IN OVO IMMUNIZATION OF AVIAN EMBRYOS WITH OIL-EMULSION VACCINES

Abstract: Avian diseases, particularly those which threaten birds early in life, are controlled by embryonal vaccination using oil emulsion vaccines. The site of inoculation is the albumen end of the egg via entry through the air cell end of the egg.

Description: IN OVO IMMUNIZATION OF AVIAN EMBRYOS WITH OIL-EMULSION VACCINES BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a method for immunizing avian embryos with oil-emulsion vaccines in ovo. Description of the Prior Art Manual administration of emulsion vaccines to young avian flocks requires handling of individual birds and may involve corporate liability claims when self-injection occurs accidentally. Newly hatched chicks have been routinely inoculated against disease prior to being placed in brooder houses. However, vaccines do fail because the young chicks may become exposed to a virulent form of a disease too soon after vaccination before they have developed adequate immunity. There have been a number of reports of in ovo vaccination of avian embryos. In U.S. Patent No. 5,206,015 ('015), to Cox et al., a method is disclosed for introducing an aqueous preparation of unattenuated probiotic bacteria into the digestive tract of a bird to exclude . undesirable bacteria from colonizing the digestive tract. The bacterial culture is administered by depositing it in the air cell (large end) of an egg. The digestive tract of the hatchling of the innoculated eggs is found to be colonized by the bacterial culture at the time of hatch. In this method a hole is punched into the air cell end (large end) of the egg with a first sterile needle, then the bacteria is administered using a smaller sterile needle, and finally the hole is either left unsealed or sealed with a bacteria-impermeable material. U. S. Patent 4,458,630 ('630), to Sharma et al. discloses an embryonal vaccination for Marek's disease using unattenuated turkey herpesvirus (HVT) where the injection site is within either regions defined by the amnion or yolk sac. That is, the injection is midway along, and perpendicular to, the longitudinal axis for amnion penetration through the large end of the egg with a one inch needle so that the needle passes through the outer and inner shell membranes enclosing the air cell and amnion and terminates in the fluid above the chick or in the chick itself. As in '015 patent, a hole is punched or drilled in the shell and this may be resealed with paraffin or the like. U. S. Patent No. 4,040,388 ('388), to Miller teaches an automated method and apparatus for injecting embryonated eggs prior to incubation with a variety of substances into the albumin end (small end) of the egg. The reference teaches coagulative cooking of the surrounding albumin to seal the hole made by the injection. The drawbacks are that the vaccine is susceptible to inactivation during the heat coagulation step. Furthermore, Sharma et al. ('630) report that albumin has an inhibitory effect on the transport of an inoculant to the embryo at the egg's opposite end. U. S. Patent No. 2,851,006 ('006) to Taylor et al. teaches a method for increasing the hatch rate of bacterially infected eggs by means of in ovo treatment with a suitable bacteriophage in an aqueous preparation. The phage is introduced to the interior of the egg prior to incubation by any variety of -techniques including by hyperdermic syringe, pressure differential in a dipping fluid and jet spray. With the hyperdermic syringe, a 26 gauge short shank needle is inserted at an oblique angle into the albumin end of the egg. The patent teaches that the hole is sealed with a cellulose tape patch or a drop of melted paraffin. In U. S. Patent No. 3,120,834 ('834), Goldhaft et al. expands the application taught in Taylor to a variety of substances including antibiotics, sulfonamides, vitamins, enzymes, nutrients, and inorganic salts. These agents are introduced through the shell prior to incubation by means of vacuum impregnation. U. S. Patent No. 3,256,856 ('856) to Nicely et al. offers an improvement to the method of Goldhaft et al. in providing one or more holes in the egg shell for facilitating penetration. The hole(s) is (are) made in the air cell end (large end) of the egg, not extending beyond the inner shell membrane. The commercial practicality of the vacuum impregnation technique is limited by the unreliability of obtaining a uniform treatment and the economic unfeasibility of charging the dipping vats with expensive vaccine. Oil-emulsion vaccines prepared with mineral oil are highly efficacious formulations used widely against poultry diseases in various monovalent and polyvalent forms. Mineral oil vaccines cause excessive tissue reactogenicity, the oil persists too long, is practically non-digestible, and is considered carcinogenic. A 42 day holding period is required before slaughter of poultry if a mineral oil vaccine is administered. Animal and vegetable oil vaccines have been developed to replace mineral oil vaccines. However, these have also resulted in tissue reactions (Stone, Avian Diseases Vol. 34:979-983. 1990; Stone, Avian Diseases Vol. 37 (2) :399-405. 1993, all herein incorporated by reference) . While there are various methods for in ovo immunization using aqueous live vaccines and biologicals, there remains a need in the art for a method of in ovo immunization using oil-containing vaccines. The present invention provides a method which is different from prior art methods and overcomes problems associated with oil-containing vaccines and prior art in ovo immunization methods such as tissue reactogenicity and sealing the hole made to administer the vaccine to the embryo. Furthermore, inactivated antigens are successfully used in an in ovo oil emulsion vaccine. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method of in ovo immunization of avian embryos. Another object of the present invention is to provide a method of in ovo immunization using oil emulsion vaccines. A further object of the present invention is to provide a method of in ovo immunization wherein the vaccine is deposited near or into the albumin of the egg. A still further object of the present invention is to provide an avian egg which includes an embryo which is immunized with an oil-emulsion vaccine. Further objects and advantages of the invention will become apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a cross-section of chicken embryo 6 air cell end 1 up illustrating how needle 8 is placed in albumin 4 where the vaccine is deposited. The embryo 6 in the illustration is younger than when the injection actually is administered. Figure 2 shows the embryo development from 9-10 days to 18 days of age. Figure 2A shows an embryo of 9 to 10 days of age, Figure 2B shows a 13 day embryo, Figure 2C shows a 15 day embryo, Figure 2D shows a 17 day embryo, and Figure 2E shows an 18 day embryo being vaccinated. Figures 2A - 2C are viewed from the large end. Figures 2D and 2E are viewed as the egg lays on its side. The embryo at day 18 is curled around the center line which allows needle 8 to usually miss the embryo during the injection process. DETAILED DESCRIPTION OF THE INVENTION The method of this invention is applicable to any avian animal, whether domestic or wild, and particularly to those which are commercially reared for meat or egg production. Without limitation thereto, exemplary avians include chickens, turkeys, geese, ducks, pheasants, and the like. Birds which are reared in high density brooder houses such as broiler and layer chickens are especially vulnerable to environmental exposure to infectious agents and would largely benefit from prehatch vaccination. The advantages of this invention are in the prevention of lethal diseases which threaten avians early in life. Avian diseases include any disease or contamination of viral, bacterial, or other microbial origin. Examples of such, without limitation thereto, include Newcastle's disease, avian leukosis, infectious bursal disease, adenovirus disease, reovirus, pox, laryngotracheitis, infectious bronchitis, reticuloendotheliosis, influenza, infectious coryza, fowl typhoid, fowl cholera, Salmonella, and Marek's disease. The prior art in ovo injection systems have shown that chickens are immune competent as late stage embryos and that advantages of early immunization convenience, safety, labor, and time-saving are