Qingfang YANG, Kanglin YANG, Jing YAO, Chunmao JIANG,

1. Jinzhong Vocational & Technical College, Jinzhong 030600, China;

2. Tibet Vocational Technical College, Lhasa 850000, China;

3. Wuxi Agricultural Technology Promotion Center, Wuxi 214000, China;

4. Jiangsu Agri-husbandry Vocational College, Taizhou 225300, China

As one of the most abundant and important biomacromolecules in the natural world,polysaccharide forms the most basic four living matters with protein, nucleic acid and lipid[1], its structure and function have received extensive attention,thus it has become the third milestone of exploring the life after protein and nucleic acid[2]. In recent years, some studies found that Chinese medicine polysaccharide, as the active ingredient of traditional Chinese medicine, its most important function is immunoregulatory activity[3].In the experiment, the polysaccharides were extracted from three kinds of traditional Chinese medicines like Astragalus,Epimedium and Isatis indigotica Fort.As the adjuvants to vaccinate the chicken with Newcastle disease vaccine, then the dynamic changes of weight gain rate, serum antibody titer and the proliferation of peripheral T lymphocyte were determined, so as to provide a theoretical basis for the development of immunopotentiator of Chinese medicine polysaccharides.

Materials and Methods

Experimental materials

Astragalus, Epimedium and Isatis indigotica Fort. were purchased from local medical companies, and water extraction and alcohol sedimentation technique was used to extract Astragalus polysaccharides (ASP),Epimedium polysaccharides (EPP)and Isatis root polysaccharides(IRPS); and the contents of the three polysaccharides were determined using sulfuric acid-anthrone method,which were 68.5%,63.8% and 53.4%,respectively.Each polysaccharide was diluted as high-dose concentration(H,8 mg/ml)and low-dose concentration(L,4 mg/ml) using deionized water according to net content,then high pressure disinfection was carried out routinely for reserving.

Experimental animals and grouping

240 one-day-old healthy and nonimmune Roman chicken were randomly divided into 8 groups, including blank control group (BC group), immune control group(IC group),immunity groups of each Chinese medicine(ASPHgroup,ASPLgroup,EPPHgroup,EPPLgroup, IRPSHgroup and IRPSLgroup), each group had 30 chicken.Until 14 days old of the chicken, except BC group which adopted normal saline to drop noses and eyes, IC group and immunity groups of each Chinese medicine used Newcastle disease vaccine to drop noses and eyes(2 doses/chick)as the first immunity, then the second immunity was carried out at the 28-day-old. On the day of the first immunity,3 d before the second immunity, the day of the second immunity and 3 d after the second immunity,high-dose concentration and low-dose concentration of ASP, EPP and IRPS were used for the immunity groups of each Chinese medicine using the gavage, and 0.5 ml for each chick.

Sample collection and item measurement

On the 7th, 14th, 21stand 28thday after the first immunity, 10 chicken of each group were randomly got and weighed, and the weight of each was recorded and the weight gain rate was calculated;on the 7th,14th,21stand 28thday after the immunity,0.5 ml blood of each chick was collected from the wing vein, then the serum was separated,the antibody titer was measured using HI[4];the anticoagulation was collected from the heart (the anticoagulant was sodium citrate) using MTT[5],the absorbancy D570nm, as a proliferation index of T lymphocyte, was measured on enzyme linked immunity instrument.

Data processing

The statistical analysis of difference was carried out for experimental data using SPSS software.

Results

The change of weight gain rate of different day-old chicken

As shown in Table 1, on the 7thd after the immunity, there was not statistical difference on weight gain rate among different groups of chicken(P＞0.05); on the 14thd after the immunity,the weight gain rate of each treatment group was significantly higher than that of blank control group (P ＜0.05),but it had not significant difference with immune control group (P ＞0.05), and there was not statistical difference between immune control group and blank control group(P＞0.05); on the 21stand 28thd after the immunity,except ASPH group, the weight gain rate of other treatment groups was all significantly higher than that of immune control group and blank control group (P ＜0.05), but there was not statistical difference between immune control group and blank control group (P ＞0.05).

