Sterol Metabolism

Abstract

This paper presents an overview of sterol metabolism in both crustaceans and mollusc. The autor will survey information avaliable from biochemical studies and relate this to the results of feeding experiments, focusing, where possible, on important aquaculture species. Crustacea generally do not have the capacity for the novo sterol synthesis but are able to dealkylate dietary C28 and C29 sterols to cholesterol. The inclusion of cholesterol in teh diet is shown to improve the growth and survival of Paneaeus japonicus and Homarus americanus juveniles. The addition of cholestrol to the diet is also shown to improve the survival of P. japonicus lavae. Molluscan sterol metabolism differs from class. Gastropoda synthesize cholesterol and dealkylate some phytosterols to cholesterol. In contrast, althougth pelecypods posses the ability to dealkylate some C28 and C29 sterols to chloesterol, they are capable of only limited sterol synthesis and therefore presumably require sterols for growth. However, feeding experiments using defined, artificial diets have yet to be carried out with pelecypods.