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1.
The free‐living nematode Panagrellus redivivus was mass produced on a solid culture medium enriched with sunflower oil or fish oil by means of a new technology. Nematodes with different fatty acid compositions were obtained. A 7‐day experiment was performed in order to compare the lipid enriched nematodes with Artemia as live food for first feeding common carp (Cyprinus carpio L.) larvae. Larvae fed nematodes doubled their body mass and had a mean survival rate higher than 80%. No significant differences could be observed between the two groups fed nematodes. Fish larvae fed with Artemia showed almost no mortality and had a final body mass five times higher than larvae fed nematodes. It is concluded that mass produced nematodes are a promising food source for first feeding common carp larvae. However, further research is needed on the development of improved culture media to increase the nutritional value of P. redivivus.  相似文献   

2.
The nematode Panagrellus redivivus (Linné) has been suggested as a source of live food in the rearing of larval fish and shrimp species. This study tested the use of P. redivivus in the early rearing of the bottom‐feeding catfish Synodontis petricola (Matthes). A comparison of feeding rates of 5000–10 000 nematodes larva−1 day−1 showed that fish receiving 5000 nematodes larva−1 day−1 grew faster than those fed a dry diet, but slower than treatments fed 200 and 600 Artemia larva−1 day−1. Enrichment of nematodes with SuperSelco® improved fish growth relative to a non‐enriched control treatment, with both treatments receiving 5000 nematodes larva−1 day−1. In the first two trials, feeding commenced 2 days after hatching. In the third study, fish were fed nematodes 6 days after hatching and there was no difference in growth between Artemia‐fed fish (600 Artemia larva−1 day−1) and fish fed 5000 nematodes larva−1 day−1. Thus, it is suggested to feed S. petricola at a nematode density of at least 10 000nematodes larva−1 day−1 in order to achieve growth comparable to that of fish fed Artemia, or, alternatively, to feed 5000 nematodes larva−1 day−1 to improve growth relative to that achieved with a dry diet. Furthermore, nematodes may be enriched with essential fatty acids to improve the growth of S. petricola larvae.  相似文献   

3.
The free living nematode Panagrellus redivivus has shown promise as a live food for marine shrimp and fish. This study evaluated the effect of three media on the fatty acid (FA) profile of nematodes. The media tested were: wheat flour (WF), wheat flour plus yeast (WFY), and wheat flour plus yeast plus fish oil (WFFO). The total lipid content of nematodes grown on WFFO (14.9%) was significantly higher than the lipid content of nematodes grown on WF (2.7%) and WFY (4.4%). The lipid of nematodes grown on WFFO also contained a higher percentage of n-3 highly unsaturated fatty acids (HUFA) (11.2%), especially 20:5(n-3) (7.4%) and 22:6(n-3) (3.3%), than nematodes grown on WF (4.8%) and WFY (5.7%). Nematodes grown on WFFO medium had similar lipids as Artemia, especially desirable n-3 HUFA's. Total daily yield of nematodes was highest on WFY. There was no difference in yields of nematodes on WF and WFFO. This study has shown that the nutritional value of nematodes can be influenced by the media on which they are cultured. With a proper medium, cultured nematodes can provide the inexpensive, consistently nutritious live food that can be considered for larval culture of marine crustaceans and fish.  相似文献   

4.
Panagrellus redivivus is a nematode with a high protein content and low‐cost production. It is successfully used in the larviculture of shrimp, however, it has not yet been evaluated as feed for Betta splendens larvae. Thus, the objective of this study was to evaluate P. redivivus as feed for betta larvae maintained at different depths of water. The experiment was based on a completely randomized 3 × 2 factorial design, represented by two feed types and one alternating feeding regime plus two water depths (2.5 and 5.0 cm). The Artemia feed promoted the highest weight gain, followed by the alternating feeding regime. The single use of the nematode as live feed produced the poorest weight gain. The water depth and the feeding method influenced the specific growth rate (SGR). At a depth of 2.5 cm, the alternating feeding promoted similar SGR compared to fish fed with Artemia only. Furthermore, at the greater water depth an improvement in SGR was observed in fish fed Artemia only, but the similarity to alternating feeding regime remains. Thus, the inclusion of nematode is an appropriate and lower cost feed strategy for the betta larviculture independent of water depths.  相似文献   

