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1.
High mortality frequently occurs in larval mass production of Korean rockfish, Sebastes schlegeli Hilgendorf. Nutritional deficiencies in live feeds, rotifers and Artemia nauplii, fed to larvae could be a reason. A series of experiments was carried out to evaluate the effect of nutritional enrichment of live feeds by ω‐yeast, Spirulina powder and Super SelcoTM on survival and growth rates in rockfish larvae. Preference of rockfish larvae for the live feeds was determined by analysis of stomach contents. In addition, the effect of green water produced by the use of Chlorella ellipsoidea and Spirulina powder on the growth performance of larvae was evaluated. Larvae fed rotifers nutritionally enriched with Super Selco showed significantly higher survival rates than those fed rotifers enriched with ω‐yeast. Larvae fed rotifers that were nutritionally enriched with both Super Selco and Spirulina together exhibited improved growth and survival rates. Larvae fed Artemia nauplii nutritionally enriched with Spirulina powder showed significantly higher survival than larvae fed Artemia nauplii without enrichment. When larvae were fed rotifers, Artemia nauplii or the mixture of rotifers and Artemia nauplii, the second and last group showed significantly higher survival than the first group. Fatty acid composition in live feeds was improved by enrichment of ω‐yeast and larvae fed this feed showed higher survival and growth rates compared with larvae fed non‐enriched feeds. No positive effect of green water in the tank produced with C. ellipsoidea or Spirulina powder was observed on survival and growth rates for larvae fed nutritionally enriched rotifers with Super Selco and Spirulina powder. However, when the larvae were fed Artemia nauplii that were nutritionally enriched with ω‐yeast and Spirulina powder, green water obtained by adding Spirulina powder to the tanks resulted in significantly higher growth rates of larvae than was obtained by adding C. ellipsoidea.  相似文献   

2.
The changes in the biochemical compositions and enzymatic activities of rotifer (Brachionus plicatilis) and Artemia, enriched and stored at 4°C temperature, were determined. The total starvation period was 16 h and samples were taken at the end of the 8th and 16th hours. In present study, the rotifer and nauplii catabolized a large proportion of the protein during the enrichment period. Lipid contents of both live preys increased during the enrichment period and decreased in nauplii and metanauplii throughout the starvation period but lipid content of the rotifer remained relatively constant during the starvation period. The changes observed in the amino acid compositions of Artemia and the rotifer were statistically significant (P < 0.05). The conspicuous decline the essential amino acid (EAA) and nonessential amino acid (NEAA) content of the rotifer was observed during the enrichment period. However, the essential amino acid (EAA) and nonessential amino acid (NEAA) contents of Artemia nauplii increased during the enrichment period. The unenriched and enriched rotifers contained more monounsaturated fatty acid (MUFAs) than polyunsaturated fatty acid (PUFAs) and saturated fatty acids (SFA). However, Artemia contained more PUFAs than MUFAs and SFA during the experimental period. A sharp increase in the amounts of docosahexaenoic acid (DHA) during the enrichment of the rotifer and Artemia nauplii was observed. However, the amount of DHA throughout the starvation period decreased in Artemia metanauplii but not in Artemia nauplii. Significant differences in tryptic, leucine aminopeptidase N (LAP), and alkaline phosphatase (AP) enzyme activities of Artemia and rotifer were observed during the enrichment and starvation period (P < 0.05). The digestive enzymes derived from live food to fish larvae provided the highest contribution at the end of the enrichment period. In conclusion, the results of the study provide important contributions to determine the most suitable live food offering time for marine fish larvae. Rotifer should be offered to fish larvae at the end of the enrichment period, Artemia nauplii just after hatching and before being stored at 4°C, and Artemia metanauplii at the end of the enrichment and throughout the starvation period.  相似文献   

