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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。 相似文献
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To determine the existence of p-nitrophenol (PNP)-lowering bacteria in intestine of Japanese coastal fish, the gastro-intestinal contents were incubated in Brain Heart Infusion (BHI) broth and minimal medium (MM) broths containing 1 mmol/L PNP at 30 °C for 7 days. Among 26 samples of 19 fish species, 17 samples showed a decrease in PNP of 0.5-0.8 mmol/L in BHI broth, but no decrease was shown in MM broth. Eighteen PNP-lowering bacterial strains were isolated from four fishes. All of the strains were identified as Lactococcus lactis subsp. lactis. Three L. lactis strains JS1-3 isolated from Japanese seabass Lateolabrax japonicus showed the highest PNP-lowering activity (0.44 mmol/L). Optimum temperature and pH for the growth and PNP decreasing corresponded with the marine environment. These results suggested that marine fishes have PNP decreasing bacteria in their intestine. These bacteria might protect host fish from toxicities of PNP and PNP related compounds. 相似文献
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利用MRS固体培养基从南移仿刺参肠道中分离得到1株优势乳酸菌,命名为AJC-XP-15,其最适生长温度为30°C,最适生长pH为6.5;其表面疏水性和自聚率分别为34.56%和35.61%,经16S RNA基因序列分析,并结合形态学和生理生化特性将其鉴定为乳酸乳球菌(Lactococcus lactis)。拮抗实验结果显示,菌株AJC-XP-15及其发酵上清液对塔氏弧菌(Vibriotubiashii)、哈维氏弧菌(V.harveyi)、副溶血弧菌(V. parahaemolyticus, VP)和嗜水气单胞菌(Aeromonas hydrophila)等病原菌具有很好的抑制作用;体外益生实验表明,菌株AJC-XP-15对人工胃肠液的耐受性很好,在pH3.0的模拟人工胃液处理3 h后的存活率为71.43%,在pH 6.8的模拟人工肠液处理3 h后的存活率为92.1%;抗氧化能力结果显示,菌株AJC-XP-15的无细胞提取物对DPPH自由基和羟自由基的清除能力最强,分别为(82.67±6.92)%和(15.36±2.95)%,其发酵上清液对超氧阴离子自由基的清除能力最强,为(26.36±... 相似文献
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Lactococcosis is prevalent on grey mullet (Mugil cephalus) in Hong Kong aquaculture resulting in serious economic loss. A compound formulation of Traditional Chinese Medicines (TCM) (modified Huanglian Jiedu decoction (HLJDD)) comprising Rhizoma coptidis, Radix scutellaria, Cortex phellodendri, Fructus gardeniae, Fructus forsythiae and Flos lonicerae japonicae (in a ratio of 3:2:2:3:3:5) were applied as feed supplements to deal with the disease. The Nitroblue tetrazolium activity in blood, bactericidal activity and total immunoglobulin in plasma were significantly enhanced after feeding 1% of this TCM for 28 days. The disease resistances to Lactococcus garvieae in 1% and 2% TCM feeding groups were significantly enhanced. In the in vitro study, the modified HLJDD also activated the plasma bactericidal activities (p < 0.01). Based on this study, 1% modified HLJDD feeding for 28 days may be an optimal dose to prevent L. garvieae infection and could be used in aquaculture industries. 相似文献
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