Arachidonic acid
requirements in larval summer flounder, Paralichthys dentatus
S.
Willey, D.A. Bengtson, M. Harel-2003
Aquaculture
International, 11
(1-2): 131-149
Abstract:
The arachidonic acid (20:4n-6, AA) requirements of
larval summer flounder were determined for the rotifer- and Artemia-feeding
stages. Experimental emulsions contained adequate n-3 highly unsaturated
fatty acid (HUFA) ratios and emulsion levels of AA were set at 0, 3, 6, 9,
and 12% (AA0, AA3, AA6, AA9, and AA12). Examination of fatty acid levels in
live feeds and larval tissues confirmed the physiological incorporation of
fatty acids relative to dietary levels. In the first experiment, survival,
growth, and salinity tolerance (2-h in 70‰)
were measured at 18 days after hatch (dah) after feeding the larvae the
various levels of AA. Larvae fed AA6-enriched rotifers were better able to
survive the salinity tolerance test. AA enrichment up to 12% had no effect
on growth and survival. In the second experiment, larvae were fed AA0- or
AA6-enriched rotifers until 23 dah, followed by unenriched 24- and 48-h Artemia
nauplii until 32 dah. These larvae then were subdivided and fed AA-enriched Artemia
from 33-45 dah. At the end of this experiment, larvae fed AA6-enriched
rotifers had higher survival, increased growth, and survived better in the
salinity tolerance test (2-h in 80‰). The
enrichment of Artemia did not have any effect on these variables.
Thus, the provision of AA6-enriched rotifers (10 mg AA g-1 DW)
early in larval development may serve to enhance larval stress tolerance at
the rotifer stage while also increasing larval survival, growth, and stress
tolerance later in the Artemia stage.
(Department of
Fisheries, Animal, and Veterinary Science, University of Rhode Island,
Kingston, RI, 02881, USA, e-mail: swil5979@postoffice.uri.edu)