Technological improvements for the cultivation of invertebrates as food for fishes and crustaceans. II. Hatching and culturing of the brine shrimp, Artemia salina L.

Although extensive fundamental research has been performed on the brine shrimp, the yields from hatching and culturing this organism which is widely used in mariculture, can be greatly improved. By exposing the immersed cysts to light and by using a new type of hatching cylinder and separator box, greater hatching and separation efficiencies can be obtained. Controlled mass culture of brine shrimp larvae to the adult stage has been extremely difficult until now; the literature on the subject is reviewed and a new tech-nique of high density culturing at the pilot-stage is described.     

Explanation of Size Diversity Among Artemia Cohorts: A Model of Food Uptake Kinetics

Models describing the food uptake kinetics of a growing Artemia culture and the hatching rate of Artemia cysts are combined to yield equations capable of predicting the effects of variable algal cell concentration upon the growth rates of brine shrimp cohorts. The model illustrates that the feeding ability of the brine shrimp can be viewed as one becoming increasingly more efficient as the animals mature. This increasing efficiency in a population of variable age animals (from a single hatch) results in accelerated growth of first hatched animals relative to later hatched animals, especially at algal cell concentrations below certain threshold values. Growth rates of variable age groups of brine shrimp are mathematically manipulated to predict variable size brine shrimp at low algal cell concentration and uniformly sized brine shrimp at high algal cell concentration. This predicted result is confirmed with data from Artemia growth trials at high and low algal cell concentrations. It is suggested that similar variations in population attributes of other species may be explained as an animal-food interaction in which minor initial variations in individual animal maturity (weight, size, etc.) are magnified as a consequence of continuous competition for a common pool of food.     

Using brine shrimp as a drug carrier for therapeutic applications in aquaculture

A method is described to introduce water-insoluble drugs into brine shrimp nauplii (BSN). The uptake of drug by brine shrimp may be modeled as a batch adsorption process; in this way, one can calculate the dosage required for a given population of BSN. The results of this study show that a drug can be loaded into BSN at concentrations up to 9 μg per nauplius. Such concentration is high enough to fulfill the recommended dosage for an adequate treatment of BSN-feeding fish or shrimp larvae. Results are also presented on the loss of drug upon the transfer of larvae from medicated water to drug-free water.     

利用盐田卤水池大面积养殖卤虫的试验研究

１９８９年６至９月，作者利用塘沽盐场９．３公顷的低度卤水池养殖卤虫（Ａｒｔｅｍｉａｐａｒｔｈｅｎｏｇｅｎｔｉｃａ），方法是先在卤水池中培养微藻，粪肥用量４５０ｋｇ／ｈａ·ｍｏｎ，然后接种卤虫无节幼体，密度１．５—１．７×１０４个／ｍ３。试验期间投加少量粉碎过筛后的谷糠７．５ｋｇ／ｈａ·ｄ，谷糠颗粒直径４０—５０μｍ。试验三个月，共收获成体卤虫３６７４３．６ｋｇ，平均单产３９５０．９ｋｇ／ｈａ．     

日本对虾仔虾培育试验

用无节幼体培育仔虾,采用的对虾幼体饵料有中肋骨条藻、卤虫无节幼体及台湾产的人工配合饵料,并注意饵料的配合使用及消毒工作;为维持水质稳定,整个培育期间不换水,加大布气石的密度（３．６个／ｍ２）。在３００ｍ３水体中,一茬育出仔虾２２１８万尾,成活率为６６．２％,取得了良好的经济效益。     

Nutritional Factors Affecting Stress Resistance in the Larval Mahimahi Coryphaena hippurus

Recent improvements in enriching Artemia make mahimahi culture possible without using copepods. Mahimahi survive better when cultured copepods Euterpina acutifrons are used, especially when the larvae are under stresses such as high stocking density, cold weather, or the rigors of metamorphosis. This study looked at some differences between copepods and enriched Artemia .This study tested stress resistance by holding postlarval (PL) mahimahi out of water in a hand net for varying periods of time. Recovery from this stress shock was higher in PLs whose diet was higher in docosahexaenoic acid (DHA). DHA appeared to play an important role in stress resistance. High eicosapentaenoate (EPA) or high HUFA did not confer stress resistance when DHA levels were low. Copepods contained higher levels of many essential amino acids in addition to higher levels of DHA compared with enriched brine shrimp.
Larvae sickened by disease appeared to lose fat, including DHA, but they conserved DHA relative to other fatty acids. Even when sick, mahimahi larvae fed a copepod diet resisted stress better than larvae fed an enriched brine shrimp diet.
Optimal Artemia enrichment levels of DHA for mahimahi have not been reached and this may explain why it has been difficult for others to raise this fish consistently.
E. acutifrons is relatively easy to culture, but may not be practical for commercial hatcheries, due to low yield (less than 10 g per 100 L per week).     

