Artificial propagation and hybridization combined breeding method for meat goats

Abstract

The present application discloses an artificial propagation-hybridization combined breeding method for meat goats, which relates to the technical field of animal breeding. The specific steps include: selecting a goat breed with good meat performance as the maternal parent and selecting a goat breed with a large body as the paternal parent; culturing the maternal oocytes in vitro to mature oocytes containing the first polar body, using a temperature gradient screening device to screen out highly motile sperm, fertilizing the mature oocytes with the highly motile sperm in vitro, culturing them to a hybrid blastocyst morphology, transplanting them into the maternal body to develop until natural delivery, and obtaining a hybrid F1 generation; backcrossing the F1 generation with the maternal parent, and backcrossing the backcross offspring with the maternal parent multiple times until the breeding goal is met, and then cross-crossing and fixing them to obtain a new breed / line with excellent traits; improving the sperm screening efficiency by utilizing the screening device, ensuring the quality of the screened sperm, and thus significantly improving the fertilization efficiency and embryo survival rate.

Description

Technical Field

[0001] The present invention relates to the field of animal breeding, in particular to a combined artificial breeding-hybridization breeding method for meat goats. Background Art

[0002] In the breeding practice of meat goats, traditional hybrid breeding methods occupy a dominant position. However, this method has obvious limitations. First, due to the limitation of the number of embryos in the natural reproduction process of animals, the number of offspring produced each time by traditional hybrid breeding is limited, resulting in a long breeding cycle and difficulty in quickly responding to market demand. Secondly, after the sperm that has not been strictly screened combines with the oocyte, the quality of the fertilized eggs formed is uneven, and the embryo survival rate is low, which further affects the breeding efficiency. In addition, the application of existing artificial assisted reproductive technology in meat goat breeding is still immature, especially in terms of sperm quality control, fertilization efficiency and embryo survival rate. There are still many challenges.

[0003] For example, the Chinese patent application number CN202010432054.0 is about a method for artificial propagation and hybridization of meat goats. This invention belongs to the field of animal breeding, and specifically relates to a method for artificial propagation and hybridization of meat goats. The method comprises selecting a goat breed with good meat performance as the maternal parent and selecting a goat breed with a large physique as the paternal parent; culturing the maternal oocytes in vitro to mature oocytes containing the first polar body, and treating the paternal semen with a sperm motility enhancement solution to prepare a sperm suspension; fertilizing the mature oocytes and the sperm suspension in vitro, culturing them to the hybrid blastocyst form, and transplanting them into the maternal body so that the hybrid blastocyst develops in the maternal body until natural delivery, thereby obtaining a hybrid F1 generation; the F1 generation is backcrossed with the maternal parent, and the backcross offspring are backcrossed with the maternal parent multiple times until the breeding goal is met, and then cross-crossing is fixed to obtain a new breed / line with excellent traits. This invention combines artificial assisted reproductive technology with traditional hybridization technology, which can increase the number of animal embryos and improve the survival rate of animal embryos, and has good application prospects in the field of animal breeding.

[0004] In the above method, sperm motility enhancement liquid is used to treat sperm, but the treated sperm is not screened, and the quality is uneven, which affects the subsequent fertilization efficiency and embryo survival rate. Summary of the Invention

[0005] The embodiment of the present application solves the problem in the prior art that sperm quality is uneven, affecting subsequent fertilization efficiency and embryo survival rate, by providing an artificial breeding-hybridization combined breeding method for meat goats. The temperature gradient screening device is used to improve the sperm screening efficiency, ensure the quality of the screened sperm, and thus significantly improve the fertilization efficiency and embryo survival rate.

