道分离菌株乳酸乳球菌XP-15为候选益生菌，开展菌株XP-15对仿刺参生长、免疫及肠道菌群结构的影响研究。以乳酸乳球菌XP-15投喂组为实验组（XP-15组），基础饲料投喂组为对照组（CK组），进行为期8周的养殖实验。结果显示，第1—8周，XP-15组的仿刺参肠道内的乳球菌属（Lactococcus spp.）呈现逐渐增加趋势，至第8周时占比为54.00%，明显高于CK组的7.33%，表明菌株XP-15可较好地在仿刺参肠道内定殖；于第6周取肠道进行免疫酶活力测定，结果显示，XP-15组仿刺参肠道一氧化氮合成酶（nitric oxide synthase, NOS）、酸性磷酸酶（acid phosphatase, ACP）和超氧化物歧化酶（superoxide dismutase, SOD）等免疫指标显著高于CK组。于第6周采用体腔注射法进行相对免疫保护率实验，计算结果表明，投喂菌株XP-15后仿刺参在塔式弧菌（Vibrio tubiashii）感染中的成活率为73.33%，高于对照组的33.33%。于第8周测定各组仿刺参体重计算增重率，结果显示，初始体重为(43.63±2.15) g的XP-15组仿刺参的增重率为122.19%，显著高于初始体重为(42.10±1.93) g的CK组(增重率为109.46%），表明菌株XP-15对仿刺参的生长有一定的促进作用。本研究可为乳酸乳球菌作为候选益生菌种在水产养殖上的应用提供参考依据。 |
| 关键词: 海洋生物学 仿刺参 乳酸乳球菌XP-15 生长 免疫 肠道菌群 |
| DOI：10.3969/J.ISSN.2095-4972.2022.03.005 |
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| 基金项目:福建省科技厅基本公益专项资助项目(2018R1003-1，2019R1013-5); 福建省渔业结构调整专项资助项目(2020HYJG02，2021HYJH17，2021HYJG18); 福建省海洋经济发展补助专项资助项目(FJHJF L 2020 4) |
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| Effects of Lactococcus lactis strain XP-15 on the growth, immunity and intestinal flora composition of Apostichopus japonicus |
| YANG Qiuhua |
| (Fisheries Research Institute of Fujian Province, Key Laboratory of Cultivation and Highvalue Utilization of Marine Organisms in Fujian, Xiamen 361013, China) |
| Abstract: |
| Lactococcus lactis has the ability to promote the host growth and immunity. In this study, L. lactis strain XP-15 isolated from the intestinal tract of sea cucumber (Apostichopus japonicus) was used as a probiotic candidate to study its effects on the growth, immunity and intestinal flora composition of sea cucumber. The sea cucumbers were fed with either basal diet (control group, namely CK group) or L. lactis strain XP-15-supplemented feed (108 CFU/g, experimental group, namely XP-15 group) for 8 weeks. The results showed that the relative abundance of Lactococcus increased gradually to 54.00% in 8 weeks in the intestinal tract of sea cucumber in XP-15 group, higher than that of CK group (7.33% in weeks), indicating the colonization capacity of the strain XP-15 in the intestine of sea cucumber. The immune enzymatic activity assays performed at the 6th week showed that the activities of nitric oxide synthase, acid phosphatase and superoxide dismutase in the intestine of sea cucumber in the XP-15 group were significantly higher than those in CK group. In the 6th week, 30 sea cucumbers in either XP-15 or CK group were simultaneously used for a challenge test with Vibrio tubiashii (at 108 CFU/mL by injection). As a result, the survival rates of sea cucumber in XP-15 group and CK group against V. tubiashii were 73.33% and 33.33%, respectively. In the 8th week, the weight gain rate in XP-15 group with initial weight of (43.63±2.15) g was 122.19%, which was higher than 109.46% in the CK group with initial weight of (42.10±1.93) g, indicating that the strain XP-15 had a certain promotion effect on the growth of sea cucumber. This study provides a reference for the application of Lactococcus lactis as a probiotic candidate in aquaculture. |
| Key words: marine biology Apostichopus japonicus Lactococcus lactis XP-15 growth immunity intestinal flora |
