Effects of enriched Artemia nauplii on production, survival and growth of the mysid shrimp Mysidopsis almyra Bowman 1964 (Crustacea: Mysidacea)

The effects of enriched Artemia nauplii on larvae production and survival and growth of the mysid Mysidopsis almyra Bowman 1964 are compared. There were no significant differences (P > 0.05) in production between mysids fed the Artemia nauplii (133 ± 69 mysids day⁻¹) and mysids fed the enriched nauplii (139 ± 82 mysids day⁻¹). No differences in size of newly hatched mysids or mysid growth to 15 days (P > 0.05) were found between the two diets. Survival was significantly higher (P < 0.05) for mysids fed the enriched nauplii (59.1%) compared with mysids fed Artemia nauplii (41.4%).     

The use of Artemia sp. or mysids as food source for hatchlings of the cuttlefish (Sepia officinalis L.); effects on growth and survival throughout the life cycle

Twoexperiments were conducted to determine the effects ofArtemia sp. or mysids on growth and survival ofS. officinalis hatchlings, and their effect throughout thelife cycle. For experiment I, for the first 20 days, one group was fed adultArtemia sp. and the other was fed mysid shrimp(Paramysis nouvelli). Eggs laid by females in both groupswere counted and weighed, and hatchlings were weighed, to determine differencesin both groups. For experiment II, during the first 10 days, one group was fedArtemia sp. and the other was fed mysids (P.nouveli). After the period of differentiated feeding, the 2 groupsinexperiment I were fed grass shrimp (Paleomonetes varians)to 70 days old, and dead crabs (Carcinus maenas)afterwards. Cuttlefish in experiment II were fed grass shrimp from day 10 untilthe end of the experiment. For both experiments, hatchlings fed mysids grewsignificantly bigger (p < 0.01) and survival was higher. For experiment I,eggs laid by females fed mysids and the hatchlings born from these eggs werebigger (p < 0.001) compared to the group fed Artemiasp.initially. Individual fecundity was slightly higher for females in the groupfedArtemia sp. (163 eggs female^–1) than forthe group fed mysids (144 eggs female^–1). Egg laying startedatthe age of 125 days and lasted 45 days in both groups. Time between first egglaying day and first hatchlings to be born was 21 days. The last female to die(after spawning) in both groups was 167 days (less than 6 months old).     

Lipid classes and fatty acids during embryogenesis of captive and wild silverside (<Emphasis Type="Italic">Chirostoma estor estor</Emphasis>) from Pátzcuaro Lake

Lipid classes and fatty acid levels were analyzed in freshly fertilized eggs, early and late embryo development, and freshly hatched larvae obtained from wild and captive silverside Chirostoma estor estor broodstock, as well as in plankton, Artemia, and pelleted feed. The concentration of triglycerides (TGs) and highly unsaturated fatty acids (HUFAs) in neutral lipid fraction significantly decreased during early development and especially after hatching, whereas phospholipids and HUFA in polar lipid fraction remained constant. These results indicate that TGs rather than PLs are used as energy sources and that all HUFAs [20:4n-6/arachidonic acid (ARA), 20:5n-3/eicosapentaenoic acid (EPA), and 22:6n-3/docosahexaenoic acid (DHA)] of polar lipids are selectively conserved during early development. High levels of DHA (30%, on average, of total fatty acids) and low levels of EPA (4%) were observed in eggs, embryos, and larvae and did not reflect the proportions of these fatty acids in food. Preferential accumulation of DHA from food consumed by broodstock, and then transference to eggs, was probably occurring. The main difference between eggs from both origins was a low level of ARA in eggs from captive fish (4% of total fatty acids) compared to wild fish (9%). This could be associated with a deficiency in the diet that is not compensated for by desaturation/elongation of 18:2n-6 and, possibly, with greater stress in captive fish. In any case, particular requirements of ARA should be determined to optimize the culture of C. estor.     