[0006] The present invention provides a method for artificial breeding and hybridization of meat goats, which specifically includes the following steps:

[0007] S1. Select goat breeds with good meat performance as female parents and goat breeds with large physique as male parents;

[0008] S2, culturing the isolated maternal oocyte in vitro until it becomes a mature oocyte containing the first polar body, and setting aside;

[0009] S3, fertilizing the mature oocytes with the selected high-motility sperm in vitro, culturing the fertilized eggs in vitro until they form hybrid blastocysts, and finally transplanting the hybrid blastocysts into the mother's body, allowing the hybrid blastocysts to develop in the mother's body until natural delivery, thereby obtaining the hybrid F1 generation;

[0010] The screening of high-motility sperm is as follows: a sperm suspension is placed in a screening device, and the sperm are driven by the temperature gradient to swim toward the end of the pipe. The sperm are observed in the counting area at the end of the screening device. When 30% of the sperm are counted, the screening is stopped and the high-motility sperm are collected;

[0011] S4. Select an individual with excellent comprehensive traits from the hybrid F1 generation as the male parent, and backcross it with the female parent. The backcross steps refer to S2-S3 to obtain the backcross generation;

[0012] S5. Repeat the steps of S4, i.e. backcross the backcross offspring with the mother parent multiple times until the breeding goal is met, and then cross-cross and fix it to obtain a new variety / line with excellent traits.

[0013] Furthermore, the screening device is set as a 10 cm long pipe, the temperature at the starting end of the pipe is set to 36.5°C, the temperature at the end end is set to 37.5°C, and five temperature zones of 36.5°C, 36.75°C, 37.0°C, 37.25°C and 37.5°C are set in the middle, and the temperature increases successively to form a temperature gradient.

[0014] Furthermore, the screening device is heated at 36.5°C, 37°C, and 37.5°C to maintain a temperature gradient, and both ends of the pipe are counting areas for observing and counting sperm.

[0015] Furthermore, the screening device is also provided with an injection pipeline.

[0016] Furthermore, the screening of highly motile sperm is specifically as follows: the sperm suspension is placed in a screening device, and observed in the counting area at the terminal end of the screening device. When sperm appear in the counting area at the terminal end, polyethylene glycol is quickly injected through the injection pipe of the screening device, and the terminal end counting area is continued to be observed until 30% of the sperm are counted and the screening is stopped to collect the highly motile sperm.

[0017] Furthermore, the injection pipe is arranged in the middle position of the upper part of the screening device, the concentration of polyethylene glycol is 35%-40%, and the injection amount is 4%-6% of the sperm suspension.

[0018] Furthermore, the screening device is arranged in the screening box, and the screening device can rotate around its central axis.

[0019] Furthermore, an injector is provided at the middle position of the upper part of the screening device, and the inside of the injector is filled with polyethylene glycol.

[0020] Furthermore, the injector is a capsule made of flexible material, which can expand and contract. A magnet is arranged on the upper part of the injector, and a corresponding magnet is arranged at the corresponding position of the screening box, and the magnetic poles of the two magnets repel each other.

[0021] Furthermore, the screening of highly motile sperm is specifically as follows: the sperm suspension is placed in the screening device and observed in the counting area at the terminal end of the screening device. When sperm appears in the counting area at the terminal end, the screening device rotates. The injector is in an expanded state in the initial state. When the magnet of the injector rotates to correspond to the magnet on the upper part of the screening box, the magnetic poles repel each other, the injector contracts, and polyethylene glycol is injected into the screening device. The counting area at the terminal end is continued to be observed until 30% of the sperm are counted. Then the screening is stopped and the highly motile sperm are collected.

[0022] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0023] First, through the difference in sperm's swimming ability under a specific temperature gradient, high-motility sperm can be screened. Sperm is most active when it is close to the normal human body temperature of 37°C. Therefore, by setting a temperature gradient and taking advantage of sperm's sensitivity to temperature, sperm can be guided to swim to areas with higher temperatures. By observing and counting the proportion of sperm reaching the end of the pipe, sperm with higher motility can be screened out. Through temperature gradient screening, the sperm that can be used for fertilization are the most active, thereby significantly improving the overall quality of sperm. Using high-motility sperm for in vitro fertilization can increase the success rate of sperm-egg combination, thereby improving the fertilization rate. At the same time, Due to high sperm quality, fertilized eggs are more likely to develop into healthy hybrid blastocysts during in vitro culture, thereby improving embryo survival rates. Highly motile sperm improves fertilization and embryo survival rates, reducing early embryonic death caused by low sperm quality. This shortens breeding cycles, improves breeding efficiency, and more quickly yields new breeds / lines that meet breeding goals. Using screened, highly motile sperm for hybridization can more stably transmit the superior genetic traits of both the paternal and maternal parents to offspring, enhancing the meat performance, physique, and other important traits of the new breed / line while also increasing its genetic stability and consistency.

