Bioconversion of ¹³C-labeled microalgal phytosterols to cholesterol by the Northern Bay scallop, Argopecten irradians irradians

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• 作者：José ; -Luis Giner^a ; ^{jlginer@syr.edu" class="auth_mail" title="E-mail the corresponding author} ; Hui Zhao^a ; Mark S. Dixon^b ; Gary H. Wikfors^b ; ^{Gary.Wikfors@noaa.gov" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Marine sterols ; Sterol metabolism ; Bivalve lipid nutrition
• 刊名：Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：192
• 期：Complete
• 页码：1-8
• 全文大小：766 K

文摘

Bivalve mollusks lack de novo cholesterol biosynthesis capabilities and therefore rely upon dietary sources of sterols for rapid growth. Microalgae that constitute the main source of nutrition for suspension-feeding bivalves contain a diverse array of phytosterols, in most cases lacking cholesterol. Rapid growth of bivalves on microalgal diets with no cholesterol implies that some phytosterols can satisfy the dietary requirement for cholesterol through metabolic conversion to cholesterol, but such metabolic pathways have not been rigorously demonstrated. In the present study, stable isotope-labeled phytosterols were used to supplement a unialgal diet of Rhodomonas sp. and their biological transformation to cholesterol within scallop tissues was determined using ¹³C-NMR spectroscopy. Scallops efficiently dealkylated ∆⁵ C₂₉ (24-ethyl) sterols to cholesterol, and the only C₂₈ sterol that was dealkylated efficiently possessed the 24(28)-double bond. Non-metabolized dietary phytosterols accumulated in the soft tissues. Observed formation of ∆^5,7 sterols (provitamin D) from ∆⁵ sterols may represent initiation of steroid hormone (possibly ecdysone) biosynthesis. These findings provide a key component necessary for formulation of nutritionally complete microalgal diets for hatchery production of seed for molluscan aquaculture.