Goose astrovirus egg yolk antibody as well as preparation method and application thereof

Abstract

The invention relates to the technical field of biological agents, in particular to a goose astrovirus egg yolk antibody and a preparation method and application thereof. The invention provides a goose astrovirus egg yolk antibody. The goose astrovirus egg yolk antibody is prepared by adopting an inactivated vaccine as an antigen, wherein the inactivated vaccine is prepared from a goose astrovirus GAstV / SD / 36-95P strain with the preservation number of CCTCC (China Center For Type Culture Collection) NO: V202445. The neutralizing titer of the goose astrovirus egg yolk antibody provided by the invention is high and can reach 10.5 log2, after goslings are infected by the goose astrovirus, the goslings can be protected from disease attack and death by injecting the egg yolk antibody, and the protection rate of the egg yolk antibody can reach 100%.

Description

Technical Field

[0001] The invention relates to the technical field of biological preparations, and in particular to a goose astrovirus yolk antibody and a preparation method and application thereof. Background Art

[0002] In recent years, symptoms of urate deposition have been found in the viscera, joints and peritoneum of goslings in many places, with an incidence rate of 80% and a mortality rate of 50%. The disease is named goose gout. Goose gout is caused by goose astrovirus (GoAstV), which mainly harms goslings under 3 weeks old. It can be transmitted horizontally and vertically, and can effectively cross species barriers to infect chickens and ducks. The disease is an important infectious disease that endangers the goose farming industry, causing serious economic losses to the goose farming industry. However, there is no effective goose astrovirus vaccine on the market to prevent the disease; there are no antibodies against the virus. Once the goose astrovirus infects goslings and spreads among the geese, there is no effective treatment.

[0003] At present, some researchers express the capsid protein (Cap protein) of goose astrovirus as an antigen, produce highly immune eggs after immunizing laying hens, and prepare yolk antibodies of goose astrovirus. However, this method expresses a certain protein, which only contains part of the virus antigen and cannot cover all the virus antigens. Therefore, the yolk antibodies prepared by this method may have the problem of low protection efficiency. Some researchers also culture and harvest goose astrovirus in goose embryos, prepare inactivated vaccines after concentrating the virus, and immunize laying hens to prepare yolk antibodies. However, this method requires goose embryos to culture the virus, and the virus needs to be further concentrated after harvesting the virus. The cost of preparing the antigen is high, the titer of the harvested virus is low, and the titer of the prepared highly immune eggs is also relatively low, which affects the production efficiency and product quality of the yolk antibody.

[0004] Therefore, it is urgent to develop a goose astrovirus yolk antibody with high neutralization titer and protection rate and easy to mass produce. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a goose astrovirus yolk antibody and its preparation method and application. The goose astrovirus yolk antibody has a high neutralizing titer, which can reach 10.5 log 2 After goose astrovirus infects goslings, injection of the egg yolk antibody can protect the goslings from getting sick or dying, and the protection rate of the egg yolk antibody can reach 100%.

[0006] To this end, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a goose astrovirus yolk antibody in an optional embodiment, which is prepared using an inactivated vaccine prepared from the goose astrovirus GAstV / SD / 36-95P strain with a deposit number of CCTCC NO: V202445 as an antigen.

[0008] In the present invention, goose astrovirus GAstV / SD / 36-95P (hereinafter referred to as goose astrovirus SD / 36-95P virus) was deposited in the China Center for Type Culture Collection on April 22, 2024, with a deposit number of CCTCC NO: V202445. The goose astrovirus yolk antibody provided by the present invention has a high neutralizing titer of 10.5 log 2 After goose astrovirus infects goslings, injection of the egg yolk antibody can protect the goslings from getting sick or dying, and the protection rate of the egg yolk antibody can reach 100%.

[0009] In a second aspect, the present invention provides, in an optional embodiment, a method for preparing the above-mentioned goose astrovirus yolk antibody, comprising the following steps:

[0010] S1: amplify the goose astrovirus GAstV / SD / 36-95P strain to obtain the amplified virus liquid;

[0011] S2: using the amplified virus solution to prepare goose astrovirus SD / 36-95P inactivated vaccine;

[0012] S3: Vaccinating laying hens with the goose astrovirus SD / 36-95P inactivated vaccine to obtain highly immune eggs;

[0013] S4: After the highly immune eggs are disinfected, the yolks are collected, and finally goose astrovirus yolk antibodies are extracted from the yolks.

