多糖类免疫增强剂在鱼类养殖中的应用研究进展

多糖类免疫增强剂是一种可以激活机体免疫系统,提高固有免疫和适应性免疫水平,增强机体抵御病原微生物入侵能力的活性物质,具有免疫调节性、生物可降解性、低毒性和安全性等优点,已成为水产养殖领域的研究热点之一。本文综述了近年来植物、微生物和动物来源的多糖类免疫增强剂的结构、免疫机制和在水产养殖中的应用研究进展和前景,以期为鱼类健康养殖提供参考。     

免疫刺激剂对养殖鱼类免疫系统的影响

免疫刺激剂是指能够调节动物免疫系统并激活免疫机能，增强机体对细菌和病毒等传染性病原体抵抗力的一类物质。近年来，国内外均开展了将免疫刺激剂用于水产养殖动物传染性疾病预防的研究，其主要目的是为了将其用于预防使用化学药物难于奏效的水产养殖动物的病毒和细菌性疾病。本文针对养殖鱼类的免疫机制。论述了不同免疫刺激剂对养殖鱼类的作用特点。     

免疫增强剂对鲤鱼内源蛋白酶活性的影响

<正>水产养殖中对水产动物疾病的防治常使用大量抗生素。由于抗生素等化学药物的长期使用或滥用,鱼类对抗生素的耐药致病菌株不断增多,使其免疫功能下降,药物在水产品中的残留也严重影响水产品的安全和人类的健康。近年来,国内外学者对鱼类免疫机制及其病害防治方法进行了大量研究,其中免疫增强剂因具有增强机体的抗应激能力已受到国际养殖业界的高度重视。免疫增强剂是一类具有促进或诱发宿主防御反应、增强机体抗病能力的物质。免疫增强剂能够提高     

免疫增强剂的特点及其在水产动物中的应用方法(上)

正免疫刺激剂(immunologic stimulant)是指能够调节动物免疫系统并激活免疫功能、增强机体对细菌和病毒等传染性病原体抵抗力的一类物质。将免疫刺激剂用于水产养殖动物传染性疾病预防的研究,其主要目的是为了预防使用化学药物难以奏效的水产养殖动物的病毒和细菌性疾病。一、免疫刺激剂的种类、特点与应用现有的研究结果已经证明,能激活鱼、虾类免疫     

水产用免疫刺激剂的种类与使用方法

免疫刺激剂(immunologic stimulant)是指能够调节动物免疫系统并激活免疫机能,增强机体对细菌和病毒等传染性病原体抵抗力的一类物质.近年来,国内、外均开展了将免疫刺激剂用于水产养殖动物传染性疾病预防的研究,其主要目的是为了将免疫刺激剂用于预防使用化学药物难于奏效的水产养殖动物的病毒和细菌性疾病.本文在简要叙述水产动物的免疫防御机制的基础上,比较详细地介绍了国内、外用于水产养殖动物疾病预防的免疫刺激剂种类、特性和水产用免疫刺激剂的使用方法.     

免疫增强剂对锦鲤生长性能的影响

<正>近年来,国内外学者对鱼类免疫机制及其病害防治方法进行了大量研究,其中免疫增强剂因具有增强机体的抗应激能力已受到国际养殖界的高度重视。免疫增强剂是一类具有促进或诱发宿主防御反应、增强机体抗病能力的物质。免疫增强剂能够提高水生动物自身非特异性免疫能力,对特异性免疫应答不产生影响,因此,使用免疫增强剂被认为是一种提高水生动物免疫活性及疾病抵抗力的有效方法,具有重要应用价值。     

提高水产动物自身免疫力抵抗疾病的发生已成为研究的热点

本刊讯：水产养殖过程中发生疾病，使用抗生素进行防治，会产生抗药性细菌，并对环境造成污染，给人类食品的安全造成隐患。最近研究动向，人们已开始把注意力转移到调动或激活水产动物自身的免疫系统，提高其非特异性免疫功能和抗病力，以达到预防和抵抗养殖动物疾病的目的。目前通过提高水产动物自身免疫力来抵抗疾病的发生，已成为研究的热点。目前研究免疫增强剂按其功能而言，可以分为两大类：一类是增强水产动物的非特异性免疫功能；另一类是增强由疫苗诱导的特异性免疫功能。利用免疫增强剂预防、控制疾病，当前在水产养殖上有较好的效果。     

