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1.
Low-hatch, decapsulated Artemia cysts were assessed as feed for Penaeus indicus post-larvae (PL) 1–15 days old and the problems resulting from the incorporation of decapsulated cysts into compounded feeds were evaluated. Growth and survival of PL fed on decapsulated cysts (AC) were comparable with Artemia nauplii fed PL (control) and significantly (p < 0.05) higher than observed amongst PL fed on two granulated commercial diets (G150 and G300) or a commercial flake feed (AC-F) incorporating decapsulated cysts (80%). PL fed on artificial diets showed poor growth and delay in metamorphosis. However, survival of PL fed on AC-F was significantly higher (p < 0.05) than that observed amongst granulated feeds. Decapsulated cysts processed into a granulated feed (AC-G) or dried at 90°C (AC-90) also resulted in slow growth and survival when fed to PL. Overall, artificial feeds showed poor water stability and significantly higher leaching of soluble protein and carbohydrates than decapsulated cysts. AC-90 cysts also showed a high level of bursting and leaching of material. This indicates that low-hatch Artemia cysts retain a living membrane after commercial decapsulation and drying prevents loss of highly digestible nutrients, which allows PL growth equal to that on PL fed live Artemia nauplii. Survival of PL was negatively correlated with leaching of soluble protein (p < 0.05), but no correlation was observed for leaching of carbohydrates or between growth and loss of both soluble nutrients. Hence, availability of digestible protein is critical and may influence survival of early stages of post-larval development. Water stability of artificial feeds is an essential factor in promoting efficient nutrition of PL, but other aspects related to heating during processing of feeds also appear to have a deleterious effect on nutritional quality of compounded feeds. Commercially dried, encapsulated Artemia cysts from low-hatch strains remain alive and are highly nutritious for feeding early stages of post-larval prawn but even after death may support acceptable survival when incorporated into a flake diet. © Rapid Science Ltd. 1998  相似文献   

2.
Three 30‐day experiments were conducted to evaluate decapsulated Artemia cysts with different quality (high or low hatch‐rate) as food for tench (Tinca tinca L.) larvae from the onset of exogenous feeding. In experiment 1, three diets were tested: Artemia nauplii‐only or cysts‐only for 30 days, and nauplii for the first 7 days and cysts thereafter. The cysts used had 86% hatching rate (high hatch‐rate cysts). The same feeding treatments were replicated in experiment 2 but with low hatch‐rate cysts (10% hatching rate). In experiment 3, five diets were tested: high hatch‐rate cysts only or low hatch‐rate cysts only for 30 days, and nauplii for the first 7, 4 or 2 days and low hatch‐rate cysts thereafter. In overall, survival was high, except with the low hatch‐rate cysts only diet. Feeding tench larvae with cysts resulted in higher growth and lower FCR compared to feeding with live nauplii only. High hatch‐rate Artemia cysts are a suitable food from the onset of exogenous feeding and low hatch‐rate cysts can be successfully used after 2–7 days feeding on nauplii.  相似文献   

3.
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.  相似文献   

4.
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.  相似文献   

5.
Decapsulated cysts of Artemia subjected to different heat treatments (40, 60, 80 and 96 °C) were fed to African catfish Clarias gariepinus larvae. Heated cysts, untreated cysts and live Artemia nauplii as control constituted the experimental diets. Protein denaturation and solubility, total alkaline protease and specific trypsin activities in the cyst diets were evaluated. The growth of catfish larvae and the proteolytic activity of larval samples during development were also determined. Heat treatment of cysts increased protein denaturation and decreased protein solubility. The protease activity in the cyst diets decreased with higher heating temperatures. The growth of catfish larvae differed according to the diet; higher fish growth was achieved with nauplii and cysts heated at 40 °C. The digestive enzyme activity in larval samples remained similar in all dietary treatments during larval development. The quality of food protein and the way this protein is processed might be more important for successful larval growth than exogenous enzyme supply.  相似文献   

6.
A study was conducted to compare fatty acid composition, hatching quality, and size of nauplii from four commercial sources of brine shrimp (Artemia spp.) cyse: China (CH), Colombia (COL), Great Salt Lake (GSL), and San Francisco Bay (SFB). The CH brine shrimp had a comparatively high percentage of 20:5(n-3) fatty acid (eicosapentaenoic acid or EPA), an essential fatty acid for most Iarval fishes, which was 10.4% of the total lipids. The COL, GSL, and SFB sources of cysts contained comparatively low percentages of EPA, 2.9, 1.2, and 1.6%. respectively. Hatching quality was determined by hatching cysts in salt (NaCl) water with a specific gravity of 1.02 at 27 C for 42 h. The COL cysts had the fastest hatching rate, with 50% of the cysts hatching in 13.4 h, while CH cysts hatched at the slowest rate, requiring 25.6 h for 50% of the cysts to hatch. Total percentage hatch was not significantly different among the SFB, COL, and GSL sources, with an average hatching percentage of 84.5, while CH cysts had a significantly lower total percentage hatch of 67.5. The SFB source produced the greatest number of nauplii (1.6 ± 105 per g of cysts) with the smallest length (382 μm), while CH produced the smallest number (8.7 ± 104) with the greatest length (500 μm). These results indicate that there is great variation in nutritional quality, hatching quality, and size of nauplii among commercial sources of brine shrimp cysts, and each of these criteria should be considered in selecting brine shrimp in a development of a feeding strategy for larval culture of a particular species.  相似文献   

