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1.
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   

2.
This study evaluated the effect of exogenous digestive enzymes on the survival, growth performance and morphology of the digestive tract of juveniles of the longsnout seahorse Hippocampus reidi fed exclusively with Artemia and supplemented with five different concentrations of porcine pancreatin (PP) (0, 5, 25, 50 and 75 mg/L from birth until 30 days after release). The results found in the present study clearly show that there was a significant increase in survival and growth as well as substantial changes in the morphology of intestinal villi in seahorses fed exclusively with Artemia supplemented with 75 mg/L PP. Therefore, the use of digestive enzyme supplementation constitutes an important advance for the establishment of a more efficient and practical feeding protocol (exclusive use of Artemia) for juveniles of the longsnout seahorse.  相似文献   

3.
Seahorses are ambush predators that swallow the prey through their tubular snout. In order to better understand mouth growth and its effect on prey preference by juveniles of the seahorse Hippocampus guttulatus, experimental assays were carried out by feeding juveniles (0–30 – d after male's pouch release [dar]) on a mixture of rotifers, Brachionus plicatilis; Artemia nauplii; and copepods; Acartia tonsa. Mouth development in juveniles was accomplished by growth of upper and lower jaws, which were linearly correlated with juvenile length, whereas mouth width (MW) and height (MH) grew exponentially with juvenile size. Additionally, MW and MH were exponentially correlated, so that the transversal section of the mouth increased linearly with juvenile age and length. Gut content and Ivlev' selectivity index demonstrated a permanent rejection of rotifers for the whole experimental period and a clear preference of juveniles for copepods from 0 to 15 dar and for Artemia nauplii afterwards. Results also suggest that juveniles are able to ingest larger prey than those provided as the limiting factor in prey ingestion was not MW, as for many marine fish larvae, but mouth area. A tentative feeding schedule to successfully feed H. guttulatus juveniles from 0 to 30 dar is proposed.  相似文献   

4.
The purpose of this study was to evaluate the effect of varying dietary levels of highly unsaturated fatty acids (HUFAs) in live prey (Artemia nauplii and a calanoid copepod, Schmackeria dubia) on the growth performance, survival, and fatty acid composition of the lined seahorse, Hippocampus erectus, juveniles. Artemia nauplii were enriched with a commercial product (SS? 50DE‐microcapsule as HUFA source, 2/3 DHA, 1/3 EPA. Shengsuo Fishery Feed Research Center of Shandong Province, Qingdao, China) at four concentrations of 0.0, 14.0, 28.0, and 56.0. Newly hatched juveniles were cultured for 35 days. The content of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and n‐3 HUFAs in the Artemia nauplii was positively related to the enrichment concentration. At the end of the trials, growth performance of the juveniles was positively related to the enrichment concentration as well. However, the juveniles fed prey enriched with the highest concentration of enrichment (56.0 μL/L) had the significantly lower (P < 0.05) survival rate. The juveniles fed the copepod had the best growth performance and the highest survival rate, suggesting that the copepod, S. dubia, is suitable for feeding the seahorse juveniles. The comparisons between the growth, survival, and fatty acid profiles of the juveniles fed Artemia and copepods indicate that the seahorse juveniles require dietary levels of DHA beyond those achieved by enriching prey with the HUFA enrichment. Surplus EPA resulted from an imbalance between DHA and EPA in the enriched Artemia nauplii probably caused an adverse effect on the seahorse juveniles. This study suggests that DHA and EPA requirement of the lined seahorse juveniles is roughly 32% of total fatty acid, and the optimal DHA/EPA ratio for the species is circa 4:1. To avoid an adverse effect resulting from excessive EPA, maximum proportion of EPA in enriched Artemia nauplii should not exceed 13% of total fatty acid, and a recommended minimum DHA/EPA ratio in the enriched Artemia nauplii is 1.46. Arachidonic acid (20:4n‐6) might not be an essential fatty acid for the seahorse juveniles.  相似文献   

5.
As with many species of seahorses, Hippocampus hippocampus wild populations are being subjected to uncontrolled exploitation in their natural environment. Thus, aquaculture could contribute to satisfy the commercial demand for animals while promoting the recovery of wild stocks. The present study was conducted to compare the effect of the substituting Artemia nauplii with rotifers for first feeding seahorse juveniles. Survival, growth and biochemical composition of prey organisms and fish were studied during the feeding trial. In addition, to help the biometric study, an anaesthetic test was also carried out using clove oil. The results showed excellent survival (average 60%) in juveniles exclusively fed with Artemia, with better values than those reported previously obtained by other authors for this species. By comparison, high mortality and poor growth were observed during first feeding with seahorses fed on rotifers. This could have been related to the lower energy intake and poorer nutritional value of the rotifers. Furthermore, clove oil concentrations of 25 ppm were found to work well as an anaesthetic for seahorse juveniles. Overall, first feeding Artemia alone was found to be an efficient and simplified method for feeding young H. hippocampus fry, building the principles for their culture for ornamental or re‐stocking purposes.  相似文献   

