Method for opening eggs for spectroscopic in-ovo sex determination

Abstract

The invention relates to the technical fields of bioanalytics and agriculture and concerns a method for opening eggs. The object of the present invention is to provide a method for opening an egg in which the deposition of chemical or biochemical reaction and / or erosion products of the calcareous shell and the outer shell membrane on the inner shell membrane is avoided.This problem is solved by a method for opening an egg, in which a substantially closed channel structure is created in the calcareous shell of an egg in a surface area located essentially above the air chamber by means of a laser by ablating the calcareous shell material. The depth of the channel structure is gradually adjusted at variable laser propulsion speeds. Subsequently, at least two perforations are created in the calcareous shell and the outer shell membrane, at least in the local area of the created channel structure. Finally, the calcareous shell and the outer shell membrane are removed in a single operation. The method can be used, for example, in the spectroscopic in-ovo sex determination of poultry or in commercial egg production.

Description

[0001] The invention relates to the technical fields of bioanalytics and agriculture and concerns a method for opening eggs. The method according to the invention can be used, for example, in the spectroscopic in-ovo sex determination of poultry, in animal breeding, or in commercial egg production.

[0002] A strong negative correlation between laying performance and fattening performance prevents the simultaneous use of domestic chickens as both egg producers and meat suppliers. In recent decades, specialized lines of commercial chickens have been bred, enabling either the economical production of high-quality eggs or efficient meat production. While hens from fattening lines are also fattened, roosters from laying lines can currently only be raised and marketed economically to a very limited extent. The current practice of culling male offspring from laying hen lines immediately after hatching contradicts legal regulations and animal welfare goals and thus raises ethical and legal concerns both at home and abroad.

[0003] For this reason, increased research activities are being undertaken to find alternative solutions to the killing of male day-old chicks during egg production.

[0004] To date, in addition to non-invasive methods for sexing fertilized bird eggs, invasive methods have been used for sexing fertilized chicken eggs at various incubation periods. For invasive in-ovo sexing methods, for example, the bird eggs are placed with the blunt pole facing upward, so that the air chamber in the bird egg is oriented as far upward as possible.

[0005] To perform spectroscopic in-ovo sex determination, the egg is incubated for at least three days. This allows an embryo to develop, and its sex can be detected based on molecular, biochemical characteristics. In this invasive method, the egg is opened in a small area of the air sac by removing the calcareous shell and the outer shell membrane to allow the necessary optical access to the sex-specific characteristics of the fertilized egg. The inner shell membrane and the underlying embryo remain untouched.

[0006] The particular challenge for embryonic-reaction-free egg opening, accompanied by early in ovo sex determination, arises from the composite structure of the calcareous shell and outer shell membrane. While the calcareous shell consists almost entirely of inorganic compounds, primarily carbonates, with a microscopic macrostructure, the outer shell membrane is predominantly dominated by complex, high-molecular-weight organic compounds, such as structural proteins. The inorganic calcareous shell and the organic outer shell membrane form a coherent unit and simultaneously exhibit very different chemical and physical properties.This ultimately leads to the task of developing a process that can be used in such a way that both materials of the composite can be processed according to the requirements of in ovo sex determination for the actual opening of the egg.

[0007] Various state-of-the-art solutions are known for opening an egg.

[0008] US Pat. No. 5,285,750 A discloses the opening of eggshells by cutting, drilling, or punching, or alternatively by laser cutting and drilling. Both CO2 and Nd:YAG lasers are used.

[0009] From EP 2 998 124 A2 a method for laser marking an eggshell is known which comprises controlling a laser beam directed onto the eggshell in order to discolour an outer layer of the eggshell without substantially etching the layers of the eggshell beneath the outer layer.

[0010] From DE 10 2014 010 150 A1 a method for Raman spectroscopic, in ovo sex determination of fertilized and hatched bird eggs is known, in which a hole is created in the shell in the immediate area of the connected blood vessel by means of a hole generation unit.

[0011] Furthermore, US 2015 / 0 136 030 A1 discloses a device for delivering substances to specific embryonic structures, including the heart and blood vessels, within a developing bird egg, comprising a device for aseptically cutting the outer shell of an egg so that a defined part of the shell is prepared for subsequent removal.

[0012] EP 3 437 468 A1 discloses a method and device for processing a calcareous shell in the region of the blunt pole of a bird's egg, in which the position of an air chamber located between an inner membrane and an outer membrane of the bird's egg in the region of the blunt pole is determined. Subsequently, a processing device for processing the calcareous shell in the region of the blunt pole is controlled based on the position of the air chamber determined by evaluating the image, so that the calcareous shell is processed at a distance from the inner membrane of the bird's egg. The processing device creates a weakening line in the calcareous shell, and the area defined by the weakening line is subsequently removed.