Development of a broodstock diet to improve developmental competence of embryos in European eel,Anguilla anguilla

We examined the effect of dietary arachidonic acid (ARA) and eicosapentaenoic acid (EPA) on the production of embryos and hatched larvae in the European eel, Anguilla anguilla. Two diets with high and intermediate levels of ARA and low and intermediate levels of EPA (Feed 1: ARA 1.9%, EPA 4.2%; Feed 2: ARA 1.2%, EPA 5.1% of total fatty acids) were tested against a commercial diet (DE: ARA: 0.5%, EPA: 8.2% of total fatty acids). After 24 weeks of feeding, ARA levels in the muscles and ovaries increased to 0.9% and 1.3% of total fatty acids, respectively, in Feed 1 and were significantly higher than in Feed 2 and DE. Female broodstock was not fed during hormonal treatment to induce vitellogenesis and ovulation. EPA levels in females fed the test diets decreased in the both muscle and ovary and were significantly lower in eggs from females fed Feed 1. The highest percentage of stripped females, producing viable eggs and larvae, were those females fed the highest dietary ARA levels (Feed 1). The level of lipid peroxidation products in eggs was similar among treatment, indicating that the lowest dietary levels of vitamin C and vitamin E were sufficient. In the unfertilized eggs, ARA levels were also highest (1.1% of total fatty acids) in the diet with highest ARA levels (Feed 1).     

Growth and lipid composition of phyllosomata of the southern rock lobster, Jasus edwardsii, fed enriched Artemia

Newly hatched phyllosoma larvae of Jasus edwardsii were on‐grown to stage V. Using triacylglycerol‐rich marine oil nutrient sources and microalgae, Artemia were enriched with the major polyunsaturated fatty acids (PUFA) to ratios similar to that of wild‐caught phyllosomata. Artemia enriched by different methods were fed to cultured phyllosomata. At each stage animals were counted, measured and sampled for lipid analyses. Survival was highest from stages II to III (62–86%), with mean total survival at 3–12%. From stages I to V larvae increased in mass (0.2–2.2 mg) and total length (2.1–5.8 mm), and decreased in total lipid. The major lipid class in all phyllosomata was polar lipid, followed by sterol, with no triacylglycerol detected. The main fatty acids were 18:1(n‐9)c, 18:2(n‐6), 16:0, 18:0, eicosapentaenoic acid [EPA; 20:5(n‐3)], 18:1(n‐7)c, arachidonic acid [AA; 20:4(n‐6)] and docosahexaenoic acid [DHA; 22:6(n‐3)]. On‐grown phyllosomata had levels of AA and EPA similar to that of wild phyllosomata, but contained markedly lower levels of DHA. Strategies for enhancement of DHA levels will be needed for culture of rock lobster phyllosomata.     

Effects of salinity on osmoregulation during the embryonic development of the bullseye puffer (Sphoeroides annulatus Jenyns 1842)

To evaluate the effect of salinity on the hatching rate, hatching time, survival percentage, osmoregulation pattern and the incidence of abnormalities in newly hatched larvae, embryos of Sphoeroides annulatus (Jenyns 1842) were exposed to 5, 12, 19, 26, 33, 35 and 40 psu. The hatching percentage (HP), survival percentage (PS), normal larvae (PN), deformed larvae (PD) and hatching time (HT) were significantly affected by salinity (P < 0.05). The embryos exposure to 5 psu caused that HP, PS, and PN had lower values (2.6 ± 0.32, 7.78 ± 0.88 and 70.37 ± 7.75% respectively), PD and HT had the highest values 26.67 ± 7.54% and 55.53 ± 0.59 h respectively. However, the survival of newly hatched larvae was not possible in 5 ups, though it was in 40 ups. Osmotic pressure (OP) remained constant in each salinity, whereas isosmotic points changed from 435.5 mOsm kg^?1 in 21 h post fertilization to 342.8 mOsm kg^?1 at 47 h post fertilization, obtaining a pattern of hyper‐osmoregulation at lower salinities and hypo‐osmoregulation in higher salinities. This study is the first carried out on embryos of this species; therefore, the obtained information is essential to improve strategies and growing conditions in their initial development.     

