Effect of the Nutritional Status of Semicontinuou

Authors: Martiña Ferreira Pedro Seixas Paula Coutinho Jaime Fábregas Ana Otero

Publish Date: 2011/04/13

Volume: 13, Issue: 6, Pages: 1074-

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Abstract

The rotifer Brachionus plicatilis was cultured using the microalga Isochrysis aff galbana clone TISO as feed TISO was cultured semicontinuously with daily renewal rates of 10 20 30 40 and 50 of the volume of cultures The increase of renewal rate led to increasing nutrient and light availability in microalgal cultures which caused differences in the biochemical composition of microalgal biomass Growth rate individual dry weight organic content and biomass productivity of rotifer cultures increased in response to higher growth rate in TISO cultures Rotifer growth rate showed a strong negative correlation R 2 = 090 with the C/N ratio of microalgal biomass Rotifer dry weight was also affected by nutrient availability of TISO cultures increasing up to 50 from nutrientlimited to nutrientsufficient conditions Consequently biomass productivity of rotifer cultures increased more than twofold with the increase of renewal rate of TISO cultures Rotifer organic content underwent the same trend of total dry weight Maximum content of polyunsaturated fatty acids was reached in rotifers fed TISO from the renewal rate of 40 with percentages of docosahexaenoic acid 226ω3 DHA and eicosapentaenoic acid 205ω3 EPA of 11 and 5 of total fatty acids respectively Selecting the most appropriate conditions for microalgal culture can therefore enhance the nutritive quality of microalgal biomass resulting in a better performance of filter feeders and their nutrient content and may constitute a useful tool to improve the rearing of fish larvae and other aquaculture organisms that require live feed in some or all the stages of their life cycle

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