[0013] DE 10 2010 019 683 A1 discloses a method for processing eggshells using a laser, in which the hard eggshell is perforated at specific locations. This known method is intended for decorative items and for incorporating decorative patterns into the eggshell, intended to create the impression of fine carvings. The method does not describe how a fertilized and incubated egg can be opened using laser technology while maintaining the embryo's vital functions.

[0014] From DE 10 2016 004 051 B3 a method for the optical in-ovo sex determination of fertilized and incubated bird eggs is known, in which a hole is created in the calcareous shell of the bird egg by means of a hole-making unit in order to be able to subsequently carry out spectroscopic examinations, for example by means of fluorescence radiation on the blood of the bird egg, in order to determine the sex of the embryo.

[0015] An important prerequisite for carrying out the aforementioned bioanalytical and spectroscopic investigations for in-ovo sex determination on the opened egg is that the process of opening the egg prevents the entry of undesirable substances such as calcareous shell chips into the interior of the egg and also prevents a change in the biochemical composition of the remaining inner shell membrane.

[0016] The disadvantage of the methods known from WO 2017 / 017 277 A1 and EP 3 177 918 B1 for opening eggs for in-ovo sex determination is that, in addition to the lack of automation for removing the lid, the embryonic development of the embryo can also be influenced.

[0017] Another disadvantage is that the known machining process of opening the egg can result in unwanted by-products, such as fragments of the calcareous shell, getting into the interior of the opened egg. Another disadvantage is that the methods known to date produce unwanted pyrolysis products of the outer shell membrane, which is composed predominantly of organic material, and deposit them on the embryonic and extra-embryonic tissue structures, rendering the eggs unusable for subsequent spectroscopic in-ovo sex determination. Another disadvantage is that when the calcareous shell is opened and removed, the outer shell membrane is only partially removed or not removed at all when the lid is removed, necessitating further complex and costly process steps for the subsequent removal of the outer shell membrane.A disadvantage of the known methods is that if the laser power is too low, the egg cannot be opened and if the laser power is too high, the energy input can cause a change in the inner shell membrane, which makes spectroscopic in-ovo sex determination difficult or impossible.

[0018] The object of the present invention is to provide a method for opening an egg in which the deposition of chemical or biochemical reaction and / or abrasion products of the calcareous shell and the outer shell membrane on the inner shell membrane is avoided, that the method for opening the egg is applied automatically, that an opening within a few seconds and an improved handling of the opening and closing of the egg to be analyzed is made possible and with which a more accurate implementation of the in-ovo sex determination on the opened egg is made possible.

[0019] The object of the invention is achieved by the features of the independent claims. The dependent claims represent advantageous embodiments of the features of the independent claims, which may also be combined in the form of an AND combination.

[0020] The object of the invention is achieved by a method for opening an egg which contains at least one calcareous shell and an air chamber enclosed by an outer shell membrane and an inner shell membrane, in which method a substantially closed channel structure is produced in the calcareous shell in a surface area which is located substantially above the air chamber by means of a laser by ablating the calcareous shell material, subsequently at least two perforations are produced in the calcareous shell and the outer shell membrane at least in the local area of the produced channel structure, and finally the calcareous shell and the outer shell membrane are removed in one operation.

[0021] In an advantageous embodiment of the method, the course of the channel structure is formed in a closed manner.

[0022] It is also advantageous if the channel structure is designed as a circle, oval, rectangle, square, meander shape or polygon.

[0023] Advantageously, the removal of the calcareous shell material and / or the creation of the perforations is carried out by sublimation processes.

[0024] It is also advantageous if a CO2 laser is used to create the channel structure and perforations.

[0025] Advantageously, the laser is used with an average output power of 10 W to 1000 W and a pulse energy of 1 mJ to 1 J.

[0026] It is also advantageous to use a laser with a focus range of 1 to 50 mm and a spot size of 0.05 mm to 0.5 mm.

[0027] According to the invention, the depth of the channel structure is created step by step with variable laser propulsion speeds.

[0028] Advantageously, the channel structure is created with a laser propulsion speed of 10 mm / s to 500 mm / s.

[0029] Furthermore, it is advantageous if point-shaped and / or linear perforations are created that are arranged symmetrically or rotationally symmetrically in the channel structure.

[0030] The method for opening the egg according to the invention can be used between the 4th and 6th day of incubation.

[0031] It is also advantageous if the removal of the calcareous shell and the outer membrane structure is carried out by a device that creates a vacuum, adhesive pads, freezing the calcareous shell lid to a cooled stamp, by means of needles and / or cutting.

[0032] In a particular embodiment of the method, it can advantageously be provided that, before the calcareous shell material is removed, the egg is positioned and aligned in order to determine the position of the air chamber in the closed egg.