Ration of 20:3 (n-9) to 20:5 (n-3) in Phospholipids as an Indicators of Dietary Essential Fatty Acid Sufficiency in Striped Bass,Morone saxarilis,and Palmetto Bass,M. saxatilis x M. chrysops

The effects of feeding different sources of brine shrimp nauplii with different fatty acid compositions on growth, survival, and fatty acid composition of striped bass, Morone saxarilis and palmetto bass (M. saxatilis x M. chrysops) were determined. The sources of brine shrimp were Chinese (CH), with a high percentage of 20:5(n-3), eicosapentaenoic acid (EPA), and Colombian (COL), San Francisco Bay (SFB), and Great Salt Lake (GSL), with low percentages of EPA but high percentages of 18:3(n-3), linoienic acid. None of the brine shrimp sources contained a measurable amount of 22:6(n-3), docosahexaenoic acid (DHA). After enrichment with menhaden oil to increase the content of EPA and DHA, the GSL brine shrimp nauplii were also fed to hybrid striped bass.Growth and survival of fish larvae fed brine shrimp nauplii with high percentages of EPA and DHA (CH and GSLE) were higher (P < 0.05) than those of fish fed brine shrimp with a low percentage of EPA (COL, SFB, and GSL). The ratio of 20:3(n-9) eicosatrienoic acid (ETA), to DHA in polar lipids (phospholipids) of fish, traditionally used as an indicator of essential fatty acid (EFA) sufficiency of the diet, was not a reliable indicator of essential fatty acid sufficiency of diets for larval striped bass and hybrid striped bass. However, the ratio of ETA to EPA appears to be an appropriate indicator. An ETA-to-EPA ratio in phospholipids of less than 0.10 is consistent with an EFA sufficient diet.     

盐碱地低盐水池塘网箱套养漠斑牙鲆技术研究

根据漠斑牙鲆(Paralichthys lethostigma)适广温、广盐和较强的抗逆性等优良生态习性,采用地下卤水、盐碱地渗水,通过合理淡水配兑使其适合漠斑牙鲆生理生长需求,在我国中纬度地区利用盐碱地低盐水养殖过洋、暖温性漠斑牙鲆。2004-2005年,利用盐碱地低盐水池塘虾池设置网箱套养漠斑牙鲆349.5m2,产鱼3.749t,产虾55.065t,其中2005年虾池设置网箱套养漠斑牙鲆306m2,产鱼3.245t,平均10.6kg/m2,平均全长34.0cm,体重527.4g,养殖成活率为90.5%,产虾49.003t,平均408.4kg/亩,平均规格11.9cm,养殖成活率为71.23%。虾池设置网箱套养漠斑牙鲆,可充分利用水体空间,促使池塘高产高效,提高养殖经济效益。     

用丰年虫卵壳制备甲壳素和壳聚糖

介绍了用丰年虫卵壳制备甲壳素及壳聚糖的方法及过程,通过傅立叶变换红外光谱仪的检测并与美国标准谱图库检索出的用蟹壳制备的壳聚糖光谱图对照,证实丰年虫卵壳制备的壳聚糖。     

The influence of dietary arachidonic acid on the immune response and performance of Pacific whiteleg shrimp,Litopenaeus vannamei,at high stocking density

Stocking shrimp at high densities increases yield during culture, but growth is generally compromised and weakened immune response associated with poor water quality has also been reported. Therefore, we tested if supplying more arachidonic acid (ARA) in the diet, a precursor of eicosanoids such as prostaglandins E from the series II (PGE₂) that enhance immune response can counteract the negative effect of stocking shrimp at high densities. The effect of physical crowding was separated from the effect of water quality, both a result of high density, by using tanks divided by a hard plastic net that allowed water flow between two density conditions. Crowding reduced weight gain by 8.3%, although the effect was more evident with deteriorated water quality from combined effects of high total ammonia and low dissolved oxygen levels (18.4%), but no effect on survival was found. A clear food imprinting of ARA levels in hemocytes was observed, but ARA did not clearly counteract the negative effects of high density on overall performance. However, ARA could minimize stress response of sampling and enhance some effectors of the immune system, such as clotting and respiratory burst. The increase in PGE₂ metabolite in shrimp fed with the high‐ARA diet was not consistent, and thus, the effects of ARA were not necessarily mediated by these eicosanoids.     

