Seasonal Variations in Sterol Content of the Oyster, <i>Crassostrea virginica</i> (Gmelin), from Natural Reefs in the Mississippi Sound

Abstract

Sterol composition of C. virginica was assayed by gas-liquid chromatography. Total sterol levels were determined by analyzing colorimetrically the sterol digitonides prepared from single whole oysters. The predominant sterols (~,:,)wert: cholesterol (33), campesterol (20), brassicasterol (18) and 22 dehydrocholesterol (12): also found were (ßsitosterol (6) and a C 26 sterol (9). Percentage composition of sterols in oysters was not significantly different in relation to season or sex. Total sterol level varied with season and sex. Lowest levels were seen during winter (February) at which time the sexes could not be distinguished. Male oysters had higher sterol levels than females in the spring (April) and fall (October) while females had higher levels during summer when the spawning season was ending. Total sterol content decreased with an increase in size of the oysters during all seasons; the relationship followed a polynomial function. Comparison with values reported indicated that southern oysters have higher fat but lower cholesterol than their northern counterparts.