Frozen mysids as an alternative to live Artemia in culturing seahorses Hippocampus abdominalis

This investigation examined the effects on growth and survival of seahorses Hippocampus abdominalis Leeson 1827 fed a 25% body weight (wet weight) daily ration of live Artemia sp. enriched with Algamac‐3050, frozen mysids Amblyops kempi or a combination of live enriched Artemia and frozen mysids. After 3 months there was no difference in seahorse length, wet weight, condition factor (CF), or food conversion ratios (FCR) between the treatments. Mean daily specific growth rate (SGR) was higher for the Artemia‐only treatment than for the mysid‐only treatment (P<0.05). FCRs ranged from 6.14 g to 8.72 g dry weight of food required to give a 1‐g dry weight increase in seahorses. There was no difference in survival between treatments. Fatty acid analysis revealed that mysids had a higher percentage composition of EPA, 20 : 5n‐3, and DHA, 22 : 6n‐3, but a lower composition of AA, 20 : 4n‐6, than enriched Artemia. Percentage n‐3 highly unsaturated fatty acids (HUFAs) in mysid levels were approximately twice that of Artemia. Proximate analysis revealed mysids to be higher than the enriched Artemia in protein and fats, and lower in water content. This experiment demonstrates that, although no growth advantage was derived from the use of frozen mysids, they can be used successfully as an alternative food to live enriched Artemia for H. abdominalis. The use of frozen mysids is highly recommended in commercial seahorse culture if the seahorses are to be sold into the live aquarium trade, as this may increase their chances of survival after sale.     

Effect of salinity on reproductive performance of Acanthopagrus latus (Houttuyn) in spawning tanks

More than 250 male and female yellowfin seabream (Acanthopagrus latus) were caught in the creeks near the Mahshar area in the north‐west of Persian Gulf using fishhooks to study the effects of salinity on reproductive indices. The experiments were carried out using three salinity treatments (30 ± 1 g L^?1, 35 ± 1 g L^?1 and 40 ± 1 g L^?1) with three replications. A total of six males and three females were randomly introduced to each tank. The survival rate of the broodstock was estimated at more than 90% at different salinity levels and the maximum rate was observed at 30 g L^?1 of the experiment rate. The percentage of buoyant eggs was more than 90% at 40 g L^?1 and it was significantly different from other treatments. The average number of eggs per female (312 914 ± 65 085), and the average number of eggs per kilogram of female (649 460 ± 173 574) at 40 g L^?1 were more than those in the other treatments but no significant differences were observed (P ≤ 0.05). The average percentage of fertilized eggs (86.7%) and the average percentage of hatched larvae (67%) at 40 g L^?1 treatment was more than those at 30 g L^?1 and 35 g L^?1 treatments but no significant differences were observed (P ≤ 0.05). At 40 g L^?1 salinity, in all spawning cases, the released eggs were hatched. Overall, the present study has shown that better buoyant eggs of A. latus can be obtained at salinity 40 g L^?1. On the other hand, the percentage of fertilized eggs and hatched larvae were not affected by salinity.     

Evaluation of First-Feeding Regimens for Larval Nassau Grouper Epinephelus straitus and Preliminary, Pilot-Scale Culture through Metamorphosis

Two 10-day hatchery experiments were conducted to evaluate s-type (Hawaiian strain) and ss-type (Thailand strain) rotifers Brachionus plicatilis and cryogenically preserved oyster Crassostrea gigas trochophores as first feeds for larval Nassau grouper Epinephelus striatus. Newly hatched grouper larvae were reared at densities of 11.2–20.8/L in 500-L tanks at 36–38 ppt salinity, 25–26 C, and under a 11-h light: 13-h dark photoperiod. Beginning on day 2 posthatching (d2ph), prey were maintained at a density of 20 individuals/mL, while phytoplankton (Nanochloropsis oculata) was maintained at 500 × 10³ cells/mL. In experiment 1, survival and growth were higher (P < 0.05) for fish fed small s-type rotifers (mean lorica length = 117 μm; fish survival = 7.96%) selected by sieving than for fish fed non-selected rotifers (mean lorica length = 161 μm; fish survival = 2.13%). These results demonstrated the advantage of small prey size and suggested that super-small (ss-type) rotifer strains would be beneficial. In experiment 2, three feeding regimens were compared: 1) ss-type rotifers (mean lorica length = 147 μm); 2) oyster trochophores (mean diameter = 50 μm) gradually replaced by ss-type rotifers from d5ph; and 3) a mixed-prey teatment of 50% oyster trochophores and 50% ss-type rotifers. Survival was higher (P < 0.05) for larvae fed mixed prey (15.6%) than for those fed rotifers (9.73%) or trochophores and rotifers in sequence (2.55%), which also showed the slowest growth. Oyster trochophores, although inadequate when used exclusively, enhanced survival when used in combination with rotifers, possibly by improving size selectivity and dietary quality. In a pilot-scale trial, larvae were cultured through metamorphosis in two 33.8-m³ outdoor tanks. Fertilized eggs were stocked at a density of 10 eggs/L and larvae were fed ss-type rotifers from d2ph-d20ph, newly hatched Artemia from d15ph-d18ph, 1-d-old Artemia nauplii from d18ph-d62ph. Survival on d62ph was 1.17%, with a total of 5,651 post-metamorphic juveniles produced.     