鱼类免疫增强剂的研究现状与进展

现代水产养殖业追求优质高产，但在大规模高密度的养殖生产中，往往会导致鱼体的抗应激能力下降，病害增多，成活率下降，造成重大经济损失。近年来，国内外学者对鱼类免疫机制及其病害防治方法已进行了大量研究，其中免疫增强剂因能增强机体抗疾病感染的能力，其免疫增强作用所需时间较短，且没有记忆成分，被认为是一种提高鱼体免疫活性及疾病抵抗力的有效方法，具有重要的应用价值。     

中草药免疫增强剂在水产上的开发应用

鱼病的发生是机体本身、病原体和水环境3者相互作用的结果。鱼体是否生病，除了环境条件、病原体毒力、数量、入侵途径等条件外。主要还取决于鱼体本身，即鱼体免疫力的强弱。利用免疫增强剂来提高鱼类机体免疫力，对预防疾病的发生有十分重要的作用。因此，近年来，不少水产工作者已将目光移向水产免疫     

中药免疫增强剂在黄鳝养殖上的应用试验初报

近几年来，大量研究资料表明，中草药具有抗微生物病原作用、免疫促进作用、营养平衡作用等多种功效，可应用于水产养殖动物以提高其生产性能和抗病能力。为了进一步了解中草药在黄鳝养殖上应用的可行性，我们用复方渔用中药免疫增强剂(Traditional Chinese Medicinal ImmunoIntensifier，下简称TCMI)在江西省南昌县蒋巷镇的网箱养鳝基地进行了不同添加量的养殖对比试验，现将试验情况报告如下：     

Probiotics,immunostimulants, plant products and oral vaccines,and their role as feed supplements in the control of bacterial fish diseases

There is a rapidly increasing literature pointing to the success of probiotics, immunostimulants, plant products and oral vaccines in immunomodulation, namely stimulation of the innate, cellular and/or humoral immune response, and the control of bacterial fish diseases. Probiotics are regarded as live micro‐organisms administered orally and leading to health benefits. However, in contrast with the use in terrestrial animals, a diverse range of micro‐organisms have been evaluated in aquaculture with the mode of action often reflecting immunomodulation. Moreover, the need for living cells has been questioned. Also, key subcellular components, including lipopolysaccharides, have been attributed to the beneficial effect in fish. Here, there is a link with immunostimulants, which may also be administered orally. Furthermore, numerous plant products have been reported to have health benefits, namely protection against disease for which stimulation of some immune parameters has been reported. Oral vaccines confer protection against some diseases, although the mode of action is usually linked to humoral rather than the innate and cellular immune responses. This review explores the relationship between probiotics, immunostimulants, plant products and oral vaccines.     

Nutrition and health of aquaculture fish

Under intensive culture conditions, fish are subject to increased stress owing to environmental (water quality and hypoxia) and health conditions (parasites and infectious diseases). All these factors have negative impacts on fish well-being and overall performance, with consequent economic losses. Though good management practices contribute to reduce stressor effects, stress susceptibility is always high under crowded conditions. Adequate nutrition is essential to avoid deficiency signs, maintain adequate animal performance and sustain normal health. Further, it is becoming evident that diets overfortified with specific nutrients [amino acids, essential fatty acids (FAs), vitamins or minerals] at levels above requirement may improve health condition and disease resistance. Diet supplements are also being evaluated for their antioxidant potential, as fish are potentially at risk of peroxidative attack because of the large quantities of highly unsaturated FAs in both fish tissues and diets. Functional constituents other than essential nutrients (such as probiotics, prebiotics and immunostimulants) are also currently being considered in fish nutrition aiming to improve fish growth and/or feed efficiency, health status, stress tolerance and resistance to diseases. Such products are becoming more and more important for reducing antibiotic utilization in aquafarms, as these have environmental impacts, may accumulate in animal tissues and increase bacterial resistance. This study reviews knowledge of the effect of diet nutrients on health, welfare and improvement of disease resistance in fish.     

The use of immunostimulating herbs in fish. An overview of research

The use of immunostimulants as an alternative to the drugs, chemicals and antibiotics currently being used to control fish diseases in fish culture is attracting the attention of many researchers. In this context, many have focused on the use of medicinal plant products as potential therapeutic measures for modulating the immune response and, specifically, on the use of herbs to prevent and control fish diseases. Medicinal plants (plant remedies) are a deeply rooted component of the cultural heritage of many people from diverse cultures and countries and are, as such, closely linked to the maintenance of good health. The aim of this paper is to review research currently being carried out on the herbs and herbal extracts that have been shown to modulate the immune system of fish. Special attention is given to the use of Chinese and Indian herbs.     

