水产养殖中益生菌研究进展

益生菌在水产养殖中能够净化水质、预防疾病、促进生长且安全、环保、无抗性,是抗生素的理想替代品,具有重要的研究价值和广阔的应用前景。本文主要从益生菌制剂的定义概述、作用机理及特性进行阐述,分析益生菌制剂存在的问题,探讨水产养殖用益生菌制剂的研究方向。     

The use of probiotics in shrimp aquaculture

Shrimp aquaculture, as well as other industries, constantly requires new techniques in order to increase production yield. Modern technologies and other sciences such as biotechnology and microbiology are important tools that could lead to a higher quality and greater quantity of products. Feeding and new practices in farming usually play an important role in aquaculture, and the addition of various additives to a balanced feed formula to achieve better growth is a common practice of many fish and shrimp feed manufacturers and farmers. Probiotics, as 'bio-friendly agents' such as lactic acid bacteria and Bacillus spp., can be introduced into the culture environment to control and compete with pathogenic bacteria as well as to promote the growth of the cultured organisms. In addition, probiotics are nonpathogenic and nontoxic microorganisms without undesirable side-effects when administered to aquatic organisms. These strains of bacteria have many other positive effects, which are described in this article.     

Towards a compatible probiotic–antibiotic combination therapy: assessment of antimicrobial resistance in the Japanese probiotics

Aim:  To determine the antimicrobial resistance of the Japanese probiotics available in the market without a pharmacist’s supervision. Methods and Results:  A total of 43 isolates were obtained from 40 samples of probiotics (30 dairy products and 10 products in tablet form). Isolates were identified using 16S rRNA gene sequencing and tested for their susceptibility to 14 antimicrobials. They were screened using PCR for some antibiotic resistance genes. Inactivation of cefepime, clarithromycin and vancomycin by different inocula of 11 strains was evaluated using the antibiotic inactivation bioassay. None of the dairy probiotics showed a level of constitutive resistance or carried inducible resistance genes, making them suitable to be administrated with macrolides. Among the probiotics in tablet form only Enterococcus faecium strains carrying the msrC gene showed an MIC₉₀ of 4 μg ml^?1. Extended‐spectrum β‐lactams, tetracyclines and ampicillin exhibited powerful germicidal activity against the vast majority of the probiotic strains. Conclusions:  There is a limited choice of the Japanese probiotics that can be administered with clinically used antibiotics. Significance and Impact of the Study:  Japanese probiotics are widely distributed all over the world. Through the findings of our study, we have attempted to provide guidance for clinicians interested in using the Japanese probiotics in combination with antibiotics.     

富硒益生菌的功效研究进展

硒是人体必需的微量元素,对人体健康有重要作用。益生菌能够将硒元素转化为有机硒,降低硒的毒性,同时硒又提高了益生菌的生物活性,富硒益生菌具备了硒和益生菌的双重功效。本文主要综述了近年来富硒益生菌的功效,如抗氧化、抑制有害菌、调节肠道菌群、抗癌等。     

Prospects of using marine actinobacteria as probiotics in aquaculture

In the present study, optimum culture conditions for the production of extracellular polysaccharides (EPS) in submerged culture of an edible mushroom, Laetiporus sulphureus var. miniatus and their stimulatory effects on insulinoma cell (RINm5F) proliferation and insulin secretion were investigated. The maximum mycelial growth (4.1 g l⁻¹) and EPS production (0.6 g l⁻¹) in submerged flask culture were achieved in a medium containing 30 g l⁻¹ maltose, 2 g l⁻¹ soy peptone, and 2 mM MnSO₄·5H₂O at an initial pH 2.0 and temperature 25°C. In the stirred-tank fermenter under optimized medium, the concentrations of mycelial biomass and EPS reached a maximum level of 8.1 and 3.9 g l⁻¹, respectively. Interestingly, supplementation of deep sea water (DSW) into the culture medium significantly increased both mycelial biomass and EPS production by 4- and 6.7-fold at 70% (v/v) DSW medium, respectively. The EPS were proved to be glucose-rich polysaccharides and were able to increase proliferation and insulin secretary function of rat insulinoma RINm5F cells, in a dose-dependent manner. In addition, EPS also strikingly reduced the streptozotocin-induced apoptosis in RINm5F cells indicating the mode of the cytoprotective role of EPS on RINm5F cells.     