[0033] The solution according to the invention provides a method for opening an egg that can be applied automatically, enables improved handling when opening the egg to be analyzed and enables more accurate in-ovo sex determination on the opened egg.

[0034] The aforementioned technical advantages are achieved by a method for opening an egg, which may, for example, be a bird's egg. The technical features of the method are particularly effective in processing the egg in the area of the calcareous shell, the outer shell membrane, and the air chamber enclosed by the outer shell membrane and an inner shell membrane.

[0035] According to the invention, in a first step, a substantially closed channel structure is created in the calcareous shell in a surface area located substantially above the air chamber by laser ablation of the predominantly inorganic calcareous shell material. The ablation process is advantageously carried out in such a way that sublimation of the inorganic calcareous shell material occurs without subjecting the adjacent outer shell membrane, which consists of predominantly organic compounds, to such an energetic load that undesirable pyrolytic processes occur, resulting in the deposition of reaction products on the inner shell membrane.

[0036] The channel structure to be created in the calcareous shell can be understood as a type of targeted material weakening of the shell structure, which defines the contour of the calcareous shell cap to be removed. It is important to use a laser, preferably a CO2 laser, which, on the one hand, preferably sublimes the calcareous shell material, without allowing microscopic particles or even detectable chips of the calcareous shell material to enter the interior of the egg. Furthermore, a targeted contouring and defined channel structure are created, which leads to easier opening without the edge of the calcareous cap breaking away.

[0037] The canal structure is essentially closed, which defines the geometric shape of the cap to be removed. A substantially closed canal structure is defined as a contouring effect created by material removal exclusively in the calcareous shell, which is only partially imprinted in the depth of the calcareous shell, does not penetrate the calcareous shell at any point, and is formed as a geometric shape without a canal beginning or end.

[0038] A channel structure that forms an oval, rectangle, square, meander, or polygon is conceivable and advantageous. It has proven particularly advantageous to create a circular channel structure, as this allows for chip-free removal of the calcareous shell along with the outer shell membrane in a single process step, in a simple and cost-effective manner.

[0039] A feature of the method according to the invention is that the depth of the canal structure is created step by step using variable laser advancement speeds. This is particularly important so that the depth of the canal structure can be adjusted to the thickness of the egg's calcareous shell. Thus, it is conceivable that the laser could ablate and remove a larger amount of calcareous material when creating the canal structure at a lower laser advancement speed, and subsequently ablate and remove a smaller amount of calcareous shell material at a higher laser advancement speed to avoid complete removal of the calcareous shell in the area of the canal structure.

[0040] It is advantageous to traverse the canal structure three times with the laser beam. The speed of the third circular laser processing can be used to take differences in the calcareous shell formation into account. Pauses can be inserted between the laser processing steps to allow the eggshell and the inner shell membrane to cool down. During the pauses, other eggs can be processed with the same laser so as not to increase the overall processing time. The canal structure can advantageously be created with laser propulsion speeds of 10 mm / s to 500 mm / s using a CO2 laser with an output of 30 watts. With higher laser power, the laser propulsion speed can be increased considerably. In addition to changing the laser propulsion speed, it is also possible to adjust the laser power for each of the three laser processing steps.

[0041] In an advantageous embodiment of the method, it can be provided that a laser with a focus range of 1 to 50 mm and a spot size of 0.05 mm to 0.5 mm is used.

[0042] If a laser processing system without focus control is used, a laser with a long focus range of 0.05 mm to 0.5 mm and a spot size well below 1 mm is advantageous due to the different egg sizes. If the laser processing system used allows focus control and the position of the shell to be removed is known, for example, through triangulation measurements, the focus range can be reduced to less than 10 mm, and the spot size can be less than 0.1 mm.

[0043] According to the invention, after the creation of the channel structure, a subsequent process step proposes creating at least two perforations in the calcareous shell and the outer shell membrane directly in the area of the previously created channel structure. The perforations are intended to destabilize the calcareous shell and the outer shell membrane, while the inner shell membrane remains intact.

[0044] The technical effect of the proposed perforations is to create locally defined material weakenings in the calcareous shell and the outer shell membrane, which support the chip-free fracture process of the remaining calcareous shell material below the canal structure. A further advantage is that the targeted damage to the structural protein structures of the outer shell membrane reduces the stability of the molecular network. This allows the outer shell membrane to be segmented in a defined manner during the subsequent removal of the contoured lid of the calcareous shell. Finally, the calcareous shell and the outer shell membrane are removed together, for example, using a device that generates a vacuum.

[0045] Therefore, a significant technical advantage of introducing only individual perforations in the local area of the created channel structure is that only a very small amount of pyrolysis products is produced during perforation, which significantly reduces the impact on the air chamber and the inner shell membrane.