[0024] Secondly, by setting up a heat dissipation area above the screening device, a temperature gradient is also formed in the longitudinal direction inside the device, providing a more complex and precise temperature environment for sperm; the introduction of the longitudinal temperature gradient makes the swimming path of sperm more diverse during the screening process, and sperm of different motility will show the best state in their respective suitable temperature ranges, making it easier to be accurately screened; sperm's swimming ability and directionality will change under temperature stimulation at different heights. This change provides more information for screening, thereby more accurately identifying highly motile sperm; the longitudinal temperature gradient makes the difference in sperm's swimming ability in different temperature zones more obvious, thereby speeding up the screening process. The screening device can more quickly identify sperm that can quickly adapt to and swim to the higher temperature zone on the right, that is, highly motile sperm; single gradient screening is slow and there is a problem of missing highly motile sperm, while the introduction of the longitudinal temperature gradient provides a more refined screening environment for sperm, which can capture more potential high-quality sperm and avoid the problem of missing high-quality sperm due to improper screening conditions;

[0025] Third, by introducing the combined effects of polyethylene glycol and temperature gradient, the accuracy and efficiency of screening are further improved, thereby improving breeding efficiency. By providing an injection pipe in the middle of the upper portion of the screening device and rapidly injecting polyethylene glycol when sperm appear in the terminal counting area, Example 3 can accurately screen out highly motile sperm. By changing the viscosity and fluidity of the liquid environment, and forming a concentration gradient and microfluid flow, the efficiency of screening and the fertilization rate are effectively improved. During the screening process, low-motility sperm are blocked on the left, while high-motility sperm can follow the liquid flow and move toward the high-temperature zone at a higher rate. This screening method not only avoids interference from low-motility sperm, but also ensures the effective collection of high-motility sperm, thereby improving the fertilization rate and breeding efficiency, and promoting new varieties / lines with more stable genetic characteristics.

[0026] Fourthly, by introducing a rotatable screening device and a magnetically controlled injector, precise injection of polyethylene glycol is achieved, which not only ensures the stability of the injection, but also changes the chemical potential energy in the sperm suspension, provides rotational flow, and accelerates the movement of highly motile sperm; utilizing the principle of magnetic pole repulsion, when the magnet of the injector rotates to correspond to the upper magnet of the screening box, a repulsive force is generated, causing the injector to contract, thereby precisely injecting polyethylene glycol into the screening device, ensuring precise control of the injection time and amount. The rotation of the screening device not only provides a dynamic screening environment for sperm, but also accelerates the movement of sperm, especially the movement of highly motile sperm, through the centrifugal force and centripetal force generated by the rotation, further intensifying the separation of sperm with different motility, thereby improving the accuracy and efficiency of screening. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1Schematic diagram of a screening device according to embodiment 1 of the present invention;

[0028] Figure 2 This is a schematic diagram of a screening device according to a second embodiment of the present invention;

[0029] Figure 3 Schematic diagram of a screening device according to embodiment 3 of the present invention;

[0030] Figure 4 Schematic diagram of a screening device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0031] To facilitate understanding of the present invention, the present application will be described more comprehensively below with reference to the relevant drawings; the drawings show preferred embodiments of the present invention, but the present invention can be implemented in many different forms and is not limited to the embodiments described herein; on the contrary, the purpose of providing these embodiments is to enable a more thorough and comprehensive understanding of the disclosed content of the present invention.