6.
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.  相似文献   

7.
T Næss  Ø Lie 《Aquaculture Research》1998,29(12):925-934
Six groups of Atlantic halibut, Hippoglossus hippoglossus L., larvae were offered calanoid cope-pods at different periods from days 11 to 25 after first feeding (1.13-3.20 mm myotome height) in order to establish at which stage normal pigmentation was determined. Artemia nauplii enriched with an oil emulsion were used prior to and after the copepod period. Control groups were fed on copepods or Artemia only. The Artemia diet initiated an earlier intake of food and higher initial growth compared to the copepod diet. After 50 days of feeding, the average dry weights of the fish fed on Artemia and copepods were quite similar to the copepod-fed fish, while the Artemia-fed fish were the smallest in size. The lowest frequency of normally pigmented juveniles was found in the Artemia-fed group (66.4%), while the copepod group showed almost 100% normal pigmentation. A significantly higher frequency of pigmentation was found in juveniles given a copepod diet close to the initiation of metamorphosis than those provided with an earlier copepod period of equal duration. A high degree of eye migration was found in all groups, but was lowest in the Artemia-fed group. The initial stage of eye migration was found to occur at a larger body size in fish given Artemia and copepods, or a copepod diet than in fish fed on Artemia alone. There was no significant correlation between eye migration and growth rates prior to metamorphosis, although the largest individuals exhibited the most complete eye migration. High pigmentation frequencies were obtained in fish with a low 22:6n-3:20:.5n-3 (DHA:EPA) ratio (< 1.0).  相似文献   

8.
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   

9.
The effects of two weaning diets and different weaning protocols on growth, survival, skeletal deformity and gut morphology of Atlantic cod larvae were studied in four groups from 16 to 45 days posthatch (dph). Cod larvae in groups 1 (early weaning with control diet) and 2 (early weaning with experimental diet) were used to evaluate the effects of different polar lipid content of weaning diets on larval and juvenile performance. Cod larvae in groups 2, 3 (early weaning with experimental diet + cofeeding with Artemia) and 4 (earlier weaning with experimental diet and earlier cofeeding with Artemia) were used to evaluate the effects of early introduction of dry diet and Artemia. From 45 to 170 dph, cod juveniles from all four groups were reared using a standard feeding protocol. No significant differences in growth, survival, deformities and gut morphology were found between cod larvae and juveniles from groups 1 and 2. Cod larvae fed on cofeeding regime with Artemia nauplii (groups 3 and 4) were bigger and had lower frequencies of jaw and neck deformities and higher foregut microvillus circumference than cod larvae from group 2. Our results demonstrate the importance of proper weaning protocols in producing better quality cod juveniles.  相似文献   

10.
The aim of this study was to compare the nutritional composition and effects of short periods with cultivated copepod nauplii versus rotifers in first‐feeding. Atlantic cod (Gadus morhua) and ballan wrasse (Labrus bergylta) larvae were given four different dietary regimes in the earliest start‐feeding period. One group was fed the copepod Acartia tonsa nauplii (Cop), a second fed enriched rotifers (RotMG), a third fed unenriched rotifers (RotChl) and a fourth copepods for the seven first days of feeding and enriched rotifers the rest of the period (Cop7). Cod larvae were fed Artemia sp. between 20 and 40 dph (days posthatching), and ballan wrasse between 36 and 40 dph, with weaning to a formulated diet thereafter. In addition to assessing growth and survival, response to handling stress was measured. This study showed that even short periods of feeding with cultivated copepod nauplii (7 days) had positive long‐term effects on the growth and viability of the fish larvae. At the end of both studies (60 days posthatching), fish larvae fed copepods showed higher survival, better growth and viability than larvae fed rotifers. This underlines the importance of early larval nutrition.  相似文献   

11.
The effect of photoperiod and tank colour on the survival and growth of juvenile seahorse Hippocampus reidi was investigated in the first 15 days after release (DAR). In the first experiment, newly released seahorses were exposed to six photoperiods – 6 h of light (L):18 h of darkness (D), 10L:14D, 12L:12D, 14L:10D, 18L:6D and 24L:0D. In the second experiment, juveniles were kept in tanks of different background colours – blue, white, black, clear and red. No significant differences were observed in the growth and survival among seahorse subjected to 10–24 h of light (P > 0.05). At the end of 15 DAR, fish exposed to 6L:18D showed lower growth in height and weight compared to other treatments (13.8 mm vs. 20.0–22.2 mm and 13.4 mg vs. 37.2–43.2 mg respectively) and lower survival (80% vs. 88–95% respectively). Tank colour did not affect growth and survival of juveniles up to 15 DAR.  相似文献   

