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粪肠球菌(E.faecalis)又叫粪链球菌,普遍存在于自然界,一般栖居在动物的肠腔,也是人体上呼吸道或肠道的常居益生菌.粪肠球菌作为乳酸类肠球菌之一是动物宿主肠道内的原生菌种,具有很好的生物安全性和优良的益生特性,但是益生菌只有在人体内存活,具有增殖能力才能发挥更好的益生作用.许多研究显示,活菌制剂进入动物消化道后难以经受低pH值的盐酸、胆汁酸等的作用,很难有足够数量的活菌数量达到肠道或定植肠道而发挥作用.目前发酵乳制品中活菌的耐酸性较弱,活菌存活率低于0.2％.研究显示,当期情况下,微胶囊技术是保护菌体活力最为有效和实用的方法之一,通过对益生菌微胶囊化,在菌种外壁增加保护层,可以有效增强其对胃酸以及胆汁等不良因子的抵抗能力,同时提高其在储藏过程中的稳定性.本试验采用肠溶性材料对菌种进行微胶囊化,并结合喷雾干燥方法,制备获得的益生菌制剂可以抵抗不良环境,使得粪肠球菌具备了实际生产应用价值. 相似文献
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益生菌又称微生态制剂、促生素、生菌素、活菌剂等,是由一种或多种有益微生物及代谢产物组成的,可供人类或动物直接使用和喂食的活菌制剂.有研究表明:益生菌可改善动物肠道菌群的平衡;增强动物机体免疫能力;促进动物生长发育,提高动物生产性能;降低肠道内有害物质的产生. 相似文献
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饲用益生菌制剂是一种通过改善肠道菌群平衡而对动物施加有利影响的活的微生物饲料添加剂．其主要通过调节动物体内消化道pH值和肠道菌群平衡．以及增强非特异性免疫功能来预防疾病,促进动物生长。益生菌制剂的功效与益生菌制剂的种类、活菌数、使用剂量、动物类型、使用条件等密切相关,因此必须掌握饲用益生菌的筛选与使用技术。 相似文献
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益生菌在犬猫上的应用研究进展 《畜牧与饲料科学》2022,43(3):46-52
益生菌是一种定植于宿主肠道,能够调节肠道微生态平衡,提高宿主机体健康水平的活菌制剂。目前益生菌已被证实能够对动物起到多种有益的作用。随着宠物医疗行业的快速发展,犬猫的健康越来越受到主人的重视,益生菌被广泛添加到宠物食品以及营养补充剂中,通过维持肠道微生态的平衡达到预防肠道疾病或提高肠道免疫力的目的。对益生菌的定义、种类和作用机制,以及益生菌在犬猫上的应用研究进展进行综述,以期为犬猫益生菌制剂的开发以及益生菌在宠物医疗行业的应用提供参考。 相似文献
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枯草芽孢杆菌属于革兰氏阳性菌,非致病菌,其芽孢是其一种休眠体,能抵御外界恶劣的环境条件。该菌细胞壁不含内毒素,具有单层细胞外膜,动物肠道中枯草芽孢能直接分泌蛋白质到胞外。枯草芽孢杆菌是一种存在于动物的肠道中的有益菌,参与维持肠道内环境的平衡与稳定,且可刺激机体释放分泌型免疫球蛋白,有利于肠道黏膜的局部免疫,进而增强机体免疫力。因其对体液免疫和细胞免疫的特性,其菌体成为当今制备黏膜免疫疫苗的一种理想的疫苗载体。枯草芽孢杆菌具有独特的优势,使其能作为便于推广的疫苗载体进行研究。文章主要对枯草芽孢杆菌的黏膜免疫机制及其作为疫苗载体研究和应用前景进行阐述。 相似文献
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肠道黏膜免疫研究进展 总被引：1，自引：0，他引：1
黏膜免疫是当前免疫学领域的研究热点,尤其是肠道黏膜免疫越来越被人们重视.近年来国内外学者分别探讨了肠道黏膜组织结构、肠道菌群及黏膜疫苗对黏膜免疫的作用及影响,研究表明,肠道黏膜组织结构中主要是M细胞、树突状细胞和巨噬细胞进行抗原摄取和转运,对起始黏膜免疫起着重要的作用.肠道菌群在免疫过程中主要是促进抗原的分泌和调节各种细胞因子的产生.合适的黏膜疫苗能够有效地激发黏膜免疫反应,具有方便、快捷、安全、有效、持续等优点.文章重点阐述了肠道菌群对黏膜免疫的影响及黏膜免疫的优点,并指出了制约黏膜免疫发展的关键因素、存在的问题及其发展前景. 相似文献
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WAN Hua-yun HU Jun-yi WANG Zi-xu CHEN Yao-xing CAO Jing DONG Yan-jun MA Bao-chen DONG Yu-lan 《中国畜牧兽医》2017,44(12):3642-3649
Intestinal epithelial cells (IECs) are the first line of defense against pathogenic microorganisms of animal organism, which are important component of mucosal mechanical barrier, immune barrier and chemical barrier, they have absorption and barrier double function. In the intestine, there are many kinds of microorganisms. According to its relationship with the host, it is divided into three types of commensal bacteria, conditional pathogenic bacteria and pathogenic bacteria, it plays an important role in the construction of intestinal barrier. Firstly, IECs identify the intestinal microbes by direct or indirect ways, and distinguish their own and non-self, it is immune tolerance to their own substances (such as, commensal bacteria), and produce specific immune response to non-self-substances (pathogenic bacteria). Both of IECs and intestinal commensal bacteria together against pathogens maintain intestinal health. When the pathogenic microorganisms invade the intestine, IECs defense pathogenic microorganisms mainly through extracellular secretions and cell surface mucus layer, and the former largely include mucin, antibacterial molecular