3.
Nutritional efficacy of fairy shrimp (Streptocephalus sirindhornae) nauplii, as a live food, was studied for growth performance and survival rate of giant freshwater prawn (Macrobrachium rosenbergii) postlarvae. A feeding experiment was designed with four different feeds: dry commercial feed, fairy shrimp nauplii, Artemia sp. nauplii and adult Moina macrocopa. Results from the nutritional composition revealed that fairy shrimp nauplii had protein and lipid contents of 54.58 ± 2.8 g kg?1 and 255 ± 2.8 g kg?1, respectively. The highest value for an individual amino acid in fairy shrimp was lysine (140.7 ± 1.6 g kg?1). The essential amino acids content in the whole body of the larval prawns was in the range of 66.7–67.5 g kg?1. Fairy shrimp nauplii had the highest essential amino acid ratio (A/E) of lysine, similarly, in musculature of prawn larvae. Weight gain and specific growth rate of the postlarvae fed with fairy shrimp nauplii were significantly higher than those fed with Artemia nauplii, adult Moina and dry commercial feed. The presented results suggest that S. sirindhornae nauplii can be used as a nutritionally adequate food for freshwater prawn M. rosenbergii postlarvae.  相似文献   

4.
We have evaluated the potential of a formulated diet as a replacement for live and fresh feeds for 7-day post-hatch Panulirus ornatus phyllosomata and also investigated the effect of conditioning phyllosomata for 14–21 days on live feeds prior to weaning onto a 100% formulated diet. In the first trial, the highest survival (>55%) was consistently shown by phyllosomata fed a diet consisting of a 50% combination of Artemia nauplii and 50% Greenshell mussel, followed by phyllosomata fed 50% Artemia nauplii and 50% formulated diet and, thirdly, by those receiving 100% Artemia nauplii. The second trial assessed the replacement of on-grown Artemia with proportions of formulated diet and Greenshell mussel that differed from those used in trial 1. Phyllosomata fed a 75% combination of formulated diet and 25% on-grown Artemia and 50% on-grown Artemia and 50% Greenshell mussel consistently showed the highest survival (>75%). Combinations of Greenshell mussel and formulated diet resulted in significantly (P < 0.05) reduced survival. In trial 3, phyllosomata were conditioned for 14, 18 or 21 days on Artemia nauplii prior to weaning onto a 100% formulated diet, which resulted in survival rates that were negatively related to the duration of feeding Artemia nauplii. In the final trial, phyllosomata were conditioned for 14 days on live on-grown Artemia prior to weaning onto one of three formulated diets (one diet with 44% CP and two diets with 50%). Phyllosomata fed a 44% CP diet consistently showed the highest survival (>35%) among all treatments, while those fed a 50%-squid CP diet showed a significant (P < 0.05) increase in mortality at day 24. The results of these trials demonstrate that hatcheries can potentially replace 75% of live on-grown Artemia with a formulated diet 7 days after hatch. The poor performance associated with feeding combinations of Greenshell mussel and formulated diet, and 100% formulated diet as well as conditioning phyllosomata for 14–21 days on live feeds prior to weaning onto a formulated diet highlights the importance of providing Artemia to stimulate feeding.  相似文献   