[0032] It should be noted that the terms “vertical”, “horizontal”, “up”, “down”, “left”, “right” and similar expressions used in this document are for illustrative purposes only and do not represent the only implementation method.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains; the terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0034] Example 1: A method for artificial breeding and hybridization of meat goats, comprising the following steps:

[0035] S1. Select goat breeds with good meat performance as female parents and goat breeds with large physique as male parents;

[0036] S2, culturing the isolated maternal oocyte in vitro until it becomes a mature oocyte containing the first polar body, and setting aside;

[0037] The paternal in vitro semen was soaked in sperm motility enhancement solution for 30-40 minutes, centrifuged at 2000 rpm for 10-15 minutes, the sperm pellet was washed with sperm motility enhancement solution, and centrifuged again at 2000 rpm for 10-15 minutes. Finally, the pellet was suspended in sperm supernatant to prepare a sperm suspension.

[0038] The formula of sperm motility enhancement solution is as follows: embryo culture water 97ml, MgSO4·7H2O 0.02-0.03g, KCl 0.05-0.06g, streptomycin 0.005g, penicillin 0.006g, NaHCO3 0.04-0.05g, sodium pyruvate 0.004g, CaCl2·2H2O 0.02g, FBS 3ml;

[0039] Screening of high motility sperm, specifically: Figure 1 As shown, a sperm suspension is placed in a screening device. Driven by the temperature gradient, the sperm swim toward the end of the pipe and are observed in the counting area at the end of the screening device. When 30% of the sperm are counted, the screening is stopped and the highly motile sperm are collected.

[0040] The screening device is set as a 10 cm long pipe. The temperature at the starting end of the pipe is set to 36.5°C, the temperature at the end is set to 37.5°C, and five temperature zones are set in the middle: 36.5°C, 36.75°C, 37.0°C, 37.25°C and 37.5°C. The temperature increases in sequence to form a temperature gradient. Heating is performed at 36.5°C, 37°C and 37.5°C to maintain the temperature gradient. The two ends of the pipe are counting areas for observing and counting sperm.

[0041] S3, fertilizing the mature oocytes with the selected high-motility sperm in vitro, culturing the fertilized eggs in vitro until they form hybrid blastocysts, and finally transplanting the hybrid blastocysts into the mother's body, allowing the hybrid blastocysts to develop in the mother's body until natural delivery, thereby obtaining the hybrid F1 generation;

[0042] S4. Select an individual with excellent comprehensive traits from the hybrid F1 generation as the male parent, and backcross it with the female parent. The backcross steps refer to S2-S3 to obtain the backcross generation;

[0043] S5. Repeat the steps of S4, i.e. backcross the backcross offspring with the mother parent multiple times until the breeding goal is met, and then cross-cross and fix it to obtain a new variety / line with excellent traits.

[0044] The following experiments were performed for this embodiment:

[0045] S1. Select Lüliang Black Goats with good meat performance as the female parent, and select Jintang Black Goats with large physique as the male parent;

[0046] S2. (1) The maternal oocytes are treated with conventional ovulation induction, and the isolated maternal oocytes are cultured in vitro until they become mature oocytes containing the first polar body, and a total of 13 mature oocytes are collected for future use; (2) The paternal semen is collected in a conventional manner, and after being soaked in a sperm motility enhancement solution, a sperm suspension is prepared, and the sperm suspension is placed in a screening device. Driven by the temperature gradient, the sperm swim toward the end of the pipe, and are observed in the counting area at the end of the screening device. When 30% of the sperm are counted, the screening is stopped and the highly motile sperm are collected;

[0047] Formula of sperm motility enhancement solution: embryo culture water 97ml, MgSO4·7H2O 0.02g, KCl 0.05g, streptomycin 0.005g, penicillin 0.006g, NaHCO3 0.04g, sodium pyruvate 0.004g, CaCl2·2H2O 0.02g, FBS 3ml, Hepes 0.5g;