5.
The free-living nematode, Panagrellus redivivus, was tested as live food for grouper Epinephelus coioides larvae during the first feeding stage. A series of experiments were conducted to determine the acceptability of the free-living nematodes in grouper larvae at first feeding, the optimum nematode density and the response of the larvae to nutritionally enriched nematode. All experiments were conducted in 200-L conical tanks filled with 150-L filtered seawater and stocked at 15 larvae L−1. Duration of feeding experiments was up to day 21 (experiment 1) and 14 days (experiment 2 and 3). Brachionus plicatilis and Artemia (experiment 1) and Brachionus plicatilis alone (experiment 2 & 3) was used as the control treatment. Observations indicated that the grouper larvae readily fed on free-living nematodes as early as 3 days posthatching, the start of exogenous feeding. Optimum feeding density for the larvae was 75 nematodes ml−1. The enrichment of cod liver oil or sunflower oil influenced the total lipids and n-3 highly unsaturated fatty acids of P. redivivus, which in turn influenced those of the grouper larvae, however, growth and survival of the larvae were not affected (P > 0.05). The results from this investigation showed that the nematode, P. redivivus, can be used as first live food for grouper larvae from the onset of exogenous feeding until they could feed on Artemia nauplii.  相似文献   

6.
A large effort has been dedicated in the past years to the development of nutritional balanced inert diets for marine fish larvae in order to suppress the nutritional deficiencies of live feed. In this study growth performance, Artemia intake, protein digestibility and protein retention were measured for Senegalese sole (Solea senegalensis Kaup), in order to provide insight into how protein utilization affects growth performance. Three feeding regimes were tested: ST – standard live feed; ArtRL – live feed and 20%Artemia replacement with inert diet (dry matter basis) from mouth opening; ArtRH – live feed and 58%Artemia replacement with inert diet from mouth opening. Artemia intake and protein metabolism were determined at 6, 15 and 21 days after hatching using 14C‐labelled Artemia protein and subsequent incubation in metabolic chambers. At the end of the experiment, sole fed exclusively with live feed were significantly larger than sole from Artemia replacement treatments. Protein digestibility decreased during sole ontogeny, and more sharply in ArtRH sole. Concomitantly retention efficiency increased during ontogeny but with a slight delay in ArtRH sole. Senegalese sole larvae growth and protein utilization is depressed when co‐fed high levels of inert diet and Artemia, mostly during metamorphosis climax.  相似文献   

7.
The nematode Panagrolaimus sp. was tested as live feed to replace Artemia nauplii during first larval stages of whiteleg shrimp Litopenaeus vannamei. In Trial 1, shrimp larvae were fed one of four diets from Zoea 2 to Postlarva 1 (PL1): (A) Artemia nauplii, control treatment; (NC) nematodes enriched in docosahexaenoic acid (DHA) provided by the dinoflagellate Crypthecodinium cohnii; (N) non‐enriched nematodes; and (Algae) a mixture of microalgae supplemented in C. cohnii cells. In Trial 2, shrimp were fed (A), (NC) and a different treatment (NS) with nematodes enriched in polyunsaturated fatty acids (PUFAs) provided by the commercial product S.presso®, until Postlarva 6 (PL6). Mysis 1 larvae fed nematodes of the three dietary treatments were 300 μm longer (3.2 ± 0.3 mm) than control larvae. At PL1, control shrimp were 300 μm longer (4.5 ± 0.3 mm) than those fed DHA‐enriched or PUFAs‐enriched nematodes. No differences were observed in length and survival at PL6 between control larvae and those fed DHA‐enriched nematodes (5.1 ± 0.5 mm; 33.1%–44.4%). Shrimp fed microalgae showed a delay in development at PL1. This work is the first demonstration of Panagrolaimus sp. suitability as a complete substitute for Artemia in rearing shrimp from Zoea 2 to PL6.  相似文献   