黄颡鱼早期发育阶段受精卵和鱼体脂肪酸组成变化

研究了黄颡鱼受精卵孵化期间和仔鱼发育阶段脂肪含量和脂肪酸的组成变化规律.采用常规化学分析方法和气相色谱法对黄颡鱼从鱼卵受精开始至仔鱼孵化后未投饵的7 d内的脂肪含量和脂肪酸组成进行测定.结果表明,受精卵在整个孵化期间脂肪含量有下降趋势.受精卵中不饱和脂肪酸含量大于饱和脂肪酸含量.受精卵在整个孵化期间各种脂肪酸含量无明显变化.仔鱼孵化后,鱼体总脂肪含量急剧下降,总脂含量从0日龄的4.57%降低到7日龄的0.75%.仔鱼在饥饿期间鱼体脂肪酸组成发生明显变化,单不饱和脂肪酸含量下降最为明显,尤其是C18:1.仔鱼在饥饿期间,脂肪酸按n-9>n-6>n-3顺序被先后利用,黄颡鱼仔鱼发育阶段主要以单不饱和脂肪酸作为能量代谢基质,而C20:4n6(AA)和C22:6n3(DHA)优先于C20:5n3(EPA)被保存下来.     

Optimal first feed organism for South African mud crab <Emphasis Type="Italic">Scylla serrata</Emphasis> (Forskål) larvae

It is not known whether rotifers or Artemia nauplii are the best first food for South African mud crab Scylla serrata larvae. In order to test this, larvae were fed with five different test diets. These were rotifers for the first 8 days and newly hatched EG^® type Artemia nauplii (San Francisco Bay) from day 6 onwards (treatment R6A); newly hatched EG^® type Artemia nauplii throughout the rearing period (treatment EG); newly hatched Vinh-Chau strain (Vietnam) Artemia nauplii throughout the rearing period (treatment VC); decapsulated cysts of EG^® type Artemia throughout the rearing period (treatment DECAP); or decapsulated cysts supplemented with low densities of Artemia EG type Artemia nauplii (treatment MIX). Two experiments were conducted approximately 1 month apart using larvae from two different female crabs. Although results showed it is possible to rear S. serrata larvae through metamorphosis on Artemia nauplii exclusively, larval performance (development, survival and successful metamorphosis) was enhanced by the inclusion of rotifers as a first feed.No significant difference in performance was recorded between larvae fed on the two strains of Artemia nauplii. Larvae fed on decapsulated cysts in treatments DECAP and MIX performed poorly, but there were indications that decapsulated cysts and other inert diets may have potential as supplements to live food in the rearing of S. serrata larvae.     

Rearing techniques and nutritional quality of two mysids from Gran Canaria (Spain)

This paper presents the preliminary results of different trials carried out with two species of mysids from Gran Canaria: Leptomysis lingvura (G.O. Sars, 1866) and Paramysis nouvel. Experiments lasting 21 days showed significantly higher fecundity and survival in L. lingvura than in P. nouveli (P<0.05). We also report the biochemical profile of both species fed 48‐h‐Artemia nauplii enriched with Easy‐DHA‐Selco^® for 7 days. A comparison of our results with those of for Artemia and rotifers, organisms frequently used as live food in aquaculture, showed that mysids have a high percentage of protein per dry mass (73.38% in P. nouveli, and 74.19% in L. lingvura). Furthermore, the percentage of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (AA) in total fatty acids was higher in both species than that reported by Roo and colleagues for rotifers and Artemia. In addition to the content of these fatty acids, their ratios between them are also important for normal growth and larval development. We found that the ratio, DHA:EPA, was 0.85 0.02 and 0.89 0.01; the ratio, DHA: AA, 6.25 0.26 and 4.74 0.14; and the ratio, EPA:AA, 7.32 0.26 and 5.32 0.2, respectively, for P. nouveli and L. lingvura in cultures and these ratios do not significantly differ (P>0.05) from organisms in the wild. Here, we argue that as mysids are prey for many commercially important fish, cephalopods and rays, it is likely that the biochemical composition of mysids in their natural environment is “optimal” for these predators. Therefore, we studied the lipid profile of both species as they naturally occur in their environment. The results indicate that these mysids could be used to develop high quality live fish food.     

