Accumulation of Heavy Metals in the Nauplii of Artemia salina

Artemia salina cysts (San Francisco Bay Brand) were exposed in seawater containing multiple concentrations of either a single heavy metal (Hg, Cu, Zn, Pb, Cd, Co, Ni, Cr, Mn and Fe) or combination of heavy metals. The heavy metal accumulation in Artemia nauplii increased linearly with an increase in the heavy metal concentration in water. The metals could be detected in nauplii exposed to a single heavy metal at dosages of 5 μg/L for Hg, Zn, Mn, Fe and Cu; 25 μg/L for Cd and Cr; 50 μg/L for Co; 100 mUg/L for Ni; and 250 μg/L for Pb. Cysts exposed to several heavy metal combinations had minimum effective dosages equal to or lower than the single heavy metals- 5 μg/L for Cu, Cr, Zn, Mn and Fe; 25 μg/L for Cd and Ni; 50 μg/L for Co; and 250 μg/L for Pb. The accumulation of Cu, Ni and Co by Artemiu nauplii did not differ for animals exposed to single or combined heavy metal solutions. Cr, Zn and Pb had a synergistic effect of heavy metal uptake in combined heavy metal element solutions, however, Fe, Cd and Mn had an antagonistic effect.     

Vibrio spp. Control at Brine Shrimp,Artemia, Hatching and Enrichment

Experiments were conducted to evaluate different prophylactic methods to control the bacterial load in brine shrimp, Artemia, hatching. The first experiment evaluated three treatments to control Vibrio spp. during the Artemia hatching: microalgae (Chaetoceros calcitrans), probiotic (Bacillus spp.), and antibiotic (Florfenicol). In the second experiment, Artemia metanauplius were enriched in distinct treatments with C. calcitrans, probiotic, and emulsion rich in docosahexaenoic and eicosapentaenoic fatty acids. Enriched Artemia metanauplius and nauplii (control) were offered to white shrimp, Litopenaeus vannamei, postlarvae (PL₇–PL₁₉). Presumptive Vibrio were quantified in Artemia, PL, and rearing water. Microalgae and probiotic were effective to control Vibrio spp. in Artemia nauplii. The enrichment process increased the Artemia bacterial load but did not affect Vibrio load in L. vannamei.     

卤虫的营养

卤虫(Arem ia)是水产经济动物苗种生产中重要的活饵料之一,卤虫营养价值的高低直接影响到苗种生产的成败与效益。笔者拟就卤虫的营养价值研究作一综述,供学者参考。1卤虫粗蛋白及氨基酸的研究卤虫一直被水产界认为是高蛋白的生物饵料。不同发育阶段、不同产地和不同投喂条件下的卤虫,其体内的粗蛋白含量不同。随着卤虫的生长,粗蛋白的含量有逐步增加的趋势。国内文献报道卤虫卵粗蛋白含量为45.44%[1],卤虫去壳卵的粗蛋白含量为43.03%~57%[1-3],以新疆巴里坤盐湖卤虫卵粗蛋白含量最高(57%),卤虫初孵无节幼体粗蛋白含量为54.61%~59.92%[2],养…     

提高卤虫休眠卵孵化率的技术因子探讨

卤虫休眠卵的孵化是目前海水鱼虾育苗工作中的活饵料供应体系，本文结合上海地区低盐度海水对虾育苗工作，经多年实验观察，归纳总结提高卤虫休眠卵孵化率的主要技术措施，其中包括孵化设备装置、水质控制、加快脱壳处理、以及鉴别卵的质量标志等     

Hatching events in the cysts of Artemia salina

Prior to hydration, the cysts of Artemia salina are cup-shaped with a diameter of approximately 0.18 mm. Upon immersion in sea water, the cysts slightly increase in diameter to 0.19 mm and assume a spherical shape. Hatching begins with the splitting of the surface coat. The split runs along a straight line, approximately one-half the circumference of the cyst. The exposed fracture in the surface coat reveals three distinct regions: (1) a thin (1.2 μm) smooth outer layer; (2) a thick (4.7 μm) ‘spongy’ layer; and (3) a thin (1.8 μm) fibrous inner layer. The split becomes more pronounced as the nauplius, enclosed within a transparent hatching membrane, slowly emerges. Once completely emerged from the cyst, the nauplius begins a series of beating movements which rupture the hatching membrane, allowing the nauplius to swim free.     