5.
ABSTRACT

The Japanese flounder, Paralichthys olivaceus, is one of the most common finfish cultured in Japan and Korea. Despite the relatively high production of fingerlings, some problems remain, mainly related to the larval feeding and cost of maintaining microalgae and rotifers. In order to determine the effects of different diets on the Japanese flounder larval growth and survival, a series of experiments was carried out related to the size and nutritional value of different live feeds. The larvae culture conditions were at 10 or 20 larvae/L in 50 to 2,000 L tanks, with aeration and with or without “green water,” and a temperature range of 18.5 to 22.5°C. The live foods used were microalgae (Chlorella ellipsoidea and Nannochloris oculata), baker's yeast, experimental n-yeasts, oyster trochophore larvae, three strains of rotifer Brachionus plicatilis (L-type, S-type and U-type) and Artemia nauplii. Variations were detected in size, dry weight, and chemical composition of the three strains of rotifers used. The maximum number of rotifers ingested by flounder larvae increased steadily from 7 individuals, at first feeding (3.13 mm), to 42 individuals at 5.25 mm of total length (6 days after first feeding). There was a relationship between larval total length and size of the rotifers ingested. The effect of rotifer size on larval growth and survival appeared to be limited to the first two days of feeding. Of the diets tested in the growth and survival of larval flounder during 14 days after hatching, rotifers fed on C. ellipsoidea and raised in green-water gave the best results. Rotifers cultured on enriched N. oculata and n-yeasts did not support larval growth and caused higher mortalities. The n-yeasts used as rotifer enrichment appeared to satisfy, partially, the nutritional requirement of 7-day-old flounder larvae, as did n-yeast squid wintering oil the requirements of 14-day-old larvae. From 7-9-days after hatching and throughout the second 14-day period, rotifers and Artemia cultured on N. oculata improved the survival of flounder compared with those fed on rotifers cultured on C. ellipsoidea. Moreover, the larval growth did not vary significantly between both microalgae-rotifer feedings. No clear relation was found between total protein, lipid, amino acids and fatty acids of live feeds with the growth and survival of flounder larvae, although the total lipid was higher in C. ellipsoidea than in N. oculata. The Artemia nauplii San Francisco strain appeared to be more suitable for the growth and survival of flounder larvae, than the Utah strain. The nutritional value of Artemia nauplii (Utah strain) for flounder larvae remained unchanged despite the use of either microalgae as nauplii enrichment.  相似文献   

6.
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.  相似文献   

7.
Larval rearing of many marine organisms is dependent on the availability of live food. The aim of this study was to optimize larval first feeding for the mud shrimp Upogebia pusilla, by comparing the effectiveness of the two most commonly used live feeds: Brachionus plicatilis and Artemia sp. nauplii. Survival, larval duration, molt synchronism and megalop size were compared using five feeding treatments: Artemia from zoea I to IV (B0), Brachionus during zoea I and Artemia from zoea II to IV (B1), Brachionus during zoea I and II and Artemia during zoea III and IV (B2), Brachionus from zoea I to III and Artemia during zoea IV (B3) and Brachionus from zoea I to IV (B4). The proportion of larvae that reached the megalop stage was 0.00% in treatment B0, 3.33% in treatment B1, 33.33% in treatment B2, 66.67% in treatment B3 and 76.67% in treatment B4. Larvae fed on rotifers until zoea III or zoea IV stages had a higher survival but no differences were found either in time to reach megalop or in megalop size. This study demonstrates that rotifers are essential for the survival and development of U. pusilla early larval stages but that rotifers can be successfully replaced by Artemia nauplii in the zoea IV stage.  相似文献   

8.
Considering that the use of decapsulated Artemia cysts as direct food for juvenile crayfish could be an alternative to live nauplii, a 100-day experiment was carried out under controlled conditions to evaluate the effects of cysts, comparing with nauplii, as supplement to a dry diet for salmonids on the survival and growth of juvenile signal crayfish (Pacifastacus leniusculus) from the onset of exogenous feeding (stage 2). The reduction of feeding frequency was also tested. According to a bifactorial design, six treatments, differing in the supplement and feeding frequency, were tested: the dry diet supplemented with Artemia nauplii or decapsulated cysts was supplied once a day, once every two days and once every three days. Survival rates ranged from 56.7% to 81.7%, rising significantly with increasing the feeding frequency. The highest growth (12.94 mm carapace length and 593.08 mg weight) was reached by the crayfish that received the dry diet supplemented with cysts once a day, with significant differences from the rest of the treatments. Considering the supplement, the cysts supported significantly higher growth than the nauplii. Regarding the feeding frequency, growth was higher when the food was supplied once a day, showing significant differences from the other two frequencies (once every two days and once every three days). This study shows that decapsulated cysts are better dietary supplement than live nauplii. In crustacean culture, this is the first report of successful use of Artemia cysts from the onset of exogenous feeding.  相似文献   

