Nutrition in organic aquaculture: an inquiry and a discourse

Organic aquaculture has lagged behind the agriculture sector in terms of the quantities and diversity of certified organic products because of the absence of detailed accepted standards and criteria until recently. The main challenges for organic aquaculture are to improve the coordination between production and market and to achieve an appropriate framework to drive further development. Priorities for research include organic feeds and fish nutrition, consumers’ needs, food safety, environmental concerns and trade issues. In organically cultured fish, differences in feeds and nutrition compared to conventional systems are likely to result in differences in the quality of the flesh, and this is a significant factor in consumer choice. The review covers aspects of current use of eco‐certification, formulated feeds, feed composition, aquafeed technology, sustainable alternatives to common feed ingredients, nutritional physiology and general nutritional principles and product quality in the context of the organic aquaculture. There is a future for the development of organic aquaculture but its success depends on new knowledge and technical development to meet consumers’ growing interest. The industry has to utilize the research results and update and modify the criteria and standards and thus provide high‐quality products.     

Effect of proline‐enriched abalone feed on selected metabolite levels of slow‐growing adult Haliotis midae

Abalone is currently considered South Africa's most successfully produced aquaculture export product, with a 76% share of the total value generated by the aquaculture sector. A major risk factor for this sector is slow growth rates experienced during farming. Abalone feeds are often supplemented with amino acids in an attempt to enhance abalone growth. This is a first investigation of the effect of added proline to standard abalone feed, on the metabolite profile of slow‐growing abalone. A targeted liquid chromatography tandem mass spectrometry metabolomics research approach was followed to recognise the metabolic response of abalone showing slower growth performance. The addition of proline to the standard abalone diet was found to serve as a substrate for amino acid catabolism in slower growing abalone, by means of proline breakdown to assist with energy production via the tricarboxylic acid cycle. Other amino acids and urea cycle intermediates, that is, arginine, asparagine, ornithine and creatine further support energy production via the action of protein catabolism in slow‐growing abalone. Additionally, the importance of understanding how abalone respond metabolically to modified feed highlights the use of metabolomics to answer abalone aquaculture farming questions.     

Fish nutrition research: past,present and future

The systematic, scientific investigation of nutrition dates from the eighteenth century, but for many years, there were few studies on fish. As a result, knowledge about fish nutrition still lags behind that of man and his domesticated terrestrial animals. Initially, there were few incentives to collect information about the nutritional requirements of fish, and it is difficult to carry out experiments on aquatic animals. Fish were being farmed, but the extensive rearing methods used meant that there was no pressing need to gather detailed information that could be used for preparing feeds. Research into fish nutrition started in earnest around the middle of the twentieth century. Since then information has accumulated quite rapidly as research efforts have been spurred on by the expansion of aquaculture and developments within intensive fish farming. Nevertheless, the gaining of more knowledge about the nutrition of fish still needs to be given priority to assist in the continued development and improvement of sustainable practices in aquaculture. In this brief overview, fish nutrition research is placed in a historical perspective by considering some of the major challenges faced by fish nutritionists, how these challenges were addressed, the advances made, and knowledge gaps that need to be filled. The spotlight is focused on nutrient requirements, feed ingredients and their evaluation, and the formulation of diets that promote effective production whilst serving to maintain fish health and well-being.     

鲍低氧胁迫响应机制的研究进展

鲍养殖业已成为我国海洋经济发展中的重要组成部分。近年来，因低氧胁迫，特别是高温低氧联合胁迫而导致的养殖鲍大规模死亡的现象时常发生，给鲍养殖业带来了严重的经济损失，已成为阻碍鲍养殖业健康可持续发展的重要环境因素。本文从鲍的生长、存活、生理生化指标 (包括心率、代谢、酶的活性、pH等)、免疫机能、胁迫响应基因及其表达调控等方面综述了鲍低氧胁迫响应机制的研究进展，以期为进一步研究鲍的低氧胁迫响应机制、开展鲍耐低氧新品种的选育等提供参考。此外，本文还提出了鲍低氧胁迫的预防调控措施，希望对养殖业者减少因夏季低氧胁迫诱发的养殖鲍大规模死亡而造成的损失有所帮助。     

