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.     

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.     

Survival and Growth of Crangon nigricauda Larvae (Decapoda, Caridea) Raised on Experimental Diets

Newly hatched Crangon zoeae from different maternal shrimp were raised separately using an Imhoff cone larval-rearing system. Experimental diets were Chaetoceros gracile , live Artemia nauplii, lyophilized Arremia nauplii particles, calcium alginate microencapsulated (CAM) Artemia nauplii, lyophilized Daphnia magna and CAM Daphnia magna . A dependable "atomizer" design for lab oratory preparation of CAM diets was developed. Initially, survival rates of zoeae fed either Chaetoceros or live Artemia nauplii were evaluated in order to establish a suitable control diet for subsequent growth experiments, and the interbrood and intrabrood components of zoed survival variation were analyzed.
Crangon zoeae ate every type of food offered to them, but only Chaeroceros- fed zoeae survived to metamorphosis. Zoeal survival rates were extremely variable. Interbrood variation was greater than intrabrood variation, but the difference was not statistically significant. Zoeae from smaller maternal shrimp were generally more active and had greater survival rates than zoeae from larger, presumably older and senescent shrimp. Zoeae that were fed Chaetoceros supplemented with CAM Artemia nauplii had significantly greater ( P < 0.001) growth rates than siblings fed only Chaetoceros .
Suspension feeding on Chaetoceros was probably more efficient than raptorial feeding on Artemia nauplii, resulting in greater survival rates. Supplementing a successful microalgal diet with CAM Artemia nauplii allowed greater use of zoeal feeding mechanisms, added an animal nutrient source to the diet, and affected growth rates by increasing the molt increment and decreasing the intermolt period.     

卤虫生物包囊在水产动物疾病防治中的研究现状及展望

在水产养殖中,“生物包囊”就是指以饵料生物作为载体包裹营养物质或药物,鱼虾通过摄食这种饵料生物达到营养强化、防治疾病等目的。本文以卤虫为代表,介绍了国内外利用生物包囊防治水产动物疾病方面的研究现状：包囊的优点、强化研究、药代学分析、防治效果等。并对研究中存在的问题和今后的研究方向进行了分析探讨。     

Evaluation of Live Feeds for Larval and Postlarval Mahimahi Coryphaena hippurus

Live hatchery feeds were assayed for fatty acids (FA), amino acids (AA), and their ability to support growth and survival of larval and postlarval mahimahi Coryphaena hippurus at two different hatchery stages. Euterpina acuritrons copepods (C), mahimahi yolk-sac larvae (YSL), Artemia parthenogenica brine shrimp nauplii (BSn), A. parthenogenica juveniles (BSj), and Brachionus plicatilis rotifers (R) were assayed, using several enrichment media. There was little difference in AAs among feeds.
Levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were about 10 times higher in YSL than in their feeds. This explains previous findings where first stage larval survival (0–9 days) was not affected by feed HUFA levels. Second stage survival was significantly higher when larvae were fed copepods. Enrichment with 100 ppm SuperSelco greatly improved the survival of larvae that were fed brine shrimp. The even higher omega-3 fatty acids found in copepods appear to be important for survival of larvae under more stressful conditions.
Brine shrimp juveniles enriched with SuperSelco are a good food for postlarval mahimahi. Yolksac larvae of mahimahi are an even better food, promoting faster growth at less cost, for large scale mahimahi aquaculturists. Different batches of yolksac mahimahi larvae varied by a factor of 10 in their concentration of DHA, but always had the highest level of DHA as much as 40% of total fatty acids (FAs). These "high HUFA" batches of YSL also had the highest levels of EPA and total fatty acids. The data suggest that climate and broodstock age may have considerable influence on larval nutrition.     

