Spawning and Season Affect Lipid Content and Fatty Acid Composition of Ovary in Chondrostoma regium

Abstract

Seasonal changes in fatty acid composition and total lipid content of different lipid fractions (phospholipids, triacylglycerols, and phospholipid subclasses) were investigated in the gonads of female Chondrostoma regium. Samples were collected in July, November, January, and April. Fish specimens were transported to the laboratory in insulated containers with ice, and the gonadal tissues were dissected for biochemical analysis. Total lipids were extracted following the Folch method, and the lipid fractions were separated using thin-layer chromatography. Fatty acid methyl esters (FAMEs) were prepared and analyzed by gas chromatography with flame ionization detector (GC-FID). The results showed significant seasonal variations in total lipid content and fatty acid profiles. The highest total lipid content was recorded in January (5.77% ± 0.29%), whereas the lowest was observed in April (2.39% ± 0.14%). Among polyunsaturated fatty acids (PUFAs), docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) were dominant across all fractions. Notably, the n-3/n-6 ratio varied considerably between seasons, peaking in November. In general, phospholipid subclasses such as phosphatidylethanolamine (PE) and phosphatidylserine (PS) exhibited marked seasonal changes in both saturated and unsaturated fatty acid contents. These findings provide insights into the reproductive physiology of C. regium and suggest that seasonal dynamics strongly influence the nutritional quality of gonadal lipids. These findings have implications for aquaculture, reproductive biology, and dietary value of this freshwater species.

Practical Applications: The seasonal shifts in the lipid reserves and fatty acid composition of C. regium provide useful indicators for managing broodstock nutrition and improving reproductive performance in future aquaculture programs. The timing of peaks in DHA- and EPA-rich phospholipids can guide feeding strategies to enhance the oocyte quality. These biochemical patterns also offer practical tools for monitoring reproductive status and environmental stress in the wild. Additionally, the high n-3 fatty acid content highlights the nutritional value of this species, supporting its potential use in healthy dietary applications.