Time course of changes in fatty acid composition of gills and liver from rainbow trout (Salmo gairdneri) during thermal acclimation
✍ Scribed by Sellner, Peggy A. ;Hazel, Jeffrey R.
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- English
- Weight
- 751 KB
- Volume
- 221
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
Rainbow trout (Salmo gairdneri), acclimated to 5°C or 20°C, were reacclimated to water of the opposite temperature. The time course of alterations in fatty acid composition of microsomes from gills and liver was monitored over a 28‐day period. Two to six days were required for maximum changes in fatty acid levels with acclimation to 20°C, whereas 10—17 days were required in the opposite direction. Fatty acids from gill microsomes had lower U/S (ratio of unsaturates to saturates) and UI (unsaturation index) and a shorter average chain length than liver microsomes; these differences were preserved with acclimation. In both tissues the U/S, UI, and chain length increased with cold adaptation and decreased with warm adaptation. In gill microsomes, changes in UI and U/S were due primarily to altered levels of saturated fatty acids and 20:4 (n‐6) and 20:5 (n‐3). The latter two acids, products of the Δ5 desaturation step in PUFA biosynthesis, also contributed to the changes in unsaturation indexes were initially mediated by large but transient changes in levels of saturates and monoenes, whereas changes in polyunsaturated fatty acids of the n‐6 and n‐3 families were delayed 3—6 days. Thus, changes in fatty acid composition that accompany acclimation to a different temperature can be resolved into those metabolic reactions (e.g., Δ5 desaturation) that are of major importance and, in the liver, into temporally more than one mechanism (e.g., altering monoenes and PUFA at different times).