Method for incubating and hatching of eggs

Abstract

A method for the incubation and hatching of surgically derived premature eggs removed in their shell from a bird prior to transfer of the premature egg to the cloaca of the bird, said surgically derived premature eggs being incubated and hatched in a carefully controlled manner over a period of about 21 days in a sterile environment. A number of surgically-derived premature eggs (6) are harvested (30) and incubated during an incubating phase (34) within an incubator (20) in an isolator (10) for about 18 days, carefully controlling the humidity within a range of 15% to 40% relative humidity to achieve a desired rate of egg weight loss. After incubation (34), during a hatching phase (42), the relative humidity within the incubator (20) is increased to 60%-75% relative humidity.

Description

[0001] “Method for Incubating and Hatching of Eggs”

[0002] Introduction

[0003] This invention is directed to a method for the incubation and hatching of premature eggs, in particular, premature eggs removed in their shell from a bird prior to transfer of the premature egg to the cloaca of the bird.

[0004] Background to the Invention

[0005] The invention relates to a method for incubation and hatching of eggs such as the method described in US 8,082,879 and is particularly concerned with an improved method of this type.

[0006] Summary of the Invention

[0007] According to the invention, there is provided a method for incubating and hatching surgically-derived premature eggs in their shells in a sterile environment, including the steps: cleaning an exterior of each surgically-derived premature egg prior to placing a number of cleaned premature eggs on a sterile egg tray within a sterile isolator; maintaining ambient air conditions within the isolator at a temperature in the range 18°C-21°C and a relative humidity within the range 30% to 70% relative humidity for a drying period of at least 12 hours; maintaining air pressure within the isolator within the range 130Pa- 160Pa; setting and maintaining a temperature of 37.5°C + / - 0.1 °C within the isolator during an incubating phase and during a hatching phase; transferring the eggs from the sterile egg tray into a sterile incubator within the isolator, turning the eggs within the incubator periodically during the incubating phase; maintaining the relative humidity within the incubator during the incubating phase within the range 15% to 40% relative humidity; controlling the relative humidity within the incubator during the incubating phase to achieve a desired rate of weight loss from the eggs during the incubating phase; at an end of the incubating phase, increasing the relative humidity within the incubator to 60% to 75% relative humidity and stopping turning of the eggs during the hatching phase; and hatching the eggs within the incubator.

[0008] In one embodiment of the invention, the method includes the steps of harvesting a number of surgically-derived premature eggs, wrapping each surgically-derived premature egg in a sterile wrapping sheet, placing the wrapped egg within a sterile container and closing the sterile container, sealing the sterile container within an outer sterile bag, and delivering the sealed container within the outer sterile bag to the sterile isolator.

[0009] In another embodiment, the method includes controlling the relative humidity for achieving a desired rate of weight loss by weighing eggs at intervals during the incubating phase and controlling the relative humidity within the incubator in response to the mean weight loss of the eggs.

[0010] In another embodiment, the method includes maintaining air pressure within the incubator at about 150Pa.

[0011] In another embodiment, the method includes the steps of measuring egg weight at a number of spaced-apart weighing points during the incubation phase, sensing the relative humidity within the incubator at each weighing point, adjusting the relative humidity within the incubator within a range of 5% to 10% in response to the measured egg weight at each weighing point during the incubation phase deviating from a preset ideal egg weight for that weighing point. In another embodiment, the method includes the step of adjusting the speeds of the air inlet fan and the air outlet fan for controlling the air pressure within the isolator. In another embodiment, the method includes the step of laying each egg on it’s side during the hatching phase.

[0012] In another embodiment, the method includes checking for viable embryos by candling each egg on day 7 or day 8 of the incubating phase, and removing dead embryos.

[0013] In another embodiment, the incubating phase is 18 days.

[0014] In another embodiment, the hatching phase is 3 days. Brief Description of the Drawings

[0015] The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:

[0016] Fig. 1 is a schematic illustration of a method according to the invention for incubating and hatching surgically-derived premature eggs in their shells;

[0017] Fig. 2 is a schematic illustration of an egg transfer pouch used in the method of the invention;

[0018] Fig. 3 is a schematic plan view of a flexible isolator for housing one or more egg incubators used in the method of the invention; and Fig. 4 is an egg weight loss chart illustrating egg weight loss during the method of the invention.