[0048] S3, fertilizing the mature oocytes and sperm suspension in vitro using intracytoplasmic sperm injection (ICSI), culturing the fertilized eggs in vitro until they form hybrid blastocysts, and finally transplanting the hybrid blastocysts into the mother's body, allowing the hybrid blastocysts to develop in the mother's body until natural birth, thereby obtaining hybrid F1 generations; it should be noted that step S3 uses conventional ICSI methods, conventional hybrid blastocyst culture and transplantation methods;

[0049] S4. Select an individual with excellent comprehensive traits from the hybrid F1 generation as the male parent, and backcross it with the female parent. The backcross steps refer to S2-S3 to obtain the backcross generation;

[0050] S5. Repeat the steps of S4, i.e. backcross the backcross offspring with the mother parent multiple times until the breeding goal is met, and then cross-cross and fix it to obtain a new variety (line) with excellent traits.

[0051] The comparative example adopts the combined breeding method with application number CN202010432054.0. The difference from the experiment in this embodiment is that no screening device is used to screen high-motility sperm.

[0052] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0053] Highly motile sperm can be screened by measuring the difference in sperm motility under specific temperature gradients. Sperm is most active when it is close to the normal human body temperature of 37°C. Therefore, by setting a temperature gradient and taking advantage of sperm's sensitivity to temperature, sperm can be guided to swim towards areas with higher temperatures. By observing and counting the proportion of sperm that reach the end of the tube, sperm with higher motility can be screened.

[0054] Through temperature gradient screening, the sperm that can be used for fertilization are the most active part, thereby significantly improving the overall quality of sperm; using high-motility sperm for in vitro fertilization can increase the success rate of sperm-egg combination, thereby improving the fertilization rate. At the same time, due to the high sperm quality, the fertilized egg is more likely to develop into a healthy hybrid blastocyst during in vitro culture, thereby improving the embryo survival rate; because high-motility sperm improves the fertilization rate and embryo survival rate, and reduces the early embryo death caused by low sperm quality, it can shorten the breeding cycle, improve breeding efficiency, and obtain satisfaction more quickly. New varieties / lines as breeding targets; using screened high-motility sperm for hybridization cultivation can more stably pass on the excellent genetic characteristics of the father and mother to the offspring, enhance the meat performance, physique and other important traits of the new varieties / lines, and at the same time, enhance the genetic stability and consistency of the new varieties / lines; this method combines artificial assisted reproductive technology and traditional hybridization technology, and further optimizes the sperm quality by introducing the step of temperature gradient screening for high-motility sperm, which not only improves the sperm quality and fertilization rate, but also optimizes the breeding efficiency and enhances the genetic advantages of the new varieties / lines.

[0055] Example 2: The above-mentioned Example 1 introduces a screening device to screen high-motility sperm, which not only improves the quality and fertilization rate of sperm, but also optimizes breeding efficiency and enhances the genetic advantages of new varieties / lines. In order to further improve the sperm quality and fertilization rate, further improvements are made on the basis of Example 1.

[0056] like Figure 2 As shown, a heat dissipation area is set above the screening device so that the upper temperature of each temperature area is 0.25°C lower than the temperature of the lower temperature area, forming a temperature gradient in the longitudinal direction.

[0057] The experiment of this embodiment was conducted on the basis of the experiment of the first embodiment. The difference between the experiment of this embodiment and the experiment of the first embodiment is that a temperature gradient is set in the longitudinal direction of the screening device.

[0058] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0059] By setting up a heat dissipation area above the screening device, a temperature gradient is formed in the longitudinal direction inside the device, providing a more complex and delicate temperature environment for sperm;

[0060] The introduction of a longitudinal temperature gradient makes the swimming paths of sperm more diverse during the screening process. Sperm of different motility will perform at their best within their respective suitable temperature ranges, making them easier to accurately screen. Under temperature stimulation at different heights, the swimming ability and directionality of sperm will change. This change provides more information for screening, allowing for more accurate identification of highly motile sperm. The longitudinal temperature gradient makes the differences in sperm swimming ability in different temperature zones more obvious, thereby speeding up the screening process. The screening device can more quickly identify sperm that can quickly adapt and swim to the higher temperature zone on the right, i.e., highly motile sperm. Single gradient screening is slow and has the problem of missing highly motile sperm. The introduction of a longitudinal temperature gradient provides a more refined screening environment for sperm, which can capture more potential high-quality sperm and avoid the problem of missing high-quality sperm due to inappropriate screening conditions.