Encapsulated Spirulina Powder Feed for the Nutritional Enrichment of Adult Brine Shrimp (Artemia salina)

Abstract

Liposomes were prepared in the laboratory with lipids obtained from chicken egg yolk to encapsulate Spirulina powder. Artemia napulii were hatched and fed with lipid-encapsulated Spirulina or Spirulina powder. After 20 days of rearing, the experimental A. salina were harvested and measured for total body length and total content of protein and carbohydrates. Total body length was 45% higher, protein content was 49% higher, and carbohydrate was 35% higher in Artemia fed with liposomes as compared with those fed only Spirulina powder.     

冷冻等处理对不同孵化进程的卤虫卵存活率的影响

研究了冷冻、双氧水和干燥处理对处于不同孵化进程中的卤虫卵的存活率(孵化率)的影响。冷冻对未经孵化处理的卵的孵化率影响很小,冷冻1~8周,基本保持不变。孵化进行了3h的卤虫卵,冷冻8周后,其孵化率降低了10个百分点。孵化进行了6h的卤虫卵,冷冻8周后,其孵化率降低了31个百分点。孵化进行了9h的卤虫卵,冷冻8周后,其孵化率降低了40个百分点。处于不同孵化阶段的卤虫卵经冷冻处理8周后,再经3%双氧水处理10min和40℃干燥处理6h,其孵化率表现为不同的特点。未经孵化处理卵的孵化率基本保持不变。孵化进行了3h的卤虫卵,其孵化率再次降低5个百分点。孵化进行了6h的卤虫卵,其孵化率再次降低了20个百分点。孵化进行了9h的卤虫卵,其孵化率再次降低了37个百分点。     

The Use of Decapsulated Cysts of the Brine Shrimp Artemia as Direct Food for Carp Cyprinus carpio L. Larvae

Decapsulated Arremia cysts have been evaluated as a direct food source for larvae of the carp Cyprinus carpio L. All decapsulated cyst diets gave excellent survival of carp larvae during the first two weeks of culturing. Unlike traditionally brine-stored decapsulated cysts, dried Artemia embryos provided growth results comparable to those obtained with freshly hatched Artemia nauplii. Furthermore, except for Artemia embryos that lost their hatchability after long-term storage in air, several other inactivation treatments, simulating improper harvesting and processing of cysts, did not produce a significant decrease in the nutritional quality of the decapsulated cysts.
Using decapsulated cysts 89 a direct food source for carp larvae, instead of nauplii, the quantity of cysts needed can be reduced by about 25% to 35% after one and two weeks of culturing, respectively. Moreover, the use of decapsulated cysts advances the possible commercialition of poor-hatching and less expensive cyst products for culture of carp larvae.     

投喂量对中华卤虫解池种群产仔方式的影响

在NaCl质量浓度73g/L、25℃和光暗比12h∶12h条件下,将20日龄的中华卤虫成熟个体按每杯1雌1雄方式置于盛有约100mL高盐海水的玻璃杯中,用盐生杜氏藻按1.5×10~6、4×10~6、6×10~6、9×10~6个/杯4个投喂量培育30d,记录所产出的休眠卵和无节幼体数量,并测量休眠卵卵径、无节幼体体长和雌性亲体体长。试验结果表明,同时产休眠卵和幼体情形下的卤虫的产仔次数仅占总产仔次数的1.2%～2.9%。1.5×10~6、4×10~6、6×10~6个/杯3个试验组仅产卵的产仔次数占总产仔次数的30.4%～40%,仅产幼体的产仔次数占总产仔次数的57.5%～66.7%,而9×10~6个/杯试验组仅产卵及仅产幼体的百分比分别为61.3%和37.5%。4个试验组的单雌繁殖量分别为88.7、105.9、193、298.7个,单雌繁殖次数分别为2.7、2.9、3.9、4.7次,卵生后代比例分别为32.4%、31.1%、36.9%、66.2%。各试验组干卵径、卵生无节幼体体长和卵胎生无节幼体体长依次为1.5×10~6个/杯试验组<6×10~6个/杯试验组<4×10~6个/杯试验组<9×10~6个/杯试验组,且各试验组之间差异显著(P<0.05)。雌性亲体的最终体长随投喂量增加而显著增加(P<0.05)。研究结果表明,中华卤虫解池种群的雌体在饵料充足时偏卵生,在饵料匮乏时偏卵胎生;卤虫产仔方式受到投喂量的影响,但通过降低投喂量来改变产仔方式的做法在生产上是不经济的。     