Feeding Larval Red Drum on Microparticulate Diets in a Closed Recirculating Water System1

A feeding protocol was developed for red drum larvae based on combining a commercial microparticulate diet (Kyowa Fry Feed) with live prey (rotifers) in a closed, water reuse system. In five trials, growth and survival were measured on larvae reared on a combination of live and microdiet for 1–5 d and then microdiet alone. Results in each trial were compared to control larvae reared on live rotifers Brachionus plicatilis and brine shrimp nauplii Artemia salinas. The most satisfactory combination was feeding live food and microdiet together for the first five days and then completely discontinuing live prey, eliminating the need to feed brine shrimp to the larvae. Growth rates of larvae fed progressively larger sizes of the microdiet were as good as larvae reared on live prey. Both groups metamorphosed to the juvenile stage at less than one month. Survival rates on the five day live food and microdiet combination were a remarkable 60% from egg to the juvenile stage. The successful weaning of red drum to microdiets paves the way to produce a semipurified diet to test nutrient requirements of larval fish.     

Concentration and Composition of Astaxanthin in Black Tiger Prawn Penaeus monodon Postlarvae Fed Artemia sp. Nauplii or Mauxia Shrimsp Acetes intermedius

Minced Taiwan mauxia shrimp Acetes intermedius , an alternative to brine shrimp Artemia sp. nauplii, has long been used as a principal or supplemental feed in prawn hatcheries in Southeast Asia and India. In this study, black tiger prawn Penaeus monodon postlarvae were fed with frozen brine shrimp nauplii (diet B) or minced Taiwan mauxia shrimp (diet M) for 4 wk to compare their astaxanthin concentration and composition, survival, and growth. Diet B contained two and a half times more total carotenoid (TC) than diet M, with canthaxanthin as a major (79%) carotenoid, but without astaxanthin, a predominant carotenoid in crustaceans. Of its TC in diet M, 55% was β-carotene and 17% astaxanthin. B-prawn (postlarvae fed with diet B) had a similar growth rate as M-prawn and twice the survival rate as M-prawn. The concentrations of total astaxanthin (TA), free astaxanthin (FA), astaxanthin monoester (MA), and astaxanthin di-ester (DA) in B-prawn were all higher than those in M-prawn. Except for FA, no reduction of TA, MA, or DA concentration during the feeding interval was found in B-prawn. However, concentrations of TA, FA, MA, and DA in M-prawn all decreased. TC content of the experimental diets had a greater influence on resulting prawn astaxanthin concentration and composition than carotenoid compositions of the diets.     

Effects of nutritional enhancement of live food organisms on growth and survival of barramundi, Lates calcarifer (Bloch), larvae

Abstract Larval and juvenile barramundi, Lates calcarifer (Bloch), were reared intensively on test diets comprising nutritionally supplemented and unsupplemented rotifers, Brachionus plicatilis Muller, and brine shrimp, Artemia salina L. Both growth and survival of barramundi larvae fed on nutritionally supplemented brine shrimp were superior to those of larvae fed on untreated brine shrimp. Barramundi larvae fed diets incorporating untreated brine shrimp exhibited a mortality syndrome which commenced from 20 to 30 days after hatching and resulted in almost total mortality within the next 10 days. Analyses of the proximate, fatty acid and amino acid composition of the live food organisms used in the test diets, and reference samples comprising barramundi egg yolk and extensively reared juvenile barramundi, suggest that this mortality syndrome was primarily associated with the fatty acid composition of the food organisms, particularly the relative amount of 20:5n-3 in the brine shrimp fed to the larvae. These results, and the work of other authors, indicate that there are two mortality syndromes which affect intensively cultured L. calcarifer larvae.     