9.
The arachidonic acid (20:4n-6,AA) requirements of larval summer flounder weredetermined for the rotifer- and Artemia-feeding stages. Experimental emulsionscontained adequate n-3 highly unsaturated fattyacid (HUFA) ratios and emulsion levels of AAwere set at 0, 3, 6, 9, and 12% (AA0, AA3,AA6, AA9, and AA12). Examination of fatty acidlevels in live feeds and larval tissuesconfirmed the physiological incorporation offatty acids relative to dietary levels. In thefirst experiment, survival, growth, andsalinity tolerance (2-h in 70) were measuredat 18 days after hatch (dah) after feeding thelarvae the various levels of AA. Larvae fedAA6-enriched rotifers were better able tosurvive the salinity tolerance test. AAenrichment up to 12% had no effect on growthand survival. In the second experiment, larvaewere fed AA0- or AA6-enriched rotifers until 23dah, followed by unenriched 24- and 48-h Artemia nauplii until 32 dah. These larvaethen were subdivided and fed AA-enriched Artemia from 33-45 dah. At the end of thisexperiment, larvae fed AA6-enriched rotifershad higher survival, increased growth, andsurvived better in the salinity tolerance test(2-h in 80). The enrichment of Artemiadid not have any effect on these variables.Thus, the provision of AA6-enriched rotifers(10 mg AA g–1 DW) early in larvaldevelopment may serve to enhance larval stresstolerance at the rotifer stage while alsoincreasing larval survival, growth, and stresstolerance later in the Artemia stage.  相似文献   

10.
Different liposome formulations, includingseveral combinations of membrane composition,type of vesicle (multilamellar and largeunilamellar vesicles), preparation method, andvehiculated nutrient, have been assayed asbioencapsulation products to enrich Artemia nauplii with nutrients for feeding fish larvae.The stability of the liposome preparationsunder conditions of use as enrichment producthas been tested using water soluble fluorescentmarkers as leakage indicators. The content ofthe fatty acids and lipid classesbioencapsulated in Artemia nauplii withliposomes has been analyzed by gas and thinlayer chromatography, respectively, andcompared with other enrichment products. Theeffect of the liposome enriched Artemianauplii used as food for fish larvae has beenevaluated in sea bass cultures. Liposomes withhigh content in polyunsaturated fatty acidsleak out more than 50% of their aqueous phasein less than 2 hours, unless they arestabilized with cholesterol and formed as largeunilamellar vesicles. Such vesicles hold70% of the encapsulated material for 8 hours.Liposome enriched nauplii in this study reflectthe influence of the enrichment products,however, they are far from the commercialemulsion (Super Selco) in terms ofdocosahexaenoic acid content, except for thenauplii enriched with liposomes made of purekrill phospholipid extract by the method ofdetergent solubilization. The liposome enrichednauplii show a higher amount of polar lipids incontrast to the feed enriched with emulsions.The larvae fed liposome enriched nauplii haveonly a slightly lower docosahexaenoic acidcontent than those fed emulsion enrichednauplii. The results obtained confirm thesuitable potential use of liposomes as foodsupplement in larviculture. Problems andadvantages are discussed.  相似文献   

11.
In hatcheries, the adequate supply of live feed has a vital role in feeding fish larvae, fry and fingerlings. Furthermore, the enhancement of the nutritional quality of live feeds is well‐developed techniques in aquaculture. Essential fatty acids (EFA) such as docosahexaenoic acid (DHA; C22:6 n?3), eicosapentaenoic acid (EPA; 20:5(n?3) and arachidonic acid (ARA; 20:4(n?6) and amino acids are an essential source of proteins for larval rearing of fish. However, the common practised live feeds used for the primary feeding such as rotifers and Artemia are naturally deficient in essential nutrient components. Hence, the improvement of the nutritional quality of live feeds with different oil emulsions and commercial diets, and manipulation of the feed are necessary for fish production. The production protocols of copepods, Moina and fairy shrimps as live feed are still underdeveloped in hatcheries. The different lipid sources using for the enrichment of Artemia and rotifers are not effective on other live feeds, especially copepods and cladocerans (Moina, Daphnia) and fairy shrimps. This review focuses on the importance of live feeds by the techniques of feed enhancement or enrichment of zooplankton by direct incorporation of nutrients for feeding of early stages of fish.  相似文献   

