| This experiment was conducted to investigate the effects of different doses of fucoidan on growth performance,immune and antioxidant indices in serum,liver,spleen and small intestine of broilers.A single factor randomized blocks design was used in the experiment.192 healthy 1-day-old Arbor Acres(AA)broilers with similar body weight were selected and randomly divided into four groups,which were fed the basal diet supplemented with,respectively,0(control),125,250 and 500 mg/kg fucoidan,with 6replicates in each group and 8 chickens(4 male and 4 female)in each replicate.The experiment lasted for 42 d,which was divided into d 1-21 in the early stage and d 22-42 in the late stage.The test results were as follows:1.Compared with the control group,diets supplemented with 125 and 250 mg/kg fucoidan significantly increased the average daily gain(ADG)of broilers at the latter and the whole period of the experiment(P=0.05).The results of regression analysis showed that the average daily gain was significantly increased quadratically with the increase of the fucoidan supplemental level(P<0.01).During the whole experiment period(d 0-42),the average daily gain increased quadratically with the increase of the polysaccharide supplemental level(P=0.02).However,there was no significant effect on average daily feed intake and feed/gain ratio of broilers(P>0.05).2.In the early stage of the experiment,compared with the control group,the IL-4content in duodenum was significantly increased by the addition of 250 mg/kg(P=0.03);when the adding amount of fucoidan was 500 mg/kg,the content of IL-2 in serum significantly increased(P=0.05);when the adding amount was 125-500 mg/kg,the contents of IL-1β and IL-6 in duodenum significantly reduced(P<0.01);when the addition amount was 250-500 mg/kg,the content of Ig G in serum significantly increased(P<0.01),and the content of IL-4 in serum significantly reduced(P=0.02).At the later stage of the experiment,compared with the control group,the IL-6 content in duodenum significantly reduced when the addition amount was 125-500 mg/kg(P=0.02);when the addition amount was 250-500 mg/kg,the IL-6 content in liver significantly reduced(P<0.01);when the addition amount was 500 mg/kg,the content of IL-2 in jejunum and Ig A,Ig G and IL-2in serum significantly increased(P<0.05),and Ig G content in spleen showed an increasing trend(P=0.06),but IL-1β content in liver significantly decreased(P=0.02).3.In the early stage of the experiment,compared with the control group,the T-SOD activity in serum and CAT activity in ileum tended to increase when the addition amount of fucoidan was 125 mg/kg(P=0.07,P=0.08);the activity of CAT in duodenum tended to increase at the dose of 250 mg/kg(P=0.09);the addition amount of 500 mg/kg significantly reduced the activity of T-SOD in duodenum(P=0.03);the content of MDA in duodenum was significantly decreased at the dose of 125-250 mg/kg(P<0.01);the addition amount of 125-500 mg/kg significantly increased the activity of T-SOD in jejunum(P=0.05).At the later stage of the experiment,compared with the control group,the addition of 250 mg/kg fucoidan significantly increased the activity of T-AOC in serum(P<0.01),and significantly decreased the content of MDA in liver(P=0.04);the addition amount of 500 mg/kg significantly increased the activity of GSH-Px in ileum(P=0.04);when the addition amount was 125-250mg/kg,the activity of T-SOD in liver significantly increased(P<0.01);the addition amount of 250-500 mg/kg could significantly increase the activity of CAT in liver tissues(P<0.01).In conclusion,dietary supplementation with appropriate doses of fucoidan could improve growth performance,immune and antioxidative functions of broilers. |
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