[0014] Preferably, the amplification method in step S1 includes: inoculating the goose astrovirus GAstV / SD / 36-95P strain into a cell bottle covered with a monolayer of LMH cells, culturing at a temperature of 37°C and a carbon dioxide concentration of 5%, collecting the cells when more than 80% of the cells show pathological changes, then freezing and thawing the cells, shaking, centrifuging, collecting the supernatant, and obtaining the amplified virus liquid. The virus titer of the amplified virus liquid is 10 7.0 TCID 50 / 0.1mL.

[0015] In the present invention, goose astrovirus SD / 36-95P virus is inoculated into LMH cells, and the virus titer of the strain on the cells can reach 10 7 TCID 50 / 0.1mL.

[0016] Preferably, the method for preparing the inactivated vaccine in step S2 comprises: diluting the amplified virus solution to a virus titer of 10 6.0 TCID 50 / 0.1mL, add a 0.2% formaldehyde solution and place it at 37°C for inactivation for 24h to obtain an inactivated virus, then mix the inactivated virus and sterilized Tween-80 to form an aqueous phase, then mix and emulsify 1 part of the aqueous phase and 2 parts of the oil phase to obtain a goose astrovirus SD / 36-95P inactivated vaccine. The mass ratio of the inactivated virus and the sterilized Tween-80 is 95-97:3-5; and / or, the preparation method of the oil phase is: after mixing white oil and span in a mass ratio of 94:6, add aluminum stearate and stir to mix, sterilize at 121°C for 20min to obtain an oil phase; the amount of aluminum stearate added is 3% of the mass of the white oil and span after mixing.

[0017] Preferably, the method for vaccinating laying hens in step S3 comprises: injecting each laying hen with 1 mL of the goose astrovirus SD / 36-95P inactivated vaccine by breast muscle injection, immunizing once every 14 days for a total of 3 times, and continuously collecting egg samples on the 14th to 20th day after the third immunization to obtain highly immune eggs.

[0018] Preferably, the disinfection method in step S4 includes: immersing the highly immune eggs in a 0.1% chlorhexidine aqueous solution at a temperature of 37°C for 20 minutes, and then wiping the surface of the highly immune eggs with a 75% alcohol cotton ball. The method for extracting goose astrovirus yolk antibodies in step S4 includes: adding the yolk to an acetate buffer, stirring and mixing, standing at 4°C for 24 hours, absorbing the supernatant, and then adjusting the pH to 7 with a sodium hydroxide solution, and finally filtering and sterilizing to obtain the goose astrovirus yolk antibodies. The pH value of the acetate buffer is 5.2, and the volume ratio of the yolk to the acetate buffer is 1:6; and / or, the concentration of the sodium hydroxide solution is 1 mol / L; and / or, the pore size of the filtration is 0.22 μm.

[0019] In the present invention, the cell virus solution is diluted to 10 6.0 TCID50 / 0.1mL was used to prepare an inactivated vaccine. Laying hens were immunized three times, and the high-immunity eggs were harvested. The yolk of the high-immunity eggs was taken to prepare refined yolk antibodies with a neutralizing titer of 10.5log 2 .

[0020] In a third aspect, the present invention provides a use of the goose astrovirus yolk antibody in preventing or treating goose astrovirus infection in gooselings.

[0021] Preferably, the goose astrovirus yolk antibody is diluted to 9 log 2 / 0.1mL, then give a subcutaneous injection to the goslings, with each gosling receiving 0.5-2mL.

[0022] Compared with the prior art, the present invention has one of the following beneficial effects:

[0023] 1. The neutralizing titer of goose astrovirus yolk antibody provided by the present invention is high, which can reach 10.5log 2 After goose astrovirus infects goslings, injection of the egg yolk antibody can protect the goslings from getting sick or dying, and the protection rate of the egg yolk antibody can reach 100%.

[0024] 2. The present invention cultures viruses on cells, which is less costly than culturing viruses on SPF goose embryos.

[0025] 3. The goose astrovirus yolk antibody provided by the present invention has a high titer and needs to be diluted before use.