12.
Though artificial propagation of Asian seabass Lates calcarifer (Bloch) in captivity through induced breeding techniques is standardized under Indian conditions, larval and nursery rearing techniques including suitable nursery feeds have to be standardized to obtain better survival and growth. Feeding experiments in triplicate were conducted to evaluate the suitability of the marine copepod Acartia clausi as live prey for fourteen day-old seabass larvae (6.53 ± 0.06 mm; 8.58 ± 0.33 mg) and compared with the traditional live prey, rotifers and Artemia nauplii. While A. clausi and rotifers were mass produced using algae Isochrysis galbana, Chaetoceros affinis and Chlorella marina, Artemia nauplii were produced using cysts. Nutritional quality of cultured copepods was evaluated based on the proximate composition, amino acid and fatty acid composition, and compared with that of rotifers and Artemia nauplii. Proximate composition varied significantly (P < 0.05) among the different live feeds. A. clausi showed higher protein (63.12%) and lipid (16.65%) content than Artemia nauplii and rotifers. Total essential amino acids content was 2% lower in A. clausi compared to that in Artemia nauplii. Fatty acid profiles of the live feed organisms showed that A. clausi is a rich source of n − 3 fatty acids. The total n − 3 fatty acid content of A. clausi was 33.94%. Length, weight overall weight gain and survivorship were significantly (P < 0.05) different among the dietary treatments, and weight gain was comparatively higher in A. clausi fed larvae. Survival of seabass larvae fed A. clausi was obtained highest as 58.13% against the lower values of 39.93% and 41.62% in larvae fed rotifer and Artemia nauplii respectively. Final carcass composition of the larvae of L. calcarifer fed different live-food organisms showed significant differences (P < 0.05) among the dietary treatments. The fatty acid composition of the dietary treatments was reflected to a certain extent in the fatty acid composition of the seabass larvae. The present investigation revealed the nutritional value of calanoid copepod and thus underlining its usefulness as a suitable live-food organism for rearing larvae of the commercially valuable Asian seabass.  相似文献   

13.
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.  相似文献   

14.
We evaluated the nutrient contents of rotifers sampled from larval-rearing tanks (tank rotifers) without water exchange during the seed production of amberjack Seriola dumerili at three facilities (Kamiura, Kagoshima, and Miyazaki) and compared them with the nutrient contents of freshly enriched rotifers. Compared to the enriched rotifers, the lipid contents, especially neutral lipids and proportion of 22:6n-3, tended to decrease in the tank rotifers. These trends were clearer at Miyazaki where the tank rotifers were sampled before daily supplementation of microalgae (Nannochloropsis). Crude protein content of the tank rotifers did not decrease markedly although the proportion of lysine tended to decrease. Vitamin C and E contents of the tank rotifers decreased significantly only at Miyazaki. Calcium content of the tank rotifers increased at Kamiura and Miyazaki, and the increases in iron and manganese contents of the tank rotifers at Miyazaki and zinc content at Kagoshima were pronounced. These results suggest that the nutritional value of rotifers in larval-rearing tanks without water exchange can be maintained by appropriate supplementation of microalgae. The effect of certain minerals that became high in tank rotifers on subsequent larval development requires further investigation.  相似文献   

