Effect of Radix rehmanniae Extract on Immune Organ Indexes and H9 Vaccine Immune Efficacy of Chicks

This study was aimed to investigate the effect of the Radix rehmanniae extract on immune organs indexes and H9 vaccine immune efficacy.1 200 1-day-old healthy chicks fed with basal diet were chosen and randomly devided into 6 Groups on 14-day-old:GroupⅠ,Ⅱ and Ⅲ adding 2‰,3‰ 0.4‰ Radix rehmanniae extract,respectively;Group Ⅳ adding 1‰ astragalus polysaccharide;Group Ⅴ immunned with H9 vaccine and fed with basal diet;Group Ⅵ was blank control group which didn't immunned with H9 vaccine and fed basal diet.After 7 days medicine-feeding,the samples were collected at 14,21,28,35,42,49 and 56 days and the immune organs indexes and the H9 antibody levels were determined.The results showed as follows:①Compared with group Ⅵ,the spleen and bursa indexes of groupⅠ,Ⅱ,Ⅲ and Ⅳ were significantly increased (P < 0.05),indicating that dietary supplementation with Radix rehmanniae extract and astragalus polysaccharide could improve spleen and bursa development (P < 0.05).Compared with group Ⅰand Ⅲ,the bursa and spleen indexes of group Ⅱ were significantly increased (P < 0.05),while there was no significant difference between group Ⅱ and Ⅳ (P > 0.05).②Dietary supplementation with Radix rehmanniae extract and astragalus polysaccharide could improve H9 antibody titers and hold it at a higher level.Compared with group Ⅰand Ⅲ,the H9 antibody titer of group Ⅱ was significantly increased from 42 days (P < 0.05),while there was no significant difference between group Ⅱ and Ⅳ (P > 0.05).In conclusion,the Radix rehmanniae extract could improve immune organs development and immune function of chicks,and keep antibody titers at high levels when matches with H9 vaccine.And the recommended supplemental level of Radix rehmanniae extract was 2‰ in diet for chicks.