Effects of Varying Dietary Fatty Acid
Composition on Growth and Survival of Seahorse, Hippocampus Sp., Juveniles
M. Chang, P.C. Southgate-2001
Aquarium Sciences and Conservation, 3(1/3): 205-214
Abstract:
Three commercially available fatty acid enrichment emulsions (DC Selco, DC
DHA Selco and DC Super Selco) were used to enrich Artemia nauplii fed to
seahorse, Hippocampus sp. fry. The emulsions varied in their n-3 highly
unsaturated fatty acid (HUFA) composition. Total n-3 HUFA content ranged
from 200 to 450 mg g^-1 between the three emulsions while levels of
eicosapentaenoic acid (EPA, 20 : 5n-3) and docosahexaenoic acid
(DHA, 22 : 6n-3) ranged between 47–220 and 80–190 mg g^-1,
respectively. Survival and growth of seahorses at the end of the 30 day
growth trial were greater in treatments receiving enriched Artemia.
Seahorses receiving Artemia enriched with DC DHA Selco and DC Super Selco
showed significantly (p < 0.05) greater mean survival (71.6 ± 6.0% and
78.3 ± 6.0%, respectively) than those receiving unenriched Artemia (48.3 ±
6.0%). Mean standard length was also significantly greater (p < 0.05) in
fry fed DC DHA Selco and DC Super Selco enriched Artemia (20.2 ± 0.3 and
19.7 ± 0.3 mm, respectively) compared to those fed unenriched Artemia
(18.1 ± 0.3 mm). The results show that dietary n-3 HUFA are essential
for optimal growth and survival of Hippocampus sp. and, based on the fatty
acid compositions of the enriched Artemia used in this study, indicate that
the level of dietary DHA supporting optimal growth and survival is greater
than 9.3 mg DHA g^-1
dry weight.