8.
The free-living nematode Panagrellus redivivus is a potential source of live food for first feeding fish. The digestion and assimilation of nematodes by larval fish were investigated with the aid of a histological and stable isotope approach. Larvae of whitefish Coregonus lavaretus were reared for 8 d with nematodes and compared with an unfed control. Nematodes were readily ingested by 3-d-old larvae. Different stages of nematode digestion could be observed in transverse sections of fish larvae sampled on Day 6 at regular intervals after feeding. Nematodes were produced on corn medium. In this way nematodes with a stable carbon isotope signature clearly different from the isotopic pattern of the fish larvae could be obtained. Stable carbon isotope signatures for lipids and lipid-free matter of fish larvae sampled on Days 2 and 8 after first feeding were clearly influenced by the stable isotopic pattern of the nematodes. The high acceptance of the nematodes by Coregonus lavaretus larvae and the early onset of digestion and nutrient retention positively confirm the potential of PanagreUus redivivus as a live food for first feeding fish larvae.  相似文献   

9.
This study assessed the performance of L. alexandri postlarvae (2 days after hatching) with different diets (Artemia and Panagrellus redivivus), food amounts (C300-C500-C700), and feeding frequencies (F1-F3-F6) in two experiments lasting 10 days. The best performing food type, Artemia and Artemia with P. redivivus, presented the highest survival rates as well as fish with the greatest weight, length, and specific growth rate (SGR). In the second experiment with Artemia, the weight, length, and SGR presented significant differences, increasing with higher amounts of prey. The best performance was obtained from a daily diet (F1) with the greatest amount of prey (C700).  相似文献   

10.
The suitability of decapsulated cysts of the fairy shrimp, Streptocephalus dichotomus as a sole diet was evaluated for the ornamental angelfish Pterophylum scalare larvae. Brine shrimp, Artemia sp., and microworms, Panagrellus redivivus, were used as comparison foods. The results indicate an appreciable weight gain of 15.22±1.69 mg and a growth (length) of 0.876±0.03 cm in experimental fish fed decapsulated fairy shrimp cysts compared with the growth and weight of fish fed other foods. The influence of the experimental diets was further reflected in the composition of fatty acid and amino‐acid profiles of the experimental fish. Angelfish larvae readily consumed the decapsulated cysts and utilized them efficiently during the early days of exogenous feeding.  相似文献   

11.
Problems of limited number of dry feeds as supplement or replacement of live feeds have led to poor larval nutrition in many species of fish. Therefore, the suitability of co‐feeding 8‐day‐old African catfish (Clarias gariepinus) posthatch larvae using live feed (Artemia salina) and formulated dry diet containing freshwater atyid shrimp (Caridina nilotica) during weaning was investigated. The experiment ended after 21 days of culture and respective groups compared on the basis of growth performance, survival, feed utilization and nutrient utilization. Larvae co‐fed using 50%Artemia and 50% formulated dry diet resulted in significantly (P < 0.05) better growth performance, food gain ratio (FGR), protein efficiency ratio (PER) and productive protein values (PPV) than other treatments. The lowest growth performance occurred in larvae weaned using 100% formulated and commercial dry diets. Better survival of over 90% was obtained in larvae weaned using 50%Artemia and 50% dry diet, while abrupt weaning using 100% dry diets resulted in lower survival (<75%). These results support a recommendation of co‐feeding C. gariepinus larvae using a formulated dry diet containing C. nilotica and 50% live feed when weaning is performed after 8 days posthatching period.  相似文献   

12.
The specific activity of alkaline protease, trypsin and pepsin‐like enzymes was measured in yolk sac stage Acipenser persicus larvae and over a 1‐month feeding experiment using live Artemia nauplii (ND), formulated feed (FD) or mixed food (MD). Artemia nauplii group larvae showed significantly higher growth and survival during the first 15 days while FD larvae showed the lowest growth and survival. At day 30, MD larvae exhibited significantly higher growth than the ND group. Alkaline protease activity showed the lowest activity on day 15; the highest activity was observed in the MD group larvae. Pepsin‐like activity showed a drastic increase from day 1 to 5 in all treatments, but remained stable throughout the next 25 days, with the lowest and the highest activity in the FD treatment on day 10 and in the MD treatment on day 30 post‐feeding respectively. Trypsin‐like activity in group ND remained almost the same from day 5 to 30, whereas in groups MD and FD, it decreased significantly from day 10 to 30. The contribution of the naupliar proteases was moderate but effective. Additionally, better performance in Artemia fed sturgeon larvae may also be due to the structure and digestibility of proteins and the food intake stimulation by the nauplii.  相似文献   