Shrimp (Litopenaeus vannamei) production and stable isotope dynamics in clear‐water recirculating aquaculture systems versus biofloc systems

Closed recirculating aquaculture systems (RAS) offer advantages over traditional culture methods including enhanced biosecurity, the possibility of indoor, inland culture of marine species year‐round and potential marketing opportunities for fresh, never‐frozen seafood. Questions still remain regarding what type of aquaculture system may be best suited for the closed‐system culture of marine shrimp. In this study, shrimp (Litopenaeus vannamei) were grown in clear‐water RAS and in biofloc‐based systems. Comparisons were made between the system types with respect to water quality, shrimp production and stable isotope dynamics used to determine the biofloc contribution to shrimp nutrition. Ammonia and nitrite concentrations were higher, and shrimp survival was lower in the biofloc systems. Although stable isotope levels indicated that biofloc material may have contributed 28% of the carbon and 59% of the nitrogen in shrimp tissues, this did not correspond with improved shrimp production. Overall, the water column microbial communities in biofloc systems may be more difficult to manage than clear‐water RAS which have external filters to control water quality. Biofloc does seem to offer some nutritional contributions, but exactly how to take advantage of that and ensure improved production remains unclear.     

Automation in stock-culture maintenance and juvenile separation of the mysid Mysidopsis bahia (molenock)

A batch system with subgravel filter for stock-culture maintenance of Mysidopsis bahia in artificial sea water is described. The feeding of mysids on Artemia is optimized through the cyclic pumping of brine shrimp instar I nauplii from a refrigerator to the stock-cultures. An easily constructed incubator-separator apparatus is described for the standardized harvesting of mysid juveniles to be used as test organisms.     

Quality Evaluation of Four Sources of Brine Shrimp Artemia spp.1

A study was conducted to compare fatty acid composition, hatching quality, and size of nauplii from four commercial sources of brine shrimp (Artemia spp.) cyse: China (CH), Colombia (COL), Great Salt Lake (GSL), and San Francisco Bay (SFB). The CH brine shrimp had a comparatively high percentage of 20:5(n-3) fatty acid (eicosapentaenoic acid or EPA), an essential fatty acid for most Iarval fishes, which was 10.4% of the total lipids. The COL, GSL, and SFB sources of cysts contained comparatively low percentages of EPA, 2.9, 1.2, and 1.6%. respectively. Hatching quality was determined by hatching cysts in salt (NaCl) water with a specific gravity of 1.02 at 27 C for 42 h. The COL cysts had the fastest hatching rate, with 50% of the cysts hatching in 13.4 h, while CH cysts hatched at the slowest rate, requiring 25.6 h for 50% of the cysts to hatch. Total percentage hatch was not significantly different among the SFB, COL, and GSL sources, with an average hatching percentage of 84.5, while CH cysts had a significantly lower total percentage hatch of 67.5. The SFB source produced the greatest number of nauplii (1.6 ± 10⁵ per g of cysts) with the smallest length (382 μm), while CH produced the smallest number (8.7 ± 10⁴) with the greatest length (500 μm). These results indicate that there is great variation in nutritional quality, hatching quality, and size of nauplii among commercial sources of brine shrimp cysts, and each of these criteria should be considered in selecting brine shrimp in a development of a feeding strategy for larval culture of a particular species.     