Expanding the utilization of sustainable plant products in aquafeeds: a review

Continued growth and intensification of aquaculture production depends upon the development of sustainable protein sources to replace fish meal in aquafeeds. This document reviews various plant feedstuffs, which currently are or potentially may be incorporated into aquafeeds to support the sustainable production of various fish species in aquaculture. The plant feedstuffs considered include oilseeds, legumes and cereal grains, which traditionally have been used as protein or energy concentrates as well as novel products developed through various processing technologies. The nutritional composition of these various feedstuffs are considered along with the presence of any bioactive compounds that may positively or negatively affect the target organism. Lipid composition of these feedstuffs is not specifically considered although it is recognized that incorporating lipid supplements in aquafeeds to achieve proper fatty acid profiles to meet the metabolic requirements of fish and maximize human health benefits are important aspects. Specific strategies and techniques to optimize the nutritional composition of plant feedstuffs and limit potentially adverse effects of bioactive compounds are also described. Such information will provide a foundation for developing strategic research plans for increasing the use of plant feedstuffs in aquaculture to reduce dependence of animal feedstuffs and thereby enhance the sustainability of aquaculture.     

中国大菱鲆养殖20年成就和展望——庆祝大菱鲆引进中国20周年

大菱鲆Scophthalmus maximus具有生长速度快和低温耐受力强等特点,是世界上养成范围最广、产量最大的鲆鲽类养殖良种。自1992年引进至今,大菱鲆养殖已经发展成为年产量超过6万t的海水养殖支柱产业。作者综述过去20年里,我国大菱鲆在产业发展、苗种生产、良种选育、养殖模式、营养与饲料、疾病防控、加工与质量控制、养殖经济以及市场开拓等方面所取得的系列成果,并就发展前景进行了展望,旨在为我国大菱鲆和鲆鲽类养殖的可持续发展提供参考。     

The importance of live‐feed traps – farming marine fish species

This article analyses the challenges of different live‐feed regimes for the rearing of marine finfish larvae and discusses the potential alternative live feeds to avert a future live‐feed trap. Live feeds are indispensable for the successful rearing of larvae of most marine fish species. Brine shrimps (Artemia) and rotifers comprise the live feeds of choice in marine aquaculture today. However, their nutritional composition is deficient in especially essential fatty acids, and enrichment with fish oil is needed. Fish oil is considered a limited resource owing to its origin in fully exploited wild fish stocks. Moreover, fluctuations of the natural population of Artemia will, most likely, influence future availability and prices. This emphasizes the need for optimal exploitation of available live‐feed resources and development of new sustainable alternatives, such as copepods. An array of solutions to these problems are presented to avoid a future live‐feed trap and to reduce dependence on limited resources that influence future production possibilities, species diversification, price volatility and productivity in the aquaculture sector.     

Probiotics in fish and shellfish culture: immunomodulatory and ecophysiological responses

Aquaculture is emerging as one of the most viable and promising enterprises for keeping pace with the surging need for animal protein, providing nutritional and food security to humans, particularly those residing in regions where livestock is relatively scarce. With every step toward intensification of aquaculture practices, there is an increase in the stress level in the animal as well as the environment. Hence, disease outbreak is being increasingly recognized as one of the most important constraints to aquaculture production in many countries, including India. Conventionally, the disease control in aquaculture has relied on the use of chemical compounds and antibiotics. The development of non-antibiotic and environmentally friendly agents is one of the key factors for health management in aquaculture. Consequently, with the emerging need for environmentally friendly aquaculture, the use of alternatives to antibiotic growth promoters in fish nutrition is now widely accepted. In recent years, probiotics have taken center stage and are being used as an unconventional approach that has numerous beneficial effects in fish and shellfish culture: improved activity of gastrointestinal microbiota and enhanced immune status, disease resistance, survival, feed utilization and growth performance. As natural products, probiotics have much potential to increase the efficiency and sustainability of aquaculture production. Therefore, comprehensive research to fully characterize the intestinal microbiota of prominent fish species, mechanisms of action of probiotics and their effects on the intestinal ecosystem, immunity, fish health and performance is reasonable. This review highlights the classifications and applications of probiotics in aquaculture. The review also summarizes the advancement and research highlights of the probiotic status and mode of action, which are of great significance from an ecofriendly, sustainable, intensive aquaculture point of view.     