evident. These advantages are also greatly desired for oil emulsion vaccine administration which requires even more time, labor, liability risks, and contact with chickens. The term vaccine is defined to mean all types of biological agents used to produce active immunity or competitive exclusion. Oil emulsion vaccines include any water-in-oil emulsion or oil-in-water emulsion which is compatible with avian tissues (Gast et al., Avian Diseases Vol 37(4), 1993; Stone, Avian Diseases Vol. 37:399-405, 1993; Stone et al. , Avian Diseases, Vol. 34:979-983, 1990; Stone et al. , Avian Diseases, Vol. 27 (3) : 688-697, 1983; and U.S. Patent No. 3,919,411, Glass et al., 1975, all herein incorporated by reference) . Examples of useful oils include mineral oil, such as Drakeol 6VR; terpene oils such as squalene and squalane; vegetable oils such as soybean oil, olive oil, corn oil, jojoba oil, peanut oil, cotton-seed oil, sunflower oil, safflower oil, sesame oil, apricot oil, avocado oil, wheat germ oil, canola oil, Linseed oil, and almond oil; fish oils such as shark oil, orange roughy oil, Menhaden oil, and cod liver oil; animal oils such as mink oil, lard oil, and chicken fat oil. Examples of surfactants used in emulsion vaccines include Arlacel 80 (sorbitan monooleate), Tween 80 (Polysorbate 80), Span 80, Arlacel 83 (sorbitan sesquioleate) , Arlacel 85 (sorbitan sesquioleate) , and Tween 61 (polyoxyethylene sorbitan) , for example. Surfactants suitable for animal and vegetable water-in- oil vaccines include crude yellow, and purified beeswax, for example. Furthermore, surfactants suitable for vaccines containing squalene and squalane include Arlacel and Tween 80. It has been found that vaccinating and immunizing chick embryos with oil emulsion vaccines containing inactivated antigens in ovo induces protection in very young chicks through and beyond the life span of broiler chickens (>7 weeks) . The vaccine is deposited on or near the inside surface of the small end 4 (albumin end) of egg 10 with needle 8 placed through the idline of the egg beginning at the large end 1 (air cell end) (see Figure 1) . Embryo 6 is curled around the center line which allows needle 8 to miss the embryo 6 proper when needle 8 follows the center line (see Figure 2) . Not all of the oil emulsion vaccine remains in the albumin 4. Since it is oil and lighter than the aqueous egg fluids, it floats upward when egg 10 is air-cell-up 1 (large end up) which is how the egg is placed for vaccination and further incubation prior to being placed on their sides in hatching trays. The vaccine becomes dispersed in the fluids of the egg by the movement of the embryo and the presence of the mixture of the surfactants which allows dispersement in aqueous medium by virtue of the surfactant hydrophilic groups. The phenomenon can be observed directly as the shell can be broken into small pieces and peeled off the chorion (the membrane next to the inner shell membrane) which encloses and keeps the entire embryo and membranes intact. The vaccine appears as milky white droplets. Furthermore, the vaccine is seen in many 1-day hatched chicks in the abdominal areas either subcutaneous (SC) , intraperitoneal (IP) or in the wall of the peritoneal cavity. Before the embryo hatches, the skin completes its growth on the abdominal surface and in the process encloses the vaccine which sometimes can be seen subcutaneously in opened hatched chicks. This method simulates subcutaneous vaccination. Also as albumin 4 and yolk sac 5 enter the peritoneal cavity some of the vaccine may be enclosed intraperitoneally simulating intraperitoneal vaccination. Manual administration of emulsion vaccines to young chickens requires handling of individual chickens and may involve corporate liability when self-injection occurs accidentally. Immunologic competence in avian embryos develops in the final quarter of the incubation period, before which embryos are highly susceptible to infectious agents. Therefore, avian embryos should be inoculated at least about three days prior to hatch. In the chicken, for example, an injection could be given between 15 and 18 days of incubation with a most preferable time being the eighteenth day of the 21 day