Preparation And Patial Biologic Characterization Of Antibacterial Peptides From The Intestine Of Chicken And Duck

Antibacterial peptides are the basic defensive materials which immune system defense microbial invasion, have become a hot research spot by international researcher now.To explore the biological activity and the effects to the immune system of animals of antibacterial peptides from intestine,we extract the antibacterial peptides from chicken and duck intestinal mucosa,study its antibacterial activity in various physical and chemical factors and its effect to lymphocytes proliferation in vitro. Meanwhile, we want to find its effect in vivo lymphocyte proliferation and transformation of animal body weight and index of immune organs by adding antibacterial peptides into the chicken's drinking water.The specific content and result are as follows:1. Preparation of antibacterial peptides from intestineThe antibacterial peptides were extracted from chicken's and duck's intestinal mucosa by acetic acid diffusion and test the activity of the product of each step using inhibitory effect on E. coli,gel filtration chromatography with the Sephadex G-50,the elution products which have inhibitory activity were purified by SDS-PAGE,their molecular weight were 6.078kDa and 6.095kDa. The extraction products'substances were corresponded to the antimicrobial peptides'characteristics.2. Antibacterial activity of ABPs in various physical and chemical factorsIt showed that the antibacterial peptides have heat resistance throw testing it's antibacterial activity after treated it at different temperatures. Its antibacterial activity has a little change at 40℃-80℃to deal with 20min, but decreases exceed 90℃. We look the antibacterial activity of untreated antibacterial peptides by hot as a reference standard. The antibacterial activity of antibacterial peptides from chicken's and duck's intestinal mucosa has a good sensitivity in different pH. It has a strong antibacterial activity in the environment of pH 6.0-8.0,the antibacterial activity largely decline in the pH 5.0 and pH 9.0.3. Effect of ABPs to lymphocytes proliferationCultured peripheral blood lymphocytes from chicken and duck in vitro,observed the effects about different concentrations of antimicrobial peptides from intestine alone or combined with PHA-P/LPS to lymphocyte transformation proliferation in vitro by MTT. It was showed that antibacterial peptides from chicken's and duck's intestinal mucosa could be able to stimulate the transformation of lymphocytes proliferation separately. The antibacterial peptides from chicken's and duck's intestinal mucosa could promote the transformation of lymphocyte proliferation in low concentration when combined with PHA-P/LPS,but reduce in too high concentration. In order to study the effects of antimicrobial peptides from intestine to different daytime chicken's and ducklings'lymphocyte proliferation in vivo,it was added into chicken's and ducklings'water. The result showed that antibacterial peptides from chicken and duck intestine could not increase lymphocyte proliferation in vivo transformation,the effect was not significant.4. Effect of ABPs to animal body weight and index of immune organBy adding antibacterial peptides from intestine in chicken's and ducklings'water,study its effect on weight and immune organ index. We found that it had no significant difference on body weight and index of immune organ.The above study showed that:The antibacterial peptides were successfully extracted from chicken's and duck's intestinal mucosa. This antibacterial peptides from intestine has a better heat resistance,but more sensitive to changes in pH and has a good antibacterial activity in the near-neutral pH environment. This antibacterial peptides from intestine mucosa could be able to stimulate the transformation of lymphocytes proliferation separately and promote the transformation of lymphocyte proliferation in low concentration when combined with PHA-P/LPS. Animal experimental results showed that this antibacterial peptides had no obvious effect on the lymphocyte proliferation,body weight and organs index. We provided a basic content about antibacterial peptides'development and application in animal husbandry.