Extraction Of Rice Bran Polysaccharide And Its Effects On Modulating Immune Function Of Chickens Infected With IBDV

In this paper, the extraction method, component analysis, acute toxicity to animalsof Rice Bran Polysaccharide (RBP) and its effects on modulating immunologicalfunctions in chickens infected with IBDV were studied respectively.To evaluate the extracting ratio of the Polysaccharide from rice bran by hottemperature water extracting method in different extracting time and water: bran ratio.For extraction of RBP, a series of procedures were used to remove impurities existingtherein, such as starch, protein, etc. It's showed that the optimal extracting ratio of RBPcould be obtained at the conditions of 100℃, 5h,water:bran 8:1 and it's 0.76%. Thecomponents of extracted RBP were analyzed by Anthrone-sulfuric acid method, Kjeldahmethod, drying method, calor method, Soxhlet extraction method and iodine reagentmethod respectively. The results showed that there were 86. 30% polysaccharide, 2.30%protein, 10.30% moisture, 1.45% crude ash in the extracted RBP, no fat and starch werefound. The extraction had obvious absorption peak at 200nm wavelength by ultravioletspectro-analysis; this showed that the extraction was polysaccharide, not protein ornucleic acid. Acute toxicity test showed that the extracted RBP had no acute toxicity onmice.In order to investigate the mechanism of RBP on modulating immunologicalfunctions, different dose of RBP were gavaged to chickens that artificial infected withinfectious bursal disease virus (IBDV). Two hundred and fifty healthy male chickenswere randomly divided into five groups, 50 chickens per group. Groupâ… ,â…¡,â…¢weretreated by RBP, Groupâ…£,â…¤were IBDV control group and normal control group. At10-day-old of age, Groupâ… ,â…¡,â…¢were gavaged with RBP at dosage of 50mg/(kg·d),100mg/(kg·d) and 200mg/(kg·d) respectively, and Groupâ…£, Vwere gavaged withphysiological saline at 1mL per chicken respectively for 5 days. At 15-day-old of age thechickens in Groupâ… ,â…¡,â…¢andâ…£were injected with IBDV suspension (100×ID₅₀),0.1mL per chicken. The chickens in Groupâ…¤were injected with physiological saline,0.1mL per chicken. Then each groups were injected with 20%SRBC suspension, 0.5mLper chicken, at the same time all chickens were vaccinated with ND vaccine, and a weeklater AI vaccine were used. Incidence rates and death rates were observed after the chickens were infected with IBDV. Lymphocyte proliferation, natural killer cell activity,interleukin-2 activity, sheep erythrocyte antibody titers, ND titers, AI titers wereexamined respectively before 1 day of infected IBDV and after 7d, 14d and 21d ofinfected IBDV. At the same time fresh spleen and bursa were collected and manufacturedpathological section. The results showed: (1) The chickens were gavaged with RBP atdifferent dosage for five days, incidence rates and death rates were lower than those ofIBDV control group. (2) At different stage, lymphocyte proliferation, natural killer cellactivity, dinterleukin-2 activity were higher than those of IBDV control group (P＜0.05 orP＜0.01). At the end of experiment, the chickens treated with RBP could recover healthylevel like control group. (3)Compared with IBDV control group, the high dosage of RBPgroup improved the antibody titers of SRBC, ND, and AI (P＜0.05 or P＜0.01), there wasno significant effect in the middle and low dosages of RBP groups. (4) Compared withthe IBDV control group, RBP could reduce pathological damage of bursa and spleen byIBDV.The experiment data confirmed that the chickens infected with IBDV and gavagedwith RBP at dosage of 50mg/(kg·d)～200mg/(kg·d) could enhance lymphocyteproliferation, natural killer cell activity, dinterleukin-2 activity, antibody titers of SRBC,and the immune response of AI, ND vaccines. Pathological damage of immune organ wasalso abated.