|
|
|
| Registros recuperados: 79 | |
|
| |
|
|
| Lavens, P.; Sorgeloos, P.. |
| It is generally accepted, that a major constraint in the further development of marine fish and crustacean aquaculture, is the variable quality of eggs and larvae used for the hatchery-production of fry. Nonetheless, valid criteria to evaluate optimal egg quality have not been identified yet. Instead, particular indicators, are used, e.g. the fertilization and hatching rate, overall culture success during the first rearing period, etc., but these are not totally objective because hatchery-specific conditions may interfere. The biochemical composition of the egg may be one of the possible determinants of egg quality, which can be evaluated on a more objectie basis. In this respect, studied have been initiated to analyze in freshly-released eggs, the levels... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aquaculture techniques; Biochemical composition; Crustacean culture; Eggs; Fatty acids; Fish culture; Hatcheries; Quality control; Vitamin C. |
| Ano: 1991 |
URL: http://www.vliz.be/imisdocs/publications/262328.pdf |
| |
|
|
| Vanhaecke, P.; Lavens, P.; Sorgeloos, P.. |
| Variations in dry weight, caloric content and ash content during cyst hatching and early larval development have been studied for various geographical strains of <i>Artemia</i> . In general, decapsulated cysts contain 30 to 40% more energy than freshly hatched nauplii; for Chaplin Lake and Buenos Aires <i>Artemia</i> this difference amounts to 57%. Ash contents increase as decapsulated cysts hatch into instar I and molt into instar II-III nauplii. Over a 24h larval developmental period individual dry weights and energy content of the nauplii decrease with 16-34% and 22-37% respectively.A small but significant correlation exists between the survival rate of starved nauplii and either the energy content of instar I and instar II-III... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cysts; Energy budget; Larval stages; Artemia. |
| Ano: 1983 |
URL: http://www.vliz.be/imisdocs/publications/261926.pdf |
| |
|
|
| Merchie, G.; Lavens, P.; Verreth, J.; Ollevier, F.P.; Nelis, H.; De Leenheer, A.P.; Storch, V.; Sorgeloos, P.. |
| The effect of three dietary ascorbic acid (AA) concentrations, each applied via two feed types, on production characteristics and physiological condition of African catfish (<i>Clarius gariepinus</i>) larvae has been assessed in two 10-day culture trials. Three treatments received only <i>Artemia</i> nauplii enriched with an experimental emulsion containing 0, 10 or 20% ascorbyl palmitate (AP) and yielding 530, 1200 and 1600 µg AA g<sup>-1</sup> DW <i>Artemia</i> , respectively; the other three treatments were fed the same <i>Artemia</i> diets which were partially substituted by an artificial diet containing no vitamin C (ratio 20:80). No differences in survival could be observed: however, from... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Fish larvae; Food organisms; Vitamin C; Clarias gariepinus. |
| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2963 |
| |
|
|
| Merchie, G.; Lavens, P.; Storch, V.; Übel, U.; Nelis, H.; De Leenheer, A.P.; Sorgeloos, P.. |
| Stable forms of vitamin C were verified as dietary sources of ascorbic acid (AA) for the nursery stages of European sea bass and turbot. In a first experiment, various concentrations of ascorbyl palmitate (AP) and one level of AA 2-polyphosphate (ApP) were evaluated in a semi purified diet for European sea bass, <i>Dicentrarchus labrax</i>. A significantly lower AA concentration was detected in the fry fed the AP-supplemented diets compared to the ApP-fed group, providing evidence that AP is an inferior source of vitamin C for young stages of sea bass. ApP was subsequently selected for the determination of the AA requirements of both sea bass and turbot (<i>Scophthalmus maximus</i>) fry. The AA levels incorporated in the body... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Dicentrarchus labrax (Linnaeus; 1758) [Bass] Scophthalmus maximus (Linneaus; 1758). |
| Ano: 1996 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3045 |
| |
|
|
| Coutteau, P.; Lavens, P.; Sorgeloos, P.. |
| In this study baker's yeast was evaluated as a substitute for live <i>Dunaliella tertiolecta</i> algae in the culture of the brine shrimp <i>Artemia</i> . Consumption of fresh baker's yeast resulted in poor growth and survival of brine shrimp. However, the nutritional value of the yeast significantly improved after complete removal of the yeast cell wall by enzymatic treatment. Baker's yeast was also made digestible for <i>Artemia</i> by simple chemical treatment which did not reduce rigidity of the yeast cell. The external mannoprotein layer of the yeast cell wall is probably the major barrier to digestion by <i>Artemia</i> . Chemically treated baker's yeast offers promising possibilities as a substitute for... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diets; Yeasts; Artemia; Saccharomyces cerevisiae. |
| Ano: 1990 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3064 |
| |
|
|
| Lavens, P.; Tackaert, W.; Sorgeloos, P.. |
