Patent Publication Number: US-2004040511-A1

Title: Methods of injecting substances into eggs with reduced contamination

Description:
RELATED APPLICATION  
     [0001] This application claims the benefit of U.S. Provisional Application No. 60/402,274 filed Aug. 9, 2002, the disclosure of which is incorporated herein by reference in its entirety as if set forth fully herein. 
    
    
     
       FIELD OF THE INVENTION  
       [0002] The present invention relates generally to eggs and, more particularly, to methods and apparatus for treating eggs.  
       BACKGROUND OF THE INVENTION  
       [0003] Injections of various substances into avian eggs have been employed to decrease post-hatch mortality rates, increase the potential growth rates or eventual size of the resulting chicken, and even to influence the gender determination of the embryo. Similarly, injections of antigens into live eggs have been employed to incubate various substances used in vaccines which have human or animal medicinal or diagnostic applications. Examples of substances that have been used for, or proposed for, in ovo injection include vaccines, antibiotics and vitamins. In addition, removal of material from avian eggs has been employed for various purposes, such as testing and vaccine harvesting.  
       [0004] Examples of in ovo substances and methods of in ovo injection are described in U.S. Pat. No. 4,458,630 to Sharma et al. and U.S. Pat. No. 5,028,421 to Fredericksen et al., the contents of which are incorporated by reference herein in their entireties. The selection of both the site and time of in ovo injection can also impact the effectiveness of the injected substance, as well as the mortality rate of the injected eggs or treated embryos. See, e.g., U.S. Pat. No. 4,458,630 to Sharma et al., U.S. Pat. No. 4,681,063 to Hebrank, and U.S. Pat. No. 5,158,038 to Sheeks et al., each of which is hereby incorporated by reference herein in its entirety.  
       [0005] Poultry eggs (hereinafter “eggs”) are typically inoculated on or about the eighteenth day of incubation. Typically, eggs are held in flats on racks in carts for incubation in relatively large incubators. At a selected time, typically on the eighteenth day of age, a cart of eggs is removed from the incubator for the purposes of inoculation. Typically, all eggs are inoculated, including non-viable eggs. Ideally, however, separating out non-viable eggs (namely, dead eggs, rotted eggs, empties, and clear eggs) and inoculating only the live eggs should occur at the eighteenth day of incubation.  
       [0006] Conventionally, devices for injecting material into eggs and for removing material from eggs are configured to pierce and enter an egg along a generally vertical direction. Eggs are generally positioned in an upright, vertical orientation with the longitudinal axis of the egg substantially aligned with vertical.  
       [0007] Egg injection techniques incorporate aseptic (sterile) introduction of a needle through the shell of an egg and subsequently through the chorioallantoic membrane below the blunt end of an egg. The sterility of the injection solution (diluent or media) should be maintained. The introduction of bacteria, microbes, viruses and other pathogens into a developing embryo may be lethal as well as cause depressed growth and development if the embryo survives. Depending upon the characteristics of the specific pathogen, the number needed to cause problems can be very small (e.g., 1-10 bacteria colony forming units (cfu)).  
       [0008] Typically, egg injection systems address the issue of pathogen invasion through the use of sanitizing fluid (e.g., a buffered chlorine solution) that bathes the injection device between egg injections. In addition, an antibiotic or other sanitizing agent may be incorporated into an injection solution. This can be effective in the prevention of infection in most cases; however, pathogen carryover (from a contaminated egg to a clean egg) can occur. Furthermore, the exterior and interior (lumen) of injection devices have been shown to be actual sites of pathogen carryover.  
       SUMMARY OF THE INVENTION  
       [0009] In view of the-above discussion, a method of introducing a substance into an avian egg such that potential contamination is substantially reduced includes removing an avian egg containing a live avian embryo from an incubator; applying a sanitizing fluid to the shell of the egg to kill pathogens attached thereto; forming an opening in the shell; inserting an injection device through the opening; releasing a substance into the egg via the needle; retracting the injection device from the egg; and applying a sanitizing fluid to the needle to kill pathogens attached thereto. Prior to injection, the sanitizing fluid is applied to substantially the entire surface of the egg shell, with priority given to the site of shell penetration. After injection, the sanitizing fluid is applied to each part of the injection device that came into contact with the egg, including the interior and exterior of the punch tube and the exterior of the injection needle.  