15.
Enrichment of Artemia nauplii with a known probiotic yeast Saccharomyces boulardii (SB) and its role in enhancing resistance against the pathogen Vibrio harveyi was investigated. SB was cultured, then fed to instar II Artemia nauplii in three different treatments; 102 (T1), 103 (T2) and 104 (T3) colony forming units (CFU) per ml in triplicate. The algae Nanochloropsis sp. was used as control diet. Survival and total count of CFU nauplii−1 was observed on different media (Sabouraud, for enumerating yeasts, thiosulphate citrate bile salts sucrose, for enumerating Vibrio and seawater agar, for enumerating total aerobic flora) for each replication. Enhanced survival of nauplii was observed in treatments as compared to control. Results indicated that enrichment of SB in Artemia nauplii proceeded in a linear fashion, and up to 3500 CFU of SB could be detected in one nauplii at 104 CFU ml−1 treatment. No conclusive trend could be observed in the count of Vibrio and total aerobic flora due to treatment. Enriched nauplii were then challenged with the pathogen V. harveyi for 24 and 48 h at a concentration of 6.1 × 106 CFU ml−1. The survival counts at 48 h showed that the resistance of the nauplii was significantly (P < 0.01) improved in those fed with 104 CFU  ml−1 SB (90% survival rate after 48 h of challenge versus less than 40% for the infected control group without SB and treatments T1 and T2). This study shows that SB, which has been used for the first time in an aquatic live feed organism, has a profound beneficial effect on the nauplii by increasing its resistance to a pathogenic Vibrio infection. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

16.
The suitability of the harpacticoid copepodTisbe holothuriae as a diet for larval and juvenile Dover sole (Solea solea) was assessed by rearing groups of sole for 42 days under a range of dietary regimes. Larval sole, approximately 1 week old, were reared onTisbe, Artemia, or a mixedTisbe-Artemia diet for 13 days. No significant differences in length between sole larvae from any diet were found after this time, but larvae offeredArtemia alone showed a significantly higher frequency of malpigmentation than those offered the other diets. After metamorphosis (day 16), survivors of this experiment were reared for a further 29 days on various diets to give the following dietary sequences:Tisbe-fed larvae, fed onArtemia as juveniles (Tis.-Art.);Artemia-fed larvae, fed onArtemia as juveniles (Art.-Art.);Artemia-fed larvae, fed onTisbe as juveniles (Art.-Tis.) and mixed diet fed larvae, fed on a mixed diet as juveniles (AT-AT). At the end of this period AT-AT and Tis.-Art.-fed juveniles were significantly larger than those on the Art.-Art. dietary regime. Juveniles from the Tis.-Art. dietary regime consumed more prey items than the Art.-Art group. AT-AT juveniles consumed similar amounts of food to Art.-Art. juveniles but were significantly larger after 29 days culture. This was attributed to the presence ofTisbe in their diet. Overall, the best larval and juvenile diet appeared to be a mixed diet throughout the culture period.  相似文献   

17.
The giant freshwater prawn, Macrobrachium rosenbergii, is cultured widely in the Mekong Delta region of Vietnam but it is often difficult or expensive for hatchery operators to purchase commercial diets used as a feeding supplement to Artemia nauplii. Therefore, in the present study, the effects of lipid sources and lecithin on the growth and survival rate of M. rosenbergii larvae were examined in order to develop suitable hand-prepared larval diets for seed production of M. rosenbergii in this area. Six egg custard diets consisting of various ratios of lipid (originating from soybean oil and squid oil) and lecithin were used for rearing Macrobrachium rosenbergii larvae. Treatments in which larvae were fed diets containing squid oil exhibited the highest body length and survival rates (7.14–7.43 mm and 51.1–68.1%, respectively), and differed significantly from other treatments (P<0.05). Use of dietary soybean oil yielded the lowest body length and survival rates (6.29–6.75 mm and 22.0–48.7%), respectively). The supplementation of dietary lecithin did not increase final body weight but did improve larval survival rates. The n-3 HUFA content of prawns fed dietary squid oil was higher than those of animals provided with other diets. These results indicated that the most appropriate diet for rearing M. rosenbergii larvae is the diet containing 3% squid oil and 1.5% lecithin.  相似文献   

