Dietary Inclusion of Duckweed ( Lemnaceae ) Modulates Growth Efficiency, Fillet Quality, and Sensory Properties in Common Carp ( Cyprinus carpio )

Identifying alternative protein sources is essential for the sustainable development of aquaculture. Duckweed ( Lemnaceae ) represents a promising alternative feed ingredient for aquaculture, yet research into its applications as a dietary component is scarce. In this study, 240 mirror carp ( Cyprinus carpio var. specularis ) with an average weight of 73.4 g, were fed diets containing either 0% (DW0), 10% (DW10), 15% (DW15), or 20% (DW20) duckweed over a 14‐week period. Overall, duckweed inclusion in carp diets significantly influenced performance, fillet composition, colour, and sensory attributes. The fish accepted the diets across all treatments. Yet, growth performance was lower in groups receiving duckweed‐inclusive diets ( p < 0.05) while less differences were found between the inclusion rates. No alterations in meat quality were observed. Fillets from duckweed‐fed carp exhibited higher crude protein and ash content, but reduced fat and moisture levels. Skin and fillet colour shifted towards more green and yellow hues in accordance with the increasing dietary duckweed levels. Fatty acid analysis revealed increased proportions of omega‐3 and omega‐6 fatty acids in fish fillets with inclusion of duckweed, while levels of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were comparable across feeding types. Sensory evaluations indicated stronger fishy notes in duckweed‐fed carp along with increased sweet odour and a trend towards a buttery taste. This study demonstrates the applicability of duckweed in common carp aquafeeds and its prospects for performance, composition, meat quality, pigmentation and sensory perception, thereby laying the groundwork for further investigations into consumer acceptance, digestibility, and its use in other fish species.