几个因子对内蒙古自治区卤虫卵孵化率的影响

采用常温、冷冻和盐水浸泡的方法.用3％双氧水、3％甲醛和3％高锰酸钾处理卤虫卵,研究诸因子对卤虫卵孵化率的影响。试验结果表明:产于内蒙古自治区的卤虫卵最佳孵化盐度为35;用3％双氧水和3％甲醛处理卤虫卵均能提高其孵化率;用粗盐饱和溶液处理是保存卤虫卵的好办法。     

饵料对卤虫,金丝鱼和对虾脂肪酸组成的影响

研究了饵料对卤虫(Artemia salina)、金丝鱼(Tonichthys albonubes Lin)和对虾(Penaeus orientalis)脂肪酸组成的影响。结果表明,饵料中的脂肪酸影响到上述养殖对象体内的脂肪酸。为了提高养殖对象体内Omega—3(ω—3,也有用n—3)多烯脂肪酸含量,可以选择富含ω—3多烯脂肪酸的生物饵料,也可用富含ω—3多烯脂肪酸的人工配合饵料。     

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.     

摇瓶法测定卤虫卵的孵化率

作者设计一种摇瓶法与目前国内常用的烧杯法对同一卤虫卵样品进行孵化率测定，其平均值分别为８４．８５％和８０．９０％，前者显著高于后者。两种方法比较，摇瓶法的测定结果更准确。     

Effect of pH and Decapsulation on the Toxicity of Ammonia to the Brine Shrimp Artemia franciscana

Artemia franciscana were hatched and tested for tolerance to ammonia at pH 6.5 and 8.5 in artificial seawater with a salinity of 17 ‰. Nauplii seemed to be less tolerant of ammonia at pH 6.5 despite the fact that more of the ammonia is in the ionized form (NH₄⁺). It is suggested that this greater sensitivity is a result of the NH₄⁺ competing with the Na⁺ during gut transfer. Nauplii hatched from decapulated cysts were more tolerant of ammonia than those hatched from whole cysts, probably because of a greater energy reserve.     

Influence of Body Weight and Food Density on Kinetics of Ammonia Excretion by the Brine Shrimp Artemia franciscana

This study was undertaken to quantify the relationships between the rate of ammonia excretion by brine shrimp and dry weight (body size) and food density. Measurements of the rate of ammonia excretion of the brine shrimp were made at 25 C in darkness. Under these conditions, the excretion rate of ammonium-nitrogen can be generalized as a function of body weight and food (Nannochloropsis sp.) density. The relationship between the body weight (W) and excretion rate of ammonium nitrogen (E_N) is expressed as E_N=α W^γ, where α is the metabolic level. The parameter α is dependent on ration, such that α=α_o±α_r where α_o= metabolic level in starvation and α_r= the metabolic level which increased with feeding or changed with the food density. In experiments in which the animal starved, the equation above becomes E_N=α_oW^γ, and the values of α and γ were 0.22 and 0.93, respectively. The rate of ammonium excretion rose from 5.42 × 10^?4 to 2.28 × 10^?1μg N/animal/h as dry weight measured from 1.57 × 10^?3? 1.04 mg dry weight per animal. Next, it is convenient to express α_r as α_r=α_fmax= (1 ? 10^?kc), where α_fmax is the maximum rate of α_f at saturated level of food density, C is the mean cell density, and k is a constant defining the rate of change of the metabolic rate with cell density. Therefore, the rate of ammonia excretion by brine shrimp could be expressed as E_N=α_o [1 ? a(l ? 10^?kC)]W^γ, and a =α_fmax/α_o. The values of the kinetics parameters obtained from experiments where shrimp were fed were a = 2.3 and k = 0.15×10^?7. Consequently, the maximum rate of ammonia excretion at a saturated food density is equivalent to 3.3 times the rate of animals that are not fed.     

