The aim of this study is to evaluate the effect of Dunaliella salina and Spirulina (D + S) mixture on performance, carcass yield, kidney and liver markers, lipid profile, and immune responses of fattening chicks. Two hundred broiler chicks at 7 days old were distributed into 5 experimental groups, 5 replicates each with 8 chicks each. Group 1 was fed on only basal diet; group 2 was fed with basal diet and 0.50 g/kg (D + S); group 3 was fed with basal diet and 1.00 g/kg (D + S); group 4 was fed with basal diet and 1.50 g/kg (D + S); and group 5 was fed with basal diet supplemented with 2.00 g/kg (D + S). The additive mixture (D + S) consisted of (1 D. salina: 1 Spirulina). The experiment lasted for 6 wk. The results demonstrated significantly improved better live body weight, body weight gain, and feed conversion ratio (P<0.01) for groups that received (D + S) at levels of 1.0 and 1.5 g/kg diet compared to other groups at 6 wk of age. There was no significant influence of different levels of dietary feed additives on feed intake or carcass traits. The lipid profile was improved through a reduction of total cholesterol and low-density lipoprotein (LDL) values and increasing high-density lipoprotein (HDL) values, as well as the immune response, which was improved through increasing values of complement 3, immunoglobulin M (IgM), and immunoglobulin G (IgG) in the birds treated with (D + S) compared to the control group. The inclusion of all levels of (D + S)/kg decreased triglyceride, while total protein, albumen, and globulin values (P<0.05 or P<0.01) were higher compared to other groups. The inclusion of the different levels of (D + S)/kg improved liver function, whereas aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values were lower than in other groups (P<0.001). The lowest values of creatinine, urea, and uric acid were noted in birds fed a diet supplemented with 1.50 g (D + S)/kg. Antioxidant levels were improved through increasing values of catalase (CAT) and reduced glutathione (GSH) enzymes in the treated birds with (D + S) compared with the control chicks. Furthermore, digestive enzymes and microbial content were improved in broiler checks fed on diet supplemented with (D + S) compared to the control group. In conclusion, supplementing broiler chicks with a dietary D. salina and Spirulina combination increased their productive performance, immunity, kidney and liver function, lipid profile, and digestive enzymes.