7.
The effects of culture parameters of tank color and feeding regimes were examined on larval white bass Morone chrysops during 1994–1995. Under high surface illumination (998 lux), dark tank walls were essential for effective prey capture. Larvae reared in clear glass aquaria did not grow and had died by day 6 of the study. In contrast, 48.7% of the larvae reared in black-walled tanks were alive on day 24 and had grown to 17.2 mm total length (TL). In another study, larvae were fed rotifers Brachionus plicatilis and Artemia nauplii in different feeding protocols. In one treatment only rotifers (10/mL) were fed day 1 (4 d post-hatch), rotifers and Artemia (3/mL) were fed days 2–4, and Artemia fed days 5–15. This protocol produced similar growth (mean size 11.7 mm TL) and survival (mean 30.3%) as slower weaning times from rotifers to Artemia . Juveniles (27-day-old, 17.2 mm TL) were converted to a dry crumble diet over a 14-d period by slow transfer from a combination diet consisting of live Artemia nauplii, frozen adult Artemia , plankton flakes and dry crumbles. Survival offish weaned to the dry diet was 64.5%. Most of the mortalities during the weaning period were fish with uninflated swim bladders which were cannibalized by larger fish. Using the above tank culture techniques, white bass were reared to a mean size of 73.2 mm TL (mean weight 5.8 g) over a 73-d period. This essentially closes the life cycle of white bass.  相似文献   

8.
Decapsulated Arremia cysts have been evaluated as a direct food source for larvae of the carp Cyprinus carpio L. All decapsulated cyst diets gave excellent survival of carp larvae during the first two weeks of culturing. Unlike traditionally brine-stored decapsulated cysts, dried Artemia embryos provided growth results comparable to those obtained with freshly hatched Artemia nauplii. Furthermore, except for Artemia embryos that lost their hatchability after long-term storage in air, several other inactivation treatments, simulating improper harvesting and processing of cysts, did not produce a significant decrease in the nutritional quality of the decapsulated cysts.
Using decapsulated cysts 89 a direct food source for carp larvae, instead of nauplii, the quantity of cysts needed can be reduced by about 25% to 35% after one and two weeks of culturing, respectively. Moreover, the use of decapsulated cysts advances the possible commercialition of poor-hatching and less expensive cyst products for culture of carp larvae.  相似文献   

9.
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10.
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   

11.
Nauplii of the brine shrimp, Artemia , and cultures of the soil nematode, Panagrellus redivivus , were fed a suspension of the water-insoluble antibacterial Romet-30 (sulfadimethoxine plus ormetoprim) to determine if they could be used as a mechanism for delivery of the drug to larval penaeid shrimp.
Romet-30 was added to groups of brine shrimp nauplii and nematodes in 1 L beakers to achieve a concentration of 3 mg of drug per ml of seawater. After a 4 h uptake period, predetermined numbers of organisms were assayed for antibiotic content using the micro-plate diffusion method and a Romet-30 sensitive strain of Vibrio alginolyticus as the indicator. The resulting zones of inhibition were compared to that of a standard Kirby-Bauer sensitivity disc containing 25 μg of the drug that was placed on each plate as standard control. Negative controls consisted of equal numbers of nauplii and nematodes that were not exposed to the antibiotic. Artemia nauplii and nematodes accumulated approximately 0.1 μg of the drug per nauplius and approximately 0.25 μg per nematode. They exhibited no signs of toxicity from exposure to the drug and contained the antibiotic in sufficient quantity to provide a theoretical therapeutic dose of the drug when fed to penaeid larvae.
In subsequent tests, normal and diseased larval Penaeus stylirostris readily accepted Romet-30 enriched Artemia . Diseased larvae fed the drug in this manner exhibited a statistically greater overall survival and a greater survival to the post-larval stage by Student's t -test at the 5% significance level.  相似文献   

12.

