Abstract:Improving the body′s immunity is of great significance for promoting musculoskeletal system development and preventing osteoporosis. In this study，a musculoskeletal system dietary supplement was formulated based on calcium and vitamin D3，with the addition of whey protein and leucine，to explore its effect on immune function in mice. A total of 160 ICR mice were randomly divided into a blank group and low，medium，and high-dose groups. After 30 days of continuous gavage，the immune organ/body weight ratio，cellular immunity，humoral immunity，and serum cytokine levels were evaluated. The results showed that compared with the blank group，gavage with low and medium doses of the supplement significantly increased the thymic index，low and medium doses of the supplement significantly increased antibody production capacity，and serum tumor necrosis factor-α （TNF-α） concentration （P＜0.05）. Furthermore，medium and high doses significantly enhanced the ear swelling rate，macrophage phagocytosis rate，natural killer （NK） cell activity，and serum interleukin-6 （IL-6） concentration in mice （P＜0.05，P＜0.01）. Additionally，there were no significant changes in serum interleukin-1β （IL-1β） and interleukin-10 （IL-10） concentrations across all groups（P＞0.05），but gavage with the medium dose significantly increased the number of empty spots and the carbon contour phagocytosis index （P＜0.05）. These results suggested that the nutritional supplement had the effect of enhancing both cellular and humoral immunity，with the medium dose （3.8 g/kg BW） showing significant effects.