The safety of Bacillus subtilis and Bacillus indicus as food probiotics

Aims:  To conduct in vitro and in vivo assessments of the safety of two species of Bacillus , one of which, Bacillus subtilis , is in current use as a food supplement.
Methods and Results:  Cultured cell lines, Caco-2, HEp-2 and the mucus-producing HT29-16E cell line, were used to evaluate adhesion, invasion and cytotoxicity. The Natto strain of B. subtilis was shown to be able to invade and lyse cells. Neither species was able to adhere significantly to any cell line. The Natto strain was also shown to form biofilms. No strain produced any of the known Bacillus enterotoxins. Disc-diffusion assays using a panel of antibiotics listed by the European Food Safety Authority (EFSA) showed that only Bacillus indicus carried resistance to clindamycin at a level above the minimum inhibitory concentration breakpoints set by the EFSA. In vivo assessments of acute and chronic dosing in guinea pigs and rabbits were made. No toxicity was observed in animals under these conditions.
Conclusions:  Bacillus indicus and B. subtilis should be considered safe for oral use although the resistance of B. indicus to clindamycin requires further study.
Significance and Impact of the Study:  The results support the use of B. subtilis and B. indicus strains as food supplements.     

Bioactives from probiotics for dermal health: functions and benefits

Probiotics have been extensively reviewed for decades, emphasizing on improving general gut health. Recently, more studies showed that probiotics may exert other health‐promoting effects beyond gut well‐being, attributed to the rise of the gut–brain axis correlations. Some of these new benefits include skin health such as improving atopic eczema, atopic dermatitis, healing of burn and scars, skin‐rejuvenating properties and improving skin innate immunity. Increasing evidence has also showed that bacterial compounds such as cell wall fragments, their metabolites and dead bacteria can elicit certain immune responses on the skin and improve skin barrier functions. This review aimed to underline the mechanisms or the exact compounds underlying the benefits of bacterial extract on the skin based on evidences from in vivo and in vitro studies. This review could be of help in screening of probiotic strains with potential dermal enhancing properties for topical applications.     

The use of immunostimulants in fish larval aquaculture

The production of fish larvae is often hampered by high mortality rates, and it is believed that most of this economic loss due to infectious diseases is ca. 10% in Western European aquaculture sector. The development of strategies to control the pathogen load and immuno-prophylactic measures must be addressed further to realise the economic "potential" production of marine fish larvae and thus improve the overall production of adult fish. The innate defence includes both humoral and cellular defence mechanisms such as the complement system and the processes played by granulocytes and macrophages. A set of different substances such as beta-glucans, bacterial products, and plant constituents may directly initiate activation of the innate defence mechanisms acting on receptors and triggering intracellular gene activation that may result in production of anti-microbial molecules. These immunostimulants are often obtained from bacterial sources, brown or red algae and terrestrial fungi are also exploited as source of novel potentiating substances. The use of immunostimulants, as dietary supplements, can improve the innate defence of animals providing resistance to pathogens during periods of high stress, such as grading, reproduction, sea transfer and vaccination. The immunomodulation of larval fish has been proposed as a potential method for improving larval survival by increasing the innate responses of the developing animals until its adaptive immune response is sufficiently developed to mount an effective response to the pathogen. To this end it has been proposed that the delivery of immunostimulants as a dietary supplement to larval fish could be of considerable benefit in boosting the animals innate defences with little detriment to the developing animal. Conversely, there is a school of thought that raises the concern of immunomodulating a neotanous animal before its immune system is fully formed as this may adversely affect the development of a normal immune response.     

益生菌与幽门螺杆菌对黏膜屏障的影响及其机制的研究进展

消化系黏膜屏障对致病菌有防御功能,但是在根除幽门螺杆菌(H. pylori)过程中会导致黏膜屏障的破坏。大量研究表明,益生菌通过修复上皮细胞以及细胞间连接、减少黏液分泌和炎症反应以及缓解消化道菌群紊乱等方式修复黏膜屏障。本文主要综述幽门螺杆菌对消化系黏膜屏障的损害及其机制,以及益生菌对黏膜屏障损伤的保护及修复机制研究的进展。     

