Abstract: Objective: To examine the protective effects of three types of dairy products on immune vulnerability in vinorelbine-treated zebrafish. Methods: A zebrafish model of immunity vulnerability was established by intravenous injection of 0.2 mg/mL vinorelbine. The fish were randomly divided into five groups with 30 fish in each group: normal control, model control, low temperature yogurt (8 333 μg/mL), normal temperature pure milk (70.4 μL/mL), and frozen yogurt ice cream (33 333 μg/mL). The effects of the dairy products on the number of macrophages and T lymphocytes and macrophage phagocytosis in immunosuppressed zebrafish were evaluated using fluorescent microscopy. Results: Compared with the normal control group, the number of macrophages, the phagocytic function of macrophages and the number of T cells were significantly reduced in the model control group (P < 0.001). Compared with the model control group, the number of macrophages and T lymphocytes were significantly increased by treatment with each of the dairy products (P < 0.05, P < 0.01 or P < 0.001). Normal temperature pure milk and frozen yoghurt ice cream but not low temperature yoghurt could significantly enhance the phagocytosis capacity of macrophages (P < 0.05). Compared with low temperature yoghurt, normal temperature milk significantly increased the number of macrophages (P < 0.05), but resulted in no significant difference in the number of T cells or the phagocytic function of macrophages (P > 0.05); frozen yogurt ice cream also resulted in no significant difference in all of the parameters (P > 0.05). Conclusion: All these diary products can enhance the immune function of vinorelbine-treated zebrafish with immune vulnerability via increasing the number of macrophages and T lymphocytes and improving macrophage phagocytosis.

Key words: dairy products; immunity function; macrophages; T lymphocytes