STEROL-METABOLISM OF PACIFIC OYSTER (CRASSOSTREA-GIGAS) SPAT

The sterol metabolism of Pacific oyster (Crassostrea gigas) spat was i nvestigated. H-3-squalene, H-3-desmosterol and H-3-fucosterol were mix ed with oleic acid and separately encapsulated in gelatin-acacia micro capsules (GAM). Spat were fed one type of GAM for 1 days and were then unfed for 2 days. No labeled sterols were detected in spat fed GAM co ntaining H-3-squalene, demonstrating the absence of de novo sterol syn thesis in C. gigas spat. H-3-desmosterol, a C-27 sterol, was alkylated to the C-28 sterols 24-methylenecholesterol and 24-methylcholestero a nd was also reduced to cholesterol. In spat fed GAM containing H-3-fuc osterol, a C-29 sterol, radioactive desmosterol and cholesterol (C-27 sterols) and radioactive 24-methylenecholesterol and 24-methylcholeste rol (C-28 sterols) were recovered. These results demonstrate that C. g igas spat is capable of both alkylation and dealkylation of dietary st erols. (C) 1998 Elsevier Science Inc.