Bioencapsulation of Therapeutic Quantities of the Antibacterial Romet-30 in Nauplii of the Brine Shrimp Artemia and in the Nematode Panagrellus redivivus

Nauplii of the brine shrimp, Artemia , and cultures of the soil nematode, Panagrellus redivivus , were fed a suspension of the water-insoluble antibacterial Romet-30 (sulfadimethoxine plus ormetoprim) to determine if they could be used as a mechanism for delivery of the drug to larval penaeid shrimp.
Romet-30 was added to groups of brine shrimp nauplii and nematodes in 1 L beakers to achieve a concentration of 3 mg of drug per ml of seawater. After a 4 h uptake period, predetermined numbers of organisms were assayed for antibiotic content using the micro-plate diffusion method and a Romet-30 sensitive strain of Vibrio alginolyticus as the indicator. The resulting zones of inhibition were compared to that of a standard Kirby-Bauer sensitivity disc containing 25 μg of the drug that was placed on each plate as standard control. Negative controls consisted of equal numbers of nauplii and nematodes that were not exposed to the antibiotic. Artemia nauplii and nematodes accumulated approximately 0.1 μg of the drug per nauplius and approximately 0.25 μg per nematode. They exhibited no signs of toxicity from exposure to the drug and contained the antibiotic in sufficient quantity to provide a theoretical therapeutic dose of the drug when fed to penaeid larvae.
In subsequent tests, normal and diseased larval Penaeus stylirostris readily accepted Romet-30 enriched Artemia . Diseased larvae fed the drug in this manner exhibited a statistically greater overall survival and a greater survival to the post-larval stage by Student's t -test at the 5% significance level.     

卤虫卵孵化强化剂的初步研究

对不同品系的低孵化率卤虫卵进行了孵化对比试验，分为试验组和对照组，其中试验组添加孵化强化剂与对照组进行同等条件的试验，2组对照组的孵化率分别是66．8％、64．9％，试验组的孵化率分别是84．3％、81．5％增幅超过15个百分点，说明这种针对低孵化率卤虫卵研制的强化剂有效可行，可做进一步推广试验。     

卤虫卵壳营养成分分析

采用一般营养物质测定方法及液相色谱和气相色谱方法测定了卤虫卵壳营养成分。结果表明:蛋白质58.91％,脂肪5.63％,灰分8.92％;17种氨基酸总量为干物质的57.73％,必需氨基酸含量占氨基酸总量的36.60％;卤虫卵壳含有多种不饱和脂肪酸,其中EPA占8.54％;卤虫卵壳含有多种无机元素,其中钙为13865.23μg/g,铁为9928.17μg/g。卤虫卵壳含有丰富的营养成分,因此可将其开发为营养强化剂或其它动物饲料。     

卤虫卵化学成分的分离与分析

本试验对卤虫卵的化学成分进行分离和分析。卤虫卵的含油量为7．1％，油中不皂化物的含量为4．9％，主要为胆甾醇。脂肪酸中含有较大量的油酸、棕榈酸、棕榈油酸、花生四烯酸和二十碳五烯酸。卤虫卵含蛋白质为20．9％，还含有多种氨基酸。     

Ingestion Rate and Feeding Behavior of the Peppermint Shrimp Lysmata wurdemanni on Artemia Nauplii

A laboratory study was conducted to examine the effects of food level and water temperature on the ingestion rate in the larvae of the peppermint shrimp Lysmata wurdemanni , a popular aquarium spe cies. Artemia nauplii were used as the food item. Number of newly hatched Artemia nauplii consumed by the larvae (from zoea II to zoea VII, zoea I can metamorphose to zoea II without exogenous nutrition in about one day) was measured daily at four food concentrations (2, 5, 10 and 20 Artemia nauplii/mL) and two temperature levels (25 C and 28 C). The experiment was conducted in 500-mL beakers with three replicates for each treatment. The results show that the shrimp consumed significantly more food at 28 C than at 25 C (P < 0.01). Ingestion rate increased with increasing food concentration in all larval stages and with larval development except for the lowest food level ( 2 Artemia nauplii/mL) where insufficient food supply limited the ingestion rate to around 35 Artemia nauplii/ larva per d after zoea IV stage. The larval development rate was significantly lower (P < 0.05) in the shrimp subjected to the two lowest food concentrations (2 and 5 Artemia nauplii/mL) in the 500-mL beakers. But in a separate experiment conducted in the 1,400-mL beakers, the results were reversed: both survivorship and development rate were significantly lower at the two higher food levels (6 and 12 nauplii/mL) than those at 3 nauplii/mL level. During molting period, ingestion rate decreased significantly, followed by a sharp rise to the normal rate the following day.