The using of Chlorella pyrenoidosa and Daphnia magna as feed supplements for common carp, Cyprinus carpio: growth performance, somatic indices, and hemato-biochemical biomarkers

The present study was carried out to evaluate the using of phytoplankton; Chlorella pyrenoidosa (ChP), zooplankton; Daphnia magna (DaM), and their combination as feed supplements for common carp, Cyprinus carpio L. Seven diets were formulated as a commercial diet (T1) without any feed supplement, T2 – T3; a commercial diet enriched with 25 g and 50 g ChP/kg diet, respectively, T4 – T5; with 25 g and 50 g DaM/kg diet, respectively, T6; with 25 g ChP + 25 g DaM/kg diet, and T7; with 50 g ChP + 50 g DaM/kg diet. Fish (27.5–29.1 g) were fed on one of the experimental diets up to apparent satiation twice a day for 12 weeks. It was noticed that the supplements of ChP, DaM, and their combination significantly (P < .05) improved the growth performance of common carp. It was also noticed that fish fed on DaM (T4 – T5) showed superior growth over those fed only ChP (T2 – T3). Moreover, both feed supplements (ChP + DaM) significantly improved the feed intake and its highest amounts were obtained at T5 – T6; meanwhile, there were no significant (P > .05) differences in values of feed conversion ratio. No significant differences were observed in condition factor, or different somatic indices of liver, gills, viscera, kidney, and spleen of fish fed different diets. Significant increases were also observed in values of white blood cells, red blood cells, hemoglobin, and hematocrit accompanied with significant (P < .05) declines in values of mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration in fish fed diets enriched with ChP, DaM, and their combination. Compared to the control group, serum total protein and triglycerides were significantly (P < .05) increased in experimental fish groups with no difference among them. Other blood parameters including serum glucose, cholesterol, both low density and high density lipoprotein, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase did not show significant (P > .05) differences between the control and experimental groups. The results of the present study demonstrated that combination of ChP and DaM could be used as feed supplements at levels of 25 g ChP + 25 g DaM/kg diet where both of them possess a significant role in improving the growth and health of common carp.