Change in nutrient composition of Artemia grown for 3–4 days and effects of feeding on‐grown Artemia on performance of Atlantic halibut (Hippoglossus hippoglossus,L.) larvae

Major challenges in culture of Atlantic halibut larvae have been slow growth during the late larval stages and inferior juvenile quality due to pigmentation errors and incomplete eye migration during metamorphosis. The hypothesis of this study was that feeding on‐grown Artemia would alleviate these problems. Artemia were grown for 3–4 days on Origreen or Origo. The growth and nutrient composition of Artemia nauplii and on‐grown Artemia were analysed, and both Artemia types were fed to Atlantic halibut larvae, on‐grown Artemia from 15 days post‐first feeding (dpff). The body length of Artemia increased with 20%–70% in response to on‐growing. In all experiments, protein, free amino acids and the ratio of phospholipid to total lipid increased, while lipid and glycogen decreased. The fatty acid composition improved in some cases and not in others. The micronutrient profiles were not negatively affected in on‐grown Artemia. All these changes are thought to be beneficial for marine fish larvae. The final weight of Atlantic halibut postlarvae was similar, and 90% of the juveniles had complete eye migration in both groups. It is concluded that the present version of Artemia nauplii probably covers the nutrient requirements of Atlantic halibut larvae.     

Rhodovulum sulfidophilum,a phototrophic bacterium,grown in palm oil mill effluent improves the larval survival of marble goby Oxyeleotris marmorata (Bleeker)

Survival of marble goby larvae fed either Rhodovulum sulfidophilum, a phototrophic bacterium cultured from palm oil mill effluent (pPB), or microalgae ( Nannochloropsis sp.) was evaluated at two salinities. Larvae directly fed pPB had survival of 0–29% at 5 g L^?1 salinity and 0–19% at 10 g L^?1 salinity, whereas larvae directly fed microalgae suffered complete mortality after 20 days of culture at both salinities. However, larvae indirectly fed pPB or microalgae, i.e. via rotifers (Days 1–30) and Artemia nauplii (Days 21–30) cultured solely from pPB or microalgae, showed improved survival of 35–55% or 44–49% at 5 g L^?1 salinity respectively. In all experiments, fish larvae reared at 5 g L^?1 salinity showed significantly higher (P < 0.01) mean survival than those reared at 10 g L^?1 salinity. The survival of larvae fed the bacterial‐based diet was higher compared with microalgal diet used in previous studies. The pPB had higher total polyunsaturated fatty acids and docosahexaenoic acid (DHA) than the microalgae, which had very high eicosapentaenoic acid (EPA). Larvae with very high ratios of DHA/EPA (>11) or/and ARA (arachidonic acid)/EPA (>5), attributable to their given diet, however suffered the highest mortality.     

Reproductive performance and offspring quality of Chinese mitten crab Eriocheir sinensis (H. Milne-Edwards) females fed an optimized formulated diet and the razor clam Sinonovacula constricta