In this study, we analyzed the effects of supplying two alternative Patagonian-autochthonous probiotic strains of Bacillus sp. and Lactococcus sp. or no probiotic at all (control treatment) on the survival, stage duration, molting success to the next larval instar, and speed of vertical displacement of the zoeae I of the southern surf crab Ovalipes trimaculatus, also considering two alternative methods for their administration: (i) direct inoculation into the rearing seawater or (ii) bio-encapsulation in Artemia persimilis nauplii. Both probiotic strains were effectively bio-encapsulated by the nauplii at high CFU x naupli?1. Probiotic inoculation in the rearing seawater improved the performance of the zoeae over the control treatment and also outperformed bio-encapsulation. Bio-encapsulation in Artemia nauplii resulted in lower survival and molting success to zoeae II compared to the control treatment. No significant differences were observed between the mean effects of either one of the two probiotics. Overall, our results show that the direct inoculation of any of both probiotics into rearing seawater improves the larval culture of the portunid crab.

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13.
A series of ingestion trials were conducted to determine the ingestion rate of Artemia nauplii by Eriocheir sinensis zoea larvae with increasing densities of Artemia and with or without rotifers as a co-feed. At each zoeal stage, 10 groups of 10 larvae were reared individually in glass beakers and fed with increasing densities of newly hatched Artemia nauplii (0.5, 2.5, 5, 10 and 20 individual (ind.) mL−1) with or without rotifers (15–25 ind. mL−1) as a co-feed. The average number of ingested Artemia was measured over 24 h. In addition, the average larval development rate (Larval Stage Index, LSI) over a longer period (time needed for the best treatment to reach 100% moult or metamorphosis to the next larval stage) was compared. The results showed that Artemia ingestion rate of E. sinensis larvae increased with increasing prey densities and larval development, and had a significantly negative correlation with rotifer consumption for all zoeal stages. Rotifers as an alternative prey significantly affected the intake of Artemia at early larval stages (Z1 and Z2) and promoted LSI at a lower Artemia density. Further experiments are needed to clarify the effect of prey density on survival and larval development when larvae are reared communally.  相似文献   

14.
ABSTRACT:   In the present study, Schizochytrium limacinum OUC88, a thraustochytrid with high content of docosahexaenoic acid (DHA, 22:6 n −3), was used as feed for rotifer Brachionus plicatilis and Artemia franciscana . The rotifer and Artemia were harvested at 3, 6, 9, 12, 18, and 24-h intervals, analyzed for fatty acid composition, and compared with the control which fed on yeast only. The highest DHA content resulted from an enrichment period of 12 h for both fed organisms, reached 13.4 and 10.9% of the total fatty acids (TFAs) in rotifers and Artemia nauplii, respectively, and the DHA level reduced sharply if enrichment time was longer than 12 h. The pseudoalbinism rate of turbot Scophthalmus maximus juveniles fed enriched rotifers and Artemia nauplii reduced greatly (40% lower than in control group). Thus, enrichment of rotifers and Artemia nauplii by DHA-rich Schizochytrium limacinum OUC88 may provide a practical strategy for feeding fish juveniles in aquaculture.  相似文献   

15.
Abstract— The effects of four kinds of foods ( Artemia nauplii, rotifer, and microalgae Chaetoceros gracilis and Isochrysis galbana ) and four temperature regimes on survival and development of larval Lysmata wurdemanni , a marine ornamental shrimp, were determined. The larvae fed with Chaetoceros or Isochrysis only survived for a maximum of 17 d, before developing to zoea IV. The survivorship of the larvae fed with Artemia nauplii or rotifer from zoea II to post-larvae was 66.7% and 68.9%. respectively, without significant difference ( P > 0.05). But larvae fed with Artemia nauplii grew significantly ( P < 0.05) faster than those fed with rotifer. Larvae fed with Artemia nauplii reached postlarvae in 29–32 d, compared with 32–36 d in the rotifer treatment. Artemia nauplii are also suitable food for the postlarvae and juveniles of L. wurdemanni . The 30 postlarvae fed on Artemia nauplii all survived to reach sexual maturity in 50 to 70 d, growing from about 7 to 28 mm in total length. The effects of four temperature regimes on larval development of L. wurdemanni was also investigated. The duration (mean ± SD d) to the postlarvae at temperatures of 26 C (37.4 ± 5.4) and of 26–30 C daily (40.2 ± 5.8) was significantly ( P < 0.05) longer than that at 28.5 C (29.3 ± 4.8) and at 27–29 C daily (28.7 ± 3.5).  相似文献   

