Fatty acid composition of lipids in the trout-I. Influence of dietary fatty acids on the triglyceride fatty acid desaturation in serum, adipose tissue, liver, white and red muscle

Abstract

1. 1. The present study examined the influence of 6 and 10% lipid-diets on the fatty acid composition of triglyceride body compartments and the influence of two diets differing by their n-6 and n-3 HPUFA content on the bioconversion of 18:2 n-6 and 18:3 n-3. 2. 2. A 6% fat diet caused a high level of 18:1 n-9 as previously reported in fish and mammals for low fat diets. 3. 3. The lipid content of trout serum was very high (about 2000 mg/100 ml) but the apolar (triglycerides + cholesteryl esters) and more polar (phospholipids + free cholesterol) components in trout serum were balanced as in man. 4. 4. A useful index [P + Σ(n-x)]/P, where P is the precursor of the n - x series, allows us to determine the relative importance of the Δ9, or Δ6, desaturation. 5. 5. The n-3 HPUFA seem to present a feedback effect on the n-x and n-6 FA bioconversions as reported by some authors whereas the Δ6 desaturation of 18:1 n-9 was blocked. 6. 6. The general decreasing importance of the Δ6-desaturation in the compartments is as followed: liver, serum, intestine and muscle, adipose tissue. © 1981.