Fatty acid composition, sarcoplasmic reticular lipid oxidation, and immunity of hard clam (Meretrix lusoria) fed different dietary microalgae

Fatty acid profiles, activities of biomembrane lipid peroxidation, and immunity of a seawater clam (Meretrix lusoria) fed three species of dietary microalgae were investigated. Clams of a marketable size (25 g mean weight) were fed Tetraselmis chui, Chaetoceros muelleri, or Isochrysis galbana for 8 weeks. Fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), in the polar lipid fractions of clams reflected those of the dietary algae species. Clams fed with T. chui and C muelleri contained higher proportion of non-methylene interrupted (NMI) fatty acids than those fed I. galbana. Proportion of DHA in lipids of the clams fed with I. galbana was the highest among test groups. The NADH-dependent sarcoplasmic reticular lipid peroxidation activity of clams fed I. galbana was significantly greater (p < 0.05) than that of clams fed T chui or C muelleri. The hemocyte adhesion capacity of clams fed C muelleri or I. galbana was significantly higher (p < 0.05) than that of clams fed T chui. No significant differences (p > 0.05) in total hemocyte count, phenoloxidase activity, clearance efficiency hemocyte and phagocytosis were detected among clams fed different microalgae. (C) 2015 Elsevier Ltd. All rights reserved.