Dietary n-3 long-chain polyunsaturated fatty acid deprivation, tissue lipid composition, ex vivo prostaglandin production, and stress tolerance in juvenile Dover sole (Solea solea L.)

Larval Dover sole fed an Artemia diet supplemented with n-3 long-chain (C-2 0 + C-22) polyunsaturated fatty acids (PUFA) are known to be more resistant to low-temperature injury. Here we explore the relationship between tissue fatty acid composition and tolerance of stressful environmental conditions over the larval and early juvenile periods. Artemia nauplii supplemented w ith n-3 long-chain PUFA-deficient and PUFA-enriched oil emulsions were fed to two groups of larvae. Whole body tissue samples from the resulting PUFA- deficient and -enriched juveniles possessed 12.1 and 21.9% n-3 long-chain P UFA, respectively. These differences were at the expense of C-18 PUFA, whil e proportions of saturated fatty acids, monounsaturated fatty acids, and to tal PUFA were unaffected. Brain and eye tissues from the PUFA-deficient fis h contained lower levels of 22:6n-3, known to be important for optimal nerv ous system function, incorporating instead a range of fatty acids of lower unsaturation. PUFA-deprived juveniles showed substantially greater mortalit y when exposed to a combination of low temperature and low salinity, as wel l as to high temperature and to hypoxia. After adaptation to the different diets, both dietary groups were fed a common formulated feed high in n-3 lo ng-chain PUFA. Tissue PUFA in both groups progressively increased to the sa me high value, with a consequent loss of the differences in cold-susceptibi lity. These correlated changes support a link between dietary manipulation of n-3 long-chain PUFA and development of a stress-sensitive phenotype. PUF A deprivation had no detectable effect upon static hydrocarbon order of pur ified brain membranes (as assessed by fluorescence polarization) but was as sociated with an increase in the whole-body content of prostaglandins. We c onclude that susceptibility to environmental stress is responsive to dietar y n-3 long-chain PUFA manipulation, possibly due to altered tissue developm ent or the overproduction of eicosanoids.