[0061] By more accurately screening out highly motile sperm, the fertilization rate and breeding efficiency are improved. The success rate of highly motile sperm combining with oocytes is higher, and the fertilized eggs are more likely to develop into healthy hybrid blastocysts during in vitro culture. Since the screening process is more efficient and accurate, the breeding cycle is shortened and the cultivation speed of new varieties / lines is accelerated. Using precisely screened highly motile sperm for hybrid culture can more stably pass on the excellent genetic characteristics of the father and mother to the offspring, thereby enhancing the meat performance, physique and other important traits of the new variety / line, and improving its genetic stability and consistency.

[0062] Example 3: The above-mentioned Example 2 improves the accuracy and efficiency of screening by introducing a longitudinal temperature gradient to screen high-motility sperm, avoids the problem of omission, and thus improves the fertilization rate and breeding efficiency. In order to further improve the sperm quality and fertilization rate, further improvements are made on the basis of Example 2.

[0063] The screening device is also provided with an injection pipeline;

[0064] Screening of high motility sperm, specifically: Figure 3 As shown, a sperm suspension is placed in a screening device and observed in the counting area at the terminal end of the screening device. When sperm appear in the counting area at the terminal end, polyethylene glycol is quickly injected through the injection pipe of the screening device. The terminal end counting area is continuously observed until 30% of the sperm are counted. Then, screening is stopped and highly motile sperm are collected.

[0065] The injection pipeline is arranged in the middle position of the upper part of the screening device, the concentration of polyethylene glycol is 35%-40%, and the injection amount is 4%-6% of the sperm suspension.

[0066] This embodiment was conducted on the basis of the experiment in Example 2. The difference between this embodiment and Example 2 is that when sperm appears in the counting area at the end point, polyethylene glycol is quickly injected through the injection pipe of the screening device. The concentration of polyethylene glycol is 38%, and the injection amount is 5% of the sperm suspension.

[0067] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0068] When sperm first appears in the counting area at the end point, polyethylene glycol is injected into the pipe through the injection pipe set in the middle position of the upper part of the screening device. The injection of polyethylene glycol increases the concentration of the liquid in the pipe, making it more viscous, which further affects the swimming ability and direction of the sperm. The change in viscosity affects the flow characteristics of the liquid, forming a micro-fluid flow. In the micro-fluid flow, the diffusion and movement of sperm are affected by the driving force of the fluid. Sperm is sensitive to temperature and will show different swimming abilities under specific temperature gradients. The injection of polyethylene glycol further affects the swimming behavior of sperm under this temperature gradient, affecting the swimming speed and direction of sperm by changing the viscosity and fluidity of the liquid environment. In a viscous liquid environment, sperm, as tiny biological molecules, will be affected by molecular potential energy. Sperm with medium and low motility are more easily blocked by the viscous liquid environment due to their low molecular potential energy, while sperm with high motility can overcome this resistance and continue to move to the high-temperature zone.

[0069] The injection of polyethylene glycol creates a concentration gradient within the tube. The high-concentration liquid area exerts pressure on the sperm, making it more difficult for low-motility sperm to pass through the high-concentration area and being blocked on the left. The combined effects of the concentration difference and temperature gradient create microfluidic flows within the tube, which encourage sperm to diffuse toward the high-temperature area and increase their driving force. Under the influence of the microfluidic flow, sperm are affected by their molecular potential energy and rheotaxis. Sperm with medium and low motility are more likely to be blocked or deviate from the mainstream due to their lower potential energy. High-motility sperm, on the other hand, can follow the flow and move toward the high-temperature area at a higher rate, further improving the accuracy and efficiency of screening.