[0019] Detailed Description of the Preferred Embodiments Referring to the drawings, a method according to the invention for incubating and hatching surgically-derived premature eggs in their shells will be described. A method 1 according to the invention is schematically illustrated in Fig. 1.

[0020] An egg transfer pouch 2 used in the method of the invention is shown in Fig. 2. The egg transfer pouch 2 comprises an outer sterile plastic bag 3 for reception of a 250ml sterile container 4 having a lid 5. An egg 6 wrapped in sterile paper or a sterile gauze swab 7 can be stored within the container 4.

[0021] Fig. 3 illustrates a flexible isolator 10 forming a sterile chamber having transparent side walls 11 and end walls 12. An air inlet 14 and a transfer port 15 with inner and outer doors are provided in one end wall 12 and an air outlet 16 is located at an opposite end wall 12. Flexible sleeves 18 with gloves attached are mounted on a front side wall 11 of the isolator to allow persons access to an interior 19 of the isolator 10 for handling objects within the isolator 10. An incubator 20 is shown mounted within the isolator 10 in accordance with the method of the invention, the incubator 20 having a number of eggs 6 mounted on an egg carrier 22 within the incubator 20. The egg carrier 22 has an associated egg turning system for turning the eggs 6 at preset time intervals, for example every 45 minutes.

[0022] While only one incubator 20 is shown mounted within the isolator 10, it will be appreciated that two or more incubators 20 may be mounted within the isolator 10 where space permits.

[0023] A controller 23 is operably connected to a humidity controller 24 mounted at the air inlet 14 to control the air humidity within the isolator 10. A humidity sensor 25 and a temperature sensor 26 within the isolator 10 also connect to the controller 23, as do an air inlet fan 27 and an air outlet fan 28 mounted at the air inlet 14 and the ait outlet 16 respectively, and an associated air pressure sensor 29 mounted within the isolator 10. Thus, the controller 23 is operable to control air throughput, pressure, temperature and relative humidity within the isolator 10.

[0024] Fig. 4 shows an egg weight loss chart illustrating an ideal weight 39 for each day of an incubating phase 34 of the method 1 of the invention and a number of measured egg weights 35, 36 taken at intervals during the incubating phase 34 according to the method 1 of the invention. The measured egg weight 35,36 is used to control humidity within the isolator 10 to keep the egg weight at or as close as possible to the ideal egg weight 39 during the incubating phase 34 according to the method 1 of the invention.

[0025] The method 1 of the invention includes harvesting 30 a number of surgically-derived premature eggs 6, for example, by a method such as that described in US Patent No. 6,718,909 B2, the contents of which are incorporated herein by reference. Each surgically-derived premature egg 6 is wrapped in a sterile wrapping sheet such as sterile paper or sterile gauze swab 7 and placed in the 250ml sterile container 4 which is then sealed within the outer sterile plastic bag 3, as shown in Fig. 2.

[0026] A number of egg transfer pouches 2 with the sealed containers 4 are loaded in a box and delivered through the transfer port 15 into the isolator 10. Using the gloved sleeves 18, a person can reach into the isolator 10 and carefully remove each premature egg 6 from the associated sterile container 4. Each egg 6 is dried with sterile gauze or sterile paper and an outer surface of the egg 6 is cleaned. Cleaned eggs are placed on a sterile cardboard tray (not shown) within the isolator 10 with the pointed end (taglion) of each egg 6 downwards for drying 32 for a period of at least 12 hours, prior to placing each egg 6 within an incubator 20 within the isolator 10. During this drying period 32, the interior of the isolator 10 is maintained at a temperature in the range of 18°C to 21°C and a humidity in the range 30% to 70% relative humidity.

