| Summary: | 碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 93 === Aquatic animals usually have higher unsaturated fatty acid content than terrestrial animals. Autooxidation of the unsaturated fatty acid can lead to the generation of free radicals, which in turn result in the peroxidation of protein, nucleic acid, and lipid in cells and damage the cells, tissues, and their normal functions. The increase of body astaxanthin (AX) can enhance the antioxidation capability in shrimp. Since AX is a precursor of vitamin A (VA), it is speculated that VA might have antioxidation capability to some extent.
Therefore, this study aimed to compare the difference in in vivo antioxidation capability of white shrimp Litopenaeus vannamei when various dosages of AX and VA were injected into the body through various durations. LPO (lipid peroxide) and TBARS (thiobarbituric acid reactive substances) were used as indicators for antioxidation capability or lipid peroxidation prohibition ability (LPPA).
Shrimp were injected with 6 dosages (0.5, 0.47, 1.01, 1.34, and 2.01 n mole/g body weight) of AX or VA. After 1, 3, and 5 days, shrimp blood was withdrawn and its LPO and TBARS value were determined. The blood was then mixed with linoleic acid, a peroxidative lipid, and LPO was continuously monitored for 5 consecutive days.
Decreasing values of LPO with increasing dosage of AX indicated that LPPA of AX increased with AX dosage. LPPA of VA increased with its dosage up to 0.47 nmole and decreased at 1.01 and 1.34 n mole. Both LPO and TBARS increased with elapsed time, showing LPPA of both AX and VA weakened with time. While AX reacted with linoleic acid, if its dosages were ≧1.01 nmole and ≧1.34 nmole after injection for 1-3 days and 5 days, respectively, the changes in LPO were minimal. These results further confirmed that higher dosage of AX would be required to sustain its LPPA longer. On the contrary, 1 and 3 days after injection, the LPPA of VA at 0.5-1.01 nmole was higher than ≧1.34 nmole, which indicated that high dosage of VA would not necessarily increase it LPPA.
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