| Using cyst material produced in an indoor cyst production system from 4 <i>Artemia</i> strains belonging to the species <i>A. franciscana</i> (San Francisco Bay, California, USA; Macau, Brazil; Great Salt Lake, Utah, USA) and <i>A. parthenogenetica</i> (Lavalduc, France), different factors were studied that affect dormancy in brine shrimp cysts. Preliminary experiments under varying (a)biotic culture conditions revealed an interaction between environmental conditions and hatching characteristics. Results obtained under better-defined conditions demonstrated a significant positive correlation between the amount of food available to the adult <i>Artemia</i> populations and the hatchability of their encysted... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cysts; Diapause; Food availability; Hatching; Artemia; Artemia franciscana; Artemia parthenogenetica. |
| Ano: 1986 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3227 |
| |
|
|
| Sorgeloos, P.; Dehasque, M.; Dhert, Ph.; Lavens, P.. |
| Dependable availability of quality fry to stock grow-out production systems has been one of the most critical factors in the commercial success of industrial production of fish and shellfish. Large-scale production of marine fish fry was realized only from the 1980s onwards. Although Japan was the pioneer with the red sea bream (<i>Pagrus major</i>), the most competitive hatchery methods were eventually developed in Europe for the sea bass (<i>Dicentrarchus labrax</i>) and the gilthead sea bream (<i>Sparus aurata</i>). Improved knowledge of larval dietary requirements, not the least with regard to (n-3) highly unsaturated fatty acids (HUFAs), combined with the adoption of live-food enrichment protocols allowed the... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1995 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2627 |
| |
|
| |
|
|
| Kontara, E.K.M.; Merchie, G.; Lavens, P.; Robles, R.; Nelis, H.; De Leenheer, A.P.; Sorgeloos, P.. |
| L-ascorbyl-2-polyphosphate (ApP) was used as a vitamin C source to study the ascorbic acid (AA) requirements for the early postlarval stages of white shrimp (<i>Penaeus vannamei</i>). First the stability of ApP in the diets was determined: ApP losses after pelletizing and 10 min immersion in seawater were 25-35% and 30%, respectively. Semipurified diets with five levels of ApP (0, 20, 40, 100 and 200 mg kg<sup>-1</sup> expressed as active AA were fed <i>ad libitum</i> to <i>P. vannamei</i> (PL-14 stage, mean dry weight 0.73 mg) for 26 days. Each treatment was run in five replicates. No significant differences in growth were observed among treatments after 26 days of feeding. As of day 19 of feeding, increased... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Diets; Polyunsaturated fatty acids; Shrimp culture; Penaeus vannamei. |
| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2959 |
| |
|
| |
|
|
| Dhert, Ph.; Lavens, P.; Dehasque, M.; Sorgeloos, P.. |
| The rotifer feeding regime for larval turbot could be improved by more regular feeding and adjusted food distributions as to prevent overfeeding and digestion problems. All tests were successfully run in clear-water conditions indicating that the administration of algae is not essential during the rotifer stage. Larval requirements with respect to (n-3) RUFA, and more specifically DRA and DRA/EPA ratio appeared to change according to the age of the larvae and the physiological condition at the different larval stages. As early as the first week the stress resistance of the larvae could be improved by feeding rotifers specifically enriched in DRA. However, the continuous feeding of these live preys did not result in the best larval output, indicating that... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Scophthalmus maximus (Linneaus; 1758). |
| Ano: 1995 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2553 |
| |
|
|
| Lavens, P.; Sorgeloos, P.. |
| A flow-through culture system is described for the controlled production of <i>Artemia</i> cysts in 10 liter aquaria using 50 promille artificial seawater enriched with Fe-EDTA as culture medium, micronised rice bran as food source and cyclic flushes of the cultures with N<sub>2</sub>-gas as induction mechanism for oviparity. The culture water is recirculated over a rotating biological contactor, a settling tank and a UV disinfection unit. Cysts are continuously harvested by filtration of the culture effluent. Production yields average 0.5 g dry cysts per day and per aquarium. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aquaculture techniques; Artemia. |
| Ano: 1984 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3267 |
| |
|
|
| Huo, J.-Z.; Nelis, H.; Lavens, P.; Sorgeloos, P.; De Leenheer, A.P.. |
