Summary: | 碩士 === 國立臺灣大學 === 漁業科學研究所 === 87 === The giant tiger prawns, Penaeus monodon, are very importent culturing shrimps in Taiwan. But recently, serious disease had widely spread among them, which had caused mass mortality and the aquaculture farmers lost a lot. In order to seek a solution to this problem is the top urgent. This present study was conducted to evaluate the efficacy of Penaeus monodon juveniles on the growth and disease resistance to white spot syndrome virus (WSSV) by supplementation of Negarich, Ge-132, Gracilaria and its lipid fractions with different contents in diets.
The experiment was performed in two parts. Experiment I was conducted to investigate the influence on the growth and disease resistance abilities of Penaeus monodon juveniles using WSSV diagnostic polymerase chain reaction (PCR) after oral infected with WSSV by supplemented of 1% and 1.5% Negarich, 10% Gracilaria sp., its lipid fraction and other residues. After 50 days feeding trial, diets supplemented of 1% Negrich or Gracilaria lipid fraction can promote shrimps’ growth, weaken the infected level and reduce their mortality among the 6 diets.
According to the results of Exp. I, Experiment II was the further study which was designed to findout the effective elements and the optimum requirements of the treatment which had better growth and disease resistance in the Exp. I. The diets were supplemented of different contents in germanium (0.05-0.2mg/100g) and Gracilaria lipid fraction (0.07-0.30%) to feed the shrimps. And then we observed the growth and the immune abilities of the shrimps after oral infected with WSSV. Results are as follows: After 50 days feeding trial, diets supplemented of 0.2mg/100g germanium or 10% Gracilaria sp. can promote shrimps’ growth and reduce their mortality among the 10 diets. The shrimps fed with diets supplemented of 0.07% and 0.15% Gracilia lipid fraction have lower accumulative mortality (20-25%), but the shrimps fed with diets supplemented of nothing and 0.3% Gracilaria lipid fraction have higher accumulative mortality (50-60%). However, the shrimps fed with diets supplemented of Negarich or organic germanium have more seriously dying condition.
According to the results of diagnostic PCR to check the infected level of the shrimp body, the shrimps fed with diets supplemented of 0.1mg or 0.2mg/100g germanium or 0.15% Gracilaria lipid fraction have slightly infected level. Examing the phenoloxidase (PO) activity of the shrimp hemocyte lysate, it shows that diet with 0.1mg/100g germanium has higher degree than the control group. No mater infected with WSSV or not, the shrimps fed with diets supplemented of 0.15% Gracilaria lipid fraction have higher PO activity than the control group, so that immune ability are more powerful. Diets supplemented of 0.1mg/100g germanium or 0.07-0.15% Gracilaria lipid fraction can induce Penaeus monodon juveniles to have better growth and disease resistance abilities to WSSV.
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