碩士 / 國立海洋大學 / 水產養殖學系 / 84 / During enrichment of rotifer, the problems of surface film and
oil aggregat-ion often occur and hence cause the deterioration
of water quality and unfedresidual. This study aimed to
investigate whether the mixture of fine zeoliteand emulsified
fish oil could improve the problems arising from
rotiferenriching and fish larva rearing. There were three
experiments for this study.Experiment 1 was to find out the
absorption rate of zeolite on emulsified oil.Fine zeolite 3 g
per sample was mixed with different amount of emulsified
oil(0.6 g, 0.9 g, 1.2 g, 1.8 g, 2.4 g, 3.0 g and 3.6 g).
Then the mixture ofzeolite and emulsified oil samples were
centrifuged by three centrifuge force (3.07 kg, 12.3 kg, 27.7
kg) to discard the upper liquid layer. The crude lipidcontent
of the mixture samples was extracted to determine the
percentage oflipid absorbed by fine zeolite. The results
showed that the best absorptionrate of zeolite on emulsified
oil was at zeolite: emulsified oil equal to 1 : 0.8 (3.0 g fine
zeolite : 2.4 g emulsified oil). The emulsified oil which was
unabsorbed and coated on the surface of zeolite were mostly
removed by the centrifuge force at 12.3 kg. Experiment 2 was
to study the effects of emulsified zeolite (mixture of
zeolite and emulsified oil) on the population growth and fatty
acid composition of rotifer (Brachionus plicatilis) and the
water quality of the culture environment after rotifers were
enriched with emulsified zeolite. There were 5 treatment
groups for 24-hour enrichment of rotifer: group Blank, only
natural sea water was used for rotifer culture; group A, only
algae was used; group B, algae plus emulsified oil; group C,
algae plus fine zeolite; group D, algae plus emulsified
zeolite. The initial (0 hr) and final (24 hr) rotifer
density (number / ml) were recorded. The rotifer samples and
water samples before and after 24 hour treatment were
collected for fatty acid and water quality analyses. The
results showed that there was no significant among groups for
rotifer population growth. The pH of water samples of group
Blank and D tended to increase after 24 hours. The COD of
group Blank was significantly higher than that of group A and
D. Thereduction of COD in group D may be due to the emulsified
oil trapped inside holes of zeolite was not only taken by
rotifer, but also became favorable substrate for
microorganism growth; therefore, microorganism could make use of
organic matter more efficiently and cause COD decrease. The
proportion of 20:5n3 in group Blank rotifer was the lowest, and
the highest were group B and C. Group Blank and A had the lowest
n-3 HUFA, and group B had the highest. The absorption of rotifer
on n-3 HUFA and 20:5n3 was not significantly different between
the zeolite treatment groups (D and C) and emulsified oil
treatment group (B). Hence, the amount of emulsified oil
absorbed by zeolite could fulfill the demand of rotifer
sufficiently. 20:5n3 and n-3 HUFA of group C rotifer were
higher than that of group A; although group C had no addition
of emulsified oil, the existence of zeolite may be helpful to
rotifer to obtain HUFA from the culture environment. Experiment
3 was to study the effects of emulsified zeolite on Japanese
sea bass (Lateolabrax japonicus) larva rearing after the fish
larvae were fed with rotifer enriched with emulsified zeolite.
The 5 treatments as in experiment 2 were used to enrich rotifer
for 24 hours, then fish larvae were fed with those enriched
rotifer for 6 days. The survival and growth rate of fish larvae
were recorded.The fish larvae samples and water samples before
and after 6 days were collected for fatty acid and water
analyses. The results showed that the survival rate was not
significantly different among the 5 treatment groups. The length
increase and growth rate of group Blank fish larvae were
significantly lower than those of group B and D. Orthophosphate
of group D water sample was significantly lower than that of
group A;this may imply that group D fish larvae had lower
metabolic waste than group A. Fish larvae fed with rotifer
enriched with emulsified zeolite resulted in lower
metabolite production than those fed with rotifer enriched
with algae alone.Rotifer cultured in sea water had certain
amount of n-3 HUFA, but obviously not enough to provide
the need of fish larvae; hence, the low survival and growth
rate were found in group Blank fish larvae.
| Identifer | oai:union.ndltd.org:TW/084NTOU0086005 |
| Date | January 1996 |
| Creators | Torey, Mientje, 陳明潔 |
| Contributors | Chien Yew-Hu, Huang Yii-Shing, 陳瑤湖, 黃沂訓 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 64 |
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