1990 Fiscal Year Final Research Report Summary
Studies on the Improvement of Flesh Quality and Integumentary Color of Cultured Striped Jack Pseudocaranx dentex
| Project/Area Number |
01860026
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Research Field |
Fisheries chemistry
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| Research Institution | Tokyo University of Fisheries |
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Principal Investigator |
WATANABE Takeshi Tokyo University of Fisheries, Department of Aquatic Biosciences, Professor, 水産学部, 教授 (60017051)
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| Co-Investigator(Kenkyū-buntansha) |
SATOH Shuichi Tokyo University of Fisheries, Department of Aquatic Biosciences, Lecturer, 水産学部, 講師 (80154053)
OKAMOTO Nobuaki Tokyo University of Fisheries, Department of Aquatic Biosciences, Associate Prof, 水産学部, 助教授 (40114912)
TAKEUCHI Toshio Tokyo University of Fisheries, Department of Aquatic Biosciences, Associate Prof, 水産学部, 助教授 (70092591)
ISO Naomichi Tokyo University of Fisheries, Department of Food Science and Technology, Profes, 水産学部, 教授 (10017080)
YAMAGUCHI Katsumi The University of Tokyo, Faculty of Agriculture, Professor, 農学部, 教授 (50011896)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Striped Jack / Flesh Quality / Spirulina / Integumentary Color / Diet / Gamma Linolenic Acid / Carotenoid |
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| Research Abstract |
Various trials were conducted in order to improve the quality of cultured striped jack, Pseudocaranx dentex, in terms of pigmentation of skin, taste and texture.
The results of the first experiment showed that feeding of Spirulina was very effective for this purpose. The supplementation of Spirulina at 10% level depressed the lipid levels of the dorsal muscle, liver and viscera, and improved not only the integumentary color and texture, but also the taste ofventral muscle at 5% significance. The skin color of fish fed diets containing the alga at 5% or 10% became iridescent greenish gray at the back with a characteristic yellow band near the lateral line, whereas those on the control diet without the alga or minced raw sardine exhibited dark gray. The three yellow components - tunaxanthin, lutein and zeaxanthin - constituted more than 95% of the carotenoids (0.28-1.5 mg/100g tissue) in the dorsal integuments and all of them increased on supplementation of Spirulina. These results were also confirmed using a newly developed soft-dry pellet which high palatability and acceptability to striped jack.
In the final experiment Spirulina was separated into the acetone, methanol, water and ethyl ether soluble fractions and polar lipid fraction, whereupon each was fed to fish to identify the effective component in the alga. The results have shown that gamma linolenic acid (GLA) in the methanol soluble or polar lipid fraction was effective for improvement of flesh quality, reducing the lipid content in muscle and liver. Thus, in practice, it is recommended that aquatic diets could be fortified with about 100 mg GLA per 100 dry pellet.
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