Fish antibiotherapy: bioencapsulation of flumequine using adult brine shrimp (Artemia salina)

Optimization of antibiotic delivery strategies to aquatic environment and to the specific characteristics of the target species is essential for the improvement of bacterial infection control measures. This work aimed at standardizing the use of Artemia salina to deliver flumequine to fish as antimicrobial treatment. Adult Artemia were used to bioencapsulate flumequine. A flumequine concentration of 358 μg mL⁻¹ was found adequate to perform bioencapsulation during 24 h without causing mortality. Antibiotic concentration in Artemia, quantified by means of a microbiological assay based on MIC determination, using Escherichia coli ATCC 25922 as control strain was 256.55 mg g⁻¹ (±71.22). The therapeutic doses of 10 mg kg⁻¹ BW, calculated on the basis of a consumption of about 4% BW/day, would then be delivered by the consumption of 7.8 Artemia g⁻¹ of fish.     

Bioencapsulation of five forms of erythromycin by adult Artemia salina (L.)

Uptake of five chemical forms of erythromycin by adult Artemia salina (L.) (erythromycin phosphate – EP, erythromycin stearate – ES, erythromycin estolate – EE, erythromycin hydrate – EH and crystalline erythromycin – CE) was investigated in two trials. In each trial, final erythromycin concentration in Artemia tissue and survival after a 12‐h bioencapsulation period were determined. In the first trial, Artemia tissue concentration after a 12‐h bioencapsulation period was significantly (P < 0.05) affected by erythromycin form with ES (68.5 ± 3.3 μg mL^?1, mean ± SEM) ≈ EH (61.2 ± 3.4 μg mL^?1) > CE (37.1 ± 10.7 μg mL^?1) > EP (16.4 ± 7.7 μg mL^?1) > control. In trial 2, Artemia tissue concentration was also significantly (P < 0.05) affected by erythromycin form with EE (111.4 ± 9.6 μg mL^?1) > CE (89.1 ± 1.7 μg mL^?1) > ES (78.9 ± 1.6 μg mL^?1) > EP (33.4 ± 5.2 μg mL^?1) > control. Survival was significantly affected by erythromycin form in trial 1 with EP=control (100 ± 0.0%) > ES (74.4 ± 2.0%) > CE (32.2 ± 0.3%) > EH (8.8 ± 4.4%). In trial 2, survival was also significantly affected by erythromycin form with EP=control (100 ± 0.0%) > ES (67.1 ±3.7%) > CE (52.5 ± 7.7%) > EE (5.0 ± 2.5%). Based on both uptake and survival, EP and ES appear to be appropriate compounds for bioencapsulation of erythromycin using live adult Artemia.     

Influence of different diets on the growth,survival, fecundity and proximate composition of brine shrimp Artemia franciscana (Kellog, 1906)

Artemia franciscana was studied under in vitro conditions, and fed with five different microalgae species, two organic diets and one mixed diet to evaluate the nutritional profile and growth performance. The A. franciscana instar‐I nauplii were stocked at a density of 100 per litre of ground borewell water with a salinity of 70 ppt in a plastic container and the culture continued for 12 days. The A. franciscana was fed with five microalgal species, such as Tetraselmis sp., Chaetoceros sp., Isochrysis sp., Thalassiosira sp. and Nannochloropsis sp., and organic diets of rice bran, soybean meal, and a mixture of Tetraselmis sp. and Chaetoceros sp. with rice bran, giving a total of eight experiments. The growth of A. franciscana was measured by length, and was observed to be the greatest (10,850 μm) in the group that was fed the mixed algae combination, and the lowest (7,290 μm) in the group that was fed Nannochloropsis sp. Among the different treatments, the highest survival value of 76% was seen in the group that was fed Chaetoceros sp. The fecundity was higher in A. franciscana that were fed with algae Chaetoceros sp., while the lower rate was observed with the group that was fed Nannochloropsis sp. Analysis of proximate composition showed increased levels in the animals fed with Chaetoceros sp. (lipid, 19.40%; eicosapentaenoic acid, 6.70 mg; docosahexaenoic acid, 10.20 mg; amino acids: proline, 2.06 μg; histidine, 0.77 μg, arginine, 0.65 μg, glycine, 0.80 μg, glutamic acid, 1.75 μg; threonine, 1.42 μg) and the mixed diet (protein, 58.59%; carbohydrate, 21.30%; amino acids: asparagine, 0.90 μg; serine, 1.65 μg; tryptophan, 1.66 μg; leucine, 1.50 μg; phenylalanine, 1.14 μg; valine, 0.66 μg). All components showed the lowest level in the diet fed with Tetraselmis species. These A. franciscana populations showed better survival, higher fecundity and biochemical profiles when cultured with microalgae Chaetoceros sp. These data are useful to improve A. franciscana culture in aquaculture to produce quality cysts and biomass, especially in feeding larvae of marine species.     