[0026] 4. The goose astrovirus yolk antibody provided by the present invention can prevent or treat goose astrovirus infection in gooselings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the sterility test result of goose astrovirus yolk antibody in Example 2 of the present invention;

[0028] Figure 2 The safety test results of goose astrovirus yolk antibody in Example 2 of the present invention;

[0029] Figure 3 The photographs and autopsy results of the goslings in the egg yolk antibody prevention group and the normal saline control group in Example 4 of the present invention in the prevention of goose astrovirus SD / 36 infection in goslings;

[0030] Figure 4 This is a graph showing the PCR test results of the egg yolk antibody prevention group and the normal saline control group in preventing goose astrovirus SD / 36 infection in goslings according to Example 4 of the present invention, wherein M represents marker, 1-4 represents the egg yolk antibody prevention group, and 5-8 represents the normal saline control group;

[0031] Figure 5 The photographs and autopsy results of the goslings in the egg yolk antibody treatment group and the normal saline control group in Example 4 of the present invention during the treatment of goose astrovirus SD / 36 infection in goose;

[0032] Figure 6This is a graph showing the PCR test results of the egg yolk antibody treatment group and the normal saline control group in the treatment of goose astrovirus SD / 36 infection in goslings according to Example 4 of the present invention, wherein M represents marker, 1-2 are the PCR results of the egg yolk antibody treatment group on the 3rd day of infection, 3-4 are the PCR results of the egg yolk antibody treatment group on the 5th day of infection, and 5-8 are the PCR results of the normal saline control group on the 3rd and 5th days of infection. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0035] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0036] Example 1

[0037] This embodiment provides a method for preparing goose astrovirus yolk antibodies, comprising the following steps:

[0038] S1: The goose astrovirus GAstV / SD / 36-95P strain (hereinafter referred to as SD / 36-95P) was inoculated into a cell bottle with a monolayer of LMH cells at an MOI of 0.01, and cultured at a temperature of 37°C and a carbon dioxide concentration of 5%, and observed twice a day. When more than 80% of the cells showed pathological changes, they were harvested, and the cells were repeatedly frozen and thawed twice, then shaken, centrifuged at a speed of 10000rpm for 5min, and the supernatant was collected and packaged, and stored at -80°C for later use. The amplified virus was diluted 10 times, and the dilution range was 10 -1 -10 -8 100 μL of virus solution at each dilution was inoculated into a 96-well plate with LMH cells. The cytopathic effect was observed after 3 days and the TCID was calculated using the Reed-Mucnch method. 50 The results showed that the titer of the amplified SD36-95P virus liquid was 10 7.0 TCID 50 / 0.1mL.

[0039] S2: Add formaldehyde solution with a final concentration of 0.2% to a 10% 6.0 TCID 50 / 0.1mL virus solution, placed at 37°C for inactivation for 24h (shaking once every 4-6h during this period), to obtain inactivated virus, the inactivated virus and sterilized Tween-80 were fully mixed at a mass ratio of 96:4 until Tween-80 was completely dissolved, to obtain an aqueous phase, white oil and span were mixed at a mass ratio of 94:6, and aluminum stearate (the amount added was 3% of the mass of the white oil and span after mixing), stirred until light yellow and clear and transparent, and then sterilized at 121°C for 20min to obtain an oil phase. Finally, 2 portions of the oil phase were slowly stirred in a tissue homogenizer, and 1 portion of the water phase was slowly added at the same time, and after the addition was completed, it was emulsified at a speed of 10000r / min for 15min to prepare a goose astrovirus SD / 36-95P inactivated vaccine.

[0040] S3: 20 healthy laying hens (120 days old) were selected and randomly divided into 2 groups, with 10 chickens in each group. Group 1 was immunized with goose astrovirus SD / 36-95P inactivated vaccine by breast muscle injection. Each chicken was injected with 1.0 mL of inactivated vaccine, once every 14 days, for a total of 3 immunizations. Egg samples were collected continuously 14-20 days after the third immunization to obtain highly immune eggs. Group 2 was injected with physiological saline as a negative control.

[0041] S4: Immerse the collected high-immunity eggs in a 0.1% chlorhexidine aqueous solution at a temperature of 37°C for 20 minutes, then wipe the surface with a 75% alcohol cotton ball and place it in a clean bench to dry. After disinfection, beat the eggs manually or mechanically, fully remove the egg white, embryonic disc and yolk ligament, and collect the yolk. According to the volume of the yolk, add 6 times the volume of the yolk acetate buffer (PH = 5.2), stir and mix thoroughly, place at 4°C, and after 24 hours of rest, absorb the supernatant, adjust the pH to 7.0 with 1mol / L NaoH, and filter and sterilize with a filter element with a pore size of 0.22um to obtain goose astrovirus yolk antibody, which is placed at 4°C for standby use.