[0027] After drying 32 the eggs 6 undergo the incubating phase 34 within a sterilised incubator 20 housed within the isolator 10. Weighing 36 of each egg 6 is carried out before placing the egg in the incubator 20. This provides a mean initial egg weight 35 (Fig. 4) for the eggs. Eggs 6 are moved from the sterile tray into the incubator 20 on the first day of the incubating phase 34. The eggs 6 are mounted on the egg carriers 22 within the incubator 20, being placed with the pointed egg (taglion) downwards. During the incubating phase 34 the turning system associated with each egg carrier 22 is operable to turn the eggs 6 every 45 minutes.

[0028] After starting the incubating phase 34, the eggs 6 are weighed 37 at spaced intervals during the incubating phase 34. Eggs 6 will lose between 11% to 13% of their weight during the incubating phase 34, as shown in Fig. 4. During egg weighing 37 the mean egg weight 36 is calculated. The mean measured egg weight loss is used for controlling 38 the relative humidity within the isolator 10 and hence within the incubator 20 in order to achieve the ideal rate of weight loss. Values for mean intermediate egg weights 36 are compared to the ideal weight loss corresponding to the time the weight is measured and the humidity within the isolator 10 and incubator 20 is adjusted, if necessary, to control the rate of weight loss to achieve the ideal rate of weight loss, as illustrated on the chart in Fig. 4.

[0029] Egg weight is measured at a number of spaced-apart weighing points 36 during the incubating phase 34. At each weighing point 36 the controller 23 senses the relative humidity within the incubator 20 (and isolator 10) and, if necessary, adjusts the relative humidity within the incubator 20, within a range of 5% to 10%, in response to the measured egg weight at each weighing point 36 during the incubating phase 34 deviating from a preset ideal egg weight 39 for that weighing point 36 to bring the rate of weight loss back to the optimum rate 39 of weight loss.

[0030] Depending on the measured weight change since the previous mean measured egg weight 35,36 was calculated, relative humidity within the isolator 10 and incubator 20 will be increased or decreased by 5% to 10% to match the ideal weight loss, as shown in Fig. 4. That is, if the eggs 6 are not losing sufficient weight, the relative humidity is decreased by 5%-10%. If the eggs 6 are losing too much weight, then the relative humidity is increased by 5%-10%.

[0031] Candling 40 of the eggs 6 is carried out at day 7 or day 8 of the incubating phase 34 and at day 18, at the end of the incubating phase 34 and before a hatching phase 42. Infertile or dead embryo eggs 6 are discarded 41 and removed from the incubator 20 and isolator 10 following every candling 40 procedure.

[0032] After the incubating phase 34 of at least 18 days, the eggs 6 undergo the hatching phase 42. Eggs 6 are removed from the incubator 20 and placed in an egg tray within the isolator 10. After removal of the egg carriers 22 from each incubator 20, a presterilised hatching mat is mounted on a floor of each incubator 20. The eggs 6 are then placed directly onto the hatching mat, laying on their long side. The egg turning system is turned off and there is no egg turning during the hatching phase 42.

[0033] For the hatching phase 42, humidity within the isolator 10 is increased to 60%-75% relative humidity and the temperature within the isolator 10 is maintained at 37.5°C + / - 0.1 °C for the hatching phase 42. Chicks will start to hatch after three days of the hatching phase 42.

[0034] The chicks are transferred to a sterile isolator cabinet where, in a sterile environment maintained within the isolator cabinet, the chicks are grown into mature egg-laying hens, and subsequently, germ-free eggs laid by the hens within the isolator cabinet are collected.

[0035] It will be noted that during the incubating phase 34, the relative humidity within the incubator 20 is maintained within the range 15% to 40% relative humidity and the temperature is set at 37.5°C + / - 0.1 °C. The relative humidity set point will only change during the incubating phase 34 in response to mean measured egg weight deviating from the ideal egg weight as described previously.

[0036] Throughout the incubating phase 34 and the hatching phase 42, a positive air pressure is maintained within the isolator 10 of at least 10Pa and more preferably in the range 130Pa to 160Pa, and ideally approximately 150Pa, these pressures being gauge pressure. An air inlet fan 45 delivers air through the air inlet 14 and an associated air outlet fan 46 extracts air through the air outlet 16 of the isolator 10. The speeds of the fans 45,46 are adjusted to maintain the required positive air pressure within the isolator 10. Ideally, the air inlet fan 46 is operated at maximum speed and the air outlet fan 46 is operated at a minimum speed, with an air outlet valve 47 at the air outlet 16 adjusted to achieve the desired positive air pressure of approximately 150Pa within the isolator 10 during the incubating phase 34 and the hatching phase 42.

