| Summary: | 碩士 === 國立海洋大學 === 水產養殖學系 === 84 === This study was conducted to investigate the effects of diets
with different sources of lipid and different quantity of
polyunsaturated fatty acids (PUFA) or highly unsaturated fatty
acids (HUFA) on the growth and survival of juvenile crabs. In
Experiment 1, juvenile crabs were fed with diets supplemented
with 4 % cod liver oil, corn oil, olive oil, soybean oil and
sesame oil for 10 weeks. The results showed that juvenile crabs
fed with 4 % cod liver oil had the best growth. Juvenile crabs
fed with diets containing corn oil, olive oil, soybean oil and
sesame oil showed no significant differences. Juvenile crabs fed
diets containing cod liver oil had high level of EPA and DHA of
body tissue of juvenile crabs. These results showed that the
fatty acid composition of tissue of crabs was obviously
reflected from fatty acid composition of diet. Weight gain
and survival responses and analyses of fatty acid composition of
tissue were used to investigate the nutritional value of C18
polyunsaturated fatty acids (PUFA) provided to juvenile crabs in
a purified diet. There were seven isonitrogenous and
isoenergetic diets containing pure triglycerides of 0.2, 0.4 and
0.6﹪18:3n-3 (trilinolenin) and 18:2n-6 (trilinolein) and 0.2
﹪22:6n-3 (tridocosahexaenoin) as control diet for experiment 2
. All diets were formulated to contain a total of 4﹪lipid and
were fed to juvenile crabs for 12 weeks. The results showed that
juvenile crabs fed diets containing 0.2﹪tridocosahexaenoin
showed better growth than those fed diets containing
trilinolenin and trilinolein. Diets containing high proportion
of trilinolein or trilinolenin could not improve the growth of
juvenile crabs. The high level of 18:2n-6 and 18:3n-3 in the
polar and neutral lipids of tissue of juvenile crabs was found
that crabs were fed diets containing trilinolein or
trilinolenin. Crab fed diet containing 0.2 % tridocosahexaenoin
had high level of EPA and DHA in the polar lipid of crab tissue.
Weight gain and survival responses and analyses of fatty acid
composition of tissue were used to investigate the nutritional
value of C≧20 highly unsaturated fatty acids (HUFA) provided to
juvenile crabs in a purified diet. There were isonitrogenous and
isoenergetic diets containing pure triglycerides of 0.2, 0.4 and
0.6﹪20:4n-6 (triarachidonin) and 22:6n-3 (tridocosahexaenoin).
Reference diet was included cod liver oil as the lipid source.
All diets were formulated to contain a total of 4﹪lipid. A
diets containing only saturated (14:0, 16:0, and 18:0) and
monounsaturated (16:1n-7 and 18:1n-9) fatty acids as lipid
sources, in proportions similar to that found in a 2:1 cod liver
oil/corn oil mixture, served as a conditioning and control diets
for experiment {= 3 \* ROMAN|III}. At the termination of the
feeding trials, that juvenile crabs fed diets containing 0.4 %
tridocosahexaenoin and 4 % cod liver oil had the best growth.
The control group (diet included without PUFA and HUFA) had the
lowest growth and survival. Crab fed diets containing 0.6 %
triarachidonin and control group had high mortality. Crab fed
diets containing triarachidonin (20:4n-6) and tridocosahexaenoin
(22:6n-3) had high level of 20:4n-6 and 22:6n-3 in the tissue.
However, crab fed diets containing tridocosahexaenoin (22:6n-3)
had high level of EPA and DHA in the polar lipid of crab tissue.
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