Requirement of dietary n-3
highly unsaturated fatty acids for juvenile flounder (Paralichthys
olivaceus)
K.-D. Kim, S.-M. Lee-2004
Aquaculture, 229(1-4): 315-323
Abstract:
The effect of dietary n-3 highly unsaturated fatty
acids (n-3 HUFA) level on growth and body composition was investigated to
determine the n-3 HUFA requirement for juvenile flounder. Eight diets of
different n-3 HUFA levels ranging from 0.0% to 2.4% were fed to juvenile
flounder for 8 weeks. For varying n-3 HUFA level, mixtures of mainly EPA
(0.0–1.1%) and DHA (0.0–0.9%) were used except one diet containing only
1.2% EPA. Weight gain, feed efficiency and protein efficiency ratio
increased significantly with increasing dietary n-3 HUFA level up to 0.8%;
however, those values gradually decreased after n-3 HUFA level became higher
than 1.6%. The result of second-order polynomial regression showed that the
maximum weight gain could be attained at 1.0% n-3 HUFA level. The weight
gain was significantly lower for the diet containing 1.2% EPA than for the
1.2% n-3 HUFA diet containing both EPA and DHA. The contents of DHA and n-3
HUFA in whole body polar lipid increased with dietary n-3 HUFA level.
Monoenoic fatty acids content and 18:1n/n-3 HUFA ratio decreased with
increasing dietary n-3 HUFA level. The results suggest that the requirement
of dietary n-3 HUFA for juvenile flounder is about 0.8–1.0%; however,
excessive n-3 HUFA supplement may impair the growth of juvenile flounder.
(Faculty of Marine Bioscience and Technology,
Kangnung National University, Gangneung 210-702, South Korea, e-mail of
S.-M. Lee: smlee@kangnung.ac.kr)