Melano-macrophage centres and their role in fish pathology

Melano-macrophage centres, also known as macrophage aggregates, are distinctive groupings of pigment-containing cells within the tissues of heterothermic vertebrates. In fish they are normally located in the stroma of the haemopoietic tissue of the spleen and the kidney, although in amphibians and reptiles, and some fish, they are also found in the liver. They may also develop in association with chronic inflammatory lesions elsewhere in the body and during ovarian atresia. In higher teleosts, they often exist as complex discrete centres, containing lymphocytes and macrophages, and may be primitive analogues of the germinal centres of lymph nodes. Melano-macrophage centres usually contain a variety of pigments, including melanins, and these increase in range and volume in older fish or in the presence of cachectic disease. Melano-macrophage centres act as focal depositories for resistant intracellular bacteria, from which chronic infections may develop. Iron capture and storage in haemolytic diseases appears to be a primary function, but antigen trapping and presentation to lymphocytes, sequestration of products of cellular degradation and potentially toxic tissue materials, such as melanins, free radicals and catabolic breakdown products are among other functions that have been ascribed. Recent work suggests that they are a site of primary melanogenesis rather than mere storage. Melano-macrophage centres increase in size or frequency in conditions of environmental stress and have been suggested as reliable biomarkers for water quality in terms of both deoxygenation and iatragenic chemical pollution.     

Current research on the use of plant‐derived products in farmed fish

Over the years, aquaculture has shown increasing development in terms of production. However, due to intensive farming practices, infectious diseases represent the main problem in fish farms, causing heavy economic losses. The use of antibiotics for controlling diseases is widely criticized for its negative impact, including selection of antibiotic‐resistant bacterial strains, immunosuppression, environmental pollution and accumulation of chemical residues in fish tissues. On the other hand, though vaccination is the most effective prophylactic method of preventing disease outbreaks, the development of effective formulations is often hindered by high production costs and the antigenic heterogeneity of the microbial strains. Recently, there has been increased interest in the possibility of using medicinal herbs as immunostimulants, capable of enhancing immune responses and disease resistance of cultured fish. Plant‐derived products seem to represent a promising source of bioactive molecules, being at the same time readily available, inexpensive and biocompatible. The aim of this article is to provide an overview of recent research dealing with the use of medicinal plants in aquaculture. Special attention is given to the information about the effects of plant extracts/products on fish growth, haematological profiles, immune responses and resistance to infectious diseases.     

棕点石斑鱼中草药免疫增强剂的快速筛选

采用离体外周血白细胞与中草药水提液共同孵育法,快速筛选棕点石斑鱼中草药免疫增强剂。39种生药量浓度为100 mg/ml 的中草药水提液及添加5.0 mg/ml 酵母聚糖的中草药水提液分别与棕点石斑鱼外周血白细胞孵育后,采用氮蓝四唑(NBT)还原法检测各种中草药水提液对棕点石斑鱼外周血白细胞氧呼吸爆发活性的影响,再以吞噬乳胶微球法检测具有显著增强白细胞氧呼吸爆发活性效果的中草药对棕点石斑鱼白细胞吞噬活性的影响,筛选中草药免疫增强剂,并将其拌料饲喂棕点石斑鱼,考察其对棕点石斑鱼外周血和头肾白细胞氧呼吸爆发活性的影响。结果显示,39种中草药中有10种对棕点石斑鱼离体白细胞氧呼吸爆发活性显著提高15%以上,3种酵母聚糖添加组对白细胞氧呼吸爆发活性提高70%以上;筛选出可同时提高棕点石斑鱼离体白细胞的氧呼吸爆发活性和吞噬活性的 3种中草药,它们分别为鸡血藤、黄柏和墨旱莲。拌料饲喂实验结果显示,饲喂1%的鸡血藤、黄柏和墨旱莲可显著提高棕点石斑鱼体内外周血和头肾白细胞氧呼吸爆发活性。     

Essential fatty acid requirements of cultured marine fish larvae

Feeding of marine fish larvae is, in most cases, limited to the administration of two species of live prey. This reduction in the range of food available for the cultured larvae may occasionally lead to nutritional imbalances or deficiencies. A large amount of research has been recently devoted to the study of the essential fatty acid requirements of marine fish larvae. Studies on the biochemical composition of developing eggs and larvae, as well as the comparison of the patterns of loss and conservation during starvation, pointed out the importance of n-3 HUFA and arachidonic acid as essential fatty acids for larvae of marine fish. The biochemical composition of marine fish larvae, in terms of lipid content and fatty acid composition of total and polar lipids, is modified by dietary levels of essential fatty acids. Larval growth, survival and activity have also been reported to be affected by dietary levels of essential fatty acids. In addition, some pathological signs, such as hydrops or abnormal pigmentation, have been related to essential fatty acid deficiency in these fish. Based on these effects, the essential fatty acid requirements of marine larval fish have been reported to range between 0.3 and 55 g kg^?1 n-3 HUFA on a dry weight basis, suggesting that quantitative requirements of fish larvae may differ from those of juveniles or adults. But quantitative requirements for larvae of the same species reported by various authors are often contradictory. These differences are discussed in relation to the dietary lipid content, ratio 20:5n-3/22:6n-3 and culture conditions used.     

