Abstract: To study the effects of the small molecular Donkey-hide gelatin (SDG) on immune function of mice.Methods:Adult female ICR mice were orally administrated with the SDG at doses of 0.18,0.35 and 1.05 g/kg for 30 days consecutively.The cellular immunoregulation of the mice was verified with delay-type hypersensitivity (DTH) test and proliferation and transformation of spleen lymphocyte.The humoral immunoregulation was assessed with antibody-producing cell and serum hemolysin level test.Nonspecific immune regulation was monitored with carbon clearance,macrophage phagocytosis test and activity of natural killer (NK) cells.Spleen index and thymus index of the mice were also determined.The result is that the middle dose group increased the number of antibody producing cells (P<0.05)，the high dose group promoted lymphocyte transformation rate (P<0.01) and the macrophage phagocytosis index(P<0.05)and NK cell activity (P<0.05),the delayed type hypersensitivity ability of the middle and high dose groups increased(P<0.01),the level of serum hemolysin were increased in all dose groups (P<0.05 or P<0.01).So the small molecular Donkey-hide gelatin can enhance the immune function of ICR mice.

Key words: small molecular donkey-hide gelatin, oligopeptide, ICR mouse, immune regulation