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试验分别从商业益生菌及中国明对虾和矛尾刺虾虎鱼的肠道中分离出53株乳酸菌(LAB)菌株,并对这些菌株的抗菌性和黏附活性进行测定。结果表明,戊糖乳杆菌HC-2和屎肠球菌NRW-2分别具有较高的抗菌性和黏附活性,菌株的鉴定是基于16S r RNA基因序列分析方法。本研究的目的是探讨和比较屎肠球菌NRW-2、L-戊糖乳杆菌HC-2及其相应上层清液对虾(南美白对虾)的生长性能和免疫反应的影响,采用实时荧光定量PCR方法检测中肠、肝胰腺中免疫和消化相关基因的表达水平。研究结果表明,屎肠球菌NRW-2对所有测试的基因有较强的刺激作用,除了喂养2周后中肠Crus tin基因和4周后的pro PO基因,而L-戊糖乳杆菌HC-2和相应的上清液在肝胰腺中有较强的基因诱导作用。根据激发实验,所有治疗组的存活率均显著高于对照组。此外,饲喂菌株的对虾特定生长率比对照组高,而L-戊糖乳杆菌HC-2组低于对照组,但差异不显著。研究表明,所选择的菌株可以用作虾饮食的有效成分,且比L-戊糖乳杆菌HC-2的上层清液效果更好。
Fifty-three LAB isolates were isolated from the commercial probiotics and the intestinal tract of M. japonicus and P. gigas respectively. The antibacterial activity and adhesion activity of these isolates were determined. The results showed that Lactobacillus pentosus HC-2 and Enterococcus faecium NRW-2 had high antibacterial activity and adhesion activity, respectively. The identification of strains was based on 16S rRNA gene sequence analysis. The purpose of this study was to investigate and compare the effects of Enterococcus faecium NRW-2, L-Lactobacillus pentosus HC-2 and their corresponding supernatant on the growth performance and immune response of shrimp (Penaeus vannamei). Real-time fluorescence quantitative PCR Methods The expression of immune and digestive related genes in midgut, hepatopancreas were detected. The results showed that Enterococcus faecium NRW-2 had a strong stimulating effect on all the tested genes except the Crus tin gene in the midgut after 2 weeks of feeding and the pro PO gene after 4 weeks, while L-pentosyl-L-HC-2 and The corresponding supernatant in the liver and pancreas have a strong gene induction. According to the challenge experiment, the survival rates of all the treatment groups were significantly higher than that of the control group. In addition, the specific growth rate of shrimp fed the strain was higher than that of the control group, while L-L-Lactobacillus HC-2 group was lower than the control group, but the difference was not significant. Studies have shown that the selected strains can be used as an active ingredient in the shrimp diet and perform better than the supernatant of L-Lactobacillus HC-2.