13.
Supplementation of microalgae and Artemia nauplii with practical formulated feeds containing fresh or dried Artemia biomass for larval rearing of black tiger shrimp, Penaeus monodon, was assessed. Five feeding treatments were carried out in a recirculating seawater system with fifteen 30-L fiberglass tanks. Shrimp nauplii were stocked at a density of 150 L?1 for 23 days. In the control treatment, live feed was supplemented with commercial formulated feed (Inve Aquaculture NV, Belgium). In two other treatments, live feed was supplemented with a pelleted feed based on either fresh or dried Artemia. In the remaining two treatments live feed was supplemented with a combination of 50% commercial feed and 50% fresh or dried Artemia feeds. Overall, performance of PL in the combination treatments (commercial feed and Artemia diets) were equal to or better than those fed commercial feed alone as seen by the better growth rate and higher resistance to formalin stress. The results indicate that feed containing fresh or dried Artemia biomass can partially supplement live feeds for larval rearing of P. monodon.  相似文献   

14.
The tongue sole Cynoglossus semilaevis, an inshore fish in China, has showed great potential in aquaculture recently. However, poor survival was recorded during the period of weaning from live Artemia to artificial diets. In this paper, the influence of co‐feeding larvae with live and inert diet on weaning performance was described. The C. semilaevis larvae were reared at 21 ± 1 °C and fed four different feeding regimes from 6 days post‐hatching (dph): A, Artemia (10 individuals mL?1); B, Artemia (5 individuals mL?1); C, mixed diet (10 Artemia individuals mL?1 and 12 mg L?1 inert diet); and D, mixed diet (5 Artemia individuals mL?1 and 12 mg L?1 inert diet). Rotifers were also supplied in all cases during the first days of feeding. Mixed diets of commercial formulated feed and live prey (rotifers and Artemia) allowed larvae to complete metamorphosis, achieving similar specific growth rate (SGR) (18.5 ± 1.4% and 18.7 ± 1.6%) and survival (40 ± 7.6% and 48.5 ± 6.8%) compared with larvae fed on live feed alone (SGR of 18.3 ± 1.2%, 19.3 ± 1.9% and survival of 41.2 ± 11.3%, 38 ± 4.9%). However, in metamorphosed fish, when live feed was withdrawn on 31 dph, there was significant difference (P < 0.05) in survival and growth among treatments. Metamorphosed fish, previously fed mixture diets during larval stages, had similar survival (62.1 ± 7.6% and 62.8 ± 3.9% for regimes C and D, respectively) but higher than that obtained for fish that previously fed on live feed (49.3 ± 2% and 42.1 ± 3.9% for regimes A and B, respectively) after weaning (day 60). The SGR of weaned fish previously fed live feed was similar (3.1 ± 0.6% and 2.92 ± 0.6% for regimes A and B, respectively) but lower than that recorded for fish that was fed from day 6 to day 30 on the mixed diet (4.5 ± 1.1% and 4.9 ± 0.3% for regimes C and D, respectively). It is suggested that weaning of C. semilaevis from early development would appear to be feasible and larval co‐feeding improves growth and survival.  相似文献   

15.
Live food supply is a key factor contributing to the success of larval fish rearing. However, live food densities vary greatly between fish species and management protocols across fish hatcheries. The growth, survival, food selection and consumption of yellowtail kingfish larvae were examined at different regimes of live food supply in an attempt to identify a suitable live food feeding protocol for larval rearing in marine fish. This study was divided into two feeding phases: rotifer phase from 3 to 14 DPH (phase I) and Artemia nauplii phase from 15 to 22 DPH (phase II). In phase I, four rotifer densities (1, 10, 20 and 40 mL−1) were used. In phase II, Artemia started at 0.8 nauplii mL−1 on 15 DPH, and then the density of Artemia was daily incremented by 50%, 70%, 90% and 110%, respectively, in four treatments from 15 to 22 DPH. In phase I, rotifer density significantly affected larval growth, but not survival. By 7 DPH, the number of rotifers consumed by fish larvae reached 170–260 individuals, but did not significantly differ between rotifer densities. During cofeeding, fish larvae selected against Artemia nauplii by 10 DPH, but by 14 DPH Artemia nauplii became the preferred prey item by fish larvae exposed to the 10, 20 and 40 rotifers mL−1. In phase II, both fish growth and survival were affected by Artemia densities. Fish daily consumption on Artemia by 20 DPH reached 500–600 individuals but did not significantly differ between prey densities. The result suggests that rotifer densities be offered at 20–40 mL−1 before 6 DPH and 10–20 mL−1 afterwards to support larval fish growth and survival. Likewise, Artemia is recommended at a daily increment of 90–110% of 0.8 mL−1 from 15 to 22 DPH. This study proposes a management protocol to use appropriate type and quantity of live food to feed yellowtail kingfish larvae, which could be applicable to larval culture of other similar marine fish species.  相似文献   