[0042] Example 2

[0043] This example is to perform sterility and safety tests on the goose astrovirus yolk antibody prepared in Example 1.

[0044] The method of sterility test is: perform sterility test according to the appendix of the current Chinese Veterinary Pharmacopoeia. Figure 1 .

[0045] pass Figure 1 It can be seen that the goose astrovirus yolk antibody has no growth of bacteria, molds and other microorganisms, and the sterility test is qualified.

[0046] The safety test method is: randomly select 20 2-day-old susceptible goslings and divide them into 4 groups, 5 in each group. Groups 1-3 are injected intramuscularly with 0.5mL / goose, 1mL / goose, and 2mL / goose, respectively, and group 4 is a blank control. The mental state, growth and injection site of the goslings are observed for 14 days. The results are shown in Figure 2 .

[0047] pass Figure 2 It can be seen that during the observation period, the goslings in groups 1 to 3 survived healthily, and there was no significant difference in mental state, behavior, feces, drinking water, and food intake compared with the control group (see Figure 2 B), the antibody was well absorbed at the injection site, with no adverse reactions such as redness, swelling, and nodules (see Figure 2 A).

[0048] Example 3

[0049] This example is to test the titer of goose astrovirus yolk antibodies prepared in Example 1, including the following steps:

[0050] Dilute the goose astrovirus yolk antibody 2-fold with PBS buffer solution. -5 -2 -12 The dilution gradient was 200 TCID 50 Mix the virus solution of equal volume and mix well, then place in a water bath at 37°C for 1 hour. Pipette 100 μL of the neutralization product of each dilution and inoculate it into a 96-well plate with LMH cells, with a cell density of 70-90%. At the same time, set up positive and negative controls, of which the positive control is 200 TCID 50 The virus solution was mixed with an equal volume of PBS, and the negative control was PBS solution. Each dilution was repeated for 6 wells. After adsorption for 1 hour, the neutralization product was discarded, and the cells were washed twice with PBS buffer solution. 100 μL of cell maintenance solution (purchased from Sigma-Aldrich Technology Co., Ltd.) was added to each well and placed in an incubator at a temperature of 37°C and a carbon dioxide concentration of 5%. The cells were observed for 5 consecutive days. The PD was calculated using the Reed-Mucnch method based on the cell lesion. 50 The titer of yolk antibody after extraction can reach 10.5log 2 .

[0051] Example 4

[0052] This example is an evaluation of the preventive and therapeutic effects of the goose astrovirus yolk antibody prepared in Example 1.

[0053] The goose astrovirus yolk antibody prepared in Example 1 was diluted to 9 log with PBS buffer solution. 2 / 0.1mL.

[0054] Evaluation of the preventive effect of goose astrovirus yolk antibody:

[0055] Twenty-four healthy susceptible goslings at 2 days old were randomly divided into 2 groups, 12 in each group. Group 1 was the egg yolk antibody prevention group, which was injected intramuscularly with diluted goose astrovirus egg yolk antibody, 1 mL / goose (antibody titer: 9log 2 / 0.1mL); then 12h later, goose astrovirus SD / 36 strain was injected intramuscularly, 0.5mL per goose. Group 2 was the normal saline control group, which was injected intramuscularly with sterile normal saline, 1mL / goose; 12h later, goose astrovirus SD / 36 strain was injected intramuscularly, 0.5mL per goose. On the 3rd and 5th days after infection, 3 goslings were randomly selected from each group and killed to observe visceral lesions and PCR detection of viruses; the remaining 6 goslings were observed for 14 consecutive days and the results were statistically analyzed. The results are shown in Table 1, Figure 3 and Figure 4 .

[0056] Table 1 Results of goose astrovirus yolk antibody prevention experiment

[0057] Group Yolk antibody prevention group Normal saline control group Number of goslings 6 6 Number of cases / 0 6 Incidence 0％ 100％ Number of deaths / 0 6 mortality rate 0％ 100％ Protection rate 100％ 0％

[0058] Conclusion: According to Table 1, Figure 3 and Figure 4 It can be seen that the protection rate of the goslings in the first group of yolk antibody prevention group was 100%; the goslings in the first group of yolk antibody prevention group were in good spirits, had normal appetite, normal feces, and no typical symptoms were found after autopsy (see Figure 3 A and Figure 3 C); after PCR testing, it was negative for goose astrovirus (see Figure 4 The goslings in the second group of saline control group had a protection rate of 0%; the goslings in the second group of saline control group were listless and had decreased appetite (see Figure 3 B); after autopsy, the kidneys were enlarged and bleeding, and urate deposits were found in the ureters (see Figure 3 D); after PCR testing, it was positive for goose star (see Figure 4 ).