Anaesthesia of farmed fish: implications for welfare

During their life cycle as farmed animals, there are several situations in which fish are subjected to handling and confinement. Netting, weighing, sorting, vaccination, transport and, at the end, slaughter are frequent events under farming conditions. As research subjects, fish may also undergo surgical procedures that range from tagging, sampling and small incisions to invasive procedures. In these situations, treatment with anaesthetic agents may be necessary in order to ensure the welfare of the fish. The main objective of this paper is to review our knowledge of the effects of anaesthetic agents in farmed fish and their possible implications for welfare. As wide variations in response to anaesthesia have been observed both between and within species, special attention has been paid to the importance of secondary factors such as body weight, water temperature and acute stress. In this review, we have limited ourselves to the anaesthetic agents such as benzocaine, metacaine (MS-222), metomidate hydrochloride, isoeugenol, 2-phenoxyethanol and quinaldine. Anaesthetic protocols of fish usually refer to one single agent, whereas protocols of human and veterinary medicine cover combinations of several drugs, each contributing to the effects needed in the anaesthesia. As stress prior to anaesthesia may result in abnormal reactions, pre-anaesthetic sedation is regularly used in order to reduce or avoid stress and is an integral part of the veterinary protocols of higher vertebrates. Furthermore, the anaesthetic agents that are used in order to obtain general anaesthesia are combined with analgesic agents that target nociception. The increased use of such combinations in fish is therefore included as a special section. Anaesthetic agents are widely used to avoid stress during various farming procedures. While several studies report that anaesthetics are effective in reducing the stress associated with confinement and handling, there are indications that anaesthesia may in itself induce a stress response, measured by elevated levels of cortisol. MS-222 has been reported to elicit high cortisol release rates immediately following exposure, while benzocaine causes a bimodal response. Metomidate has an inhibitory effect on cortisol in fish and seems to induce the lowest release of cortisol of the agents reported in the literature. Compared to what is observed following severe stressors such as handling and confinement, the amount of cortisol released in response to anaesthesia appears to be low but may represent an extra load under otherwise stressful circumstances. Furthermore, anaesthetics may cause secondary adverse reactions such as acidosis and osmotic stress due to respiratory arrest and insufficient exchange of gas and ions between the blood and the water. All in all, anaesthetics may reduce stress and thereby improve welfare but can also have unwanted side effects that reduce the welfare of the fish and should therefore always be used with caution. Finally, on the basis of the data reported in the literature and our own experience, we recommend that anaesthetic protocols should always be tested on a few fish under prevailing conditions in order to ensure an adequate depth of anaesthesia. This recommendation applies whether a single agent or a combination of agents is used, although it appears that protocols comprising combinations of agents provide wider safety margins. The analgesic effects of currently used agents, in spite of their proven local effects, are currently being debated as the agents are administrated to fish via inhalation rather than locally at the target site. We therefore recommend that all protocols of procedures requiring general anaesthesia should be complemented by administration of agents with analgesic effect at the site of tissue trauma.     

Lactic acid bacteria in fish: a review

Fish are continuously exposed to a wide range of microorganisms present in the environment, and the microbiota of fish have been the subject of several reviews. This review evaluates lactic acid bacteria in fish, and focuses on the several investigations that have demonstrated that Streptococcus, Leuconostoc, Lactobacillus, and Carnobacterium belong to the normal microbiota of the gastrointestinal tract in healthy fish. However, it is well known that the population level of lactic acid bacteria associated with the digestive tract is affected by nutritional and environmental factors like dietary polyunsaturated fatty acids, chromic oxide, stress and salinity. Pathogenic lactic acid bacteria such as Streptococcus, Enterococcus, Lactobacillus, Carnobacterium and Lactococcus have been detected from ascites, kidney, liver, heart and spleen. Some antibiotic treatments and vaccinations have been proposed to cure or prevent these diseases that seem, however, to spread with the development of fish culture. It has also been reported that some lactic acid bacteria isolated from the gastrointestinal tract of fish can act as probiotics. These candidates are able to colonise the gut, and act antagonistic against Gram-negative fish pathogens. These harmless bacteriocin-producing strains may reduce the need to use antibiotics in future aquaculture.