After feeding female Eriocheir sinensis on an optimized formulated diet or fresh razor clam Sinonovacula constricta for 7 months, their reproductive performance and offspring quality were compared. To evaluate diet nutrient contents, the proximate, fatty acid and amino acid compositions of the formulated diet and the razor clam were analysed. The nutritional value of the diets was determined by assessing survival, gonadosomatic index (GSI) and hepatosomatic index (HSI) of female crabs from both diet treatments, together with the percentage of females that spawned, total egg production per female and fecundity (number of eggs g^?1 female wet weight). Furthermore, the quality of eggs and newly hatched larvae from the two dietary treatments were determined using the following parameters: egg diameter, wet weight and dry weight, hatchability, proximate and fatty acid profile of eggs, larval carapace length, resistant to starvation and osmotic shock, larval survival and development to the zoea II stage. Higher protein, phospholipids (PL) and amino acids (AA) contents were found in the razor clam while the formulated diet contains higher levels of ash, total lipid (TL) and 18:1n‐9, 18:2n‐6 and 22:6n‐3 fatty acids. Although female crabs fed the two different diets showed similar reproductive performances, newly hatched zoea I larvae produced by the crabs fed the formulated diet had significantly longer mean carapace length and shorter development time to the zoea II stage under identical culture condition (P<0.05). Moreover, dietary fatty acid appeared to have more significant effects on the fatty acid composition of the hepatopancreas than it did on mature ovaries or eggs. This suggests that the fatty acid profile of mature ovaries is indicative of the specific fatty acid required for ovarian development in E. sinensis. In conclusion, our results show that the optimized formulated diet developed in this laboratory can totally replace the razor clam, a broodstock food widely used in E. sinensis hatcheries in China. This encouraging result should facilitate more reliable hatchery production of this important aquaculture species.     

Lipid Nutrition and Feeding of Cobia Rachycentron canadum Larvae

This study examined the fatty acid composition of cobia Rachycentron canadum eggs and yolksac larvae, as well as the ovaries of wild caught females as an initial guide to lipid nutritional requirements. A 2-wk feeding study also was conducted to investigate the effectiveness of four dietary treatments on the growth and survival of cobia larvae. Cobia eggs in the tailbud stage contained 31.4 ± 1.3 μg lipid/egg. After hatching, the amount of lipid decreased significantly (P < 0.05) from 28.3 ± 0.3 to 23.2 ± 0.1 μg lipid/larvae during the yolksac larval stage (days 1 to 3 after hatching). Ovaries from wild caught adults and captive spawned eggs and yolksac larvae contained high levels of PUFAs with docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) accounting for approximately 80% of the total suggesting that cobia larvae may have a high dietary requirement for these fatty acids. For the feeding study, larvae were fed: 1) Artemia only; 2) enriched rotifers for 1 d only + microparticulate diet (day 313); 3) enriched rotifers for 3 d (day 3–5) + Artemia (day 3–13); and 4) enriched rotifers for 6 d (day 3–8) + Artemia (day 3–13). Cobia larvae began feeding on rotifers 3 d after hatching and on newly hatched Artemia nauplii by the fifth day following the onset of exogenous feeding (day 7). On day 7, no differences in larval growth were found among larvae fed rotifers for 3 versus 6 d, whereas larvae fed only Artemia or rotifers for I d followed by microparticulate diet were significantly smaller (P < 0.05) and did not survive beyond day 9 and 13, respectively. The results of the feeding study indicate that cobia larvae require rotifers for a minimum of 4 d following the onset of exogenous feeding.     

The use of preserved copepods in sea bream small‐scale culture: biometric,biochemical and molecular implications

Considering the well‐known problems arising from the use of rotifers and Artemia as live prey in larval rearing in terms of fatty acid deficiencies, the aim of this study was to evaluate a partial or complete replacement of traditional live prey with preserved copepods during the larviculture of gilthead sea bream (Sparus aurata). Sea bream larvae were randomly divided into 4 experimental groups in triplicates: group A larvae (control) fed rotifers followed by Artemia nauplii; group B fed a combined diet (50%) of rotifers–Artemia and preserved copepods; group C fed rotifers followed by preserved copepods; and group D fed preserved copepods solely. Survival and biometric data were analysed together with major molecular biomarkers involved in growth, lipid metabolism and appetite. Moreover, fatty acid content of prey and larvae was also analysed. At the end of 40 days treatment, a stress test, on the remaining larvae, was performed to evaluate the effects of different diets on stress response. Data obtained evidenced a positive effect of cofeeding preserved copepods during sea bream larviculture. Higher survival and growth were achieved in group B (fed combined diet) larvae respect to control. In addition, preserved copepods cofeeding was able to positively modulate genes involved in fish growth, lipid metabolism, stress response and appetite regulation.     

