Effects of Artemia
enriched with eicosapentaenoic and docosahexaenoic acid on survival and
occurrence of molting failure in megalop larvae of the mud crab Scylla
serrata
M. Agus Suprayudi, T. Takeuchi, K.
Hamasaki-2004
Fisheries
Science, 70(4):
650-658
Abstract:
The present study was conducted to
investigate the effect of eicosapentaenoic acid (20:5n-3, EPA) and
docosahexaenoic acid (22:6n-3, DHA) on the survival and the occurrence of
molting failure to megalops of mud crab Scylla serrata larvae fed
enriched Artemia. Survival rate, intermolt period, carapace width at
the first crab stage, ratio of chela to carapace length at the fifth zoeal
stage and the occurrence of molting failure to megalops were observed. Mud
crab larvae were reared in 1-L plastic beakers and fed with Artemia
enriched at five different levels of EPA (0.31% to 1.36% EPA; referred to as
E25, E50, E75 and E100) or four different levels of DHA (0.75-0.95% EPA and
0.49-1.38% DHA; referred to as D25, D50, D75 and D100). As a negative
control, larvae were fed Artemia enriched with oleic acid (OA). Mud
crab larvae fed Artemia containing low (0.41-0.45% EPA and trace DHA)
or high (1.36% and 0.95% EPA and 0.16% and 1.38% DHA) amounts of EPA and DHA
showed a significantly lower survival rate and prolonged intermolt period (P < 0.05).
Moreover, a high frequency of molting failure to the megalops stage (34 and
33%) occurs coincident with a high chela to carapace length ratio (43 and
44%) in mud crab larvae fed high amounts of EPA and DHA (E100 and D100),
suggesting that both of these treatments contain EPA and DHA in excess.
These results indicate that during Artemia feeding, EPA and DHA
content should be adjusted to 0.71-0.87% and 0.49-0.72% for maintaining a
high survival, accelerating the intermolt period, and producing larger
carapace width in the first crab stage.
(Department of Marine Biosciences, Faculty of Marine
Science, Tokyo University of Marine Science and Technology, Minato, Tokyo
108-8477, Japan, Tel: 81-3-546-0545. Fax: 81-3-5463-0545. Email of T. Takeuchi: take@s.kaiyodai.ac.jp)