| This experiment aims to explore the effect of Artemisia ordosica ethanol extract(AOEE)on the immunity and antioxidant function of broilers,and to obtain the appropriate dosage,which provided a reference for the application of AOEE as an animal feed additive.In the experiment,240 healthy one-day-old AA broilers with similar body weight(37.35±0.23)were selected and randomly divided into five treatment groups(0,250,500,750 and 1 000mg/kg AOEE were added to the basal diet),six repetitions per group,eight chickens per repetition.The experiment lasted for 42 days.Slaughter sampling on the 21 st and 42 nd day of the experiment.(1)The initial body weight,final body weight and feed intake of the test chickens were recorded by weighing,and the body weight gain and feed conversion rate of each period(early,late,and full period)were calculated to evaluate effect of AOEE on broilers growth performance.The results found that with the increase of AOEE addition,the body weight gain showed a significant linear increase effect during the early stage(P<0.05),and the body weight gain in the later stage and the whole experiment period showed a significant linear or quadratic increase(P<0.05);feed conversion ratio showed a significant quadratic increase effect during the early stage(P<0.05),and a significant linear increase effect in the later stage and the whole experiment period(P<0.05).(2)Weighing immune organ(spleen,thymus and bursa)of broilers,calculating the immune organ index;measuring the contents of immunoglobulins and cytokines in liver,spleen,duodenum,jejunum and ileum tissues of broilers,and the relative expressions of immune-related genes in each tissue were determined to explore effects of AOEE on the immune function of broilers.The results showed that: on day 42,with the increase of AOEE addition,the spleen index and the thymus index showed a significant linear or quadratic increase effect.(P<0.05);on day 21,with the increase of AOEE supplementation,the contents of IgA and IgM in liver,the contents of IgA,IgG and IgM in spleen,the contents of three immunoglobulins and IL-2 in jejunum and ileum showed a significant linear or quadratic increase effect(P<0.05);on day 42,with the increase of AOEE addition,the contents of IgM in the liver showed a significant quadratic increase effect(P<0.01),the contents of IL-2 and IL-4 in the liver and spleen showed a significant linear or quadratic increase(P<0.05),and the levels of sIgA and IL-2 in the duodenum showed a significant linear elevating effect(P<0.05),the contents of sIgA,IgG,IgM and IL-2 in jejunum and ileum showed a significant linear or quadratic increase effect(P<0.05);the relative expressions of TLR4,MyD88,NF-κB p65,NF-κB p50,IL-1β and IL-6,and the contents of IL-1β and IL-6 decreased with the increase of AOEE level.(3)The activities of antioxidant enzymes and the relative expressions of antioxidantrelated genes in various tissues were determined to explore the effect of AOEE on the antioxidant function of broilers.The results showed that: on day 21,with the increase of AOEE addition,the activity of antioxidant enzyme in the liver and spleen and antioxidant enzyme activity in duodenum and jejunum,and T-AOC content showed a significant linear or quadratic increase effect(P<0.05),but MDA content in liver showed a significant linear or quadratic reduction effect(P<0.05);on day 42,with the increase of AOEE addition,the activity of GSH-Px and SOD in the liver and the activity of CAT in the spleen of broilers decreased linearly or quadratically in broilers(P<0.05),and the activity of GSH-Px and TAOC in duodenum showed significant quadratic reduction effect(P<0.05),the activity of CAT,SOD in duodenum and jejunum and the activity of CAT in ileum of broilers showed a significant linear or quadratic increase effect(P<0.05);the relative expression levels of Nrf2,GSH-Px,CAT,SOD and HO-1 increased with the increase of AOEE level. |
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