Bioencapsulation and pharmacokinetic study of oxolinic acid in rotifers (Brachionus plicatilis), Artemia franciscana nauplii and metanauplii

The uptake of oxolinic acid by the rotifer Brachionus plicatilis, Artemia franciscana nauplii and metanauplii was studied as a function of its concentration in the enrichment medium and the duration of the enrichment period. An emulsion containing 5, 10, 20 or 30% (w/w) oxolinic acid was administered and the enrichment period lasted 4, 8, 12 or 36 h. Highest incorporation of oxolinic acid was achieved using a 20% emulsion and a 12 h enrichment for rotifers (205.05 ± 17.1 μg g^?1 dry weight), a 24 h enrichment for nauplii (2528.8 ± 254.6 μg g^?1 dry weight), and an 8 h enrichment for metanauplii (1236.58 ± 22.9 μg g^?1 dry weight). Higher concentrations of oxolinic acid in the enrichment emulsion or longer enrichment times resulted in decreased survival. Two hours post enrichment the contents of the drug appeared significantly decreased. The concentration data of oxolinic acid were best fit to a two phase exponential elimination model, the first phase elimination half‐life (t_1/2α) being 1.86, 1.08 and 1.74 and the terminal phase elimination half‐life (t_1/2β) 26.83, 29.67 and 17.48 in rotifers, nauplii and metanauplii correspondingly. Enrichment with an emulsion containing 20% oxolinic acid is recommended employing a duration of 12, 24, or 8 h enrichment for rotifers, nauplii and metanauplii respectively, while enriched carriers should be used shortly after enrichment.     

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．     

Efficacy of selection in sexually breeding Artemia (Artemia franciscana,Kellogg, 1906)

Bi‐directional selection for smaller naupliar size (SNS) and bigger naupliar size (BNS) was practiced to develop two divergent lines. The efficacy of bi‐directional mass selection in Artemia franciscana was evaluated by comparing the predicted genetic gains with the realized genetic gains. Two sets of predictions were made using two heritability estimates, e.g., the heritability estimate from full‐sib analysis (h²) and the estimate from regression of offspring on mid parent (b_op). Predictions with the full‐sib heritabilities were of very high magnitude as compared with predictions with b_op heritabilities. The predictions based on b_op were more or less in agreement with realized genetic gain, while the predictions with heritability estimates based on full‐sib analysis were much higher than the realized gains. Ratios of realized gain to predicted gain based on full‐sib heritabilities were 0.2302 and 0.2152, respectively, for males and females of the SNS line, and 0.0471 and 0.2248, respectively, for males and females of the BNS line. Ratios of realized gain to predicted gain based on b_op were 1.5348 and 0.6069 for males and females of the SNS line and 0.1028 and 0.9503 for males and females of the BNS line. Ratios of realized gain to predicted gain based on full‐sib heritability were of low magnitude in all the cases as the heritability estimates based on full‐sib analysis were inflated by non‐additive genetic variance. The ratios of realized gain to predicted gain based on b_op were high in both sexes of SNS and females of BNS, indicating high efficacy of selection as b_op includes only additive genetic variance. However, it was of low magnitude in BNS males. Thus, the heritability estimates based on regression of offspring on mid parent (b_op) are more reliable than that of heritability estimates based on full‐sib analysis (h²) for predicting the selection response in Artemia.     

Data envelopment analysis for production efficiency improvement: An empirical application on brine shrimp Artemia franciscana culture in the Mekong Delta,Vietnam

