The Fatty Acid Composition in Tuna (Bonito,Euthynnus pelamis) Caught at Three Different Localities from Tropics to Temperate
✍ Scribed by Saito, Hiroaki; Ishihara, Kenji; Murase, Teruaki
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 191 KB
- Volume
- 73
- Category
- Article
- ISSN
- 0022-5142
No coin nor oath required. For personal study only.
✦ Synopsis
The present paper describes the e †ect of habitat on the fatty acid composition of the lipid of bonito (Euthynnus pelamis), which was caught at three di †erent localities, Philippine Sea (the tropical zone ; seawater temperature at the Ðshing ground was 27É8¡C), East China Sea (the subtropical zone ; seawater temperature was 29É7¡C), and the PaciÐc coast of Japan (the temperate zone ; seawater temperature was 20É3¡C). The total lipids of various organs and stomach contents were extracted and their fatty acid composition analysed by gas chromatography (GC). Docosahexaenoic acid (DHA ; 22 : 6n-3) was the major unsaturated fatty acid in the lipid of all specimens examined from all localities. The mean DHA content accounted for more than 25% (mean ^standard error : 26É0 ^0É6%) of the total fatty acids (TFA) in the lipids of all organs, a lipid proÐle markedly di †erent from that of other Ðsh species whose fatty acid composition is generally variable. Particularly, the mean DHA content of lipids in bonito caught in the northern sea-area sample (the temperate zone) was always high (28É4 ^0É7% TFA) in the lipid of every organ. Because the DHA contents of lipids of the stomach contents Ñuctuated between 9É9 and 31É9% TFA, bonito did not simply incorporate the fatty acid proÐle of the lipids of its prey Ðshes, but selectively accumulated the DHA. Though the mean DHA content in the lipid of all bonito from the tropical to the temperate zone was markedly higher than other marine Ðsh species such as sardines and herrings, there was a small di †erence between those in the northern (28É4 ^0É7% TFA) and southern samples (the subtropical and tropical samples, 24É7 ^0É8% TFA) (P \ 0É05). It is suggested that the di †erence between them may be due to environmental e †ects, for example, the temperature of the seawater and the fatty acid composition of the lipids of prey organisms.