and antimicrobial immunoglobulin. The intestinal symbiotic bacteria can resist the pathogenic microorganisms and maintain the normal intestinal mucosal barrier function through the competitive identification sites, the secretion of antimicrobial substances, the increase of mucus secretion, the induction of IECs renewal, proliferation and repair. In the process of resisting invasion of gut microbes, pathogenic microorganisms through their own movement, secretion of toxins and enzymes to destroy the intestinal epithelial barrier, and directly contact with IECs to damage them. So the interaction between IECs and intestinal bacteria maintain the intestinal homeostasis. In this paper, a review is made of the IECs and intestinal microbial structure and functional adaptations, and hope to elaborate the mechanism of intestinal microbial-epithelial cell barrier interaction. 相似文献
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肠道上皮细胞（intestinal epithelial cells,IECs）是动物机体抵御病原微生物的第一道防线,是黏膜机械屏障、免疫屏障和化学屏障的重要组成部分,具有吸收和屏障双层功能。肠道中微生物数量庞大、种类繁多,根据其与宿主的关系,主要分为共生菌、条件致病菌和病原菌3类,在肠道屏障的构建中发挥重要作用。IECs首先通过直接或间接方式对肠道微生物进行识别,区别自身与非自身,对自身物质（即共生菌）免疫耐受,对非自身物质（即病原菌）产生特异性免疫反应。IECs与肠道共生菌共同抵御肠道病原微生物,维持肠道健康,病原微生物侵入肠道,IECs主要通过胞外分泌物和细胞表面黏液层双重屏障发挥作用,其中胞外分泌物主要包括黏蛋白、抗菌分子和抗微生物免疫球蛋白。肠道共生菌可以通过竞争识别位点,分泌抗菌物质,增加黏液分泌,诱导IECs更新、增殖和修复等方式抵御病原微生物,维护正常的肠黏膜屏障功能。在IECs抵御肠道病原微生物入侵过程中,病原微生物通过自身运动、分泌毒素和酶等破坏肠上皮屏障,直接接触IECs,对其进行损伤。因此IECs和肠道菌群间相互作用,共同维持肠道内环境稳态。作者就IECs和肠道微生物结构、功能的适应性变化作一综述,以期阐述肠道微生物-上皮细胞屏障互作的机制。 相似文献
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分泌型IgA(secretory IgA,SIgA)作为一种包被于肠道黏膜的抗体,能保护肠道免受病原微生物和毒素的攻击而不引起炎症反应,对激活黏膜免疫和维持肠道内环境稳态起到重要作用。在动物肠腔中,SIgA能通过调节肠道上皮细胞受体的识别能力,阻断病原微生物侵入黏膜相关淋巴组织,随后在肠道蠕动和黏液绒毛的协助运动下,最终将病原微生物清除;且最近也有报道揭示SIgA在肠上皮胞吞转运作用下的新机制。因此,作者主要阐述SIgA在肠道黏膜免疫及其内环境方面发挥关键的生物学特征和功能,以及探讨胞吞转运机制下SIgA的潜在作用。 相似文献
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A new concept of slow "drip feeding" that enables activation of mucosal as well as systemic immunity following parenteral vaccination was demonstrated using Salmonella Dublin in a mouse model. The live vaccine candidate, N-RM25, generated from a wild S. Dublin strain utilising metabolic-drift (spontaneous chromosomal) mutations had a unique sensitivity to bile and restricted growth in the presence of a very low concentration of bile salts No. 3 (0.075% (w/v)) but also had the ability to survive in a high concentration (19.2%) of the substance. Following intraperitoneal administration with 10(7) cfu, N-RM25 colonised and survived (10(1)-10(3) cfu/g) in the liver and spleen of mice for over 24 days without causing disease. A small number of the mutant organisms also penetrated the gall bladder and gut, most likely via the enterohepatic circulation. N-RM25 induced significant levels of serum IgG, IgA and intestinal secretory IgA. A second metabolic-drift mutant (R-NM29) that was rapidly eliminated from the liver and spleen and highly unlikely to penetrate the gall bladder and gut, stimulated some systemic immunity, but induced no mucosal immunity because it did not reach the immune stimulation sites within the gut. In vaccine trials, N-RM25 was significantly more effective in eliminating the homologous challenge bacteria (S. Dublin wild strain FD436) from the internal organs and intestinal lumen when compared to R-NM29 and the negative control. N-RM25 prevented the development of systemic infection and produced 100% protection. 相似文献
