Abstract: Different dosage of cysteamine(CS) were added to the basal diets to study the effect of CS on immunity in piglets. Ninety newborn “Duroc× Landrace×Yorkshire” crossbred piglets were divided into 3 groups with 30 piglets each，and fed with basal diet, basal diet plus 120 mg/kg CS and basal diet plus 200 mg/kg CS， respectively. The trial was conducted for 45 d. Blood samples in 20 piglets each group were taken on 14,24,32,42 day for measuring some immune indices. The results indicated that addition of cysteamine to the basal diet increased significantly the weight and average daily gain, decreased the ratio of feed to gain in piglets, increased significantly the levels of serum IgA,IgG，phagocytosis rates of neutral granular cells and conversion rates of T- lymphocytes. Basal diet with 120 mg/kg CS could improve growth performance more preferably, and with 200 mg/kg CS could enhance the immunity of piglets more significantly. The trial implied that appropriate dosage of CS could effectively inhibit weanling stress and enhance immunity of piglets.

Key words: cysteamine; piglets; immune function