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  • 1
    Electronic Resource
    Electronic Resource
    Changes in phospholipase A2 activity and lipid content during early development of Atlantic halibut (Hippoglossus hippoglossus) (1998)
    Springer
    Marine biology 130 (1998), S. 369-376 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During early development in fish, phospholipase A2 (EC 3.1.1.4) regulates membrane lipid modifications, which relates to changes in environmental conditions and provision of fatty acids required for metabolic energy substrates and prostaglandin biosynthesis. A method to analyze phospholipase A2 in rat tissues has been modified to measure its activity in embryonic Atlantic halibut (Hippoglossus hippoglossus L.). Egg and embryo samples were collected during the 1994 spawning season. Enzyme activity was undetectable at fertilization but in 10-d embryos was 230 pmol mg−1 h−1 (at 20 °C) and increased by ∼120% at hatch (17-d). Significant alterations in the fatty acid composition of important phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), were also observed. The content of some critical polyunsaturated fatty acids, and the ratio of unsaturated/saturated fatty acids, declined significantly over development. Acyl-chain restructuring mediated through the activity of phospholipase A2, coupled with other observed lipid changes (significant increases in the PC/PE ratio and cholesterol content), would produce a decreased fluidity of membranes during embryonic development, coinciding with the predicted upward movement of larvae in the water column. Arachidonic acid (20:4n-6) removed from PE could serve as a precursor for biosynthesis of 2-series prostaglandins, and eicosapentaenoic acid (20:5n-3) from PC is a likely source for other prostaglandin types. Despite removal of polyunsaturated fatty acids, there was an overall increase in lipid and fatty acid concentration, which can be attributed to amino acid catabolism during early developmental stages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050257
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  • 2
    Electronic Resource
    Electronic Resource
    Growth and lipid composition of scallop juveniles, Placopecten magellanicus, fed the flagellate Isochrysis galbana with varying lipid composition and the diatom Chaetoceros muelleri (1999)
    Springer
    Marine biology 133 (1999), S. 461-471 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effect of feeding the flagellate Isochrysis galbana (Parke; clone T-Iso) of modified lipid composition on the growth and lipid composition of juvenile scallops [Placopecten magellanicus (Gmelin)] was investigated in the spring of 1993. I. galbana grown in 85-liter cage culture turbidostats under conditions of nitrogen limitation had a significantly higher total lipid content than when grown under nutrient-replete conditions. This was due mainly to a doubling in the amount of less unsaturated triacylglycerol in the cells. The concentrations of methyl and ethyl ketones were also greater in nitrogen-limited cells. Diets of nitrogen-limited I. galbana and nutrient-replete I. galbana grown in continuous and semi-continuous cultures were compared. Scallop juveniles were batch fed daily, and measurements of ingestion were determined. Samples of juveniles were removed periodically for determination of organic weight. The juveniles did not grow when fed nitrogen-limited or nutrient-replete I. galbana alone; however, when each diet was supplemented with 20% of the diatom Chaetoceros muelleri (Lemm.), there was a significant increase in growth in the juveniles receiving the nitrogen-limited I. galbana compared with juveniles on other diets. In comparison with I. galbana,  C. muelleri provided a rich source of carbohydrates and the essential fatty acid 20:4ω6. This study shows the importance of providing optimal dietary levels of ω3 and ω6 polyunsaturated fatty acids, as well as less unsaturated fatty acids and carbohydrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050486
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  • 3
    Electronic Resource
    Electronic Resource
    Lipid composition of malpigmented and normally pigmented newly settled yellowtail flounder, Limanda ferruginea (Storer) (2002)
    Oxford, UK : Blackwell Science Ltd
    Aquaculture research 33 (2002), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The lipid composition of malpigmented (MP) and normally pigmented (NP), newly settled yellowtail flounder (Limanda ferruginea, Storer) was compared in order to elucidate a possible connection between lipids and pigmentation development. Larvae were fed commercially enriched live food for 12 weeks post hatch and then differences in lipid composition and size were analysed. NP fish were found to be significantly larger (standard length 35 mm) than MP fish (32 mm) at 100% settlement. There were higher proportions of triacylglycerols in NP fish (P = 0.01), whereas MP fish had an increased percentage of phospholipids (P = 0.01). NP fish had a higher percentage of docosahexaenoic acid (DHA) in the polar lipids of their body (P = 0.03) and total lipids of their eyes (P = 0.04). These data support previously proposed theories for the importance of DHA in pigmentation development. Principal components analysis (PCA) described the majority of the variance (77%) within the data set using just two principal components axes. PCA demonstrated that differences between body zones were greater than those between NP and MP fish within a given zone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2109.2002.00761.x
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  • 4
    Electronic Resource
    Electronic Resource
    Lipids in eggs from first-time and repeat spawning Atlantic halibut, Hippoglossus hippoglossus (L.) (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Aquaculture research 24 (1993), S. 0 
    Details
    ISSN: 1365-2109
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The production of viable larvae is critical to any aquaculture venture. Since lipids are important components of fish eggs, the amount and nature of the lipid may be crucial to the survival of the larvae. In this study the lipid content of unfertilized eggs from first-time and repeat spawning Atlantic halibut females was compared. The egg lipid content for the first-time spawner ranged from 0·18 to 0·41mg/egg; the range for the repeat spawner was 0·27 to 0·38mg/egg. However, the mean total lipid per egg values were similar for both fish at ca. 0·31mg/egg. The repeat spawner prodticed more eggs than the first-time spawner, thus allocating more lipid to egg production. In the eggs from the two fish 62–84% of the lipids was phospholipid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2109.1993.tb00540.x
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    Paper (German National Licenses)
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