incubation, corresponding to the time when embryonated eggs are routinely transferred to hatching trays. The mechanism of injection is not particularly critical provided it does not unduly damage the tissues and organs of the embryo or the extraembryonic membranes surrounding it. A hypodermic syringe 9 fitted with a #22 gauge needle 8 is suitable for the injection. The length of needle 8 is dependent on the height of the egg. For example, for an average egg height of 1 15/16 inches, a 1 1/2 or 1 3/4 inch needle would be suitable. For an average egg height of 2 5/16", a three inch needle would be suitable. Needle 8 is inserted vertically from the center of the large end 1 of a chicken egg 10 through the center line to the small end of the egg 4. For an average egg height of 1 15/16 inches, a 1 1/2 inch needle would be fully inserted. When using a needle which is longer than the egg height, needle 8 is inserted into the large end 1 of egg to the end of the small end 4 and is withdrawn from the shell a small distance in order to push the vaccine out of the needle. One of ordinary skill in the art could readily determine the needle length based on the height of the particular avian egg that will be injected. In an automated system, it is envisioned that a penetrating device such as, for example, that taught by Miller in U. S. Patent 4,040,388 or Paul et al. in U. S. Patent No. 5,176,101 could be modified to carry out the method of the present invention. While it would not be desirable to apply heat to the needle for sterilization purposes, or suggested in the Miller patent, to the extent of inactivating the vaccine or cooking the egg's interior, sterilization between injections would be beneficial in preventing cross-contamination. Embryonal vaccination under the aforementioned conditions is characterized by a hatch rate greater than 80% for 18-day embryos and doses of 300 ul or less, approximately about 85-87, for white leghorn chickens and approximately about 82-85% for white rock chickens. Untreated eggs have a hatch rate of greater than 95% for 18-day embryos. Furthermore, in ovo immunization with oil emulsions containing inactivated antigen confers immunity to newly hatched chicks and the vaccination persists past the hatch date. The following examples illustrate the invention and are not intended to limit the scope of the invention as defined by the claims. A Newcastle disease virus vaccine with chick embryos is used as a test model system EXAMPLE 1 Embryonating eggs of specific-pathogen-free (SPF) white rock and white leghorn chickens were from the USDA, Agricultural Research Services' Southeast Poultry Research Laboratory flocks which are free of Newcastle Disease, avian leukosis, infectious bursal disease, adenovirus disease, reovirus, pox, laryngotracheitis, reticuloendotheliosis, infectious coryza, fowl typhoid, fowl cholera, salmonella, avian influenza, infectious bronchitis, mycoplasma, Marek's disease, and avian encephalomyelitis antibodies. Eggs, to be incubated, were collected twice daily, held at approximately about 50-55°F until set, then at approximately about 99.5 ± 5°F and approximately about 55 ± 0.5% relative humidity, and selected for cleanliness. Groups of vaccinated eggs were placed and hatched in separate enclosed wire hatching cages in an incubator at approximately about 99.5°F and approximately about 55% relative humidity. Hatched chicks from each group were wing banded for identification at 1-day-old, transferred, and mixed with other hatchmate groups in a brooder battery. Chickens losing wing bands were killed and discounted from their groups. They had access to a 95°F heated area with feed and water available ad libidum for two weeks and then were transferred to growing batteries. Chickens were housed in disease containment buildings with filtered air and temperature control (70°F) . Serum samples were collected at 1-week intervals from all chickens beginning 2 weeks posthatch for Hemagglutination- inhibition (HI) tests. Noninjected control eggs were used as an indication of normal hatch rates. EXAMPLE 2 Ulster Newcastle disease virus (NDV) in allantoic fluid (hemagglutinin [HA] titer = 1600, 50% embryo-lethal-dose ml) was propagated