CAS Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China.
Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing, 100049, China.
Fish Shellfish Immunol. 2019 Mar;86:1194-1206. doi: 10.1016/j.fsi.2018.12.073. Epub 2018 Dec 29.
The interactions of microbiota in the intestines play an important role in promoting or maintaining the health of hosts. The present study aim to investigate the effects of the surface proteins of Lactobacillus pentosus HC-2 on the immune response and the bacterial composition of Litopenaeus vannamei, thus, the immune-related genes, surface condition, HC-2 numbers and the bacteria diversity in midgut were explored after shrimp feeding the normal HC-2 and 5 M - lithium chloride (LiCl) treated HC-2 for four weeks. Obvious improvements in the intestinal surface were observed in R group than the control group and L group. qPCR analysis demonstrated that the selected immune-related genes of lysozyme, proPO, LGBP, PEN-3α, crustin, and lvLec were significantly up-regulated in group R than in group L. Meanwhile, in the challenge test, shrimp in R group received 72% relative percent survival, which was significantly higher than the L group (RPS = 9%). The bacteria composition analysis showed that the abundance of Proteobacteria were significantly higher in group R and L than in group C, and the Bacteroidetes were significantly higher in group C than in group R and L, whereas the numbers of Chloroflexi were significantly higher in group R than in group C and L. The bacterial community difference analysis revealed that the harmful bacteria such as genus of Vibrio, Tenacibaculu and Thalassobius were decreased and the beneficial bacterium as Ruegeria and Lactobacillus were increased in R group, whereas this phenomenon were not found in L group. Taken together, above results indicating that the surface proteins were indispensable for L. pentosus HC-2 adhesion and colonization in shrimp intestines to improve intestine condition, enhance immune response, competitively exclude the pathogens, and promote the beneficial bacteria growth to protect the shrimp from pathogens infection. The findings in this work will help to promote the understanding of the roles of probiotics in shrimp intestines displaying probiotic-function by regulating the intestinal bacteria.
肠道中的微生物相互作用在促进或维持宿主健康方面发挥着重要作用。本研究旨在探讨戊糖片球菌 HC-2 的表面蛋白对凡纳滨对虾免疫反应和细菌组成的影响，因此，在投喂正常 HC-2 和 5M 氯化锂（LiCl）处理的 HC-2 四周后，研究了虾的免疫相关基因、表面状况、HC-2 数量和中肠细菌多样性。与对照组和 L 组相比，R 组虾的肠道表面有明显改善。qPCR 分析表明，与 L 组相比，R 组的溶菌酶、原卟啉氧化酶、LGBP、PEN-3α、壳聚糖和 lvLec 等选择的免疫相关基因显著上调。同时，在攻毒试验中，R 组虾获得了 72%的相对存活率，明显高于 L 组（RPS=9%）。细菌组成分析表明，R 组和 L 组的变形菌门丰度明显高于 C 组，C 组的拟杆菌门丰度明显高于 R 组和 L 组，而 R 组的绿弯菌门丰度明显高于 C 组和 L 组。细菌群落差异分析表明，R 组中弧菌属、Tenacibaculu 属和 Thalassobius 属等有害菌数量减少，而 Ruegeria 属和 Lactobacillus 属等有益菌数量增加，而 L 组则没有这种现象。综上所述，这些结果表明，表面蛋白对于 L. pentosus HC-2 在虾肠道中的黏附和定植是必不可少的，这可以改善肠道状况，增强免疫反应，竞争性排除病原体，并促进有益细菌的生长，从而保护虾免受病原体感染。本研究结果将有助于促进对益生菌在调节肠道细菌方面发挥益生菌功能的理解。