18.
In three separate experiments, harpaticoid copepods Tisbe monozota (alive and dead) and a microparticulate microbound diet were evaluated as alternatives to live Artemia nauplii as food, beginning at either stage PZ2 or M1, in the larval culture of Litopenaeus vannamei. Larvae were cultured in 2 L round bottom flasks at a density of 150 L− 1 (Experiment 1) and 100 L− 1 ( 3.2 and 3.3) at 28 °C, 35‰ salinity and 12:12 LD photoperiod, and fed 4×/day- 1. Larvae were initially fed a mixture of phytoplankton to stages PZ2 or M1 and then fed either live Artemia, live or dead copepods, or a microparticulate microbound diet. The experiments were terminated and all larvae were harvested when more than 80% of larvae had molted to postlarvae 1 (PL1) within any flask representing any of the treatments. The comparative value of the different diets and feeding regimes was determined by mean survival, mean dry weight and total length of individual larva, and percentage of surviving larvae that were PL1. Trypsin activity of samples of larvae from each treatment was also determined. The microparticulate microbound diet effectively served as a complete substitute for Artemia nauplii when fed beginning at stage M1. When fed at the beginning of the PZ2 stage, survival was comparable to that of larvae fed Artemia, but mean dry weight, mean total length, and percent of surviving larvae that were PL1 generally were significantly less. Responses to the feeding of copepods, whether fed dead or live, as a substitute were generally significantly less than those of larvae fed either the Artemia nauplii or the microparticulate diet. Values of trypsin activity (10− 5 IU/μg- 1 dry weight) corresponded to the relative proportions of the different larval stages within a treatment, with higher activity being characteristic of early stages. Previously demonstrated successful results with another species of crustacean suggest that the microparticulate microbound diet has characteristics that should be effective in the culture of the carnivorous stages of other crustacean and fish larvae that are currently fed live Artemia nauplii.  相似文献   

19.
Two experiments were carried out to test microparticulate diets forweaning hatchery-produced larvae and juveniles of bullseye pufferSphoeroides annulatus. The diets were formulated with differentprotein sources: diet 1 with a combination of decapsulated cysts ofArtemia and fishmeal, and diet 2 with a combination offishmeal, squid, tuna gonad and shrimp meal. In the first experiment60-days-old fish were weaned with the microdiets over five days. Fishsurvival after 11 weeks of feeding was 92% for diet 1, 85%for diet 2, and 95% for the control fish fed Artemianauplii. Once it was determined that bullseye puffer can be adequatelyreared with artificial dry diets, diet 1 was used to test earlier timesfor weaning to reduce the period of Artemia feeding. In thesecond experiment, three different times were tested for initiation ofweaning in sibling fish larvae, i.e., at 29, 34, and 39 days post-hatch.Small differences in weight, length and survival were found amongweaning treatments after 23 days of feeding. When weaned at day 29post-hatch, fish larvae grew from an initial weight of 38.4 mg andlength of 11.1 mm to a final weight and length of 405.7 mg and 25.1 mmrespectively. Final survival in this treatment was 49.3%. Thereduced period of Artemia feeding would provide an economicalalternative for the species to take into consideration for its cultureat commercial scale.  相似文献   

20.
This study evaluated the use of live and frozen copepods collected from shrimp ponds for rearing juveniles of the spotted seahorse Hippocampus kuda. Protein and HUFA contents in frozen copepods were all higher than in Artemia nauplii, the conventional live food for seahorse juveniles. The results of this study showed that copepods can be used as feed for rearing seahorse fry and juvenile. The spotted seahorse showed obvious preference for live copepods and rarely fed on dead copepods on the tank bottom. Furthermore, the combination of frozen copepods and live Artemia nauplii resulted in highest growth and highest survival of the experimental seahorses. Further research on possible effects of DHA:EPA ratio on survival and growth of young H. kuda is recommended.  相似文献   

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