Effects of compound Chinese herbal medicine on production performance and immune indexes of purified core population of Duck Tambusu virus in Sansui ducks

In order to purify Duck Tambusu virus（DTMUV） from Sansui duck and explore the effect of purified compound Chinese herbal medicine on performance and immune indexes of core population, a total of 170 573 samples of mecano, blood, cloacal cotton swab and egg white were collected. Duck Tambusu virus antigen was detected by ELISA and PCR. According to the test results, positive ducks were eliminated, and combined with the comprehensive prevention and control measures of avian diseases, five generations of Duck Tambusu virus purification programs were implemented to establish the Duck Tambusu virus core purification group of ducks, and the reproductive performance indexes（laying rate, fertility rate, hatching rate, duckling survival rate, and breeding rate） were measured. At the 4th generation after purification, a total of 120 7-day-old Sansui ducks were selected from the core group and divided into four groups（low, medium, high dose and control groups, respectively） with three replicates per group and ten ducks per replicate. The low, medium and high dose groups were supplemented with 0.1%, 0.2% and 0.3% compound Chinese herbs in the basal diet, respectively, while the control group was fed only the basal diet. Performance indexes（average daily gain, average daily feed intake, feed to gain ratio, average final weight, average egg production） and immune indexes（immunoglobulin A IgA, immunoglobulin M IgM, immunoglobulin G IgG, interleukin-2 IL-2, interleukin-4 IL-4, interleukin-6 IL-6,and γ interferon IFN-γ） were measured after 30 days of continuous feeding. The results showed that after 5th generations of purification, DTMUV antigen positive rate of Sansui ducks decreased from 5.11% in the 0 generation to 0 in the 4th generation, and the average production performance of laying rate, fertility rate, hatching rate, duckling survival rate, and breeding rate increased by 21.53%, 11.06%, 2.87%, 3.95%, and 5.38% compared with the 0 generation, respectively. The average daily gain, average daily feed intake, average final weight and average egg production of Sansui ducks in high dose group were significantly higher than those in control group（P ＜ 0.05）, and the mass concentrations of IgA, IFN-γ, IL-2, IL-4 and IL-6 in serum in low, medium and high dose groups were significantly higher than those in control group（P ＜ 0.05）. The mass concentrations of IgG and IgM in medium and high dose groups were significantly higher than those in control group（P＜0.05）, but there was no significant difference between low dose group and control group（P ＞ 0.05）. These results indicated that the purification effect was good, and adding 0.3% compound Chinese herbal medicine to the basic diet could improve the production performance and immune function of Sansui duck.