16.
A docosahexaenoic acid (DHA), 22:6(n-3), rich strain of Schizochytrium sp. was used in a spray-dried form to evaluate the enhancement of highly unsaturated fatty acids (HUFAs) in Artemia franciscana nauplii (Utah biotype) and the rotifer Brachionus plicatilis . This heterotrophic microalga was selected because of its high concentration of the longest chain HUFAs in the n-3 and n-6 series, DHA and docosapentaenoic acid (DPA), 22:5(n-6), respectively. When 24-h-old Artemia nauplii were fed 400 mg/L of the algae for 24 h, the DHA content of the nauplii went from undetectable levels to 0.8% of dry weight and the omega-3 HUFA eicosapentaenoic acid (EPA), 20:5n-3, content went from 0.1% to 0.5% of dry weight in the nauplii. Similarly, 22:5(n-6) increased in the nauplii from undetectable levels to 0.4% of dry weight, with a concomitant increase in arachidonic acid, (20:4n-6), from trace to 0.3% of dry weight even though there was no arachidonic acid in the algal biomass. Similar enrichment patterns were observed in rotifers. The results suggest that spray-dried cells of Schizochytrium sp. are effective in enriching Artemia naupli and rotifers in both n-3 and n-6 HUFAs. The results also suggest that Artemia nauplii and rotifers are capable of readily retroconverting 22:6(n-3) to 20:5(n-3) and 22:5(n-6) to 20:4(n-6) through the process of β-oxidation, a well-known process in mammals.  相似文献   

17.
The aquaculture of marine finfish in Newfoundland presents a challenge due to the cold-water (<0 C) conditions which occur over a four to five month period. As part of a continuing research program on the culturing of cold-water marine finfish species we report on preliminary results of two "new" aquaculture species. The lumpfish and the Ocean pout both occur along the coast of Newfoundland and are adapted to a cold-water environment. Lumpfish have been reared from egg masses collected from the wild or from eggs stripped in the hatchery. Eggs and larvae are relatively large and larvae are well developed at hatch. Larvae will feed on day-old Artemia nauplii after four to six days. Survival over the first eight weeks is high but declines over the first year. Lumpfish cultured in the laboratory become sexually mature and produce eggs (roe) at the end of their second year. Ocean pout have been cultured only from egg masses collected from the wild. Eggs and larvae are extremely large compared to other marine finfish currently being cultured. Larvae hatch during the cold-water period, absorb the yolk-sac within 24 hours and are ossified at hatch. Juveniles feed on Artemia nauplii within two days at very low temperatures. Survival is comparatively high (75–80%) over the first year. Initial results are encouraging but more research is required before commercial production of these species would be feasible.  相似文献   

18.
Artemia salina cysts (San Francisco Bay Brand) were exposed in seawater containing multiple concentrations of either a single heavy metal (Hg, Cu, Zn, Pb, Cd, Co, Ni, Cr, Mn and Fe) or combination of heavy metals. The heavy metal accumulation in Artemia nauplii increased linearly with an increase in the heavy metal concentration in water. The metals could be detected in nauplii exposed to a single heavy metal at dosages of 5 μg/L for Hg, Zn, Mn, Fe and Cu; 25 μg/L for Cd and Cr; 50 μg/L for Co; 100 mUg/L for Ni; and 250 μg/L for Pb. Cysts exposed to several heavy metal combinations had minimum effective dosages equal to or lower than the single heavy metals- 5 μg/L for Cu, Cr, Zn, Mn and Fe; 25 μg/L for Cd and Ni; 50 μg/L for Co; and 250 μg/L for Pb. The accumulation of Cu, Ni and Co by Artemiu nauplii did not differ for animals exposed to single or combined heavy metal solutions. Cr, Zn and Pb had a synergistic effect of heavy metal uptake in combined heavy metal element solutions, however, Fe, Cd and Mn had an antagonistic effect.  相似文献   

19.
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.  相似文献   

20.
Nauplii hatching from Artemia cysts are crucial in larviculture nutrition. Artemia cysts may be exposed to repeated hydration/dehydration (H/D) cycles pre-harvesting or during processing and storage. To observe the effect of these cycles on cyst quality, Artemia franciscana cysts were exposed to a comprehensive set of various H/D treatments, differing in the number of cycles (1, 2, or 3) and the duration of the freshwater hydration period (2 or 4 h). Cyst quality was assessed using the criteria of immediate relevance for aquaculture use, such as hatching percentage directly after H/D treatment and after ?18 °C storage up to 1 month, longevity of axenically hatched starved nauplii, cyst and naupliar energy content, and (for the most extreme H/D treatment) cyst and naupliar fatty acid and vitamin C content. Repeated H/D cycles resulted in significantly (P < 0.05) decreased cyst hatching, reduced starved naupliar longevity and individual energy content, loss in vitamin C and fatty acid content, and moreover a close correlation between these parameters as a function of progressive H/D treatments. This is of immediate relevance for aquaculture nutrition, as commercial Artemia cysts may have gone through an unknown sequence of H/D cycles in nature or in the processing line, which affects the nutritional quality of the nauplii used in larviculture operations.  相似文献   

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