Impact of Cobalt Levels on Fatty Acid Profile and Nutritional Quality of Common Carp Muscle ( <i>Cyprinus carpio</i> )

The aim of this study is to evaluate the toxic effects of cobalt chloride concentrations (2 μg/LCoCl₂ (D1), 25 μg/LCoCl₂ (D2), and 50 μg/LCoCl₂ (D3)) on the fatty acid profile and nutritional quality of Cyprinus carpio muscle. After 3 days of treatment, our results have shown an induction of lipid peroxidation affirmed by significant increases in malondialdehyde (MDA) and peroxide value (PV) levels for fish treated with D2 and D3 doses. We noted decreases in saturated fatty acids (SFA) and an increase in polyunsaturated fatty acids (PUFA) in all treated groups. The docosahexaenoic (DHA) and eicosapentaenoic (EPA) acid levels declined in all fish exposed to CoCl₂ graded doses (p ≤ 0.001). The decrease in the conversion enzyme ratios D5D and D6D desaturases explained these changes in EPA and DHA levels. However, PUFA (n-6) and arachidonic acid (ARA) increased (p < 0.001) in all treated groups. These increases in ARA were associated with the enhancement of linoleic acid (LA) and D5D' desaturases activity. Our treatment showed significant declines in PUFA (n-3)/PUFA (n-6) ratio and in flesh lipid quality (FLQ) and an increase in the PUFA/SFA ratio. Our experiment suggested the harmful effects of cobalt, confirmed by the alteration of fatty acid composition and deterioration of the nutritional quality of C. carpio muscle.