Mariculture potential of the spot prawn, Pandalus platyceros Brandt

Biological characteristics and culture methods were investigated for the spot prawn, Pandalus platyceros Brandt. Ovigerous adults were caught in the local fishery; six of these produced 2 628 to 4 669 larvae. The larval period ranged from 26 to 35 days (9.5–12.0°C). Maximum larval survival was about 70%, with mortalities being most frequent during ecdysis. The relation of wet weight (g) to carapace length (mm) for the first 26 months was calculated as log W = ?3.0843 + 2.9308 log L. Prawns showed good survival between 9.5 and 21.0°C. Mortality increased sharply when temperatures exceeded 21.0°C. Salinities below 22‰ resulted in a sharp increase in mortality.A diet of brine shrimp nauplii sufficed for newly hatched larvae. Growth was enhanced when larvae were fed a unicellular algal supplement (Phaeodactylum tricornutum), although mortality was somewhat higher. Larvae progressed rapidly to foraging on larger brine shrimp and diced foods. Six-month-old spot prawns raised on a squid diet averaged 3.4 g, and at 1 year the mean weight was 6.3 g. A feeding experiment, incorporating 12 diets, disclosed that highest growth rates and best food conversion ratios were achieved on a combined California seamussel and giant red sea urchin diet. However, the best growth rate achieved was considered marginal for mariculture.It was concluded that unless the growth rate could be accelerated by other food formulations or culture techniques, a monoculture system for mass cultivation would not be feasible. The spot prawn may have potential in a polyculture system.     

Effects of various levels of dietary protein on survival,molting frequency and growth of juvenile blue crabs (Callinectes sapidus)

An 18-week study was conducted to examine growth characteristics of the juvenile blue crab (Callinectes sapidus Rathbun) fed various levels of dietary protein. Hatchery raised individuals (157) of identical age (160 days) from the same gravid female were assigned to one of four dietary treatments: adult brine shrimp (Artemia salina Leach) and artificial pelleted diets containing crude protein levels of 23, 37, and 49%.Growth rate, measured as a function of mean weight and mean carapace width, indicated that brine shrimp-fed crabs were larger (P < 0.05) than crabs fed artificial pelleted diets. Also, blue crabs fed either 37 or 49% crude protein were larger than crabs fed the 23% crude protein diet. Molting frequency was greater in the brine shrimp-fed crabs than in those fed the artificial diets. No differences in growth were detected when comparing males vs. females fed the artificial diets. However, females demonstrated greater growth than males within the brine shrimp treatment. Protein concentration of freeze-dried whole blue crab carcasses was greater in brine shrimp-fed crabs than in crabs fed the artificial pelleted diets (P < 0.05).     

Design and development of a flowing bed reactor for brine shrimp culture

An automatic self-cleansing high density brine shrimp reactor has been designed and tested, and the concept appears successful. Initial experiments suggest that extra-ordinarily high densities of brine shrimp may be maintained in such a system. The concept of a flowing film of glass beads appears to be a very useful technique in scouring waste material from animal culture tanks. The concept is particularly useful for culture of small marine herbivores in continuous culture. The bead flow rapidly removes waste material while allowing for water passage, yet completely containing the animals.Further design improvement and development should result in a high density brine shrimp culture system which is both simple and inexpensive to build, as well as reliable and cost effective to operate, and capable of efficient algal cell removal from culture water.     

INTERNATIONAL STUDY ON Artemia:1 XXI. INVESTIGATIONS INTO WHY SOME STRAINS OF Artemia ARE BETTER FOOD SOURCES THAN OTHERS. FURTHER NUTRITIONAL WORK WITH LARVAE OF THE MUD CRAB,Rhithropanopeus harrisii

In a series of studies conducted by members of the International Study on Artemia, differences in nutritional quality were documented between geographical strains of the brine shrimp Artemia. Concomitant with, and possibly related to nutritional effectiveness are differences in biometric traits and biochemical composition. Since these initial experiments could only hint at causal relationships, a series of experiments were carried out to further our understanding of cause and effect. In one experiment we tried to ascertain whether the factors responsible for poor survival in larvae fed some brine shrimp strains are cumulative throughout larval development or whether there are critical periods when larvae are more sensitive. Our results indicate that the factors contributing to poor growth and survival are cumulative. In a second experiment, we contaminated Brazil Artemia with diel-drin, chlordane and combinations of the two and fed them to mud crab (Rhithropanopeus harrisii) larvae. The levels of contamination were chosen to approximate those suspected of contributing to the poor food value of some brine shrimp strains. In this experiment, however, diel-drin and chlordane contamination appeared to have no effect on growth and survival of R. harrisii larvae. In a third experiment, we fed Utah strain Artemia on Isochrysis galbana for 24 hours and then fed these brine shrimp to mud crab zoeae. Previous work had shown that this regime made Utah Artemia more suitable as a food source for a prawn. However, in our experiments, it did not improve survival of R. harrisii.     