in 9-day-old embryos until 50% or more died, then virus containing allantoic fluid was harvested, pooled, and inactivated with 0.1% beta-propiolactone (BPL) for approximately about 2-4 hours at approximately about 24°C, and frozen (-20°C) until used. The inactivated virus is also referred to as the antigen. Inactivation of NDV was confirmed by embryo inoculation. The antigen was also used for the hemagglutination- inhibition (HI) tests. The same antigen was used for all experiments and was undiluted. Avian influenza (Al) strain A/Turkey/Wisconsin/68 (H5N9) is propagated in the allantois of 9-day-old embryonating chicken eggs by inoculation of approximately 10 3 fifty percent egg infective doses (EID 50 ) of virus. The eggs are incubated for approximately about 48 hours at 37°C and are chilled to 4°C before allantoic fluids are harvested. The allantoic fluids contain approximately about 10 8 - 9 embryo-lethal dose 50 /0.1 ml and have a hemagglutination titer of 1:1600. Inactivation of the fluids for antigen is by treatment with 0.1% beta-propiolactone for 4 hours at approximately about 24°C. The absence of residual infectivity was confirmed by egg inoculation. The antigen is used unconcentrated and is kept at -20°C until use. No preservatives are added to the preparation. Salmonella enteritidis (SE) strain SE-E6 is grown up in an overnight culture of tryptic soybroth (TSB) culture. The cultures were set up as three 1.5 liter/flask cultures, each inoculated with approximately about 0.3 ml of loop picked SE from overnight nutrient agar plates. Broths are incubated at approximately about 39°C overnight. The cultures are centrifuged to pellet the bacteria. The pellets are resuspended in 200 ml phosphate-buffered saline (PBS) and divided into 9 aliquots. Each aliquot is washed twice in PBS and the pelleted bacteria is inactivated with 10 ml of acetone for approximately about 2 hours at room temperature with occasional resuspension. Most of the acetone is removed by pipetting and the remainder is eliminated by evaporation in a desiccator under vacuum. Each tube is equivalent to 500 ml of culture. The SE antigen is kept at -20°C until use. The antigen is diluted with PBS and the vaccine prepared as described in Example 3. EXAMPLE 3 Water-in-oil emulsion vaccine was prepared with both oil- soluble surfactant, Arlacel 80 (Sorbitan monooleate) and water- soluble surfactant, Tween 80 (Polysorbate 80) added to mineral oil in a total content of 10% and a ratio of 3 parts Arlacel to 1 part Tween. This ratio of surfactants provides a hydrophile-lipophile balance (HLB) of 7.0 for best efficacy and is used for all vaccines unless otherwise indicated. See Schick, Nonionic Surfactants, Marcel Dekker, Inc., New York, New York, 609-611, 1966, which is herein incorporated by reference. The oil phase (oil plus surfactants) was autoclaved before vaccine emulsification. The mineral oil was Drakeol 6VR (Penreco Butler, Penn.) . Oil phase to aqueous antigen (aqueous phase is allantoic fluid for NDV and Al; PBS for SE) was 4:1 for all vaccines unless indicated otherwise. EXAMPLE 4 Vaccine efficacy for viral antigens is evaluated based on hemagglutination-inhibition (HI) antibody levels in serum of post- hatch chickens. HI antibody levels were determined by the microtest procedure described in Beard et al., Proceedings of the 77th Annual Meeting U.S. Animal Health Association, 596-600, 1973, which is herein incorporated by reference; using 8 HA units of NDV antigen. SE titers were determined by a SE microagglutination test described in Gast et al., Avian Diseases, vol. 34, 721-728, 1990, which is herein incorporated by reference. HI titers for ND and Al of 1:40 or above were considered indicative of protection induced by the vaccine against death. Tests were conducted the day serum samples were taken. EXAMPLE 5 Groups of embryonating white leghorn and white rock chicken egg ' s 10 were punctured at the longitudinal midline over the air cell 7 with an egg punch and injected with mineral oil emulsion vaccine using different doses between 25 ul and 600 ul (See Tables 1, 2, 3, and 4) in the small end of the egg. The shell holes were not sealed. HI tests were conducted weekly at 2 weeks - 9 weeks post hatch and at week 11. The different variables include length of needle 8 using same average egg height (see Tables 1 and 2) , in the orientation of the egg while the vaccine was being administered into the small end 4 of the egg via the large end 1, the point of entry in the egg. An HI titer of 3 or higher is considered protective. Furthermore, embryonating white leghorn chicken eggs were vaccinated as 18-day- old embryos directly through the small end 4 at different depths The results are shown in Tables 1 - 5. TABLE 1 Hemagglutmation-inhibition (HI) titers post-hatch of white leghorn chickens vaccinated as 18-day-old embryos. Group ul # in # HI GMT weeks post-hatch of responders no. dose group resp. 3 4 5 6 7 8 11 HI titer of 1 = 1:10, 4 = 1:80, 6 = 1:320, etc. Notes: 1. Vaccine was Drakeol 6VR with 10% Arlacel and Tween 80 at HLB 7.0. 0/A was 4:1. 2. Injection was vertical from large end through center line to small end. 3. Injection was 1-1/2 inches with 22-gauge needle. 4. Egg height was 1-15/16 inches average. 5. Hole for injection was not sealed. TABLE 2 Hemagglutination-inhibition (HI) titers post-hatch of white leghorn chickens vaccinated as 18-day-old embryos. Group ul # in # HI GMT weeks post-hatch of responders no. dose group resp. 2 3 4 5 1. Vaccine was Drakeol 6VR with 10% Arlacel and Tween 80 at HLB 7.0. 0/A was 4:1. 2. Group nos. 1-5 were injected with 1-1/2 inch 22-gauge needles. Group nos. 6-9 were injected with 1-3/4 inch 22-gauge needles. 3. Egg height was 1-15/16 inches average. 4. Injection was as m Table 1. 5. Hole for injection was not sealed. TABLE 3 Hemagglutmation-inhibition (HI) titers post-hatch of white rock chickens vaccinated as 18-day-old embryos. Group ul # in # HI GMT weeks post-hatch of responders no. dose group resp. 2 3 4 5 X 4.4 4.5 6.0 4.2 5.0 6.3 3.8 4.4 6.0 5.1 6.0 8.4 5.0 6.5 7.6 3.0 5.3 5.9 2.9 5.1 5.8 5.2 5.9 6.3 6.9 8.0 7.3 4.8 6.6 7.1 < 1 < 1 < 1 HI titer of 1 = 1:10, 4 = 1:80, 6 = 1:320, etc. Notes: 1. Vaccine and injection was the same as in Table 1. 2. Egg height was 2-15/16 inches average. 3. Group no. 6 was vaccinated from top to bottom of shell with 3-inch needle. 4. Group no. 7 was vaccinated as in No. 6 with egg inverted. 5. Group no. 8 was vaccinated as in No. 2 with egg inverted. 6. Group no. 9 was vaccinated as in No. 6 with egg inverted. 7. Group no. 10 was vaccinated as m No. 3 with egg inverted. TABLE 4 Hemagglutmation-inhibition (HI) titers post-hatch of white rock chickens vaccinated as 18-day-old embryos with ND oil emulsion vaccine. Group ul # in # HI GMT weeks post-hatch of responders no. dose group resp. 2 3 4 X 100 18 5 200 15 6 300 14 5 400 12 9 500 11 8 1000 5 4 300 10 5 300 11 6 none 18 0 HI titer of 1=1:10, 2=1:20, 3=1:40, 4=1:80, 5=1:160, 6=1:320, 7=1:640 HI titers of 1:40 or above are considered protective Notes: 1. Injection was perpendicular from the large end of egg through the mid-lme to the bottom inside surface of the small end. 2. Needles were 22-gauge, 3-ιnches long. 3. In group No. 7 the eggs were inverted then injected as described in Example 5. 4. In group No. 8 the eggs were injected horizontally from large end to small end. 5. Flock was at end of lay. 6. Egg height 2-5/32". TABLE 5 Hemagglutination-inhibition (HI) titers post-hatch of white leghorn chickens vaccinated as 18-day-old embryos with Newcastle Disease (ND) oil-emulsion (OE) vaccine given at different depths through the small end. Notes: 1. Needles were 20 gauge 1/4", 1/2", 1", and 1-1/2" respectively for groups 1, 2 , 3, and 4 2. Egg fluid was expelled when vaccine was administered at 1/4", 1/2" and 1" depths. 3. Eggs were vertical with small end up. 4. Holes were not sealed. 