[0059] Evaluation of therapeutic effect of goose astrovirus yolk antibody:

[0060] Twenty-four healthy susceptible goslings at 2 days old were randomly divided into 2 groups, 12 in each group. Group 1 was the egg yolk antibody treatment group, which was injected intramuscularly with goose astrovirus SD / 36 strain, 0.5 mL per goose; 12 hours later, diluted goose astrovirus egg yolk antibody was injected intramuscularly, 1 mL / goose (antibody titer: 9log 2 / 0.1mL). Group 2 was the normal saline control group, which was injected intramuscularly with goose astrovirus SD / 36 strain, 0.5mL per goose; 12h later, sterile normal saline was injected intramuscularly, 1mL / goose. On the 3rd and 5th days after infection, 3 goslings were randomly selected from each group and killed to observe visceral lesions and PCR virus detection; the remaining 6 goslings were observed for 14 consecutive days and the results were statistically analyzed. The results are shown in Table 2, Figure 5 and Figure 6 .

[0061] Table 2 Results of goose astrovirus yolk antibody treatment experiment

[0062] Group Yolk antibody treatment group Normal saline control group Number of goslings 6 6 Number of cases / 6 6 Incidence 100％ 100％ Number of deaths / 0 6 mortality rate 0％ 100％ Protection rate 100％ 0％

[0063] Conclusion: According to Table 2, Figure 5 and Figure 6 It can be seen that the protection rate of goslings in the first group of egg yolk antibody prevention group was 100%; after infection with the virus, the goslings showed signs of lethargy and loss of appetite, but after the egg yolk antibody treatment, their spirits returned to normal and their appetites returned to normal. After autopsy, there were no typical clinical symptoms (see Figure 5 A and Figure 5 C); after PCR testing, the virus was positive for goose astrovirus on the third day after infection and negative for goose astrovirus on the fifth day (see Figure 6 The goslings in the saline control group in group 2 had a protection rate of 0%, which was manifested by lack of energy and decreased appetite; after infection, the goslings showed clinical symptoms such as listlessness, lameness, white loose stools, white eyelids, and death (see Figure 5 B); autopsies of goslings infected for 3 and 5 days showed enlarged and hemorrhagic kidneys and obvious hydrochloride deposits in the ureters (see Figure 5 D); after PCR testing, it was positive for goose star (see Figure 6 ).

[0064] Comparative Example

[0065] This comparative example evaluates the preventive effects of the goose astrovirus yolk antibody prepared in Example 1 and three common goose astrovirus yolk antibodies on the market.

[0066] Three goose astrovirus yolk antibodies were purchased from three biotechnology companies, named goose astrovirus yolk antibodies A, B, and C. 40 healthy susceptible goslings at 2 days old were selected and randomly divided into 4 groups, with 10 goslings in each group. Groups 1-4 were injected intramuscularly with diluted goose astrovirus yolk antibodies, goose astrovirus yolk antibodies A, goose astrovirus yolk antibodies B, and goose astrovirus yolk antibodies C of Example 1, 1 mL / goose; 12 hours later, goose astrovirus SD / 36 strain was injected intramuscularly, with 0.5 mL injected per goose. After infection, the goose was observed for 14 days and the results were statistically analyzed. The results are shown in Table 3.

[0067] Table 3 Results of the prevention experiment of goose astrovirus yolk antibodies prepared in Example 1 and three common goose astrovirus yolk antibodies on the market

[0068]

[0069]

[0070] Conclusion: It can be seen from Table 3 that the protection rate of the goose astrovirus yolk antibody of the present invention is 100%, the protection rate of goose astrovirus yolk antibody A is 70%, the protection rate of goose astrovirus yolk antibody B is 60%, and the protection rate of goose astrovirus yolk antibody C is 30%. The yolk antibody of the present invention has the best effect in preventing goose astrovirus infection.