Effects of starvation and feeding on the fatty acid profiles of Stage I phyllosoma of the spiny lobster, Jasus edwardsii

Fatty acid analyses were conducted on newly hatched and 8‐day‐old‐starved and fed Stage I phyllosoma larvae of the spiny lobster, Jasus edwardsii. Fed animals were offered excess 1.5 mm juvenile Artemia (enriched using the alga Isochrysis galbana, Tahitian isolate, T. iso.). After 8 days, there were significant increases in larval dry weight and the proportion of lipid in fed phyllosoma, whereas these parameters decreased in starved phyllosoma. The abundance of the saturated fatty acids 16 : 0 and 18 : 0 increased in both starved and fed phyllosoma, whereas the main monounsaturated fatty acids 16 : 1n‐7, 18 : 1n‐9 and 18 : 1n‐7 increased with feeding but decreased with starvation. There were no significant differences in the relative proportions of the highly unsaturated fatty acids (HUFAs) arachidonic (AA, 20 : 4n‐6), eicosapentaenoic (EPA, 20 : 5n‐3) and docosahexanoic (DHA, 22 : 6n‐3) acids between newly hatched and starved animals, whereas quantitatively DHA decreased with starvation and feeding. The DHA/EPA ratio was significantly lower in the starved and fed phyllosoma (0.5) compared with that found in the newly hatched phyllosoma (0.9). The lipid profiles of the newly hatched, starved and fed phyllosoma contained large amounts of n‐6 fatty acids resulting in low n‐3 : n‐6 ratios (2.8, 2.7 and 1.6 respectively). The importance of these results and the ability of enriched Artemia to provide a suitable fatty acid profile for this species are discussed.     

Survival and growth of turbot larvae Scophthalmus maximus L. Reared on different food organisms with special regard to long-chain polyunsaturated fatty acids

Turbot larvae reared on rotifers (Brachionus plicatilis) and Artemia (San Francisco brand) nauplii (A) were compared with those fed on different copepod (Eurytemora affinis) stages (B). In one trial, growth and survival of larvae from hatching to day 21, their fatty acid pattern and that of their food organisms were examined. At the age of 21 days larvae of group A measured 11·1 ± 1·6 mm total length (TL) compared with 14·8 ± 1·1 mm TL for group B. From day 3 to 8 survival was 29% (A) and 38% (B). Long-chain polyunsaturated fatty acid composition of turbots resembled that of their corresponding diets. Artemia and Artemia fed larvae were lacking 22 : 6 n-3 fatty acid.In a further study, survival of larvae from day 11 to 21 fed on Artemia nauplii (C) or copepods (D) was found to be greater with the latter diet (73 versus 93%) whereas growth during this experiment was similar in both groups. Before the start of this trial they had been reared on a mixture of copepod nauplii and Brachionus. No influence on weaning success was observed. 22 : 6 n-3 fatty acid is seen to be essential for turbot larvae: elongations of fatty acids by the larvae were not found.     

Effects of enriched Artemia by fish and soybean oils supplemented with vitamin E on growth performance,lipid peroxidation,lipase activity and fatty acid composition of Persian sturgeon (Acipenser persicus) larvae

This study aimed to evaluate the effects of enriched Artemia by fish and soybean oils supplemented with vitamin E on growth performance, lipid peroxidation, lipase activity and fatty acid composition of Persian sturgeon (Acipenser persicus) larvae. For this purpose, five experimental diets including non‐enriched Artemia (control diet), Artemia enriched with soybean oil supplemented with 15% and 30% vitamin E (S15 and S30 diets) and fish oil supplemented with 15% and 30% vitamin E (F15 and F30 diets) were used. The larvae were fed to apparent satiation four times per day for 22 days. The results indicated that fish fed enriched Artemia had no significant differences compared with those fed non‐enriched Artemia in terms of growth and survival, but increase in vitamin E levels from 15 to 30% improved growth performance of larvae. Vitamin E content in fish fed S15 and S30 diets was significantly higher. Fish fed non‐enriched Artemia had significantly higher thiobarbituric acid and lower lipase activity. The highest HUFA and n‐3/n‐6 ratio were observed in fish fed F15 and F30 diets. Our results demonstrated that fish oil can completely replace with soybean oil in larval diets. Therefore, using S30 diet is recommended for feeding of Persian sturgeon larvae.