| Summary: | 碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 95 === Marine shrimp have requirement for poly-unsaturated fatty acid (PUFA) However, as a prooxidant, PUFA is in favor of autooxidation and the production of free radicals, which can impair normal function of cell, tissue, and organism by the peroxidation of cellular proteins, nucleotides, and lipids. The increase of astaxanthin (AX), an antioxidant, in shrimp can enhance antioxidant capacity and reduce the damage from oxidative stress. Therefore, this study was aimed to find out the joint effects of aforementioned prooxidant and antioxidant in diet on the biological function of white shrimp Litopenaeus vannamei. Twelve diets supplemented with prooxidants as 3 types of fatty acid fish oil, linoleic acid, and stearic acid and antioxidant of 4 levels of AX: 0, 40, 80, and 120 mg kg-1, each had 3 replicates, were fed to the shrimp for 8 weeks. At the end, comparisons were made on growth, survival, body AX content, body fatty acid composition, antioxidant status, and respiratory parameters under low dissolved oxygen stress. Shrimp in fish oil group had better growth and survival than shrimp in the other two fatty acid groups since fish oil contained high level of n-3 PUFA. The ratio of neutral fatty acid to polar fatty acid in shrimp was affected by the type of dietary fatty acid. Shrimp having high PUFA content exhibited high oxidation status as shown in high values of thiobarbituric acid reactive substances (TBARS) and superoxide dismutase (SOD). Dietary lipid type did not affect body astaxanthin content in shrimp. Shrimp AX content and pigmentation increased with dietary AX concentration. The higher body AX content, the higher shrimp’s survival during rearing, and the higher resistance to low dissolved oxygen stress. AX could protect the integrity of PUFA in shrimp body and enhance shrimp’s antioxidant capacity, as shown in the increase of glutathione reductase and glutathione peroxidase and reduction of SOD and TBARS. No correlations between body AX content and fatty acids indicated that either perform its biological function independently. Therefore, supplementation of fish oil and high concentration of AX is considered best dietary combination for this shrimp.
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