12.
Breeding in captivity for research or exhibition (e.g. in aquaria) can replace the capture of wild specimens of endangered species and allow controlled reinforcement of wild populations. With this aim, diet analysis and establishing the adequate prey are determinant factors for breeding success. However, non‐invasive approaches such as faecal DNA analysis are advisable for analysing the diet of these species. Therefore, the aim of the present study was to demonstrate the usefulness of faecal DNA analysis by specific PCR amplification of prey DNA for assessing the diet of the seahorse Hippocampus guttulatus. In a comparison of the suitability of different genes (COI, 18SrRNA and 28SrRNA), 18SrRNA was found to be the most suitable for designing specific primers for the prey types fed to seahorses (Artemia, Palaemonetes and Mysidae). The technique was assessed in feeding experiments in which prey ingestion was recorded daily, and faeces were collected for DNA extraction and presence/absence PCR analysis. Amplification of the prey DNA in faeces was consistent with the sequence of prey supplied (prey eaten the day before was always detected). Differences in the time between feeding and detection in faeces suggested prey‐specific gut passage times, which were shorter for Palaemonetes than for Mysidae. This fact highlights the importance of feeding trials to avoid overestimating the consumption of prey with long gut retention when PCR‐based methods are used. This molecular technique is thus applicable for studying the feeding behaviour of captive seahorses and could be adapted for use in other marine species.  相似文献   

13.
Ontogenetic development of the digestive tract and associated organs in long snout seahorse Hippocampus guttulatus juveniles was morphologically and histologically examined from the time of release from the male’s pouch until 72 h after the first meal. When released from the male’s pouch, juvenile seahorses are small adult replicates. This means that unlike other teleost fish larvae, the first developmental phase has already taken place, and juveniles are morphologically prepared and able to feed on live prey immediately following parturition. At this stage, the buccopharynx, oesophagus, and intestine already appear to be fully developed. The intestine is divided into the midgut and hindgut by an intestinal valve, and intestinal villi are visible in the midgut. When fed with DHA-Selco® enriched Artemia, H. guttulatus juveniles developed a severe condition of overinflation of the gas bladder. The continuous overinflation of the gas bladder forced air into the gut (48 h after the first meal), resulting in overinflation of both the gut and the gas bladder (72 h after the first meal), and death occurred within 120 h after the first meal. When fed natural copepods, H. guttulatus juveniles continued a normal feeding activity with no signs of intestinal disorders, and the gas bladder and intestine maintained their normal shape. This is the first study to positively associate gas bladder overinflation of juvenile seahorses with nutritionally unbalanced diets, and not to gas supersaturation alone. It is therefore necessary to develop more adequate feed and/or enrichment products to improve the survival of juvenile seahorses in captivity.  相似文献   

14.
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   

15.
The copepod Cyclopina kasignete is a potential live food in aquaculture and its fatty acid components and digestive enzymes were investigated. Three dry algal products (mixed algae, Melosira sp. and Nannochloropsis oculata) and two fresh microalgae (Tisochrysis lutea and N. oculata) were fed to the copepod for 30 days. The essential fatty acids (EFA) in copepods were altered by feeding different types of dry algae. The copepod fed dry Melosira sp. or fresh T. lutea contained higher eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and arachidonic acid (ARA), protease and trypsin than fed on other algae. The copepod contained a similar fatty acid profile and digestive enzymes by feeding either dry or fresh N. oculata. Between fresh algal species, the copepod fed T. lutea contained higher EPA, DHA and ARA than that fed fresh N. oculata. The amounts of EPA and DHA in copepods were more concentrated than those in the dietary algae, suggesting that the copepod has the ability to accumulate some EFA. This study indicates that dietary algae can modify the nutritional composition and in digestive enzymes copepods, which in turn may be able to transfer suitable nutrients and digestive enzymes to fish larvae in aquaculture.  相似文献   

16.
Live prey used in aquaculture to feed marine larval fish – rotifer and Artemia nauplii – lack the necessary levels of n‐3 polyunsaturated fatty acids (n‐3 PUFA) which are considered essential for the development of fish larvae. Due to the high voracity, visual feeding in conditions of relatively high luminosity, and cannibalism observed in meagre larvae, a study of its nutritional requirements is needed. In this study, the effect of different enrichment products with different docosahexaenoic acid (DHA) concentrations used to enrich rotifers and Artemia metanauplii have been tested on growth, survival, and lipid composition of the larvae of meagre. The larvae fed live prey enriched with Algamac 3050 (AG) showed a significantly higher growth than the rest of the groups at the end of the larval rearing, while the larvae fed preys enriched with Multigain (MG) had a higher survival rate. DHA levels in larvae fed prey enriched with MG were significantly higher than in those fed AG‐enriched prey. High levels of DHA in Artemia metanauplii must be used to achieve optimal growth and survival of meagre larvae.  相似文献   

