ObjectiveTo investigate the effects of indigowoad root polysaccharide (IRP) at different doses on the expression of IgG and SIgA positive cells in duodenum of colostrum-deprived Sprague-Dawley (SD) filial rats. MethodsForty breeds of the filial rats at day 0 were randomly divided into groups A-E:(A) colostrum group, (B)milk group, (C) milk and the high doses of IRP group, (D) milk and the medium doses of IRP group, and (E) milk and the low doses of IRP group. The groups A-E of filial rats were administered 0.9% saline, 0.9% saline, low, medium and high doses of IRP, respectively. Six of them were randomly sacrifieced to collect materials at day 0,7, 4,1, 28, respectively. The distribution and changes of IgG- and SIgA-positive cells and their secretions in the duodenum of the filial rats were examined by immunohistochemistry and using a Moticam 2306 image analysis system. ResultsIgG- and SIgA-positive cells were firstly distributed in the intestinal luminal lamina propria, and then they were also located in the villus lamina propria, and among epithelial cells and in the muscular layer by days. The numbers of IgG- and SIgA-positive cells were increased by days, and the quantities of them in the group C, D and E were larger than that in the group B between d7 to d28. The groups E, D and C had the most immunological enhancement effect on days 7-14, days 14-21, and days 21-28. ConclusionsIRP can enhance the expression of IgG and SIgA in duodenal cells of colostrum-deprived filial rats. The optimal dosage of IRP can be reduced by days. 