Changes in amino acid
content of an algal feed species (Navicula sp.) and their effect on
growth and survival of juvenile abalone (Haliotis rubra)
S.
Daume, B.M. Long, P. Crouch-2003
Journal of Applied Phycology, 15(2):
201-207
Abstract:
The growth and survival of juvenile Haliotis
rubra, when fed with the diatom Navicula sp. cultured in f/2
medium containing combined nitrogen at 24.71 mg NO3-N L-1
(high), 12.35 mg NO3-N L-1 (standard) or 2.47 mg NO3-N
L-1 (low), were compared in a 33-day trial. The alga in the low
nitrogen medium contained 37% less total amino acid than that in the high
and standard nitrogen media. There was a slightly greater reduction in
essential amino acids (40%) compared to non-essential amino acids (35%).
Juvenile abalone feeding on Navicula grown in medium with low
nitrate and lower total amino acid content grew more slowly than when fed on
the same species grown in standard or higher nitrogen medium with a higher
amino acid content. The growth rate of juveniles was highest (43 μm
d-1) in the high nitrate treatment followed (40 μm
d-1) by the standard nitrate treatment and lowest (31 μm
d-1) in the low nitrate treatment. The survival of the juveniles
was also effected by the diet. Survival was better in the high and standard
nitrogen media (88%) than the low nitrogen medium (75%). The results suggest
that in order to achieve uniformity in nutritional quality of diatoms and
good growth of abalone juveniles in commercial abalone nurseries, the
nitrogen concentration in tanks should be monitored and additional nitrate
added to provide an optimum concentration of between 2 and 12 mg NO3-N
L-1.
(School of Ecology &
Environment, Deakin University, Warrnambool, Australia; Current address:
Department of Fisheries, Mariculture Research and Advisory Group, Western
Australian Marine Research Laboratories, North Beach, 6020, Australia,
e-mail: sdaume@fish.wa.gov.au)