Biosecurity in Shrimp Farming: Pathogen Exclusion through Use of SPF Stock and Routine Surveillance

Biosecurity, as it is being applied to shrimp aquaculture, may be defined as the practice of exclusion of specific pathogens from cultured aquatic stocks in brood stock facilities, hatcheries, and farms, or from entire regions or countries for the purpose of disease prevention. To make a biosecurity program a functional concept in shrimp aquaculture, the relevant risks should be identified and the appropriate biosecurity measures put into practice to mitigate those risks. Examples of biosecurity measures put into place for this purpose may include such basics as site selection when the intent is to locate a new shrimp culture facility in an area where certain diseases are not enzootic. Standard facilitylfarm operating procedures can be adapted to minimize the risks of disease introduction and spread within a facility through such concepts as pretreatment of all source water, and reduced or “zero” water exchange. Stocking shrimp culture facilities with domesticated shrimp stocks that are free of specific diseases (“Specific Pathogen Free” or SPF) and or with stocks resistant to specific disease agents (SPR) is perhaps the most important single component of a biosecurity program. The example set by the development of domesticated SPF stocks of Litopenaeus vannamei has helped to make biosecure shrimp culture feasible. The development of these and other SPF stocks, and the diagnostic methods to develop and monitor them for specific diseases and disease causing agents, have been milestones in the development of the international shrimp farming industry in recent years, and it has contributed to the species rivaliig Penaeus monodon as the dominant farmed shrimp species. The regular monitoring (surveillance) of shrimp stocks in biosecure culture facilities is a necessary component of a biosecurity plan, as is having in place a contingency plan for disease containment and eradication should a breach occur in the physical and managerial components of a biosecure facility and a targeted disease occur.     

Experimental Infections with Baculovirus penaei in the White Shrimp Penaeus vannamei (Crustacea: Decapoda) as a Bioassay

Infections of the virus Baculovirus penaei (BP) have historically impacted penaeid shrimp production in both hatcheries and ponds. BP causes cytopathological alterations and mortality in at least four species, including Penueus vannamei . This study established experimental infections with BP in laboratory-reared P. vannamei . The most useful protocol involved BP infection in third substage protozoea (P₃) induced by feeding virus-contaminated material to rotifers and, in turn, feeding those rotifers to the shrimp larva. Infections were also established by delivering virus-containing brine shrimp to mysis (M) and postlarval (PL) stages. When virus originating from infected adults and juveniles was fed to P₃'s, the shrimp exhibited patent infections with hypertrophic nuclei, polyhedra, free virions, and occluded virions five or six days after being fed the virus. In contrast, when the source of virus material was from bioassay larvae rather than from adults and juveniles, similar patent infections developed in P₃'s by one to two days. A significant mortality in the resulting M's and PL's was associated with the infections with short but not long prepatent periods. In experimentally infected shrimp, examination by light microscopy and transmission electron microscopy revealed extensive viral infection in many cells in the anterior midgut and as many as 80–90% of the proximal and medial hepatopancreatic tubular cells. Free and occluded virions capable of producing disease ruptured into the gut lumen soon after infections became patent. Tests conducted in 1 L Imhoff cones, 160 L spat-cones, and aquaria all produced infections, usually with a prevalence of 100%. The system provides a useful method to detect and assay for infective agents, to amass infective material for research purposes, and to assess the biology of and host response to the virus under different conditions.     

DEVELOPMENT OF AN INTENSIVE SHRIMP CULTURE SYSTEM IN KUWAIT1

Development of an intensive culture system is presently being conducted in Kuwait as a means of farming penaeid shrimp in arid lands. Efficiency of commercial-scale hatchery production of Penaeus semisulcatus and P. japonicus showed significant improvement in 1981 over previous years. Three one-month hatchery rearing cycles in three 15 m³ concrete tanks yielded a total of 9.1 million post-larval shrimp with an average density of 160 PL/liter being obtained for one of these trials. Four other trials were discontinued due to low spawning rates and disease. Installation of a heat exchange system made it possible to begin larviculture in February, two months earlier than in previous years. Research in nursery and grow-out phases of intensive shrimp culture is being directed towards raceways, although Shigueno culture systems are also being investigated. Experimental work with six 18 m × 1.5 m raceways demonstrated that low water exchange rates (1 tank volume/day), combined with high aeration (9.5 liter/min) yielded the highest shrimp biomass. Unheated greenhouse structures constructed over the raceways showed that a single layer of 0.25 mm clear plastic sheeting could maintain water temperatures up to 2.7°C above those in unenclosed tanks. Rearing trials in two Shigueno tank systems demonstrated the importance of high water flow rates (3 tank volumes/day minimum) and adequate aeration. Due to sub-optimal conditions, survival was reduced to 7.5%, however, growth rates up to 6 g/month were obtained for P. semisulcatus.     

