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Amino acid pools of rotifers and Artemia under different conditions: Nutritional implications for fish larvae
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Abstract(s)
The rearing of most marine fish species still relies on live food. Amino acids (AA) are the
building blocks for protein synthesis, are important energy substrates, and are involved in specific
physiological functions. Thus, the AA pools (free and protein-bound) of the rotifer Brachionus
rotundiformis and of Artemia parthenogenetica metanauplii were analysed, after enrichment with
different diets or at different salinities. The changes in these pools were related to their impact when
used as feed for the developing fish larvae. Rotifers and Artemia were enriched for 24 h in
microalgae, in commercial diets, or starved for the same time period. The enrichment at different
salinities was also tested using Artemia. The free AA (FAA) quantity and quality was strongly
affected by the enrichment used, in both rotifers and Artemia metanauplii. The relative FAA content
was significantly higher in rotifers and Artemia enriched with microalgae than in the ones enriched
with commercial products, and between the different microalgae tested, the enrichment in T. chui
resulted in the highest FAA content for both preys. Differences regarding the FAA quantity and
quality were also found between rotifers and Artemia. With the exception of the starved preys, a
higher relative FAA content was found in rotifers than in Artemia metanauplii and while the FAA
pool of the rotifers was dominated by alanine, taurine was the dominant AA in the FAA pool of
Artemia. Salinity had only a small effect on the FAA pool of Artemia. Concerning the protein
fraction, starvation increased the relative protein content in the rotifers. Among the metanauplii, the
relative protein content was affected neither by the enrichment nor by salinity, except for a
significantly lower content found when the microalgae Nannochloropsis gaditana was used. The
quality of the protein pool is affected by the different enrichments, but not by salinity. However, the
changes in the protein-bound AA pool were less pronounced than for the FAA pool and reflect differences in the protein content and/or quality of the diet. This study showed that the AA
composition of cultured zooplankton is affected by feeding regime and by salinity. The choice of the
best zooplankton enrichment and/or mixture of enrichments for the different fish larval stages,
should take into account the AA composition, in order to fulfil the energetic and nutritional
requirements of the larvae.
Description
Keywords
Rotifers Fish larval nutrition Osmoregulation Artemia Free amino acids Protein
Citation
Aragão, C.; Conceição, L.E.C.; Dinis, M.T.; Fyhn, H.-J.Amino acid pools of rotifers and Artemia under different conditions: Nutritional implications for fish larvae, Aquaculture, 234, 1-4, 429-445, 2004