Dietary supplementation with a mixture of Dunaliella salina and Spirulina enhances broiler performance by improving growth, immunity, digestive enzymes and gut microbiota

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.