[0046] In addition to removing the calcific shell by negative pressure, it is also possible to remove the calcific shell lid by applying adhesive pads, freezing it to a cooled stamp or inserting needles or cutting tools into the area of the canal structure.

[0047] The perforations can advantageously be point-shaped or linear and can be arranged symmetrically or rotationally symmetrically in the local area of the channel structure.

[0048] It has been found that the structural and mechanical properties of the calcareous shell change during incubation and embryonic development. While immediately after fertilization, the calcareous shell still exhibits ductile properties with low porosity, the mechanical strength and porosity of the calcareous shell increase with advancing days of incubation. Therefore, depending on the mechanical properties of the calcareous shell, it is recommended that the egg be opened between the 4th and 6th day of incubation to ensure safe and chip-free egg opening for spectroscopic in-ovo sex determination.

[0049] To ensure the position of the air chamber and the associated precise position of the egg's opening, an advantageous embodiment of the method proposes performing a process for positioning the egg with the air chamber facing upwards and determining its exact position by measurement. This is intended to ensure that the inner shell membrane is neither damaged nor affected by possible pyrolysis products when the egg is opened.

[0050] The invention is explained in more detail below using an exemplary embodiment. Example

[0051] For in-ovo sex determination using fluorescence signals from blood spectra of a chicken egg, the egg to be opened is positioned with the blunt pole facing upward on day 4.5 of incubation, and the position of the air chamber in the egg is subsequently determined. After the position of the air chamber has been determined, a circular channel structure with an inner diameter of 13.8 mm is created in the area of the air chamber beneath the calcareous shell by laser ablation using a CO2 laser. The laser has a maximum power of 30 W and pulse width modulation of 50 kHz for adjusting the average laser power. Furthermore, the working distance is 200 mm, the focal width is 5 mm, and the spot size is 290 µm.To create the circular channel structure, the laser is used to make a total of three complete circular movements, with the first and second circular movements being carried out at a propulsion speed of 50 mm / sec and a third circular movement at a variable speed of > 50 mm / sec to 90 mm / sec. Since the average thickness of the eggshell depends on various environmental influences, the speed of the third circular movement is adjusted according to the results of the opening of previous eggs. If some of the eggs cannot be opened, the speed is reduced; if too many pyrolysis products are present, the speed is increased. The channel structure created in this way has a depth of approximately 320 µm. Subsequently, the same laser is used to create a total of 8 point-shaped perforations within the channel structure, which extend through the calcareous shell and the outer shell membrane.A suction device is then positioned over the circular lid, the egg itself is fixed by a corresponding device and then the lid is removed together with the essentially identical and circularly separated outer shell membrane.

Claims

[1] Method for opening an egg which contains at least one calcareous shell and an air chamber enclosed by an outer shell membrane and an inner shell membrane, in which a substantially closed channel structure is created in the calcareous shell in a surface area which is substantially above the air chamber by means of a laser by ablating the calcareous shell material and the depth of the channel structure is gradually increased with variable laser propulsion speeds, subsequently at least two perforations are created in the calcareous shell and the outer shell membrane at least in the local area of the created channel structure, and finally the calcareous shell and the outer shell membrane are removed in one operation. [2] Method according to claim 1, wherein the course of the channel structure is formed closed. [3] Method according to claim 1, wherein the channel structure is formed as a circle, oval, rectangle, square, meander shape or as a polygon. [4] Method according to claim 1, in which the removal of the calcareous shell material and / or the creation of the perforations is carried out by sublimation processes. [5] Method according to claim 1, in which a CO2 laser is used to produce the channel structure and the perforations. [6] Method according to claim 1, wherein the laser is used with an average output power of 10 W to 1000 W and a pulse energy of 1 mJ to 1 J. [7] Method according to claim 1, in which a laser with a focus range of 1 to 50 mm and a spot size of 0.05 mm to 0.5 mm is used. [8] Method according to claim 1, wherein the channel structure is produced with a laser propulsion speed of 10 mm / s to 500 mm / s. [9] Method according to claim 1, in which point-shaped and / or line-shaped perforations are produced which are arranged symmetrically or rotationally symmetrically in the channel structure. [10] Method according to claim 1, wherein the removal of the calcareous shell and the outer shell membrane is carried out by a device generating a negative pressure, adhesive pads, freezing the calcareous shell lid to a cooled stamp, by means of needles and / or cutting. [11] Method according to claim 1, in which, before the calcareous shell material is removed, the egg is positioned and aligned in order to determine the position of the air chamber in the closed egg. [12] Use of the method according to claim 1 for spectroscopic in-ovo sex determination, in which the egg is opened between the 4th and 6th day of incubation.