Immunomodulatory Effects Of Pine Pollen Polysaccharides On Embryos Infected With ALV-J Subtype

Avian Leukosis?AL?is a general term of neoplastic infectious diseases caused by Avian Leukosis Virus?ALV?and Aviansarcomavirus?ASV?viruses in the proliferation of certain cellular components in avian hematopoietic tissue.Infected chickens cause a decline in production performance,immunosuppression,tumors,and cause huge economic losses to the poultry industry.The disease is mainly transmitted through vertical and horizontal transmission.There is currently no effective immunization vaccine or therapeutic drug,and it can only be controlled by population purification.Chicken embryo inoculation was first applied to chicken embryo immunization.Studies have shown that proper chicken embryo inoculation does not affect chick hatchability,and can avoid immune blanking and earlier generation of immunity compared to traditional immunization methods.Currently,it has been widely used in hatcheries.Chicken embryo inoculation technology has been used in recent years to inoculate chicken embryos with various nutrients,traditional Chinese medicine extracts and plant polysaccharides,which have the effects of improving production performance and anti-virus.Pine pollen polysaccharide?PPPS?is a kind of natural non-toxic plant polysaccharide.Previous research in this laboratory has shown that PPPS has good anti-virus,enhance immunity function,etc.,and at the same time fights against B subgroups and J Avian Leukosis Virus Subgroup J?ALV-J?has good activity,but whether PPPS inoculated to chicken embryos can also have anti-infective infection with J subgroup avian leukemia virus and improve immune suppression.However,it is unclear whether inoculation of PPPS with chicken embryos also has anti-infective effects on the subgroup J avian leukemia virus and improves immunosuppression.This experiment mainly studies PPPS as an immune enhancer,and explores the effects of PPPS on the growth and development and immune conditioning of chicken embryos inoculated with ALV-J.Firstly,a model for simulating vertical transmission of congenital infection of ALV-J chicken embryo was established artificially.The inoculation of different concentrations of PPPS into the chicken embryo was conducted to explore the amount of virus and the dose of polysaccharides inoculated into the chicken embryo.Secondly,the growth and development status,antiviral effect,immunomodulation effect and immune enhancement effect of Newcastle disease vaccine were evaluated in chicks inoculated with PPPS through chicken embryo.This study is divided into the following two parts:1.Establishment of ALV-J chicken embryo model with congenital infection of chicken embryo and determination of polysaccharide dose of PPPS inoculated by chicken embryoIn the experiment,SPF chicken embryos were selected to hatch on the 8th day and artificially inoculated with different dilutions of ALV-J virus solution(10¹,10²,10³,10⁴TCID₅₀).The survival rate was compared within 72 hours,and chicken embryos with a nearly100%survival rate were selected.The maximum virus inoculation amount was used as the virus inoculation dose(10³ TCID₅₀)to construct a congenital infection ALV-J chicken embryo model.A total of 0.2 mL of PPPS solution with different concentrations?200 mg/mL,100mg/mL,50 mg/mL,25 mg/mL,12.5 mg/mL,6.125 mg/mL?was inoculated into the allantoic cavity of SPF chicken embryos from incubation to the 9th day.The survival rate of chicken embryos was compared within 72 hours,the three PPPS concentrations with the highest chicken embryo survival rate were selected as the polysaccharide doses for inoculation of the chicken embryo,from high to low,0.2 mL high dose group?HPPPS?was 50 mg/mL,medium dose group?MPPPS?was 25 mg/mL,and low dose group?LPPPS?was 12.5 mg/mL.2.Study on the growth and development,antiviral and immunoconditioning effects of PPPS inoculated into chicken embryo on congenital infected ALV-J chicksA total of 0.1 mL ALV-J disease venom(10³TCID₅₀)was inoculated into the yolk sac of SPF chicken embryos at the age of 8.After inoculation,they were incubated for 2⁴ h,and then inoculated with 0.2 mL PPPS solution through the allantoic cavity,and incubated to the shell.On the 7th,14th,21st,28th,35th,42th and 49th days after hatched out of the shell,tissue and organs,cloacal cotton swabs,fresh blood and serum samples of chicks were collected for the detection of related indicators.The experiment proves that the inoculation of chicken embryos with PPPS has a good effect on promoting growth and development.The HPPPS group showed that the embryo was well developed and the embryo body was free of hemorrhage.After hatching,the growth and development were normal,no immune organ atrophy,no tumor,etc.The MPPPS group and LPPPS group have certain improvement capabilities,but compared with the HPPPS group,the effect is not obvious.It shows that PPPS as an immune enhancer can promote the growth and development of ALV-J chickens with congenital infection through embryo inoculation.Experiments have shown that the inoculation of chicken embryos with PPPS has a good antiviral and immune regulating function,HPPPS group of congenital infection to early ALV-J chicken lymphocyte conversion rate,CD4,CD8 molecules,IL-2,IFN-?cell concentration in serum has obvious promotion effect,improve immune suppression,effectively reduce the infection of chicken to the external environment detoxification,and delay detoxification nearly a week.The MPPPS group has a significant improvement in the short-term after hatching.Although it has a certain immune conditioning effect in the later period,the difference is not significant compared with the ALV-J group.However,the immune conditioning effect of the LPPPS group is not obvious,which is similar to the ALV-J group,there was not much difference.Although the MPPPS group and LPPPS reduced the amount of detoxification to a certain extent and delayed the detoxification of individual chickens,the inhibitory effect was not significant.It indicates that PPPS can reduce the pathogenic effect of congenital ALV-J infection in chicken embryos,and has antiviral activity and immune conditioning effect on chicks after hatching.At the same time,PPPS inoculation through chicken embryos can improve the antibody level and delay the antibody regression of Newcastle disease N79 vaccine.In summary,PPPS inoculation in chicken embryo can effectively control the vertical transmission of ALV-J,and can be applied to inhibit intra-embryo virus infection and early control of ALV-J chickens with congenital infection.