16.
Two sets of experiments were carried out to evaluate the potential of eggs and endotrophic larvae of captive Paracentrotus lividus as alternative live prey for marine fish larvae first feeding. The first consisted in rearing sparids, Diplodus sargus and Sparus aurata, larvae until 15 days after hatching in a recirculation system. Compared with the commonly used live prey – rotifer Brachionus spp. – general lower values of survival and growth were obtained when fish larvae were fed with the alternative live prey. Among these, eggs showed to be the preferred feeding. Broodstock feed showed to play a fundamental role on prey quality and consequent fish larvae survival. In the second set of experiments, the 24‐h ingestions of the first feeding larvae in static water were determined for five currently cultured fish larvae species. Except for larger and more predatory Dicentrarchus labrax larvae, there was a trend for higher P. lividus egg ingestion, followed by pre‐plutei and prisms. Prey size, colour and movement affected food selection by fish larvae. It is concluded that, in spite of the alternative live prey being readily consumed by all tested fish larvae, they cannot however presently compete with rotifers in marine fish larvae first feeding.  相似文献   

17.
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   

18.
This article analyses the challenges of different live‐feed regimes for the rearing of marine finfish larvae and discusses the potential alternative live feeds to avert a future live‐feed trap. Live feeds are indispensable for the successful rearing of larvae of most marine fish species. Brine shrimps (Artemia) and rotifers comprise the live feeds of choice in marine aquaculture today. However, their nutritional composition is deficient in especially essential fatty acids, and enrichment with fish oil is needed. Fish oil is considered a limited resource owing to its origin in fully exploited wild fish stocks. Moreover, fluctuations of the natural population of Artemia will, most likely, influence future availability and prices. This emphasizes the need for optimal exploitation of available live‐feed resources and development of new sustainable alternatives, such as copepods. An array of solutions to these problems are presented to avoid a future live‐feed trap and to reduce dependence on limited resources that influence future production possibilities, species diversification, price volatility and productivity in the aquaculture sector.  相似文献   

19.
An experiment was conducted to evaluate the effect of different forms of Artemia biomass as a food source on survival, molting and growth rate of mud crab Scylla paramamosain. Instar 1 crablets with a mean weight of 0.0082 ± 0.0007 g were reared both individually and communally and fed with different diets consisting of fresh shrimp meat (control feed), live Artemia biomass, frozen Artemia biomass and a dried Artemia‐based formulated feed for 40 days. The highest survival was obtained for crablets receiving live Artemia (92.5% and 75.8%) followed by the groups fed with frozen biomass (90.0% and 47.5%), the control feed (72.5% and 24.2%) and the dried Artemia‐based diet (60.0% and 21.7%) for individual and communal cultures, respectively. The intermolt period, the total number of moltings and the growth rate, which were determined on individually reared crabs, showed the same pattern as for survival. The results suggest that crab performance decreased in the following order: live Artemia>frozen Artemia > fresh shrimp meat > dried Artemia‐based formulated feed. Live Artemia biomass proved an ideal feed for nursery of Scylla paramamosain crabs. Frozen Artemia biomass may be an alternative in times of shortage. Our findings illustrate the high potential for local utilization of Artemia biomass in Vietnam for reliable production of mud crab juveniles.  相似文献   

20.
Intensive grow‐out of goldfish, Carassius auratus (L.), larvae and juveniles in closed systems requires the control of environmental conditions and feeding. This study investigates the use of different types of live food and combinations of live food and dry food in a series of four rearing experiments. Juvenile goldfish can be weaned from Artemia onto live food at about 24 days after the onset of feeding without causing a reduction in growth and survival. The replacement of Artemia by Daphnia at day 10 appears feasible, as growth and survival were not significantly affected. Fish fed decapsulated Artemia cysts grew better than fish fed live Artemia. Within the first 14 days, goldfish juveniles should be fed at least 155 cysts per fish per day to achieve fast growth and to minimize size variation.  相似文献   

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