The use of bacterial spore formers as probiotics

The field of probiosis has emerged as a new science with applications in farming and aqaculture as alternatives to antibiotics as well as prophylactics in humans. Probiotics are being developed commercially for both human use, primarily as novel foods or dietary supplements, and in animal feeds for the prevention of gastrointestinal infections, with extensive use in the poultry and aquaculture industries. The impending ban of antibiotics in animal feed, the current concern over the spread of antibiotic resistance genes, the failure to identify new antibiotics and the inherent problems with developing new vaccines make a compelling case for developing alternative prophylactics. Among the large number of probiotic products in use today are bacterial spore formers, mostly of the genus Bacillus. Used primarily in their spore form, these products have been shown to prevent gastrointestinal disorders and the diversity of species used and their applications are astonishing. Understanding the nature of this probiotic effect is complicated, not only because of the complexities of understanding the microbial interactions that occur within the gastrointestinal tract (GIT), but also because Bacillus species are considered allochthonous microorganisms. This review summarizes the commercial applications of Bacillus probiotics. A case will be made that many Bacillus species should not be considered allochthonous microorganisms but, instead, ones that have a bimodal life cycle of growth and sporulation in the environment as well as within the GIT. Specific mechanisms for how Bacillus species can inhibit gastrointestinal infections will be covered, including immunomodulation and the synthesis of antimicrobials. Finally, the safety and licensing issues that affect the use of Bacillus species for commercial development will be summarized, together with evidence showing the growing need to evaluate the safety of individual Bacillus strains as well as species on a case by case by basis.     

益生菌及益生元调节骨代谢的研究进展

骨质疏松症已成为威胁中老年人健康的主要疾病之一,越来越多的人受到该病症的危害.肠道菌群是定殖在机体肠道内,与宿主形成共生关系的微生物,对宿主的免疫及代谢等产生重要影响,研究发现,肠道菌群与骨代谢之间存在密切关系,本文从肠道菌群与免疫、骨代谢与免疫、肠道菌群与骨代谢、益生菌及益生元调节骨代谢等几个方面阐述,肠道菌群有望成为骨质疏松症治疗的一个新靶点,通过益生菌或益生元来干预肠道菌群组成,进而调节免疫系统状态,抑制促炎因子的生成,从而降低骨吸收作用,达到预防和治疗骨质疏松症的目的.     

The use of inter-specific hybrids in aquaculture and fisheries

Inter-specific hybrid fishes have been produced for aquaculture and stocking programmes to increase growth rate, transfer desirable traits between species, combine desirable traits of two species into a single group of fishes, reduce unwanted reproduction through production of sterile fish or mono-sex offspring, take advantage of sexual dimorphism, increase harvestability, increase environmental tolerances, and to increase overall hardiness in culture conditions. Hybrids constitute a significant proportion of some countries' production for certain taxa; for example, hybrid striped bass in the USA, hybrid clarid catfish in Thailand, hybrid characids in Venezuela, and hybrid tilapia in Israel. Despite its widespread use, there is a general impression that inter-specific hybridization is not a very useful tool for aquaculture. We believe this impression stems from inaccurate reporting of some useful hybrids, limited testing of strains used for hybrids, and from early work on salmonids that did not result in hybrids of commercial advantage.Experimentation with new hybrid fishes is ongoing, especially in marine culture systems where sterile fish may be preferred because of the concern that fish may escape into the marine and coastal environment.Hybridization has been used in tandem with polyploidization to improve developmental stability in hybrid progeny. The results of inter-specific hybridization can be variable and depend on the genetic structure (including the sex) of the parent fish. Inadvertent hybridization and backcrossing can lead to unexpected and undesirable results in hybrid progeny, such as failure to produce sterile fish, loss of color pattern, and reduced viability.Hybridization is only one tool to improve aquaculture production and will require knowledge of the genetic structure of the broodstock, good broodstock management and monitoring of the viability and fertility of the progeny. Hybridization does represent a genetic modification wherein genes are moved between different species; implications for biodiversity conservation and regulation of this type of modification are discussed.     

