The enrichment and retention of ascorbic acid in rotifers fed microalgal diets |
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| Authors: | M R Brown S Skabo & B Wilkinson |
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| Institution: | CSIRO Division of Marine Research, Hobart, Tasmania, Australia; Department of Biochemistry, University of Tasmania, Hobart, Tasmania, Australia; Tasmanian Department of Primary Industry and Fisheries, Marine Research Laboratory, Crayfish Point, Taroona, Tasmania, Australia |
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| Abstract: | The enrichment and retention of ascorbic acid (AA) was investigated in rotifers Brachionus plicatilis fed on microalgae ( Nannochloropsis oculata and Isochrysis sp. (T.ISO)) and baker's yeast Saccharomyces cerevisiae . The concentrations of AA of the rotifer diets used in the study differed significantly: 4200 μg g?1 of dry weight in Isochrysis sp. (T.ISO), 2600 μg g?1 in N. oculata and only 77 μg g?1 in S. cerevisiae . Rotifers contained 620 μg AA g?1 prior to the experimental feeding. When subsequently fed for 3 h on microalgae at a ration of 0.13 mg dry microalgae per 106 rotifers rapidly and efficiently increased their content of AA: Isochrysis sp.-fed rotifers contained 1600 μg AA g?1 and N. oculata -fed rotifers contained 1100 μg AA g?1. Concentrations were boosted by a further feeding of a second ration of algae at three times the initial feeding ration; 21 h later, Isochrysis sp.-fed rotifers contained 2500 μg AA g?1 and N. oculata -fed rotifers contained 1700 μg AA g?1. This represented a 180% and 310% increase in the pre-feeding vitamin concentrations in Isochrysis sp. and N. oculata -fed rotifers, respectively. There were no significant changes in AA concentration in rotifers fed a similar ration of yeast throughout the feeding period (520-620 μg AA g?1). Rotifers retained AA during a subsequent 24 h non-feeding period, with no significant changes in the concentrations in any of the rotifer groups. The production of rotifers rich in AA may be particularly valuable for the culture of fish larvae that have a high requirement for the vitamin. |
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| Keywords: | ascorbic acid microalgae nutrition rotifer vitamin yeast |
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