| Polysaccharide is the energy resource and the composition of the organism. It is widely existed in the cell membrane of the animal and the plant. In recent years, with the improvement of separation technology and detection level, it was found that polysaccharide and its complexes are not only involved in various activities, but also have many specific physiological activity, such as anticoagulation, blood lipids, antiviral, antitumor, enhance immune function and anti-aging. Polysaccharide has strong biological activity and has no toxic side effect, so it is one of the ideal source of drugs which has received widespread attention. Polysaccharide of Enteromorpha(Enteromorpha polysaccharide, EP) is isolated from Enteromorpha prolifera bioactive substances, which not only has the hypolipidemic,hypoglycemic and antioxidant activity, but also has strong immunomodulatory effects, so it is a good feedstock for drug and food research and development. This study chosed the polysaccharide of Enteromorpha as the material, focused on the effect of EP on broiler immune and growth performance after the preliminary study on the structure and biological activity of EP, the main research results are as follows:Structural analysis and bioactivity assay in vitro showed that EP had the typical structure and biological activity of polysaccharide. The infrared spectroscopy analysis showed that EP had sugar typical characteristic absorption peaks and riched in sulfate groups; antioxidant capacity determination in vitro showed that EP has antioxidant activity and showed dose effect relationship, within a certain range, the antioxidant effect enhanced with the increase of the concentration and strengthen; MTT test results showed EP could promote the proliferation of peripheral blood lymphocyte of chicken, the maximum safe concentration was 125 ug/ml,the maximum proliferation rate was 28.643%, and had synergistic effect with phytohemagglutinin(PHA).200 AA broilers at the age of 1 day were selected in the experiment. With normal drinking water as control, EP was set to 3 groups including low(0.5), medium(1.0) and high(2.0) doses. The effects of EP on immune functions in chickens were studied by determinating the immune organ index, villus morphology, serum HI antibody titer and mucosal antibody level. The effects of EP on growth performance in chickens were also studied by measuring the average daily feed intake, average daily gain and feed conversion ratio. It was found that EP could promote the spleen and bursa index of the chicken. EP also increased serum HI antibody titers in chickens and that in 1.0 EP group was significantly higher than other groups(P<0.05). EP enhanced the mucosal immune response of chickens,increased the levels of specific SIgA antibody in bile, tracheal and duodenum washings and the level of SIgA antibody in1.0 EP group was the highest(P<0.05). EP increased the average daily feed intake, average daily weight gain and decreased feed meat ratio of chicken in 1.0 EP group(P<0.05). EP significantly increased the villus length and width of duodenum, jejunum and ileum and increased muscle thickness, mucosal thickness and velvet gland ratio of the chickens in 0.5 and 1.0 EP groups(P <0.05).To sum up, EP has strong antioxidant activity and promotes the proliferation of peripheral blood lymphocytes, and enhances the immune functions and growth performance of broilers The concentration of 1.0 is the best additive amount of EP. |
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