       [0010] The injection device includes an elongated needle formed from a hollow tube having a free end that is angled with respect to a longitudinal axis of the tube. The free end has an opening surrounded by a planar, peripheral surface, and is angled with respect to the longitudinal axis of the tube. In addition, the needle has a thickness that is smaller than 20 gauge. The opening in the egg is formed via a tubular punch and the elongated needle is moved through the tubular punch and then through the opening formed in the shell. The severity of pathogen carryover from one egg to the next can be reduced dramatically if the cross-sectional area of the needle is less than or equal to forty percent (40%) of the cross sectional area of the bore of the punch within which the needle is movably secured.  
       [0011] In ovo injection of substances according to embodiments of the present invention substantially reduces the potential for contamination as compared with conventional in ovo injection methods. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0012]FIG. 1 is a side view of a multiple in ovo injection head apparatus.  
     [0013]FIG. 2 is an enlarged view of an injection head in the multiple injection head apparatus of FIG. 1.  
     [0014]FIG. 3A is an enlarged side view of an in ovo injection needle, according to embodiments of the present invention.  
     [0015]FIG. 3B is a side view of the needle of FIG. 3A taken along lines  3 A- 3 A.  
     [0016]FIG. 4 is a flow chart illustrating operations for injecting substances into eggs such that the potential for contamination is substantially reduced, according to embodiments of the present invention.  
     [0017]FIG. 5A is an enlarged, side sectional view of the injection head of FIG. 2 illustrating a punch and needle disposed within the punch.  
     [0018]FIG. 5B is a cross-sectional view of the needle and punch of FIG. 5A taken along lines  5 B- 5 B. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0019] The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.  
     [0020] The term “treatment substance” refers to a substance that is injected into an egg to achieve a desired result. Treatment substances include but are not limited to vaccines, antibiotics, vitamins, virus, and immunomodulatory substances. Vaccines designed for in ovo use to combat outbreaks of avian diseases in hatched birds are commercially available. Typically, the treatment substance is dispersed in a fluid medium, (e.g., a fluid diluent or emulsion) or is a solid dissolved in a fluid, or a particulate dispersed or suspended in a fluid.  
     [0021] Referring to FIG. 1, an exemplary egg injection apparatus is illustrated and includes a flat  15  for carrying eggs, a stationary base  16 , and a plurality of conventional injection delivery devices, or heads,  25  with fluid delivery means such as lumens or needle(s) positioned therein in accordance with known techniques. The flat  15  holds a plurality of eggs  20  in a substantially upright position. The flat  15  is configured to provide external access to predetermined areas of the eggs  20 . Each egg is held by the flat  15  so that a respective end thereof is in proper alignment relative to a corresponding one of the injection devices  25  as the injection device  25  advances towards the base  16  of the apparatus. As used herein, a “lumen” is a cavity or inner open space of a tube which can be provided by a syringe or needle. A lumen for delivery of a treatment substance may be within a needle, or between a needle and an outer guide or sleeve. Multiple lumens may be formed within a single needle, with the outlet ports positioned on different locations on the needle.  
     [0022] Each of the plurality of injection devices  25  has opposing first and second ends  26 ,  27 . The devices  25  have a first extended position and a second retracted position, as is known in the art. Upon extension of the injection device  25 , the first end  26  is configured to contact and rest against predetermined areas of the external egg shell. When not injecting, the injection devices  25  are retracted to rest a predetermined distance above the eggs and stationary base  16 . The second end  27  of the injection delivery device includes first and second inlet ports  28   a ,  28   b  which are configured to receive tubing respectively from treatment substance chambers. The treatment substances can then be delivered within the needle along separate delivery paths, such as the lumen of an inner needle, and the space between the inner needle and a guide punch.  
     [0023] As shown in FIG. 2, the illustrated in ovo injection head  25  of FIG. 1 includes a body member  40  having opposing top and bottom end portions  41 ,  43  and an elongate longitudinal aperture formed therein, and a delivery device positioned in said aperture. The device includes an egg locating member, or egg engaging member, on end portion  26 , which is slidably connected to the body member and includes a spring  42  to both cushion the engagement, and hold the egg in place during the downstroke of the injection head. An outer guide is provided to pierce the egg shell, and a needle then extends beyond the outer guide and into the desired compartments of the egg.  
     [0024] Surprisingly, Applicant has discovered that the severity of pathogen carryover from one egg to the next via an in ovo injection device can be reduced by reducing the diameter of an injection needle, by increasing the volume of sanitation fluid per needle per cycle, or a combination of both needle size reduction and increased sanitation volume, and by treating the shell of eggs after incubation with a sanitizing fluid to kill pathogens thereon. Smaller diameter needles may permit greater clearance between the needle and the punch within which the needle is operably associated with.  
