Influence of diet on proximate composition and fatty acid profile in common carp (Cyprinus carpio)

The most marketed species of fish in Serbia is common carp (Cyprinus carpio), which accounts for more than 80% of the national aquaculture. This study aimed to investigate the influence of two supplementary fish feeds (maize and extruded feed) on the proximate and fatty acid composition of carp. The results show that the protein, lipid, and ash contents were higher (P ≤ 0.001) in the extruded feed compared with maize. The carp fed extruded feed exhibited significantly higher protein and moisture contents (P ≤ 0.001 and P ≤ 0.01, respectively), whereas the total lipid content was significantly higher (P ≤ 0.001) in carp fed maize. The analysis of the fatty acid profiles showed that the saturated fatty acid (SFA) content in carp fed maize (23.94%) was lower than that in carp fed extruded feed (25.36%). The monounsaturated fatty acid (MUFA) content in carp fed maize (61.83%) was considerably higher compared with carp fed extruded feed (41.95%), whereas the polyunsaturated fatty acid (PUFA) content in carp fed maize (13.66%) was lower than that in carp fed extruded feed (30.91%). The principal component analysis (PCA) of the fatty acid profile resulted in a two-principal-component model that described 75.94% of the total data variance. The most influential factors were determined from the loading plot governing this distinction. The n-6/n-3 ratio in carp fed extruded feed (5.8) was found to be more nutritionally beneficial than that in carp fed maize (13.8), which indicates the better nutritional properties of carp fed extruded feed.