Uptake and metabolism of a
particulate form of ascorbic acid by Artemia nauplii and juveniles
G.G. Smith, A.J. Ritar, M.R. Brown-2004
Aquaculture
Nutrition, 10(1):
1-8
Abstract:
A study was conducted to establish whether a
particulate form of ascorbic acid (AA), ascorbyl-2-phosphate (A2P), could be
used to enrich Artemia. In the first experiment, we examined the
efficiency of A2P conversion to and maintenance of AA by juvenile Artemia
(1.5 mm, 5-day-old) held at 9000 L-1 and 28 °C
for 24 h. Maximal uptake and assimilation was >10 000 µg
AA g-1 dry weight (dw) (representing >1%Artemia dw) at
enrichment rates of >/=1.2 g A2P L-1. In the second
experiment, a similar biomass of instar II/III nauplii (1 mm,
2-day-old) and juvenile (2.5 mm, 8-day-old) Artemia were
enriched for 6 or 24 h at 28 °C before starvation for 6 or 24 h
at 18 or 28 °C. At 0 h and after 6 and 24 h enrichment, AA
levels were 485, 3468 and 11 080 µg g-1 dw in
nauplii and 122, 4286 and 12 470 µg g-1 dw in
juveniles. When Artemia nauplii or juveniles were enriched for 6 h
and starved for 6 h at 18 or 28 °C, there was no significant
reduction in AA. Continuation of starvation to 24 h at 18 and 28 °C
reduced the level of AA to 3367 and 2482 µg g-1 dw in
nauplii and 3068 and 2286 µg g-1 dw in juveniles.
After 24 h enrichment, 6 h of starvation at 18 and 28 °C
reduced AA to 8847 and 7899 µg g-1 dw in nauplii and
to 9053 and 8199 µg g-1 dw in juveniles. Continuation
of starvation to 24 h at 18 and 28 °C further reduced AA levels
in nauplii to 6977 and 4078 µg g-1 dw and to 7583 and
5114 µg g-1 dw in juveniles. This study demonstrated
that A2P could be assimilated as AA in the body tissue of different-sized Artemia
in a dose-dependant manner and AA was depleted during starvation depending
on time and temperature.
(Marine Research Laboratories, Tasmanian Aquaculture and Fisheries
Institute, University of Tasmania, Nubeena Crescent, Taroona, Tasmania 7053,
Australia. E-mail: ggsmith@utas.edu.au)