Baker's Yeast as a Potential Substitute for Live Algae in Aquaculture Diets: Artemia as a Case Study

In this study baker's yeast was evaluated as a substitute for live Dunuliella tertiolecta algae in the culture of the brine shrimp Artemia . Consumption of fresh baker's yeast resulted in poor growth and survival of brine shrimp. However, the nutritional value of the yeast sigaificantly improved after complete removal of the yeast cell wall by enzymatic treatment. Baker's yeast was also made digestible for Artemia by simple chemical treatment which did not reduce rigidity of the yeast cell. The external mannoprotein layer of the yeast cell wall is probably the major barrier to digestion by Artemia . Chemically treated baker's yeast offers promising possibilities as a substitute for algal feeds in aquaculture.     

Effect of Shrimp Stocking Density on Size-fractionated Phytoplankton and Ecological Groups of Ciliated Protozoa within Zero-water Exchange Shrimp Culture Systems

Zero‐water exchange shrimp culture systems are being investigated to reduce water and pathogens input and effluent output. The relative abundance and diversity of ciliates have been used as indicators of water quality and ecosystem dynamics in natural systems; however, their occurrence and role in shrimp production systems have not been investigated. The objectives of this research were to describe the succession of the ciliate community in a shrimp grow out system, to investigate the impact of increasing shrimp stocking density on the characteristics of the ciliated protozoa community, and to correlate this with shrimp performance. A growth trial with Litopenaeus vannamei was conducted outdoors with zero‐water exchange and three stocking densities (50, 75 and 100 shrimp/m²). In all treatments, free‐swimming ciliates were dominant in the early weeks, while substrate‐associated ciliates appeared later. The 100 shrimp/m² treatment exhibited a lower abundance of free‐swimming ciliates but higher abundance of hypotrichous ciliates in the second half of production and higher shrimp mortality and lower shrimp growth in the last 2 wk. These results provide a preliminary examination of the role of ciliates in shrimp culture systems and direction for future work in determining the role of protozoa as indicators of water quality.     

对虾工厂化养殖的系统结构

对虾工厂化养殖是在人工控制条件下,利用有限水体进行对虾高密度养殖的一种生产方式,它依托一定的养殖工程和水处理设施作为技术支撑,融合无公害生产的管理模式,是一种高效的环境友好型养殖。文章就构建对虾工厂化养殖平台中的各系统环节及该种生产模式的概况作系统综述。     

长毛对虾海水养殖环境以及虾肠道微生物群落结构研究

为了研究长毛对虾养殖环境以及对虾肠道微生物种群结构的特征,实验分别采集养殖区进水口水体、养殖池底泥、养殖池水体以及长毛对虾肠道样品,采用构建16S rRNA基因克隆文库的方法对不同样品间的微生物群落组成进行了研究。结果表明,4组样品中共获得621条序列,操作分类单元(OTU)总数达212个,表明养殖环境微生物群落结构具有高度的多样性。从遗传进化树分析发现,进水口水体中细菌优势种群为蓝细菌(53.97%)、α-变形杆菌(13.76%)和γ-变形杆菌(10.58%);养殖池水体细菌优势种群为蓝细菌(33.55%)、γ-变形杆菌(14.84%)、厚壁菌(14.19%)、拟杆菌(12.26%)和α-变形杆菌(9.68%);养殖池底泥细菌优势种群大部分属于厚壁细菌(79.12%);对虾肠道细菌优势种群为厚壁细菌(75.79%)、梭杆菌(13.68%)和γ-变形杆菌(10.53%)。在目分类水平上,养殖池底泥、养殖池水体和对虾肠道中芽孢杆菌占有较高的比例,分别占克隆数的69.78%、13.55%和72.63%;进水口水体和养殖池水体中红细菌的比例较高,分别占克隆数的10.05%和9.68%。本研究分析了养殖环境以及对虾肠道微生物的群落结构,揭示微生物从水源到对虾肠道内的演替规律。总体上,本养殖系统微生物群落结构良好,但在养殖池水体和对虾肠道中也检测到黄杆菌类群和少量的弧菌。本研究有助于了解养殖环境对于对虾肠道微生物组成的影响,并为长毛对虾病害的预防提供参考。