Artemia culture in the Mekong Delta, Vietnam, is becoming more and more important to satisfy the global demands of cyst production. Nevertheless, Artemia cyst productivity in the Mekong Delta has been fluctuating largely due to not only technical inefficiencies and external factors but also farms’ characteristics. This study employed a data envelopment analysis to evaluate the production efficiencies in correlation with biological and cost inputs of Artemia culture in Vinh Chau and Bac Lieu located in the Mekong Delta. The key factors affecting technical efficiency (TE) were determined using ordinary least squares regression model. The empirical results indicated that production efficiencies of farms in Vinh Chau and Bac Lieu were similar with metatechnology ratios of 0.97 and 0.96 respectively. About 62.8% of surveyed farms were operating in technically inefficient circumstances. Farmers’ experience, educational level and culture technique training participation had positive effects on TE, while climate effects and water problems have been proved to have negative effects on TE. To improve production efficiency, inefficient farms are suggested to have moderately increasing combinations of organic fertilizer, chemical and feed. The use of probiotics should be reduced as it increases production cost and affects TE. Notably, a collaboration of scientists and feed processing companies is recommended to produce a specific formulated feed for Artemia in commercial scales. This study also proposes adaptive policies for local governments and cooperatives to assist coastal famers in the Mekong Delta overcome technical inefficiencies, improve cyst productivity and obtain economic sustainability in Artemia culture.     

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.     

稀土元素镧Ⅲ对海水卤虫孵化率及变态率的影响

本文研究了单一稀土镧元素对海水卤虫孵化率、变态率、成虫率的影响及卤虫对镧元素的吸收.实验发现:1.8mg/L镧元素实验组比对照提高孵化率16.5％,且二者之间有显著性差异(P<0.05);0.3～0.9mg/L实验组可提高由无节幼体变为蚤扶幼体的变态率57.3～57.8％,它们与对照组之间存在着显著性差异(P<0.01);1.5mg/L、1.8mg/L两实验组比对照组提高成虫率12.0～13.0％,差异显著(P<0.05)。     

Evaluation of different concentrations of adult live Artemia (Artemia franciscana,Kellogs 1906) as natural exogenous feed on the water quality and production parameters of Litopenaeus vannamei (Boone 1931) pre-grown intensively

A 7-week experimental study was performed to evaluate the effect of five concentrations of adult live Artemia (0, 1, 2, 3 and 4 L⁻¹) as exogenous natural feed on the water quality and production parameters of juvenile (0.2 ± 0.01 g) shrimp (Litopenaeus vannamei) pre-grown intensively (125 organism m⁻²) under laboratory conditions (80 L plastic tanks). No significant differences were observed in the environmental variables among treatments. Total ammonium nitrogen, nitrates and phosphates recorded higher concentrations in all the treatments using artemia, as compared with the treatment without Artemia. In all the cases, the levels remained within or close to the ranges considered necessary for the farming of the species. The highest weight gain and biomass were obtained in the treatments with 3 and 4 Artemia L⁻¹. The best feed conversion ratio were recorded using 2 Artemia L⁻¹ and the highest with 0 Artemia L⁻¹. No differences in survival were detected among treatments. The greatest concentrations of nitrogenous metabolites achieved at the highest densities of Artemia were lower than the LC₅₀ for penaied shrimp and no negative effect was observed on the survival of the shrimp. These results clearly indicate that the use of adult live Artemia as exogenous natural feed significantly increased the production parameters of the Pacific white shrimp.     

Phenotypic estimates and heritability values of Artemia franciscana

Artemia, in all stages of its life cycle, is suitable food for most diversified groups of aquatic animals. Although its size at different stages restricts its use as a food for some groups of fish, this problem can be overcome using selective breeding techniques. The formulation of any selective breeding programme calls for a proper understanding of the genetic architecture of the economically important traits of the population under study. Thus, heritability for certain important life history and reproductive traits was estimated in Artemia franciscana from the Great Salt Lake, Utah. In the present study, the sexwise heritability values for growth and reproduction traits were estimated using parent–offspring regression. The phenotypic parameters for the same traits are also recorded. The naupliar length was 487.0±2.0 and 490.6±1.8 μm for males and females, respectively, whereas the heritability values for naupliar length were 0.5851±0.2153 and 0.3766±0.1899 respectively. The length at 3 and 6 days of age were 1.87±0.03 and 4.10±0.08 mm, respectively, for males whereas 1.87±0.03 and 4.30±0.08 mm, respectively, for females. The heritability values for length at 3 and 6 days of age for males were 0.3272±0.3651 and 0.4965±0.2466, respectively, whereas the respective values for the females were 0.1167±0.3841 and 0.0222±0.2971. The estimates of length at first brood, pre‐reproductive period and number of offspring in first brood were 10.09±0.23 mm, 16.00±0.23 days and 53.57±1.37 days, respectively, whereas the heritability values for respective traits were 0.0403±0.1078, 0.3234±0.2874 and 0.3404±0.2202.     