5. Vaccine dose was 100 ul. EXAMPLE 6 52-day-old white leghorn chickens were challenged with the lethal Fontana strain of velogenic viscerotropic Newcastle disease virus (WNDV) at 8 weeks post-vaccination as 18-day-old embryos. The embryos received a 200 ul dose of the mineral oil emulsion with Ulster ΝDV antigen prepared as described in Examples 2 and 3 above. The mean HI titer at the time of challenge was 7.2. Individual post-hatch titers of each of the ten chickens is reported in Table 5 below. WNDV was given intraocularly in a 0.1 ml volume containing 10 V-3 ELD 50 . Chickens were observed over a two week period for morbidity and mortality. Vent and tracheal swabs were taken 5 and 14 days postchallenge for virus isolation and HI titers were determined as described above. The results are reported in Table 6 below. TABLE 6 Challenge response of 52-day-old white leghorn chickens to velogenic viscerotropic Newcastle disease (WNDV) at 8-weeks postvaccmation as 18-day-old embryos. HI titer at Chicken weeks post-hatch Mean Virus isolation No. alive/Total no. Number 2 3 4 5 6 7 titer oral cloaca controls vaccination 0/5 10/10 Notes: 1. Challenge was 10' ' WNDV in 0.1 ml given traocularly. 2. Observation period was 2 weeks. 3. Virus isolation attempts were made at 5 days postchallenge. 4. There was no morbidity in the vaccinates. 5. Vaccine dose was 0.2 ml of mineral o l emulsion with Ulster NDV (0.1% BPL) 6. All unvaccmated controls died. EXAMPLE 7 At the end of the experiments, all in ovo vaccinated chickens were sacrificed and examined in the abdominal cavity or the breast muscle for the formation of lesions which were induced by the immunization. A lesion is defined as discolored, demarcated, inflamed, edematous, granulomatous, indurated, or necrotic tissue; or if tissue contained either encapsulated or diffuse vaccine. Usually, when a newly hatched chicken is vaccinated using a mineral oil emulsion vaccine, lesions appear as early as three weeks. In the in ovo immunized chickens, there was no evidence of gross lesions in any of the meat even after 11 weeks post-hatch. None of the meat would have been condemned for meat consumption. EXAMPLE 8 The HI titers of post-hatch white leghorn chickens vaccinated in ovo were compared to that of chicks vaccinated at 1-day-old. 18-day and 19-day embryos as well as 1-day-old chicks were vaccinated with 200 ul of the Newcastle disease oil-emulsion vaccine prepared as described in Examples 2 and 3 above. 1-day old chicks received 200 ul of the vaccine subcutaneously in the nape of the neck region. 18-day and 19-day embryos were vaccinated as described in Example 5. The results are reported in Table 7 below. - li 12_R__E 7 Haτa^ut Htiα_-:_^ (HI) titers post-hatch of white lβ____m iidkais vaccinated as 18- or 19-day-αld chick enbryos (CE) or 1-day-old chicta with Newcas le Disease (ND) oil-eπulsicn vaocine. A No. Geaietric Meein HE Titers of Group No. No. % _ e___p_TB^ Feroait _te£_xxτders - Weeks (posthatch) lYfean Nuπfcer CE Hatch Hatch Tbtal R___pcnse 2 3 4 5 6 liter TRIAL 1 1 Antigen only 0 0.0 2 18-day-CE 59 5.8 3 19-day-CE 56 5.4 4 1-day-chick 90 6.8 to 5 No vacc. Ctrl. 0 0.0 6 Needle oily iπjecticn T-KEAL 2 7 18-day-CE 67 5.9 8 1-day-chick 100 7.1 9 No vacc. Ctrl. 0 0.0 ■ *___rtaryos received 200 ul of vaccire full (depth on oaiter line frαn large end to arall end of egg. Qτe-day-old chicks received 200 ul of vaccine subcuteneously in nape of neck region. EXAMPLE 9 White rock chicken embryos from flocks at the beginning of lay and flocks at the end of lay were vaccinated at 14 to 18 days using different amounts of the vaccine preparation described in Examples 2 and 3 above and in different oil phase/aqueous antigen (0/A) ratios (see Tables 8 and 9 below) . The vaccine was also placed at different depths in the egg. The results are shown in Tables 8 and 9 below. TABLE 8 Heπa^t±in_cti<_τ --___nhibiticn (HI) titers post-hatch of white rock chickens vaccinated as eπtaryoε at 18 days at di ferent depths with Newcastle disease (ND) oil-Qτulsicn vaccine. HE CM? weeiks poεthateh Vaccine of reorders O/A Ratio 3 4 5 X 4:1 4:1 4:1 4:1 r 60:40 60:40 60:40 60:40 4:1 4:1 60:40 60:40 HI titer of 1=1:10, 2=1:20, 3=1:40, etc. Notes: 1. Flock was at becjinnirg of lay. 2. Irrjection was from large end in center line to stall end of egg. 3. 22-gauge, 3-inch needles. 4. Egg height was 1-33/32" average. 5. Vaσcire was Drakeol 6VR HIB 7, 10% (Arl 80 and Iween 80) in oil phase, 0:A 4:1, Ulster EW. TABLE 9 Hetragglut_-_riatlcr -i_rhibiti-n (HE) titers post-hatch of white rock chickens vaccirBted as errbryos at 14 to 18 days and at different depths with Newcastle disease (ND) oil-eπulsicn vaccine. to HI titer of 1=1:10, 2=1:20, 3=1:40, 4=1:80, 5=1:160, 6=1:320, 7=1:640 HE titers of 1:40 or above are cαnsidered protective. Notes: 1. Vaoci dose was 0.2 l per each egg given perpendicularly through mid-line, large end tcwar small end. 2. Needles were 22-gauge, 3 inches lcng. 3. Egg height was 2-5/32 inches average. 