中国水产健康养殖的关键技术研究

健康养殖包括养殖设施、苗种培育、放养密度、水质处理、饵料质量、药物使用、养殖管理等诸多方面,采用合理的、科学的、先进的养殖手段,从而获得质量好、产量高的产品及环境均无污染,使经济、社会、生态产生综合效益,并能保持稳定、可持续发展。今后工作重点应是：(1)优化养殖条件,保护生态环境。(2)加强病害综合防治措施,规范渔用药物使用。(3)开展抗病、抗逆养殖新品种的选育。(4)开发优质高效饲料与合理使用饲料并举。(5)加快研究和推广健康养殖技术,提高经济和生态效益。(6)加快制定健康养殖标准,加强质量监督检测体系建设(不属健康养殖技术的范畴)。     

The future of genetic engineering to provide essential dietary nutrients and improve growth performance in aquaculture: Advantages and challenges

Advancements in gene technology in recent years have been driving the aquaculture industry forward. Improvements in growth performance, feed efficiency, and omega‐3 content are goals of the industry that could capitalize on applications of genetic engineering. One of the major challenges in the industry is to reduce the use of fish meal and oil, to improve the environmental and economic sustainability of aquaculture. The recent development of genetically engineered feed ingredients is one potential solution to the looming problem of fish meal and oil dependency. Furthermore, the development of transgenic fish has potential to improve production efficiency and other future desirable characteristics that relate to feed utilization and product quality. New gene technologies are beginning to revolutionize how we produce our food, and in aquaculture, will ultimately reduce pressure on wild fish stocks, help to preserve natural aquatic ecosystems, and improve nutritional profiles of farmed fish for human consumption. The purpose of this review is to provide an update on the current applications of genetic engineering technology to improve aquaculture through nutrition, including the development and use of transgenic feed ingredients, transgenic fish, and ultimately their impacts on nutrition, product quality, and consumers.     

水产养殖业可持续发展及管理的研究进展

全球水产养殖业在过去的几十年内得到了迅速发展,但同时也带来了诸多的环境、经济和社会问题,因此可持续发展水产养殖理念的提出得到了国内外众多学者的认可。本文简单介绍了全球水产养殖业近年的发展情况及可持续发展水产养殖业的理念发展进程,重点分析了可持续发展水产养殖管理涉及的六大步骤,介绍了水产养殖指标体系构建及评估的研究成果,以期为我国水产养殖可持续发展提供借鉴。     

An Analysis of Nearly One Billion Dollars of Aquaculture Grants Made by the US Federal Government from 1990 to 2015

The aquaculture industry relies on federal investments to stimulate aquaculture research and development (R&D). We conducted this study to track federal spending for aquaculture using a large database of 2957 US federal research grants awarded from 1990 to 2015. During that period, 1.04 billion US dollars (USD) were spent on aquaculture research, with 919 million USD from federal agencies and 123 million USD in matching funds. By comparison, over the same time frame, the US Department of Agriculture's R&D spending was 41 billion USD. Federal grant funding for aquaculture had a 37‐fold return on investment since 2000. Microalgae, oysters, salmon and trout, catfish, and shrimp received the most grant support, and the most common topics/disciplines were aquaculture production sciences, aquatic animal health and disease, genetics and breeding, and nutrition. Our findings can be used to identify research gaps and inform federal policy, grant making, and budget allocation.     