Retracted: Effect of concentration of the microalga Dunaliella tertiolecta on survival and growth of fairy shrimp,Phallocryptus spinosa Milne Edwards, 1840 (Crustacea: Anostraca)

We investigated the effects of concentration of the microalga Dunaliella tertiolecta on the growth and survival of fairy shrimp, Phallocryptus spinosa. Newly hatched nauplii were stocked into containers, maintained at different concentrations of D. tertiolecta (at 18, 36, 54, 72 and 90 × 10⁶ cells mL^?1). All treatments were in quadruplicate and each replicate was stocked with 100 larvae in a 2‐L cylindrical bowl. We studied the survival and growth of the fairy shrimp after 3, 6, 9, 12 and 15 days of culture. The results indicated significant differences, in terms of growth and survival, of fairy shrimps fed at different algal densities. The highest and lowest growth and survival among the treatments were observed on Day 15, the highest in animals fed at a concentration of 90 × 10⁶ cells mL^?1 and the lowest in animals fed at a concentration of 18 × 10⁶ cells mL^?1. We conclude that the growth and survival of the P. spinosa increased with increasing density of algae, to a threshold level. Within certain concentration limits, the addition of D. tertiolecta substantially improved the performance of larval culture of P. spinosa, suggesting that this fairy shrimp has potential in terms of aquaculture development.     

Effects of Heavy Metals on the Hatching Rates of Brine Shrimp Artemia salina Cysts

The effects of heavy metals (Hg²⁺, Cd²⁺, Co²⁺, Cr³+, Pb²⁺, Cu²⁺, Fe²⁺. Ni²⁺, Zn²⁺, Mn⁷⁺, Mn⁴⁺ and Mn²⁺) on the relative hatching percentage of brine shrimp, Artemia salina were assessed. Artemia salina cysts (San Francisco Bay Brand) hatched in seawater containing various heavy metal concentrations. After 48 hours, the number of hatched nauplii were counted. A negative linear relationship between hatching rate of Ariemia salina cysts and heavy metal concentration occurred, except copper which conformed to a cubic model. The relative toxicities of heavy metals on Artemia salina cysts were as follows (Cu²⁺, most toxic; Mn²⁺, least toxic): Cu²⁺ > Zn²⁺ > Ni²⁺ > Co²⁺ > Mn⁷⁺ > Cr³⁺ > Cd²⁺ > Fe²⁺ > Hg²⁺ > Mn⁴⁺ > Pb²⁺ > Mn²⁺.     

Bioencapsulation of erythromycin using adult brine shrimp, Artemia franciscana (Latreille)

Live adult brine shrimp, Artemia franciscana (Latreille), were enriched with erythromycin to determine if Artemia could accumulate therapeutic levels for subsequent feeding to young fish. Three trials were conducted to determine the erythromycin incorporation and survival rates of enriched Artemia when fed either liposomes containing erythromycin or various erythromycin suspensions. Erythromycin concentration in Artemia fed a liposome suspension was low (∼ 5 μg mL⁻¹) relative to Artemia fed the direct suspension (> 100 μg mL⁻¹) over the same time period. When enriched with suspensions up to 1 g erythromycin L⁻¹ sea water for 14 h, Artemia survival was not significantly affected ( P > 0.05) relative to controls. Using a suspension of 1 g L⁻¹, tissue erythromycin concentrations of 109 ± 16 μg erythromycin mL⁻¹  Artemia homogenate (mean ± SEM) were achieved after 12 h. Concentrations above 170 μg mL⁻¹ were obtained using suspensions of 2–5 g L⁻¹, but Artemia survival significantly ( P < 0.05) decreased.     