| A liquid chromatographic (HPLC) method has been developed for the quantitative determination of different forms of vitamin E (alpha-, gamma-, and delta-tocopherol) in aquatic organisms. The assay consists of a simple extraction with methanol containing butylhydroxytoluene (BHT) as an antioxidant, followed by reversed phase chromatography with fluorescence detection. The efficiency of the extraction method was equivalent or superior to that of more complex approaches for the isolation of tocopherols. Linearity has been achieved over the range of 0.02 to 3 µg/ml for alpha-tocopherol and within-run and between-run coefficients of variation at three levels were 0.7-2.9 and 1.2-3.7%, respectively. The recovery at three concentrations ranged from 73.8 to 96.6%... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1996 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2978 |
| |
|
|
| Dhert, P.; Lavens, P.; Sorgeloos, P.. |
| A stress test is proposed for the evaluation of the physiological condition of fish larvae in nutritional studies. The test was used in a study of quantitative (n-3) highly unsaturated fatty acids (HUFA) requirements in larval <i>Lates calcarifer</i> and <i>Siganus guttatus</i>. It enabled to suggest fast intervention at reduced larval quality and allowed to prevent mass mortalities. The stress test offered valuable information for the quantification study of fatty acid requirements in marine fish larvae. In <i>Lates</i> demands for fatty acids were detected in metamorphosis. In <i>Siganus</i> on the other hand, the sensitivity of the larvae was considerably reduced after short (n-3) HUFA boosting of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aquaculture; Fry; Quality control; Tests. |
| Ano: 1992 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2761 |
| |
|
| |
|
|
| Wouters, R.; Van Hauwaert, A.; Naessens, E.; Ramos, X.; Pedrazzoli, A.; Lavens, P.. |
| The influence of varying dietary n-3 HUFA concentrations and ratios of 22:6n-3/20:5n-3 (DHA/EPA) on culture performance and fatty acid composition of white shrimp (<i>Penaeus vannamei</i>) larvae and postlarvae was verified in two experiments. In a first experiment, shrimp (zoea 2-postlarvae 11) were fed rotifers (<i>Brachionus plicatilis</i>) and <i>Artemia</i> spp. nauplii that were enriched with different self-emulsifying concentrates: one HUFA-free coconut oil (T1), and three iso-HUFA concentrates with DHA/EPA ratios of 0.6 (T2), 2 (T3) and 4 (T4), respectively. In a second experiment, postlarvae were fed for 25 days (starting from postlarvae 10) on isolipidic semi-purified diets: one HUFA-free control (TA), and four... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2987 |
| |
|
|
| Merchie, G.; Lavens, P.; Sorgeloos, P.. |
| HPLC techniques were adapted and standardized for quantification of ascorbic acid (AA) and its derivates in both diets and target organisms. To assess the dietary needs for AA at start of exogenous feeding, the AA content in the various live diets currently used in aquaculture (algae, rotifers, <i>Artemia</i> ) was analyzed. Application of techniques for boosting vitamin C using ascorbyl palmitate as the source enabled the transfer of elevated levels (up to 2,500 µg AA/g DW) of bioactive vitamin C. Larvae of fish (<i>Clarias gariepinus, Dicentrarchus labrax, Scophthalmus maximus</i>), white shrimp (<i>Penaeus vannamei</i>) and prawn (<i>Macrobrachium rosenbergii</i>) were enriched via the live food chain.... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Crustacean larvae; Diets; Vitamin C. |
| Ano: 1997 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2962 |
| |
|
|
| Nelis, H.; Lavens, P.; Sorgeloos, P.; Van Steenberge, M.; De Leenheer, A.P.. |
| The carotenoid composition of <i>Artemia</i> cysts from 17 geographical strains was studied. All-<i>trans</i>-canthaxanthins and <i>cis</i>-canthaxanthins were quantitatively determined using a non-aqueous reversed phase chromatographic method. In dehydrated cysts, the average <i>cis</i>- and <i>trans</i>-canthaxanthin levels (+/- SD) were 152 +/- 52 and 134 +/- 42 µg/g, respectively (range 38-227 and 67-201µg/g). The corresponding concentrations in hydrated cysts were (<i>cis</i>) 177 +/- 60 µg/g (range 47-271 µg/g) and (<i>trans</i>) 112 +/- 35 µg/g (range 52-169 µg/g). The <i>cis/trans</i> concentration ratios averaged 1.13 (range 0.57-1.47) and 1.60 (range... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Artemia. |
| Ano: 1987 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3196 |
| |
|
|
| Peleteiro, J.B.; Lavens, P.; Rodríguez-Ojeja, G.; Iglesias, J.. |
| The paper presents the data relating to the spawning quality of 20 turbot females (<i>Scophthalmus maximus</i>L.) subjected to natural and controlled photoperiods and fed with two different types of food. A comparison is made between the data usually utilized in hatcheries for defining the spawning quality (number of viable eggs, fertilization and hatching rates, number of larvae produced) and the highly unsaturated fatty acid (HUFA) content of fertilized eggs at the two-cell stage. The results indicate that there is no correlation between the HUFA content of the eggs and any of the egg quality criteria examined. Nevertheless, significant differences (p<0,05) are found between the females fed with fresh trash fish (higher 18:3n-3, 20:4n-6,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Scophthalmus maximus (Linneaus; 1758). |
| Ano: 1995 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2591 |
| |
| Registros recuperados: 79 | |
|
|
|