水产动物营养与免疫研究进展

随着水产养殖集约化与规模化的发展,水产品为人类提供了大量优质食物蛋白质,为国家粮食安全、解决我国“三农”问题做出了重要贡献。长期研究实践证明,营养与饲料科技贡献在水产养殖中占有更加重要的地位。饲料组成不仅影响水产动物的营养,而且会影响水产动物的免疫与抗病能力,营养状况是决定水产养殖动物抵抗疾病的能力的重要因素之一。特别是在水产集约化、规模化养殖中,水产养殖动物面临着大量的应激,如：营养、环境因子等激烈变化,易诱发疾病,甚至死亡。反之,水产养殖动物的生理与健康状况也影响饲料的利用与代谢。营养和免疫的关系显著地影响着水产养殖生产,一直是大家关注的热点。在过去的5年中,水产动物营养与免疫方面的研究取得了重大进展,对蛋白质(氨基酸)、脂肪、碳水化合、维生素、矿物元素等多种必需营养素及其免疫、抗病能力等方面做了大量的研究。本文就营养与免疫相关的研究进展做一综述,以供参考。     

团头鲂营养需求与健康研究进展

团头鲂是我国主要的大宗淡水养殖品种之一,其养殖规模在近10年不断扩大。团头鲂的营养物质需求主要以生长和营养缺乏症为评价指标。而营养物质对鱼类健康,如免疫反应和抗病力等影响的研究尚不充分。一般认为,饲料中营养物质搭配合理、品质优良有利于维持鱼类生理健康,并能保护养殖水环境。此外,一些营养物质如维生素,在鱼类的免疫机制中发挥重要作用。未来水产饲料应具有促进水产动物生长和维持健康的双重作用,通过营养调控预防鱼类疾病是保证水产养殖可持续发展的重要策略之一。本研究综述了团头鲂对蛋白质、脂肪、碳水化合物、维生素和矿物质营养需求的研究进展,以及饲料营养元素对团头鲂免疫力及抗病力影响的最新报道,以期为团头鲂高效配合饲料的开发提供科学参考。     

THE FUTURE OF U.S. SEAFOOD SUPPLY

The United States today imports most of the seafood it consumes. Half of these imports are from aquaculture. Domestic wild capture production is limited and U.S. aquaculture production has declined in recent years. Policy, socioeconomic, and regulatory obstacles stand in the way of expanded U.S. aquaculture production. In this article, we examine the implications of two future paths for seafood supply: an increasing reliance on imports, and a shift toward increased domestic aquaculture production. We examine global trends, likely future developments in U.S. seafood demand and supply, and implications of the path of U.S. aquaculture development for U.S. seafood supply and prices, employment, ecological footprint, and seafood supply security and safety. We conclude with recommendations for a path forward that serves the interests of the nation and the global community in the search for economically sound and sustainable ways to feed a growing population.     

Nutrition and feeding research in the spotted rose snapper (<Emphasis Type="Italic">Lutjanus guttatus</Emphasis>) and bullseye puffer (<Emphasis Type="Italic">Sphoeroides annulatus</Emphasis>), new species for marine aquaculture

The spotted rose snapper (Lutjanus guttatus) and bullseye puffer (Sphoeroides annulatus) are fish species from the tropical Eastern Pacific for which controlled production of larvae and juveniles has been accomplished in recent years. Diverse topics relating to their biology and aquaculture production are currently under study, in particular the nutrition and feeding aspects required to formulate practical feeds and rearing protocols. Improvements in larval growth and survival are possible by feeding live food organisms with natural or enhanced essential fatty acids content and highly digestible artificial microdiets. The ontogeny of the digestive tract and the expression and activity of digestive enzymes have been described for S. annulatus larvae. The effect of various protein and lipid levels on growth and feed utilization has been studied in juvenile and on-growing fish. Both species have carnivorous feeding habits and require high levels of protein in their diets, from 40% to 45% (dry weight) in spotted rose snapper and above 50% in bullseye puffer, with the younger stages requiring the highest protein levels. Encouraging results have been obtained in feeding experiments with different sources of dietary protein from animal and plant origin to evaluate their suitability as feed ingredients in practical diets. Optimization of fish culture practices through feeding management has also been investigated. Trials with various fish densities and feeding frequencies in intensive culture systems are providing information to improve feed utilization and growth in on-growing fish. Further research is underway to evaluate factors in broodstock nutrition which have an impact on egg and larval quality, and into the use of various commercially available oil sources in on-growing diets. In this paper, the results on nutrition and feeding research with both species are reviewed and research needs to support their commercial production in the region are discussed.     

软体动物疱疹病毒及其对贝类养殖产业的危害

中国是贝类养殖大国,30余年来,贝类养殖产量总体稳中有升,但部分贝类的养殖产业因疫病影响出现严重萎缩、甚至消失。20世纪90年代以来,中国多种双壳贝类和杂色鲍(Haliotis diversicolor supertexta)因感染疱疹病毒出现大规模死亡,成为近年来危害中国贝类养殖业的主要病原。经流行病学调查和病原鉴定,引起中国双壳贝类和杂色鲍死亡的疱疹病毒分别为牡蛎疱疹病毒(Ostreid herpesvirus 1,OsHV-1)和鲍疱疹病毒(Haliotid herpesvirus 1,HaHV-1)。贝类疱疹病毒病不仅在中国发生,同时也在全球多个国家、地区传播和暴发,引起全球贝类养殖从业者和科研人员的广泛关注。多国学者从病毒特征、流行病学、诊断技术、生态防控和抗病育种等多个角度展开研究,以期减轻此类病毒对贝类产业造成的危害。大量科研力量的投入使OsHV-1和HaHV-1成为分类地位明确,研究最深入、最全面的贝类病毒性病原。本文对近年来OsHV-1和HaHV-1研究领域取得的主要成果进行总结,重点介绍其在中国和全球范围的发生、传播过程、产业危害和防控措施等。     

Nitrogen transformations in aquaponic systems: A review

In recent years, aquaponic systems have gained significant popularity as soilless agriculture systems for organic fruits and vegetables production with concomitant remediation of aquaculture effluent. Aquaponics is a potential sustainable food production system that integrates aquaculture with hydroponics in which nitrogen-rich effluent from the fish production is utilized for plant growth. Because nitrogen is one of the most important inputs in an aquaponic system, it is critical to investigate the nitrogen transformations in the system for enhanced recovery of resources. Since studies on nitrogen transformations and nitrogen utilization efficiency (NUE) in aquaponic systems have been very limited, this review critically examines the important fates of nitrogen from input to outputs (e.g., ammonia nitrogen generation, nitrification, nitrate assimilation and nitrogen loss) to improve NUE in aquaponic systems. Various factors affecting the nitrogen transformations are also discussed. Furthermore, an example of nitrogen imbalance between nitrate uptake and nitrate generation rates in an aquaponic system was demonstrated. This review aims to advance our current understanding of nitrogen transformations and outlines future research needs in aquaponic systems, a sustainable model for efficient water and nutrient managements, and food production.     

Short‐chain fatty acids as feed supplements for sustainable aquaculture: an updated view

Restriction or ban on antibiotic administration in aquaculture encourages the development of environment‐friendly feed additives as immunostimulants. Short‐chain fatty acids (SCFAs) and their salts are ‘Generally Regarded as Safe’ and are often used as antimicrobials in the livestock feed industry. Formate, acetate, propionate, butyrate and their salts are among the most studied SCFAs in aquaculture. These SCFAs affect the host performance as well as physiological response upon three ways: either through effects of the feeds that are being administered, through effects on the gastrointestinal tract of the animal or through direct effects on metabolism. To date, most of the available data are focused on the effects of SCFAs on growth performance and feed utilization. Despite extensive research studies on the effects of the different type of SCFAs and their salts on growth performance and feed utilization, the effects of these feed additives on the health of aquatic organisms have only been receiving attention recently. The results of the studies demonstrated beneficial effects of SCFAs as promising feed additives in aquaculture. The present review article summarizes and discusses the topic of dietary administration of SCFAs and their salts in aquaculture with a closer look at the recent findings regarding the effects of SCFAs on growth performance and health status of fish and shellfish. Furthermore, this review identifies the gaps of existing knowledge regarding the roles of SCFAs in the growth and health status of aquatic animals and suggests research areas that merit further investigations.