Feeding Artemia franciscana (Kellogg) larvae with bacterial heat shock protein, protects from Vibrio campbellii infection

Among their numerous physiological effects, heat shock proteins (Hsps) are potent immunomodulators, a characteristic reflecting their potential as therapeutic agents and which led to their application in combating infection. As an example, the up-regulation of endogenous Hsp70 in the branchiopod crustacean Artemia franciscana (Kellogg) is concurrent with shielding against bacterial infection. To better understand this protective mechanism, gnotobiotic Artemia were fed with Escherichia coli treated to over-produce different prokaryotic Hsps. This was shown to increase larval resistance to experimental Vibrio campbellii exposure. Immunoprobing of Western blots showed that the enhanced resistance to V. campbellii correlated with DnaK production in E coli . A definitive role for DnaK was then demonstrated by feeding Artemia larvae with transformed bacteria over-producing only this protein, although other Hsps such as DnaJ and grpE also provided tolerance against Vibrio infection. Feeding of bacteria synthesizing selected Hsps is therefore suggested as an alternative to antibiotic use as a means of enhancing resistance of Artemia larvae to bacterial infection, which may have potential applications in aquaculture.     

Effects of different salinities on amino acid profile in Artemia franciscana

The effects of different salinity levels, including 10–15, 30–35, 70–75, 110–115 and 150–155 ppt, were evaluated on survival and the body amino acids (BAA) of Artemia franciscana. The results were expressed as total essential (TE), non‐essential (NE) and total amino acids (TAA); also, the ratio of the TE to NE (ENAA) on days 3 and 13 of the culture is reported. The study of changes in Artemia BAA showed that with the increase in the water salinity, the TE, NE and TAA increased significantly on days 3 and 13 of the culture. However, the highest ratio of ENAA was observed in the 110 gL^?1 salinity treatment on day 3 (1.067 ± 1.25). Regarding the effects of different salinity treatments on the survival rate of Artemia, it was observed that, generally, an increase in the water salinity would reduce the survival rate of this species. This reduction was observed on day 3 of culture in the salinity treatments above 120 (66.66 ± 1.68%) and below 30 gL^?1 (89.66 ± 0.34%) and on day 13 of culture in the salinity treatments below 30 (11.86 ± 0.13%) and above 70 gL^?1. Basically, it can be concluded that A. franciscana culture at a salinity of 110 gL^?1 can lead to the biological enrichment of Artemia in terms of amino acid profile.     

Growth and lipid composition of Atlantic cod (Gadus morhua) larvae in response to differently enriched Artemia franciscana

Considerable progress has been achieved in the intensive culture of Atlantic cod (Gadus morhua). However, there is little information concerning optimum live-feed enrichments for cod larvae, since many of the techniques used during the larviculture have been borrowed from other fish species and adapted for the production of Atlantic cod. The present study compared four different protocols for the enrichment of Artemia to be used as live feed for cod larvae. The protocols tested were: (1) AlgaMac 2000, (2) AquaGrow Advantage, (3) Pavlova sp. + AlgaMac 2000, and (4) DC DHA Selco + AlgaMac 2000. Larvae were fed differently enriched Artemia between 37 and 59 days post hatch. At the end of the experiment, larvae from treatment 1 [specific growth rate (SGR) = 10.4 ± 0.4% day⁻¹] grew faster than larvae from treatments 3 (SGR = 6.9 ± 0.2% day⁻¹) and 4 (SGR = 4.9 ± 0.4% day⁻¹, P < 0.0001). However, treatments 3 and 4 resulted in better larval survival at the end of the experimental period, estimated to be 3 on a scale from 1 to 5, whereas the survival estimates for the two other groups were 2. The treatments affected the fatty-acid composition of Artemia and of cod larvae. Larvae from treatment 1 had a higher percentage of AA (20:4ω6, P < 0.0001) and ω6DPA (22:5ω6, P < 0.0001) than the other larvae. Levels of DHA (22:6ω3) were similar in larvae from treatments 1 and 4, and higher than in the other larvae (P < 0.0001). Our results suggest that Artemia containing a DHA/EPA/AA ratio of 7/2/1 result in good larval performance. Joseph A. Brown—Deceased September 2005.     

