Algae are rich in polyunsaturated fatty acids and antioxidant pigments such as beta-carotene, and have recently become a hot topic of discussion. Microalgae inclusion in animal feed could help in lowering blood cholesterol, boosting immunological function, improving the amount and quality of poultry products, and so strengthening resistance against diseases. Microalgae also help to improve microbial colonization, enhance nutritional absorption, and better the digestive system condition and function. Dunaliella salina is one of the most significant carotenoid-producing microalgae species; it is a main natural source of β-carotene, so it is quite valuable in cosmetics, medicine, and nutrition. D. salina microalgae can accumulate up to 25 % dry weight in lipids and is the most efficient natural source of β-carotene. Of its dry weight, β-carotene makes up about 10–14 % account. Furthermore, D. salina is rich in vital minerals, antioxidants, and other bioactive compounds. Along with various non-essential amino acids, it also has all the fundamental ones. This composition enhances both its nutritional profile and functional value. The natural biochemical content of D. salina and its claims as antioxidants, antimicrobial, immunostimulant, and growth promoter, in addition to its role in improving lipid profile, liver and kidney function, gut health, poultry production, and reproduction will be discussed in this review. Mechanisms of action and health-promoting effects, functional food applications for human health and applications of D. salina in several areas of the industry are also highlighted.