4. Flock was at end of lay. 5. Vaccins was mineral oil with 10% surfactant (4 parts) and 1 part MJJ Ulster iractivated (0.1% BEL) antigen eπulsified in a W&ring blender. HLB of 7. EXAMPLE 10 18-day-old white leghorn chick embryos (CE) were injected as described in Example 5 with varying amounts of oil emulsion vaccines containing inactivated avian influenza (Al) virus, Newcastle disease (ND) virus, and Salmonella enteritidis (SE) . Furthermore, a polyvalent vaccine was prepared by mixing equal parts of the three monovalent vaccines together. The O/A ratio for all the vaccines was 4:1 and the HLB=7. The inactivated antigens were prepared as described in Example 2 above and the oil emulsion prepared as described in Example 3. Titers for Al and ND are hemagglutination titers and SE titers are microagglutination titers as described in Example 4 above. The results are reported in Table 10 below. NDV and Al titers of 1:40 or above are considered indicative of protection against death. The SE titers show sensitization has occurred and hatched chickens can be revaccinated with SE for high sustained titers. TABLE 10 Vacxinaticn of 18-day-old white leghorn chick eπtaryαs (CE) with itcncvaleπt and polyvalent oil orulsicn (CE) of avian influenza (Al) Ifewcastle Disease (ND) and Salitrxella enteritidis (SE) CM Titers of Itesporders Grovp 01 ill No. CE No. CE No. Total _fterr_eπt Vfeeiks - PDstvao ination M=an Nuπber Vaccine Dose Inj . Hatch Reverse Re__p__nders 2 3 4 5 Titer 1 16 10/15 67 4.4 2 17 08/15 53 6.3 3 17 09/17 53 5.0 I 4 17 11/15 73 5.8 5 14 32/13 92 3.9 6 18 14/18 78 5.0 7 17 14/17 82 4.8 13/17 76 5.9 15/17 88 4.2 A Fblyvaleπt vaocine was farmed by adding equal parts of preformed HI, ND, and SE oil eπulsicn vaccires together Tto. of respcrriers is the greatest no. to re__pαrd during any bleeding weeks pcεthatch. c Titers far Al and ND are hai gc^ut rBtic_n-__ri-ii_biticn titers. Titers far SE are ιτ c_n_agglut__rBticn titers. The foregoing detailed description is for the purpose of illustration. Such detail is solely for that purpose and those skilled in the art can make variations therein without departing from the spirit and scope of the invention. INDEX OF THE ELEMENTS DESIGNATED BY A NUMERAL

Claims: What is claimed is: 1. A method for in ovo immunization of an avian species comprising puncturing an egg of said avian species with a puncturing means at the longitudinal midline over said egg's air cell in order to administer a vaccine in said egg's albumin end, injecting said vaccine into the egg by vertically inserting a needle means through said air cell to the albumin end. administering said vaccine into the albumin end of the egg. hatching said egg to obtain an immunized avian species. 2. The method of claim 1 wherein said egg is selected from the group consisting of chicken eggs, turkey eggs, geese eggs, duck eggs, and pheasant eggs. 3. The method of claim 1 wherein said vaccine is an oil emulsion vaccine. 4. The method of claim 1 wherein said vaccine is selected from the group consisting of monovalent and polyvalent vaccines. 5. The method of claim 1 wherein said vaccine confers immunity against viral, bacterial or microbial diseases. 6. ' The method of claim 3 wherein said diseases include Newcastle's disease, avian influenza, avian leukosis, infectious bursal disease, adenovirus disease, reovirus, pox, laryngotracheitis, infectious bronchitis, reticuloendotheliosis, infectious coryza, fowl typhoid, fowl cholera, Salmonella, and Marek's disease. 7. The method of claim 3 wherein said oil emulsion vaccine is a mineral oil emulsion vaccine. 8. An immunized avian egg produced by the method of claim 1. 9. An immunized egg produced by the method of claim 3. 10. An immunized egg produced by the method of claim 7.

Inventors: STONE HENRY D, STONE, HENRY, D.
Applicants: US AGRICULTURE, THE UNITED STATES OF AMERICA, REPRESENTED BY THE S
Application year: 1995
Main classification: A61K45
IPC codes: A61K39