摘要:

In addressing the seventh annual meeting of what is now the World Aquaculture Society, Michael New challenged members interested in crustacean nutrition to develop standardized methods so that “direct, quantitative comparison of dietary trials carried out by different groups of research workers could be achieved”. Later that year, the Society's President, Harold Webber, established the Nutrition Task Force to meet that challenge. The evolution of this task force into the International Working Group on Crustacean Nutrition is described. The original objectives of the task force were to develop open formula reference diets, to recommend standard conduct and reporting procedures, to provide for informational exchange, and to coordinate the Society's role in the nutritional sciences. The rationale for each of these objectives is examined and progress made toward achieving each is evaluated in light of changes that were occurring in the crustacean aquaculture industry. The present status of the International Working Group on Crustacean Nutrition is examined along with its intended transition to a formal organization. Suggestions also are made for future goals to enhance continued growth of the crustacean feed industry.

ISSN:1064-1262    

DOI:10.1080/10641269891314168

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

In crustaceans, assimilation of nutrients depends on their complex digestive systems. Early studies were limited to morphology and histology. More recently, biochemistry and molecular biology studies have generated interesting results about the processes of digestion and food utilization. Selection of foods in nature; consumption in aquaculture; ingestion; transit of nutrients in the digestive tract; mechanical digestion; enzyme activity and their physiological variations and control of their synthesis, use of compound diets, cellular absorption and storage as well as transfer of excreta are the main functions of the digestive tract of crustaceans. Numerous studies have addressed these subjects in relation to several crustacean species living in European waters, includingHomarus, crayfishAstacus, shrimpsCrangon,PalaemonetesandPaiaemon, crabsCancerandPortunus, as well as other genera, such asPenaeusandMacrobrachiumliving in overseas territories. This article reviews the results of these studies, mainly developed by French teams during recent years and identifies new research topics.

ISSN:1064-1262    

DOI:10.1080/10641269891314177

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The concept of replacing live feeds in larval culture is now some 20 years old and stems from the dual aims of attempts to simplify hatchery feeding regimes and investigation of feeding and nutrition in commercially important larvae. Although total replacement of live feeds is routinely accomplished in the laboratory for penaeids, it has been less successful for caridean and other crustacean larvae. In shrimp hatcheries, it is standard practice to use artificial feed, at least as a supplement or co-feed, but complete replacement with the elimination of algal culture units is rare. The development of microparticles as feed for crustaceans, fish, and even bivalves has facilitated research into the criteria controlling larval ingestion, digestion, and energetic requirements and allowed identification of some major nutritional requirements. From energetic studies, it is apparent that the feeding strategy adopted by herbivorous larvae is more efficient than that adopted by carnivorous crustacean larvae. This explains the success achieved with artificial diets for the former and identifies the requirement for easily digestible high-energy diets for the latter. One further original concept, that of supplying medicinal agents via microparticulate feeds, is also now close to reality. That has been demonstrated from recent research into the positive effects of raising the immune response of crustaceans with formalin killed pathogens, beta glucans, or by supplying the nonpathogenic bacteria as probionts.

ISSN:1064-1262    

DOI:10.1080/10641269891314186

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Because of convenience in production and their suitable biochemical composition, brine shrimpArtemiaspp. nauplii have been adopted as a standard diet in the commercial larviculture of several crustacean species. The nutritional value ofArtemia, however, is not constant, but varies both geographically and temporally. During the past decade both the causes ofArtemianutritional variability and methods to improve poor-qualityArtemiahave been identified. EnrichingArtemiaspp. with emulsified lipophilic products is a technique that has allowed delivery of extra doses of essential nutrients, for example, highly unsaturated fatty acids (HUFA) and vitamins, to crustacean larvae. The enrichment technique has limitations, however, because theArtemiaspp. currently available selectively catabolize some of the nutrients such as docosahexaenoic acid and phospholipids. Decapsulated Artemia cysts, juveniles, and adult brine shrimp are also used increasingly as suitable diets for different crustacean species.

