Dietary Chlorella vulgaris and Saccharomyces cerevisiae enhanced the growth performance, blood biomarkers, and antioxidative capacity of common carp (Cyprinus carpio)

Chlorella vulgaris (CV) has been investigated in aquaculture and shown as a potential functional feed additive. Therefore, this study tested the effects of dietary CV and Saccharomyces cerevisiae (SC) on the growth performance, blood biomarkers, and antioxidative capacity of common carp (Cyprinus carpio). Fish were allocated in four groups in triplicates, where each glass aquaria was stocked with 15 fish with 4.25±0.11 g/fish. Fish offered four test diets for 84 days: control (free from CV or/and SC), CV-supplemented diet (5 %), SC-supplemented diet (0.05 %; (10 × 10⁹ CFU/g), and a mixture of CV and SC-supplemented diet (5 % CV+ 0.05 % SC), respectively. The results indicated that fish-fed CV or SC revealed enhanced growth performance (final weight, weight gain, and specific growth rate) and protein efficiency ratio, while the feed conversion ratio was reduced compared to the control. Fish-fed dietary SC or CV and SC mixture revealed higher villi length than the control. Besides, villi width and muscular thickness enhanced significantly in carps-fed CV and SC compared to the control. Fish-fed dietary CV and/or SC revealed lower moisture content and higher crude protein and total lipids than the control. The results indicated that fish-fed CV or SC revealed higher serum total protein than the control. On the other hand, the total cholesterol and triglyceride levels were markedly reduced in carps-fed dietary CV and/or SC compared to the control. The results indicated that fish-fed CV and/or SC revealed higher lysozyme activity, catalase, and glutathione peroxidase than the control. The superoxide dismutase of fish-fed CV or SC is higher than that of the control or CV and SC mixture. Additionally, the malondialdehyde levels (MDA) were markedly reduced in carp-fed dietary CV and/or SC compared to the control group. In conclusion, dietary C. vulgaris and/or S. cerevisiae can enhance growth performance and feed utilization in common carp. Besides, the biochemical blood markers and activated antioxidative capacity indicated that common carp fed C. vulgaris and/or S. cerevisiae revealed stable health status.