[0070] By introducing the combined effects of polyethylene glycol and temperature gradient, the accuracy and efficiency of screening are further improved, thereby improving breeding efficiency; by setting an injection pipe in the middle position of the upper part of the screening device and quickly injecting polyethylene glycol when sperm appears in the terminal counting area, Example 3 can accurately screen out highly motile sperm; by changing the viscosity and fluidity of the liquid environment, and forming a concentration gradient and micro-liquid flow, the efficiency of screening and fertilization rate are effectively improved. During the screening process, low-motility sperm are blocked on the left, while high-motility sperm can follow the liquid flow and move to the high-temperature zone at a higher rate. This screening method not only avoids interference from low-motility sperm, but also ensures the effective collection of high-motility sperm, thereby improving fertilization rate and breeding efficiency, and promoting new varieties / lines to have more stable genetic characteristics.

[0071] Example 4: The above Example 3 improves the accuracy and efficiency of screening, and improves the fertilization rate and breeding efficiency by introducing an injection pipe and injecting polyethylene glycol at the right time. In order to further improve the sperm quality and fertilization rate, further improvements are made on the basis of Example 3.

[0072] like Figure 4 As shown, the screening device is arranged in the screening box and can rotate around its central axis; an injector is arranged in the middle position of the upper part of the screening device, and the injector is filled with polyethylene glycol. The injector is a capsule made of flexible material and can expand and contract. A magnet is arranged on the upper part of the injector, and a corresponding magnet is arranged at the corresponding position of the screening box. The magnetic poles of the two magnets repel each other.

[0073] The screening of high-motility sperm is specifically as follows: the sperm suspension is placed in the screening device and observed in the counting area at the terminal end of the screening device. When sperm appears in the counting area at the terminal end, the screening device rotates. The injector is in an expanded state in the initial state. When the magnet of the injector rotates to correspond to the magnet on the upper part of the screening box, the magnetic poles repel each other, the injector contracts, and polyethylene glycol is injected into the screening device. The counting area at the terminal end is continued to be observed until 30% of the sperm are counted. Then the screening is stopped and the high-motility sperm are collected.

[0074] This embodiment was experimented on the basis of the experiment in Example 3. The difference between this embodiment and Example 3 is that when sperm appears in the counting area at the terminal end, the screening device rotates. In the initial state, the injector is in an expanded state. When the magnet of the injector rotates to correspond to the magnet on the upper part of the screening box, the magnetic poles repel each other, the injector contracts, and polyethylene glycol is injected into the screening device.

[0075] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0076] By introducing a rotatable screening device and a magnetically controlled injector, precise injection of polyethylene glycol is achieved, which not only ensures the stability of the injection, but also changes the chemical potential energy in the sperm suspension, provides a rotational flow, and accelerates the movement of highly motile sperm. Utilizing the principle of magnetic pole repulsion, when the magnet of the injector rotates to correspond to the magnet on the upper part of the screening box, a repulsive force is generated, causing the injector to contract, thereby precisely injecting polyethylene glycol into the screening device, ensuring precise control of the injection time and amount. The rotation of the screening device not only provides a dynamic screening environment for sperm, but also accelerates the movement of sperm, especially highly motile sperm, through the centrifugal and centripetal forces generated by the rotation, further intensifying the separation of sperm with different motility, thereby improving the accuracy and efficiency of screening.

[0077] The magnetically controlled injector ensures that polyethylene glycol is injected at the precise moment and location, avoiding the errors and instabilities that may arise from manual injection, thereby improving the accuracy and repeatability of screening. The rotation of the screening device provides a dynamic screening environment for sperm, which more realistically simulates the swimming state of sperm in the body, thereby more accurately screening highly motile sperm. The rotating flow not only increases the contact area between the sperm and the screening device, but also accelerates the movement of sperm, especially highly motile sperm, through the effects of centrifugal and centripetal forces, thereby shortening the screening time and improving the screening efficiency.

