Age-associated variation in lipid composition and nutritional quality of the invasive bivalve Anadara kagoshimensis from the Sea of Azov.
This study examined age-associated variation in lipid composition and nutritional quality in the invasive clam Anadara kagoshimensis from the Sea of Azov. Fatty acid and sterol compositions were determined by gas chromatography in clams assigned by sclerochronology to five age classes (2-6 years). Several lipid-quality indices, including PUFA/SFA, IA, IT, hH, and HPI, exhibited their most favorable mean values in the 4-year group. The highest condition index (13.7) and the lowest n-3/n-6 ratio (1.1) were observed in the small and unbalanced group of 6-year-old clams. An exploratory linear discriminant analysis (LDA) workflow was used to examine whether primary lipid variables and mathematically derived composite features could enhance age-group separation. LDA based on primary variables yielded 78% leave-one-out classification within the present dataset. Data-driven composite-feature construction increased the within-dataset classification to 100% and graphical group separation to 85%, the values with yet restricted predictive accuracy due to the limited dataset. The results provide baseline information on age-associated lipid variation in A. kagoshimensis and illustrate a proof-of-concept workflow that can be tested in future studies using larger, balanced samples and special validation approaches.