Regulation of immune response at intestinal and peripheral sites by probiotics

The gut associated lymphoid tissue (GALT) should protect intestinal mucosa against pathogens, but also avoid hypersensitivity reactions to food proteins, normal bacterial flora and other environmental macromolecules. The interaction between epithelial cells and microflora is fundamental to establish gut mucosal barrier and GALT development. The normal colonization of intestine by commensal bacteria is thus crucial for a correct development of mucosal immune system. Probiotic bacteria are normal inhabitants of microflora and may confer health benefits to the host. The modification of the intestinal microflora towards a healthier probiotics enriched microflora may generate beneficial mucosal immunomodulatory effects and may represent a new strategy to cure intestinal and allergic diseases. The health benefits may be specific for different probiotic strains. Ongoing research is providing new insights into the probiotic beneficial effects and related mechanisms. This review represents an update of immunomodulatory activity of different probiotics and of the more accredited mechanisms underlying such activities. Presented at the Second Probiotic Conference, Košice, 15–19 September 2004, Slovakia.     

Isolation of Saccharomyces cerevisiae strains from different food matrices and their preliminary selection for a potential use as probiotics

Aims: To isolate acid‐ and bile‐resistant Saccharomyces cerevisiae strains directly from food samples and to preliminarily select them on the basis of fundamental probiotic properties. Methods and Results: A rapid screening method allowed the isolation and selection of 20 acid‐ and bile‐resistant yeasts from foods, avoiding time‐consuming isolation steps. The strains were characterized for their specific survival in simulated gastric juice and in intestinal fluid after pre‐exposure at low pH. Ten isolates demonstrated a satisfactory survival percentage in intestinal fluid after pre‐exposure to gastric juice and appreciable lipolytic and proteolytic properties, as demonstrated by the API‐ZYM test. By using molecular methods five strains were identified as Saccharomyces cerevisiae, three as Candida spp., one as Candida pararugosa and one as Pichia spp. The Saccharomyces cerevisiae strains showed considerable probiotic properties, achieving a 80< % <90 survival through the simulated gastrointestinal tract, as well as interesting glucosidase activities. Conclusions: The research represents an efficient strategy to select and identify Saccharomyces cerevisiae strains with desirable acid and bile resistances. Significance and Impact of the Study: This paper reports the direct selection of potentially probiotic yeasts from foods and provides indications about the ability of Saccharomyces cerevisiae strains to survive conditions simulating the human gastrointestinal tract.     

Diet and bacterial colonization: role of probiotics and prebiotics

The intestinal mucosa functions as a defensive barrier that limits dietary antigen transport and microbial pathogens from colonizing enterocytes. The potential role of lactic acid bacteria, specifically Bifidobacteria, in probiotic and prebiotic functional food supplements is reviewed in the context of bacterial colonization, adherence, and disease prevention. This article reviews the mechanisms of action and optimization of methods that will lead to a new generation of biotic products with enhanced biologic properties and well-being foods.     

益生菌对自身免疫病的作用及机制研究现状

自身免疫病是机体免疫功能紊乱而导致组织器官受损的一类疾病,包括类风湿关节炎、系统性红斑狼疮、多发性硬化症、自身免疫性肝炎等。糖皮质激素及免疫抑制剂是治疗自身免疫病的常用药物,但长期使用会产生代谢紊乱、免疫低下、继发感染等副作用。随着肠道菌群与自身免疫病相关研究的进展,益生菌干预自身免疫病成为一大研究热点。研究证实,益生菌缓解自身免疫病安全有效,有望成为辅助疗法甚至替代疗法。本文就益生菌缓解类风湿关节炎、系统性红斑狼疮、多发性硬化症、自身免疫性肝炎等的作用及相关机制进行综述。     

Survey of antibiotic resistance in an integrated marine aquaculture system under oxolinic acid treatment

The consequences of antibiotic use in aquatic integrated systems, which are based on trophic interactions between different cultured organisms and physical continuity through water, need to be examined. In this study, fish reared in a prototype marine integrated system were given an oxolinic acid treatment, during and after which the level of resistance to this quinolone antibiotic was monitored among vibrio populations from the digestive tracts of treated fish, co-cultured bivalves and sediments that were isolated on thiosulfate-citrate-bile-sucrose. Oxolinic acid minimum inhibitory concentration distributions obtained from replica plating of thiosulfate-citrate-bile-sucrose plates indicated that a selection towards oxolinic acid resistance had occurred in the intestines of fish under treatment. In contrast, and despite oxolinic acid concentrations higher than minimum inhibitory concentrations of susceptible bacteria, no clear evolution of resistance levels was detected either in bivalves or in sediments.