Table 1 The change of weight gain rate of different day-old chicken after the immunity

Table 2 The change of serum HI antibody titer of different day-old chicken after the immunity(log2)

The change of serum antibody titer of different day-old chicken

As shown in Table 2, on the 7thand 14thd after the immunity, there was not significant difference on serum antibody titer among different immunity groups of chicken (P＞0.05),but that of immunity groups was all significantly higher than that of blank control group(P＜0.05); on the 21stand 28thd after the immunity, the antibody titer of traditional Chinese medicine polysaccharide immune groups was all significantly higher than that of immune control group and blank control group (P＜0.05);hereinto,on the 21std of the immunity, the antibody titer of ASPH, ASPL and IRPSL groups was all significantly higher than that of other treatment groups (P＞0.05); on the 28th d of the immunity, except IRPSH group, there was not statistical difference among other treatment groups(P＞0.05). These indicated that appropriate concentration of traditional Chinese medicine polysaccharide can im-prove the antibody titer of vaccine immunity,and the immune enhancement effects of ASPLand IRPSLgroups were better.

Table 3 The dynamic change of lymphocyte proliferation of different day-old chicken after the immunity

The change of the proliferation of peripheral T lymphocyte of different day-old chicken

As seen in Table 3,on the 7thd after the immunity, except ASPH and ASPLgroups, the D570nmvalue of other treatment groups was significantly higher than that of immune control group and blank control group (P ＜0.05); among all treatment groups,except ASPHgroup,there was not significant difference among other groups(P＞0.05).On the 14th,21stand 28thd after the immunity, the D570nmvalue of each treatment group was all significantly higher than that of immune control group and blank control group (P＜0.05); among all treatment groups, on the 14thd after the immunity,there was not significant difference among all low-dose groups, and so did all highdose groups and ASPLgroup(P＞0.05);on the 21stand 28thd after the immunity,except ASPH group,there was not statistical difference among all treatment groups(P＞0.05).

Discussions

Many researches showed that the polysaccharide of traditional Chinese medicine has growth-promoting effect.Wang Xuebin et al.[6]showed that APS powder and APS injection can promote the growth of chicken. The research carried out by Liang Ying et al.[7]also indicated that adding appropriate polysaccharide of Scutellaria baicalensis into the diet can improve the growth performance of broiler chicken. In the experiment, the results showed that except ASPHgroup, the weight gain rate of chicken of other treatment groups is increased significantly, this may be caused by the complexing of high-dose ASP and fat,which inhibits the absorption of fat,thereby reducing the growth performance of chicken[8].

Serum antibody titer reflects specific humoral immunity mediated by B lymphocyte. The higher the antibody titer,the stronger the antiviral ability of chicken, and the stronger the ability of anti-infection of chicken[9]. This experiment results showed that appropriate polysaccharide of traditional Chinese medicine can significantly enhance the humoral immunity of chicken, improve the antibody titer of ND vaccine, and enhance the anti-ND infection ability of chicken,the results are consistent with the research results of Qiu Yan et al.[10]and Wang et al.[11].

T lymphocyte is the immune regulating hub of the body,its proliferation reflects the immune level of body cells[12].The immunological competence of T lymphocyte is related to anti-viral ability of the body; when the viability function of T cell reduces,the generation of different cytokines (such as interleukin, interferon and tumor factors,etc.) decreases, and the assistant role of helper T lymphocyte to B cell antibody is affected[13]. The experiment results indicated that 3 polysaccharides of traditional Chinese medicine can promote the proliferation of peripheral T lymphocyte, and show certain doseeffect and time-effect relationship.These show that appropriate polysaccharide of traditional Chinese medicine can promote the proliferation of T lymphocyte.

In the experiment, taking ASP which has already been applied in animal production as the reference, the immunological enhancement effects of EPP and IRPS were observed, and the results showed that the growth promotion and immunomodulatory effects of Chinese herbal polysaccharide show certain dose-effect relationship,the weight-increasing and immunological enhancement effects of IRPS at low dosage are the best, high-dosage IRPS and EPP also have certain weight-increasing and immunological enhancement effects. Therefore, it is necessary to further screen the effective dose in the application and development of traditional Chinese medicine.

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