Dietary supplementation of spirulina powder (Arthrospira platensis) enhances growth, antioxidant status, immune function, and cardiac health in Japanese quails

This study was conducted to evaluate the effects of dietary supplementation with different levels of Arthrospira platensis (Spirulina powder) on growth performance, antioxidant status, immune function, and lipid metabolism in Japanese quails. A total of 600 seven-day-old quail chicks were randomly assigned to four dietary treatments with five replicates of 30 birds each. The treatments included a control group (basal diet with no additive) and three experimental groups supplemented with 1,000, 3,000, and 5,000 mg/kg of Spirulina powder, respectively. Growth performance, antioxidant status, lipid peroxidation, and immune responses were assessed between days 7 and 35. Results demonstrated that Spirulina supplementation linearly improved body weight gain and feed conversion ratio, enhanced antioxidant enzyme activities (SOD, GPx, and catalase) and reduced malondialdehyde (MDA) levels in serum, liver, and muscle (P < 0.001). Relative weights of immune organs (bursa of Fabricius, thymus, and spleen) increased significantly, and serum immunoglobulins (IgY, IgM, IgA) were elevated in Spirulina-fed groups, showing predominantly linear and occasionally quadratic responses. Innate immunity markers including complement C3, interleukin-10, and lysozyme also increased. Furthermore, Spirulina supplementation decreased serum LDL and improved HDL concentrations and the LDL/HDL ratio. In conclusion, dietary inclusion of Spirulina powder exerted clear linear and, in some cases, quadratic dose-dependent effects on growth, antioxidant defense, immune responses, and lipid metabolism in Japanese quails, supporting its potential as a functional feed additive in poultry nutrition.