Elongation and desaturation of dietary fatty acids in turbot Scophthalmus maximus L., and rainbow trout, Salmo gairdnerii rich

Turbot and rainbow trout, which had previously received diets free of fat, were fed [1‐ 14 C] fatty acids. The distribution of radioactivity in the tissue fatty acids was examined 6 days later. In rainbow trout fed [1‐ 14 C] 18∶3ω3, 70% of the radioactivity was present in 22∶6ω3 fatty acid. In contrast, turbot fed [1‐ 14 C] 18∶1ω9, 18∶2ω6, or 18∶3ω3 converted only small amounts of labeled fatty acids (3–15%) into fatty acids of longer chain length. The major product of the limited modification found in turbot was the dietary acid elongated by 2 carbon atoms.