17.
The importance of a suitable diet for reproduction has been recognized as one of the major factors in ornamental aquaculture. In seahorses, mysids have been described as preys in the wild. Also, Artemia has been usually employed for rearing fish, including syngnathids. Therefore, the aim of this work was to evaluate the effect of these live preys on the spawning quality of Hippocampus hippocampus. After 108 d, no differences were found in adults concerning all biological parameters evaluated, but broodstock fed on mysids showed better results than Artemia regarding number of spawning events (12 vs. 3), brood sizes (233.50 ± 59.04 vs. 68.00 ± 57.97 juveniles), and newborn seahorses standard length (10.61 ± 0.64 vs. 8.75 ± 1.32 mm). The better nutritional quality of mysids, overall in Docosahexanoic acid, could be one of the main responsible factors. However, mysids stock is conditioned by natural catches and rearing techniques are little known. Another alternative would be to combine them with Artemia in mixed diet. Further research must be done concerning mysids breeding techniques to delineate their employment as a sustainable prey for seahorse aquaculture. This trial showed for the first time the effect of mysids to enhance reproduction efficiency in H. hippocampus.  相似文献   

18.
The short‐snouted seahorse (Hippocampus hippocampus) is a benthic fish that bases its survival on camouflage with the environment; therefore, both in wild and in captivity specimens, differences in coloration have been observed. This study was conducted to study the effect of five different diets, based on Artemia and frozen mysis, on fish survival, growth, skin colour parameters and biochemical composition. After 102 days of feeding different diets, no effect was observed on fish survival, growth, protein, ash or humidity content, except for colour changes on yellow and red fish. Differences on seahorse lipid and total carotenoids content were obtained in the experiment because of experimental diets. Fish eating Artemia showed the highest colour pattern response during the trial, with a maximum yellowness attained of 21. Additionally, a plateau of the skin colour expression for Artemia‐feeding fish was reached on day 180. A reversion of the yellowish skin colour was determined after a change of diet.  相似文献   

19.
Variations in digestive enzymes and hormones during the larval development of gilthead seabream (Sparus aurata) fed on live prey (Artemia nauplii) enriched with free lysine were investigated for 16 days (from day 24 to day 40). Prior to initiation of the experiment, newly hatched larvae were transferred from incubators to fiber glass tanks (300 l) with black walls and fed the same diet until day 24. Each experiment was performed in triplicate. The amount of free lysine in the Artemia nauplii was increased by adding a 5.3 mM free amino acid solution to the culture water during a 16-h enrichment period. Larvae were sampled four times at four-day intervals, for 16 days. Larvae fed on the control group had lower growth than those fed on the lysine group at the end of the study but the difference was not significant (P > 0.05). The highest trypsin activity and lap/leu–ala peptidase ratios were observed in the control group (P < 0.05). Significant differences between bombesin activities of the treatment groups were not found in the fifth minute after the start of feeding (P > 0.05) but were significant in the fifteenth minute (P < 0.05). Significant differences between the CCK levels of the treatment groups were found (P < 0.05). In conclusion, three main ideas are presented in this study. First, Artemia nauplii can successfully be enriched with free lysine. Second, bombesin (GRP) and cholecystokinin (CCK) activity can be stimulated by free lysine. Third, the mechanisms controlling adaptation of the activity of the trypsin to the amount of dietary protein were not activated until day 40.  相似文献   

20.
The performance of microbial flocs as food for Artemia, which were produced using waste from a recirculating aquaculture system stocking European eel (Anguilla anguilla), was investigated in an 18‐day feeding trial. Four dietary treatments were used: Chlorella only (diet 1), flocs only (diet 2), and both Chlorella and flocs offered as mixed diets in different proportions (diets 3 and 4). The survival rate of Artemia fed diets 1 and 4 were significantly higher than those fed diets 2 and 3. The survival rate of Artemia fed diet 4 was the highest among the four diets. Individual length (10.02 ± 2.44 mm) and biomass production of diet 3 (3.2 ± 0.40 g L–1) were the highest among the four diets. The crude protein contents for Artemia fed diets 2, 3 and 4 were 591.22 ± 30.15, 580.34 ± 22.42 and 533.27 ± 34.19 g kg–1, respectively, which were significantly higher than that of diet 1 (461.25 ± 10.33 g kg–1). The concentrations of free amino acids and the fatty acid compositions in the four diets were equal, except for the C24:0 content. The highly unsaturated fatty acid concentration of Artemia fed diet 2 was higher than those of the other three diets. It showed that microbial flocs produced from fish waste can be used for Artemia.  相似文献   

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