Aging extension and modifications of lipid metabolism in the monogonont rotifer Brachionus koreanus under chronic caloric restriction

Abstract

To examine the interrelationship of aging extension and modification of lipid metabolism under chronic caloric restriction (CCR; reduced concentration of the green algae Tetraselmis suecic alpha) in the monogonont rotifer Brachionus koreanus, we assessed life cycle parameters, fatty acid composition, and expression of sirtuin and genes related to lipid metabolism. B. koreanus in the 5% T. suecic alpha group showed an increased life span but decreased reproduction. Based on this finding, we chose 5% T. suecic alpha for further experiments and compared the data with those for 100% T. suecica. Upregulation of sirtuin gene expression was observed under CCR. In addition, despite the reduction in the amount of total fatty acid (FA) and the area of triacylglycerol, increases in the ratios of saturated fatty acid and monounsaturated fatty acid (MUFA) to total FA in 5%-exposed B. koreanus were observed. Furthermore, mRNA expression analysis confirmed that CCR promoted the synthesis of MUFA through Delta 9 desaturase. Moreover, expression of the docosahexaenoic acid (DHA) synthesizing gene Delta 4 desaturase was also upregulated, together with DHA content. These data suggest that CCR modified protein acetylation and lipid metabolism, leading to a decrease in reproduction and consequently resulting in life span extension.