Uptake of erythromycin by first-feeding sockeye salmon,Oncorhynchus nerka (Walbaum), fed live or freeze-dried enriched adult Artemia or medicated pellets

The potential to use adult Artemia to deliver erythromycin to first-feeding sockeye salmon, Oncorhynchus nerka (Walbaum), was investigated in three trials. In the first trial, first-feeding sockeye were fed live erythromycin enriched adult Artemia or pellets containing equal amounts of erythromycin for 35 days. At the end of the trial, tissue erythromycin concentration of the fish fed the live Artemia was significantly greater (P < 0.05, 25.52 +/- 1.29 microg mL(-1); mean +/- SEM), than the tissue concentration of the fish fed the pellets (0.72 +/- 0.01 microg mL(-1)). In the second trial, first-feeding sockeye were fed either live or freeze-dried bioencapsulated erythromycin (adult Artemia) or pellets containing erythromycin daily for 21 days. Mean daily erythromycin concentration in fish fed the freeze-dried Artemia, live Artemia, or pellets did not differ significantly. In the third trial, apparent erythromycin digestibility was determined. Significantly more (P < 0.05) erythromycin was retained by juvenile sockeye fed freeze-dried bioencapsulated erythromycin (98.3 +/- 1.0%) compared with medicated pellets (89.2 +/- 1.7%). Uptake of bioencapsulated erythromycin from adult Artemia (live or freeze-dried) appears to be greater than uptake from pellets. Freeze-dried and live Artemia were equally effective at delivery suggesting enriched freeze-dried adult Artemia could be produced into a highly palatable, consistent, off-the-shelf product.     

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。     

Chemical Decapsulation of Artemia franciscana Resting Cysts Does Not Necessarily Produce More Nauplii

Decapsulation of Artemia spp. cysts in strong hypochlorite solutions reportedly increases the number of nauplii that hatch. Commercial cysts of Artemia franciscano were subjected to four decapsulation methods prior to hatching them in aerated seawater. Samples were removed from the hatch vessels every 5 h from 15 through 45 h, and fully hatched nauplii were counted. The experiment was performed three times. No significant difference was seen between mean numbers of control nauplii and nauplii obtained using the decapsulation method that yielded the best hatch: oxidation for 15 min in equal parts Clorox® and seawater plus 6 mL of a 40% NaOH solution, followed by reduction with 100 mL of 0.7 M sodium thiosulfate. A third treatment was inferior to either of these, and two others produced very low yields. It was concluded that of the methods evaluated, none is superior to no treatment at all, and some are clearly detrimental to developing Artemia embryos.     

盐湖卤虫卵的开发利用

着重介绍了卤虫卵的采收、贮藏、加工方法,阐述了影响卤虫卵孵化率的一些因素,以达到利用盐湖卤虫卵的目的。     

高效液相色谱法测定卤虫无节幼体中精胺含量

本研究建立了高效液相色谱法测定卤虫无节幼体中精胺含量的方法。样品经5％三氯乙酸溶液提取,提取液采用丹璜酰氯柱前衍生,以甲醇一水为流动相,经C18反相色谱柱分离后用紫外检测器检测。精胺的线性范围为0．1～1000μg/ml,线性相关系数为0．9999,检出限为0．06μg/ml。3个添加浓度（0。1、1．0和5.0μg/m1）的平均回收率为86．3％～96.39/6,相对标准偏差皆小于59/6。采用此方法对卤虫中精胺进行检测,其精胺含量为0．077mg/g。本方法具有分析时间短、线性范围宽、灵敏度和精密度高等优点,适合于卤虫中精胺的检测．     

Using residual water from a marine shrimp farming BFT system. Part II: Artemia franciscana biomass production fed microalgae grown in reused BFT water

The residual water from intensive aquaculture production systems can be utilized in integrated multitrophic cultivations. In this work, Artemia franciscana received daily feedings of 10 mg L^?1 of Tetraselmis chuii, Nannochloropsis oculata and Chaetoceros muelleri, which were grown using residual water from an intensive biofloc Litopenaeus vannamei cultivation system. The goal of this study was to verify which species provide the best zootechnical performance and best crustacean biomass production efficiency. After 12 days of cultivation, A. franciscana wet biomass was 815.64 ± 18.74, 650.81 ± 83.98 and 40.76 ± 4.08 mg L^?1 with C. muelleri, T. chuii and N. oculata (P < 0.05), with significant differences in dried biomass as well. As for the microalgae cultivation in the alternative culture medium, T. chuii had higher dry biomass gain, requiring less culture volume to achieve 10 mg L^?1 and become ready to feed Artemia. Thus, T. chuii was the most efficient in Artemia biomass production with 0.83 L compared to 1.54 L g art^?1 in C. muelleri. C. muelleri is recommended for feeding A. franciscana for biomass production purposes. However, due to its better efficiency, T. chuii can be selected to be part of a multitrophic system.