长江胭脂鱼开口饵料的研究

用不同组合的饵料投喂刚能平游的长江胭脂鱼鱼苗40 d,研究长江胭脂鱼适宜的开口饵料。结果显示,用配合饲料作开口饵料时长江胭脂鱼的开口率、成活率和出池规格都显著低于水蚯蚓组和卤虫组,补充蛋黄后开口率、成活率、出池规格变化不明显,但补充螺旋藻后开口率、成活率、出池规格均显著提高。用配合饲料和卤虫作主体饵料再补充蛋黄和螺旋藻粉也获得了较高的开口率和成活率。建议在水泥池育苗条件下长江胭脂鱼的开口饵料用配合饲料和鲜活饵料作主体饵料并补充少量螺旋藻粉。     

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。     

Delivery of quinolone antibacterials to turbot, Scophthalmus maximus (L.), via bioencapsulation: quantification and efficacy trial

Abstract. The incorporation of the quinolone antibacterials oxolinic acid and sarafloxacin into Artemia fransciscana and subsequently into turbot, Scophthalmus maximus (L.), was quantified, and the therapeutic efficacy of the bioencapsulated drugs against challenge with Vibrio anguillarum 8587 was investigated. Five-week-old turbot were fed for 10 days with Artemia enriched with either oxolinic acid or sarafloxacin. Therapeutic concentrations were reached with both drugs (11.8 μg oxolinic acid per gram fresh weight: 1.8 μg sarafloxacin per gram fresh weight). Both treatments proved effective against challenge, with V. anguillarum -specific mortality rates of 6 and 14% in the oxolinic acid and sarafloxacin treated groups, respectively, compared with 75% in the infected control. However, incorporation of the drug by brine shrimp was extremely low (<1%), and therefore, bioencapsulation cannot be considered as an appropriate method to reduce impact on the environment.     

PROBIT analysis predicts hatching rates of brine shrimp Artemia sp. cysts

Thirty replicates of San Francisco Bay brine shrimp Artemia sp. cysts from one lot were weighed to 0·01 mg. The mean mass of a single cyst was 2·597 μg (±0·040 μg, 95% confidence level). Batches of 1 g from the same lot were hatched in the laboratory, and fraction hatched versus time data were fitted to a nonlinear curve using PROBIT analysis. Median time of hatch was 24·8 h with a standard error of ±3·92 h. Cysts and nauplii in 1-ml aliquots were pipetted at regular intervals and counted under a dissecting microscope. The number of cysts pipetted at the beginning of the experiment was 19% less than estimates based on the known number per volume of hatching medium, indicating that hatching data derived from pipetting procedures may contain large sampling errors. PROBIT analysis allows fraction hatched to be predicted when a particular lot of cysts is hatched under controlled conditions.     

Comparison of live food organisms and prepared diets as first food for paddlefish, Polyodon spathula (Walbaum), fry

Abstract. A feeding experiment was conducted in aquaria to evaluate growth, survival and food consumption by paddlefish, Polyodon spathula (Walbaum), fry fed live Daphnia pulex, brine shrimp nauplii, Artemia sp. (L.), from two different geographical sources, or one of three commercial dry diets. Fry were fed from first feeding (day 8 post-hatch) to day 17 post-hatch. All diets had similar percentages of crude protein and lipid. Fatty acid composition was similar in all diets except for Great Salt Lake brine shrimp nauplii which had a higher percentage of linolenic acid, 18:3 (n-3), and a lower percentage of eicosapentaenoic acid, 20:5 (n-3). Paddlefish fed live food organisms were significantly (P<0·05) larger than those fed non-living diets. Survival was significantly higher (P<0·05) for fish consuming live Daphnia (95·3%) than all other treatments. Percentage of fish with food in the digestive tract did not significantly differ (P>0·05) among treatments. Poorer growth and survival by fish fed prepared diets may have been due to limited digestibility of the dry diets by paddlefish.