[0071] Although the principles of the present invention are described in detail above in conjunction with the preferred embodiments of the present invention, those skilled in the art should understand that the above embodiments are merely explanations of the exemplary implementations of the present invention, and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute limitations on the scope of the present invention, and any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, fall within the protection scope of the present invention.

Claims

1. A goose astrovirus yolk antibody, characterized in that: The inactivated vaccine prepared by using the goose astrovirus GAstV / SD / 36-95P strain with a deposit number of CCTCC NO: V202445 was prepared as an antigen.

2. A method for preparing goose astrovirus yolk antibody according to claim 1, characterized in that: The following steps are involved: S1: amplify the goose astrovirus GAstV / SD / 36-95P strain to obtain the amplified virus liquid; S2: using the amplified virus solution to prepare goose astrovirus SD / 36-95P inactivated vaccine; S3: Vaccinating laying hens with the goose astrovirus SD / 36-95P inactivated vaccine to obtain highly immune eggs; S4: After the highly immune eggs are disinfected, the yolks are collected, and finally goose astrovirus yolk antibodies are extracted from the yolks.

3. The method for preparing goose astrovirus yolk antibody according to claim 2, characterized in that: The method of amplification in step S1 includes: The goose astrovirus GAstV / SD / 36-95P strain is inoculated into a cell bottle with a monolayer of LMH cells, cultured at a temperature of 37° C. and a carbon dioxide concentration of 5%, and collected when more than 80% of the cells show pathological changes, and then the cells are frozen and thawed, shaken, centrifuged, and the supernatant is collected to obtain the amplified virus solution; and / or, The virus titer of the amplified virus solution is 10 7.0 TCID 50 / 0.1mL.

4. The method for preparing goose astrovirus yolk antibody according to claim 2, characterized in that: The method for preparing the inactivated vaccine in step S2 comprises: The amplified virus solution was diluted to a virus titer of 10 6.0 TCID 50 / 0.1mL, add 0.2% formaldehyde solution and inactivate at 37°C for 24h to obtain inactivated virus, then mix the inactivated virus and sterilized Tween-80 to prepare an aqueous phase, then mix and emulsify 1 part of the aqueous phase and 2 parts of the oil phase to obtain goose astrovirus SD / 36-95P inactivated vaccine.

5. The method for preparing goose astrovirus yolk antibody according to claim 4, characterized in that: The mass ratio of the inactivated virus to the sterilized Tween-80 is 95-97:3-5; and / or, The preparation method of the oil phase is as follows: white oil and span are mixed at a mass ratio of 94:6, aluminum stearate is added, stirred and mixed, and sterilized at 121° C. for 20 minutes to obtain the oil phase; The amount of aluminum stearate added is 3% of the mass of the white oil and span after mixing.

6. The method for preparing goose astrovirus yolk antibody according to claim 2, characterized in that: The method for inoculating laying hens in step S3 comprises: Each goose was injected with 1 mL of the inactivated goose astrovirus SD / 36-95P vaccine by breast muscle injection, and immunized once every 14 days for a total of 3 times. Egg samples were continuously collected on days 14 to 20 after the third immunization to obtain highly immune eggs.

7. The method for preparing goose astrovirus yolk antibody according to claim 2, characterized in that: The disinfection method in step S4 comprises: immersing the high-immunity eggs in a 0.1% chlorhexidine aqueous solution at a temperature of 37° C. for 20 minutes, and then wiping the surface of the high-immunity eggs with a 75% alcohol cotton ball; and / or, The method for extracting goose astrovirus yolk antibodies in step S4 includes: adding the yolk to an acetate buffer, stirring and mixing, standing at 4° C. for 24 hours, absorbing the supernatant, and then adjusting the pH to 7 with a sodium hydroxide solution, and finally filtering and sterilizing to obtain the goose astrovirus yolk antibodies.

8. The method for preparing goose astrovirus yolk antibody according to claim 7, characterized in that: The pH value of the acetate buffer is 5.2, and the volume ratio of the egg yolk to the acetate buffer is 1:6; and / or, The concentration of the sodium hydroxide solution is 1 mol / L; and / or, The pore size of the filter is 0.22 μm.

9. Use of the goose astrovirus yolk antibody according to claim 1 in preventing or treating goose astrovirus infection in gooselings.

10. The use according to claim 9, characterized in that: The goose astrovirus yolk antibody was diluted to 9 log2 / 0.1 mL and then injected subcutaneously into goslings, with each gosling being injected with 0.5-2 mL.

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