Relationship between lipid composition and organochlorine levels in the tissues of striped dolphin

Abstract

Lipid content and lipid composition were studied in the various tissues of striped dolphins ( Stenella coeruleoalba) collected from Japanese waters in order to elucidate the relationship between the levels of organochlorine compounds and the lipid composition. Total lipid content was highest in the adipose tissues such as blubber and melon, followed by mammary gland and milk. Also kidney, pancreas and brain contained about 10% of lipid. Other tissues such as liver, muscle, spleen and lung had low lipid contents ranging from 1–5%. In the tissues with high lipid contents, triglycerides comprised more than 70% of total lipids. Phospholipids and total cholesterol were dominant in brain tissues including cerebrum, cerebellum and medulla oblongata. Organochlorine compounds such as PCBs and DDTs were mainly distributed in tissues with high lipid content and the levels of these compounds were correlated with the content of triglycerides in the tissues. Abnormalities in lipid metabolism such as fatty livers were noticed in individuals with high PCBs and DDTs.