Sustainable Aquaculture Nutrition: Impact of Chlorella vulgaris and Iron Nanoparticles and their Combination on Growth, Hematology, and Immune Stability in the Common Carp (Cyprinus carpio)

This study evaluated the effects of dietary Chlorella vulgaris (C. vulgaris) and iron nanoparticles (Fe-NPs) on growth, blood parameters, and physiological status in common carp (Cyprinus carpio). The study was done at the Fish Lab, Biology Department, University of Zakho. The trial was conducted on 80 juvenile common carp divided into four groups: T0 (control, basal diet), T1 (10% C. vulgaris), T2 (85mg/ kg Fe-NPs), and T3 (both C. vulgaris and Fe-NPs) during 60 days of experiment. The results indicated an enhancement in growth performance, as the T3 group recorded the highest final total length (24.29±0.35cm, P<0.05), final body weight (167.7 ± 5.67g, P<0.05), and relative growth rate (RGR_length: 22.35±6.1, P<0.05). The hematological parameters demonstrated a remarkable improvement, with T3 recording the highest red blood cell (RBC) count (15.4±0.25 ×10⁶mm^-3) and preserving hemoglobin (Hb) levels (10.97±0.37g/ 100ml). The white blood cell (WBC) counts, on the other hand, were preserved equally in all of the experimental groups. PCV was significantly decreased in T1 (P<0.05), but it remained stable in T2 and T3. Condition factors, such as Fulton's condition factor (F. K), were at the highest in T3 (1.242 ± 0.05). Furthermore, the modified condition factor (F. Kb) and relative condition factor (F. Kn) were also significantly improved in T1 and T3 (P<0.05). The hepatosomatic index (HSI: 2.58 ± 0.54%, P<0.05) and gill somatic index (GSI: 2.63 ± 0.33%, P < 0.05) exhibited their highest values in T3. It can be concluded that C. vulgaris and Fe-NPs profoundly improved the growth, hematological parameters, and some physiological parameters of common carp, indicating their potential as green dietary supplements in aquaculture.