[0037] Advantageously, the improved method of the invention has increased the hatchability rate of the premature eggs from 60-77% (mean 74%) achieved by our previous method to an increased hatchability rate in the range of 75-89% (mean 83%). Also, we have found that when we hatch eggs from the first generation of germ-free chicks produced according to the method of the invention, we have achieved hatchability rates of 90-98%.

[0038] Further, results of a comparative viral yield study show that the germ-free eggs produced by the hens within the isolator cabinet supported replication of human influenza virus A / H1 N1A / ictoria with yields up to 2-fold higher than two sources of Specific Pathogen Free (SPF) eggs with a 2 / 3-fold lower Interferon p response vs the two sources of SPF eggs.

[0039] The terms “comprise” and “include”, and any variations thereof required for grammatical reasons, are to be considered as interchangeable and accorded the widest possible interpretation.

[0040] The invention is not limited to the embodiments hereinbefore described but may be varied in both construction and detail within the scope of the appended claims.

Claims

CLAIMS1. A method for incubating and hatching surgically-derived premature eggs in their shells in a sterile environment, including the steps: cleaning an exterior of each surgically-derived premature egg prior to placing a number of cleaned premature eggs on a sterile egg tray within a sterile isolator; maintaining ambient air conditions within the isolator at a temperature in the range 18°C-21°C and a relative humidity within the range 30% to 70% relative humidity for a drying period of at least 12 hours; maintaining air pressure within the isolator within the range 130Pa- 160Pa; setting and maintaining a temperature of 37.5°C + / - 0.1°C within the isolator during an incubating phase and during a hatching phase; transferring the eggs from the sterile egg tray into a sterile incubator within the isolator, turning the eggs within the incubator periodically during the incubating phase; maintaining the relative humidity within the incubator during the incubating phase in the range 15% to 40% relative humidity; controlling the relative humidity within the incubator during the incubating phase to achieve a desired rate of weight loss from the eggs during the incubating phase; at an end of the incubating phase, increasing the relative humidity within the incubator to 60% to 75% relative humidity and stopping turning of the eggs during the hatching phase; and hatching the eggs within the incubator.

2. The method as claimed in claim 1 , including the steps of harvesting a number of surgically-derived premature eggs, wrapping each surgically-derived premature egg in a sterile wrapping sheet, placing the wrapped egg within a sterile container and closing the sterile container, sealing the sterile container within an outer sterile bag, and delivering the sealed container within the outer sterile bag to the sterile isolator.

3. The method as claimed in claim 1 or claim 2, wherein the method includes controlling the relative humidity for achieving a desired rate of weight loss by weighing eggs at intervals during the incubating phase and controlling the relative humidity within the incubator in response to the mean weight loss of the eggs.

4. The method as claimed in any one of the preceding claims, wherein the method includes the steps of measuring egg weight at a number of spacedapart weighing points during the incubation phase, sensing the relative humidity within the incubator at each weighing point, adjusting the relative humidity within the incubator within a range of 5% to 10% in response to the measured egg weight at each weighing point during the incubation phase deviating from a preset ideal egg weight for that weighing point.

5. The method as claimed in any one of the preceding claims, wherein the method includes maintaining air pressure within the incubator at about 150Pa.

6. The method as claimed in any one of the preceding claims, wherein the method includes the step of adjusting the speeds of the air inlet fan and the air outlet fan for controlling the air pressure within the isolator.

7. The method as claimed in any one of the preceding claims, wherein the method includes the step of laying each egg on it’s side during the hatching phase.

8. The method as claimed in any one of the preceding claims, wherein the method includes checking for viable embryos by candling each egg on day 7 or day 8 of the incubating phase, and removing dead embryos.

9. The method as claimed in any preceding claim, wherein the incubating phase is 18 days.

10. The method as claimed in any preceding claim, wherein the hatching phase is 3 days.

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