[0078] Because the selected sperm is of higher quality and more motile, its success rate in fertilizing oocytes is also higher, and the fertilized eggs are more likely to develop into healthy hybrid blastocysts during in vitro culture. This not only improves fertilization rates but also shortens breeding cycles and increases breeding efficiency. Using precisely selected, highly motile sperm for hybridization can more stably transmit the excellent genetic characteristics of both paternal and maternal parents to offspring, thereby enhancing the meat performance, physique, and other important traits of the new breed / line, and improving its genetic stability and consistency.

[0079] Performance test: The sperm quality of the comparative example and Examples 1 to 4 was tested, and the results are shown in the following table:

[0080]

[0081]

[0082] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for artificial breeding and hybridization of meat goats, characterized in that: The specific steps include: S1. Select goat breeds with good meat performance as female parents and goat breeds with large physique as male parents; S2, culturing the isolated maternal oocyte in vitro until it becomes a mature oocyte containing the first polar body, and setting aside; S3, fertilizing the mature oocytes with the selected high-motility sperm in vitro, culturing the fertilized eggs in vitro until they form hybrid blastocysts, and finally transplanting the hybrid blastocysts into the mother's body, allowing the hybrid blastocysts to develop in the mother's body until natural delivery, thereby obtaining the hybrid F1 generation; The screening of high-motility sperm is specifically as follows: a sperm suspension is placed in a screening device, an injection pipe is provided in the screening device, and observation is performed in a counting area at the terminal end of the screening device. When sperm appear in the counting area at the terminal end, polyethylene glycol is quickly injected through the injection pipe of the screening device. The terminal end counting area is continuously observed until 30% of the sperm are counted. Then, screening is stopped and high-motility sperm are collected. The injection pipe is set in the middle of the upper part of the screening device. The concentration of polyethylene glycol is 35%-40%, and the injection volume is 4%-6% of the sperm suspension. The screening device is arranged in the screening box, and the screening device can rotate around its central axis; An injector is provided at the middle position of the upper part of the screening device, and the inside of the injector is filled with polyethylene glycol; S4. Select an individual with excellent comprehensive traits from the hybrid F1 generation as the male parent, and backcross it with the female parent. The backcross steps refer to S2-S3 to obtain the backcross generation; S5. Repeat the steps of S4, i.e. backcross the backcross offspring with the mother parent multiple times until the breeding goal is met, and then cross-cross and fix it to obtain a new variety / line with excellent traits.

2. The artificial breeding-hybridization combined breeding method for meat goats according to claim 1, wherein: The screening device is set as a 10 cm long pipe. The temperature at the starting end of the pipe is set to 36.5℃, the temperature at the end end is set to 37.5℃, and five temperature zones are set in the middle at 36.5℃, 36.75℃, 37.0℃, 37.25℃ and 37.5℃. The temperature increases successively to form a temperature gradient.

3. The artificial breeding-hybridization combined breeding method for meat goats according to claim 2, wherein: The screening device is heated at 36.5°C, 37°C, and 37.5°C to maintain a temperature gradient, and both ends of the pipe are counting areas for observing and counting sperm.

4. The artificial breeding-hybridization combined breeding method for meat goats according to claim 1, wherein: The injector is a capsule made of flexible material that can expand and contract. A magnet is set on the top of the injector, and a corresponding magnet is set at the corresponding position of the screening box. The magnetic poles of the two magnets repel each other.

5. The artificial breeding-hybridization combined breeding method for meat goats according to claim 1, wherein: The screening of high-motility sperm is specifically as follows: the sperm suspension is placed in the screening device and observed in the counting area at the terminal end of the screening device. When sperm appears in the counting area at the terminal end, the screening device rotates. The injector is in an expanded state in the initial state. When the magnet of the injector rotates to correspond to the magnet on the upper part of the screening box, the magnetic poles repel each other, the injector contracts, and polyethylene glycol is injected into the screening device. The terminal end counting area is continued to be observed until 30% of the sperm are counted. Then the screening is stopped and the high-motility sperm are collected.

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