Lipid and Fatty Acid Compositions of Mytilus galloprovincialis Cultured in the Mar Grande of Taranto (Southern Italy): Feeding Strategies and Trophic Relationships

Lipid and fatty acid compositions of Mytilus galloprovincialis cultured in the Mar Grande of Taranto (southern Italy): feeding strategies and trophic relationships. Zoological Studies 49(2): 211-219. Lipid and fatty acid (FA) compositions were determined in the mussel Mytilus galloprovincialis collected from June 2006 to May 2007 in the Mar Grande of Taranto, southern Italy. Total lipids significantly differed throughout the study period (ANOVA, p < 0.05), with higher values in summer (24.7% dry weight (DW)) and the lowest values in winter (3.5% DW). Triacylglycerols (TAGs) were the dominant lipid class in spring and summer accounting for 55.28% and 60.3% of total lipids, respectively, while in the autumn and winter phospholipids (PLs) were considerably greater than TAGs, comprising 55.16% and 47.5% of total lipids, respectively. Cholesterol did not show large variations over the seasons. Predominant FAs were saturated FAs (SAFAs) followed by monounsaturated FAs (MUFAs). The amount of polyunsaturated FAs (PUFAs) was low. The 14:0, 16:0, 18:0, and 22:0 SAFAs, together with 14:1, 16:1 omega 7, 18:1 omega 9, 18:1 omega 7, 20:1 omega 9, and 24:1 omega 9 MUFAs, and the PUFA, non-methylene interrupted dienoic (NMID), were the most abundant FAs. FA biomarkers are frequently used to identify trophic relationships among marine invertebrates. In order to obtain indications on food sources of M. galloprovincialis, a variety of FA ratios and the sum of some FAs were determined. The sum of 18:1 omega 7 + odd-branched FAs indicated a moderate bacterial contribution to the mussel diet. A high 18:1 omega 9/18:1 omega 7 ratio together with a high level of 20:1w9 indicated an animal dietary input. Trophic markers suggested lows contribution of diatoms and dinoflagellates to the diet of M. galloprovincialis.