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Pirarat N Pinpimai K Endo M Katagiri T Ponpornpisit A Chansue N Maita M 《Research in veterinary science》2011,91(3):e92-e97
The use of lactic acid bacteria from human origins as a potential probiotic supplementation in aquaculture feed is now widely accepted. Here, we examined some of the properties and mechanisms of the action of Lactobacillus rhamnosus GG, originating from humans, on growth performance, gut mucosal immunity and humoral and cellular immune response in tilapia (Oreochromis niloticus). The results suggested that supplementation of L. rhamnosus gave an advantage in promoting the intestinal structure and the mucosal immunity of tilapia. Probiotic fish had a greater villous height in all parts of the intestines and, significantly, in the proximal and middle part. The population of intraepithelial lymphocytes was significantly higher in the probiotic group than in the control group in all parts of the intestines. The population of acidophilic granulocyte in the probiotic group was significantly higher at the proximal and distal parts when compared with the control group. The higher serum complement activity as well as the enhanced phagocytosis and killing ability of the head kidney leukocytes in the probiotic supplemented fish corresponded with the higher level of TNF alpha and IL-1 gene expression, suggesting that the induction of IL-1 and TNF alpha cytokines by L. rhamnosus served as an important regulator of gut associated immune systems. 相似文献
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《Research in veterinary science》2012,92(3):e92-e97
The use of lactic acid bacteria from human origins as a potential probiotic supplementation in aquaculture feed is now widely accepted. Here, we examined some of the properties and mechanisms of the action of Lactobacillus rhamnosus GG, originating from humans, on growth performance, gut mucosal immunity and humoral and cellular immune response in tilapia (Oreochromis niloticus). The results suggested that supplementation of L. rhamnosus gave an advantage in promoting the intestinal structure and the mucosal immunity of tilapia. Probiotic fish had a greater villous height in all parts of the intestines and, significantly, in the proximal and middle part. The population of intraepithelial lymphocytes was significantly higher in the probiotic group than in the control group in all parts of the intestines. The population of acidophilic granulocyte in the probiotic group was significantly higher at the proximal and distal parts when compared with the control group. The higher serum complement activity as well as the enhanced phagocytosis and killing ability of the head kidney leukocytes in the probiotic supplemented fish corresponded with the higher level of TNF alpha and IL-1 gene expression, suggesting that the induction of IL-1 and TNF alpha cytokines by L. rhamnosus served as an important regulator of gut associated immune systems. 相似文献