ISSN:1064-1262    

DOI:10.1080/10641269891314195

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Penaeus indicusandPenaeus merguiensisare the most popular shrimp species for extensive farming in Southeast Asia. Their relatively low production and survival have hampered intensive culture. Moreover, there is a lack of nutrition studies on these species. This article discusses the nutrient requirements ofP. merguiensisandP. indicus, as these are similar species. In juveniles, the protein requirements varies from 34 to 55%. Protein requirement may be related to dietary starch level, protein quality, and shrimp size. Requirements for individual amino acids have not been determined.P. indicus, like most shrimp species, has limited capacity to elongate and desaturate linoleic acid and lineolenic acid to polyunsaturated fatty acids. A combination of 1% 18:2n-6 and 3% oil rich in highly unsaturated fatty acid (HUFA) gives superior growth, survival, and feed conversion. Dietary energy levels between 2900 and 4400 kcal/kg, in 34 to 40% protein diets were reported to be optimum forP. merguiensis. Maltose and starch gave better growth and feed conversion than monosaccharides, which seem to inhibit growth. Increasing starch level from 10 to 40% with a decrease in protein-to-carbohydrate ratio increased growth, feed conversion, and survival. Dietary thiamine, pyriodoxine, niacin, panthothenic acid, and vitamin C requirements ofP. indicuswere 100, 100 to 200, 750, and 4000-8000 (or 100) mg/kg, respectively. Vitamins C and E have been found to affect egg hatching rate and larval viability ofP. indicus. Ca-to-P ratio of 1 to 1.3 at 0.51 to 0.66% of the diet were found to be optimum forP. merguiensis, but the magnesium requirement was not conclusively established. Many gaps remain to be filled before the nutrient requirements of these species are completely established.

ISSN:1064-1262    

DOI:10.1080/10641269891314203

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This article presents an overview of recent progress in the nutrition ofPenaeus monodonand its implications in feed formulation. Recently published results of many dietary trials withP. monodonhave helped build the basic framework of knowledge concerning the dietary requirements of the species. These advances will undoubtedly upgradeP. monodonfeed formulation that in the past, depended heavily on limited information and requirements derived from other species. Key subjects dealt with in this review are assessed under the headings digestion and digestibility, protein and essential amino acids, carbohydrates, lipids and sterols, and vitamins. Other dietary components such as energy, minerals, feeding stimulants, pigmentation, and immunostimulants are briefly reviewed. Recent attention has focused on essential amino acid and vitamin requirements. Studies using different dietary preparations and feeding methods have established the dietary requirements of juvenileP. monodonfor arginine, lysine, methionine (+cystine), threonine, and valine. These requirements are comparable to the known requirements of many finfish. Requirements ofP. monodonfor almost all major vitamins have been established and are not much higher than those suggested for warmwater finfish such as channel catfish, despite the shrimp's unique aspects of metabolism.

ISSN:1064-1262    

DOI:10.1080/10641269891314212

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This article provides an overview of the nutritional requirements of larval and juvenilePenaeus japonicus, referring to past studies briefly and focusing on recent studies on proteins, lipids, and other essential nutrients. Also, the quantitative requirements of nutrients in crustacean species were critically evaluated in relation to net nutrient intake inP. japonicus. Like fish and other vertebrates, larval and juvenileP. japonicusrequire 10 essential amino acids, essential fatty acids, vitamins, and minerals for their normal development, growth, survival, and reproduction. In contrast to fish and other vertebrates, however, both larval and juvenile prawns require dietary sources of sterols and some phospholipids as indispensable nutrients. Metabolic studies on juvenileP. japonicususing radioactive lipids suggested that dietary phospholipids take part in the transport of dietary lipids, especially cholesterol, through the hemolymph in their body. In nutritional studies, leaching or loss of dietary nutrients into the water is an obstacle to development of valid conclusions on nutrient requirements ofP. japonicus, particularly the larvae.