     [0025] According to embodiments of the present invention, needle size has been decreased to less than 20 gauge and the volume of sanitation fluid used to sanitize each needle after an injection has been increased to about 500-600 μl.  
     [0026] FIGS.  3 A- 3 B are enlarged partial illustrations of an in ovo injection needle  50  according to embodiments of the present invention. The illustrated needle  50  is a hollow tube having a lumen  52  through which-material to be injected into an egg flows from a source. The lumen terminates at an opening  54  in the free end  50   a  of the needle  50 . The free end is angled with respect to a longitudinal axis L of the tube. The lumen opening  54  is surrounded by a planar, peripheral surface  55  as illustrated. The angle A of the end  50   a  may be virtually any angle. An angle between about thirty degrees and sixty degrees (30°-60°) is preferred, and an angle of forty-five degrees (45°) is particularly preferred. The illustrated end  50   a  has an angle A of about 45°.  
     [0027] Conventional needles utilized for subcutaneous injection have an end portion with a three-dimensional configuration (B-bevel). This three-dimensional configuration can serve as a host site for pathogens. In contrast, Applicant has found that the flat, angled configuration of the needle end  50   a  illustrated in FIGS.  3 A- 3 B reduces the surface area that can serve as a host site for pathogens.  
     [0028] Needle thickness is referred to as “gauge.” The higher the gauge, the thinner the needle. For example, a 30 gauge needle is thinner than a 28 gauge needle. Conventional in ovo injection needles are utilized to punch through the shell of an egg. Injection needles thinner than about 20 gauge are considered too thin to repetitively penetrate an egg shell without bending. As such, conventional egg injection needles are thicker than 20 gauge.  
     [0029] Because the injection needle of the present invention is not utilized for punching through the shell of an egg, the needle thickness can be much smaller than conventional injection needles. According to embodiments of the present invention, the needle  50  has a thickness that is smaller than 20 gauge. By utilizing smaller needles, the amount of surface area of the needle that can serve as a host site for pathogens is further reduced.  
     [0030] Referring now to FIG. 4, a method of introducing a substance into an avian egg such that potential contamination is substantially reduced includes removing an avian egg containing a live avian embryo from an incubator (Block  100 ); applying a sanitizing fluid to the shell of the egg to kill pathogens attached thereto (Block  200 ); forming an opening in the shell (Block  300 ); inserting an injection device through the opening (Block  400 ); releasing a substance into the egg via the needle (Block  500 ); retracting the injection device from the egg (Block  600 ); and applying a sanitizing fluid to the needle to kill pathogens attached thereto (Block  700 ).  
     [0031] Prior to injection, the sanitizing fluid is applied to substantially the entire surface of the egg shell; however, primary concentration should be upon the site of shell penetration. After injection, the sanitizing fluid is applied to each part of the injection device that came into contact with the egg, including within the needle hollow tube.  
     [0032] According to embodiments of the present invention, the opening in an egg is formed via a tubular punch ( 60 , FIG. 5A). An elongated needle  50  is movably secured within the tubular punch  60  and is configured to be inserted into the opening formed in the shell by the punch  60 . U.S. Pat. Nos. 4,681,063; RE 35,973; 5,136,979; 6,032,612, each of which is assigned to the assignee of the present invention, Embrex, Inc., describe forming an opening in the shell of an egg with a tubular punch and then moving an injection needle through the tubular punch and then through the opening formed in the shell of the egg, and then injecting a substance through the needle and into the egg. The disclosures of each of these patents are incorporated herein by reference in their entireties.  
     [0033] Surprisingly, Applicant has discovered that the severity of pathogen carryover from one egg to the next can be reduced dramatically if the cross-sectional area of a needle is less than or equal to forty percent (40%) of the cross sectional area of the bore of a punch within which the needle is movably secured. For example, as illustrated in FIG. 5B, the cross-sectional area A 1  of needle  50  is Π*(B/2) 2  and the cross-sectional area A 2  Of the bore  62  of punch needle  60  is Π*(A/2) 2 . The severity of pathogen carryover from one egg to the next can be reduced dramatically if A 1 ≦0.4A 2 .  
     [0034] Applicant&#39;s discovery can also be described relative to volumes. For example, the severity of pathogen carryover from one egg to the next can be reduced dramatically if the volume needle  50  displaces is less than or equal to forty percent (40%) of the internal volume of the tubular punch  60 .  
     [0035] The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.