Effects of Lecithin on Cholesterol Digestibility in the Prawn, Artemesia longinaris (Crustacea, Penaeidae)

Cholesterol and dietary phospholipids are important to the growth and survival of crustaceans. Soy lecithin enhances cholesterol solubilization while phosphatidylcholine transfers cholesterol from the hepatopancreas to the hemolymph. To study the influence of dietary lecithin on digestibility and transport of cholesterol to the hemolymph in Artemesia longinaris, diets with different levels of supplemental cholesterol (0.5, 1, 1.5, and 2%) and soy lecithin (0, 0.5, 1, and 2%) were fed to prawns for two weeks. The diet containing the lowest level of cholesterol (0.5% ) and lecithin (1%) resulted in the lowest apparent digestibility of cholesterol. The diets containing 2% cholesterol and 1% or 2% lecithin resulted in the highest hemolymph cholesterol contents. There was a linear relationship (r = 0.832; p<0.01) between hemolymph cholesterol and the amount of lecithin in the diet. There were no significant differences between treatments in cholesterol contents in the hepatopancreas. In a second 6-week experiment, diets containing 1.5% cholesterol significantly improved weight gains, regardless of the lecithin content. Survival rates did not differ among treatments. Hence, the efficacy of cholesterol does not seem to be related to dietary inclusion of lecithin. Introduction Sterols are essential nutrients for prawns because crustaceans are unable to synthesize these compounds (Zandee, 1966; Teshima and Kanazawa, 1971). Feeding experiments have demonstrated the necessity of dietary sterols for growth and survival (Castell et al., 1975; Petriella et al. 1984). Essential components such as molting hormones, sex hormones, bile acids, and vitamin D are synthesized from cholesterol. Cholesterol is also a membrane component and functions in absorption and transport of fatty acids (Akiyama et al., 1991). Cholesterol is obtained directly from the diet or via the meta* Corresponding author. E-mail: [email protected]