ISSN:1064-1262    

DOI:10.1080/10641269891314221

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Penaeid shrimp culture in Australia is a relatively new industry and occurs mainly in the eastern states of Queensland and New South Wales. The major species cultured arePenaeus monodonandPenaeus japonicus, but other penaeids, includingMetapenaeus macleayi,Penaeus esculentus, andPenaeus plebejus, have been cultured in small quantities. Research with Australian penaeids has described the mechanisms of food location, feeding, and digestion (Dall, 1992). The composition of natural prey items of penaeids in the wild has been proposed as a guide to nutritional requirements, and indeed successful diets have some similarities with natural food. The major differences between natural prey for shrimp in the wild and commercial diets is that prey items are higher in ash, while commercial diets have more carbohydrate. Predation on natural food present within farming ponds has been shown to lower requirements for formulated diets during the early stages of pond culture when shrimp biomass is relatively low. More research dedicated to the improvement of the abundance and quality of natural biota as a source of food through fertilization and prevention of pond bottom deterioration is warranted. Studies on protein turnover have identified major differences in protein degradation in shrimp fed diets with different protein contents. Many studies aimed at determining protein requirements of penaeids have used different methods to calculate ‘metabolizable’ energy contents of the diets. However, as none have directly measured digestible or metabolizable energy of test diets, interactions between protein and energy may have confounded interpretation of results. This may explain some of the variation in the conclusions published. The digestive gland has been identified as the primary site for lipid synthesis, storage and assimilation. Regulation of 18:3n-3, 20:4n-6, 20:5n-3, and 22:6n-3 and chain elongation of 18:2n-6 to 20:4n-6 have been documented. Research into alternative protein sources to expensive fish and mollusk meals is underway in Australia. New techniques to determine digestibility of ingredients and net energy utilization should assist in the search for new ingredients and the evaluation of techniques to improve utilization of these ingredients in shrimp diets.

ISSN:1064-1262    

DOI:10.1080/10641269891314230

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Tropical species such asP. monodon,P. vannamei, andP. stylirostriswere first considered as candidate species for aquaculture in early 1970s or around 25 years ago. At that time, the first nutrition studies began in laboratories using wild stock. Most labs were under pressure to find quick answers to the formulation of shrimp feeds. Feed manufacturers conducted a number of proprietary experiments. Shrimp nutritionists did not link their problems to those encountered with monogastrics and specific problems were faced such as leaching of nutrients, slow feeding response of shrimp, and lack of proper methodology. Even today, despite new advances in New Caledonia withP. stylirostrisor in Ecuador withP. vannamei, empiricism is present and formulae calculated with a least cost program do not prove to be fully satisfactory. There is need for a better understanding of shrimp nutrition in the tropical climates. There is still a gap to fill between results of experiments conducted in fully managed water and from production ponds. Requirements for cholesterol, fatty acids, vitamins, and soluble proteins have been addressed by many authors. Nevertheless, the actual impact of natural productivity vs. pelleted food distributed needs to be assessed. Today, the search for a low pollution diet is important to focus on two major areas: (1) a search for quality protein through a digestibility screening, and (2) the study of metabolic activity with the measurement of energy expenditure. This goal is reasonable as it follows previously conducted salmonid experiments. The expected results would be better food conversion indices and less water-quality degradation in shrimp production ponds.

ISSN:1064-1262    

DOI:10.1080/10641269891314249

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This article provides a brief summary on recent advances inPenaeus vannameinutrition research in Ecuador. In 1988, a study was performed to identify the lipid profile of wild shrimp larvae and broodstock, collected along the Ecuadorian coast. The average fatty acid percentages relative to total lipid content in wild larvae were: 3.24% of 18:2n-6 and 1.22% of 18:3n-3, while the percentages found for the highly unsaturated fatty acids (HUFA) eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) were 13.26 and 13.91, respectively.P. vannameijuveniles were found to have higher survival and growth rates (138 mg/d) when fed a diet containing 11% dietary lipid level.P. vannameijuveniles performed best with a diet containing 40% protein. Average weight gain was 137 mg/d. The optimum vitamin C level in artificial diets, forP. vannameijuveniles, was found to be 4.6 mg ascorbic acid equivalents/100 g diet. A series of experiments designed to determine digestibility of diets containing local feedstuffs are reported here.

ISSN:1064-1262    

DOI:10.1080/10641269891314258

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor