Method for breeding new variety of black pigs in Sichuan country

Abstract

The invention relates to a method for breeding a new variety of Sichuan rural black pigs. Belongs to the technical field of breeding and breeding. The method includes the steps that Duroc pigs are used as male parents, Tibetan pigs are used as female parents, and grading hybridization is carried out until F4 generation hybridization is achieved; crossbreeding the F4-generation boars and the F4-generation sows to establish a zero-generation basic pig herd; carrying out closed breeding on the zero-generation basic swinery, and carrying out breeding on each generation until the fifth generation; wherein the breeding mode of each generation comprises the following steps: breeding the pig individuals of the generation based on the numerical value of the BLUP comprehensive selection index of the individual, carrying out hair color SNP locus genotype detection on the pig individuals of the generation through a Snapshot technology, and rejecting the pig individuals with black heterozygous genotypes in the pig herd; and determining the pig individuals of the fifth generation as the new male parent variety of the Sichuan-rural black pigs. As a male parent, the Sichuan rural black pigs bred by the method have the advantages of pure black hair color, excellent meat quality, high production efficiency and the like.

Description

Technical Field

[0001] The invention relates to the technical field of breeding and cultivation, in particular to a method for cultivating a new variety of Sichuan black pigs. Background Art

[0002] my country has abundant pig breed resources, and their meat is tender and delicious (especially Tibetan pigs: high intramuscular fat content and fine muscle fibers). However, they have shortcomings such as slow growth, low lean meat rate, and below-average reproductive capacity. They cannot adapt to the development needs of efficient pig production and the growing market demand for high-quality pork.

[0003] In order to improve the production performance of pigs, they must be hybridized with efficient paternal breeds. At present, the paternal breeds used for high-quality pig production generally adopt the method of introducing Duroc or Berkshire pigs. This method has the following problems: First, the production process of high-quality pigs involves using foreign breed pigs as sires, and the introduction of foreign breed pigs also has the problem of high costs.

[0004] Second, these introduced pigs will have obvious coat color separation when crossbred with local pigs, seriously affecting the commercial value of high-quality pigs. Summary of the invention

[0005] In order to solve the above-mentioned problems in the prior art, the present invention provides a method for breeding a new variety of Sichuan black pigs.

[0006] In a first aspect, the present application provides a method for breeding a new variety of Chuanxiang black pigs, comprising: using Duroc pigs as the paternal parent and Tibetan pigs as the maternal parent for progressive hybridization to the hybrid F4 generation; cross-crossing the boars and sows of the hybrid F4 generation to form a zero-generation basic pig herd; conducting closed breeding of the zero-generation basic pig herd, and selecting and breeding each generation until the fifth generation; wherein the method of selecting and breeding each generation comprises: selecting and breeding the pig individuals of that generation based on the value of the individual BLUP comprehensive selection index, and performing coat color SNP site genotype detection on the pig individuals of that generation through the Snapshot technology, and eliminating the pig individuals with the black heterozygous genotype in the pig herd; determining the pig individuals of the fifth generation as the paternal new variety of Chuanxiang black pigs; wherein the method of selecting and breeding each generation also comprises: detecting different SNP sites of the CAV1 gene of the pig individuals of that generation through the Snapshot technology, and breeding pig individuals with the GG genotype, or detecting the VRTN gene of the pig individuals of that generation through the PCR technology, and breeding pig individuals with the ins / ins genotype.

[0007] Optionally, the progressive hybridization with Duroc pig as the sire and Tibetan pig as the maternal parent to the hybrid F4 generation includes: hybridization with Duroc pig second generation S04 as the sire and Tibetan pig as the maternal parent to obtain hybrid F1 generation; continuing to hybridize with Duroc pig second generation S04 as the sire and sow of hybrid F1 generation as the maternal parent to obtain hybrid F2 generation; hybridization with Duroc pig third generation S04 as the sire and sow of hybrid F2 generation as the maternal parent to obtain hybrid F3 generation; hybridization with Duroc pig fourth generation S04 as the sire and sow of hybrid F3 generation as the maternal parent to obtain hybrid F4 generation.

[0008] Optionally, the breeding of each generation includes: the breeding of individual pigs of that generation includes three stages: in the first stage, the pig herd is initially selected, and 1 to 2 purebred boars and 2 to 4 sows are selected from each litter; in the second stage, the pig herd is secondary selected to eliminate individual pigs with slow growth, diseases and genetic defects; in the third stage, the pig herd is finally selected, and individual pigs are selected based on the value of the individual BLUP comprehensive selection index, and the coat color SNP site genotype of the pig individuals of this generation is detected by using the Snapshot technology to eliminate individual pigs with black heterozygous genotype in the pig herd.

[0009] Optionally, the first stage is when the individual pig weighs 30 kg; the second stage is when the individual pig weighs between 30 kg and 100 kg; and the third stage is when the individual pig weighs 100 kg.

[0010] Optionally, the individual BLUP composite selection index is associated with the body weight at age and live backfat thickness corresponding to an individual pig weight of 100 kg.

[0011] Optionally, the individual pigs of this generation are selected based on the values ​​of the individual BLUP comprehensive selection index, including: for each family, selecting sows whose individual BLUP comprehensive selection index is within the top 60%, and selecting boars whose individual BLUP comprehensive selection index is within the top 30%.

[0012] Optionally, the number of sows in the zero-generation basic pig herd is M; the number of boars is N; and the number of different bloodlines is P; wherein the range of M is 150-160; the range of N is 20-30; The range of P is greater than or equal to 10.

[0013] Optionally, the same feeding conditions are used in the selection and breeding process of each generation, and a breeding model is adopted in which sows are bred in autumn and piglets are farrowed in spring.

[0014] The beneficial effects of the present invention include: First, in this application, Duroc pigs are used as the sire and Tibetan pigs are used as the dam for hybridization to the fourth generation (hybridized F4 generation), and the F4 generation boars and sows are cross-crossed to form a zero-generation basic pig herd, and the BLUP method and Snapshot technology are used for generational breeding to prepare a new high-quality sire variety, the Chuanxiang black pig. After testing, the Chuanxiang black pig can combine the advantages of Tibetan pigs and Duroc pigs, retain the carcass performance of the parents, such as back fat thickness, lean meat rate, intramuscular fat content, etc., and the litter size can also be maintained at the same level as that of Duroc. That is, this application proposes a self-developed new sire variety to solve the current situation in which foreign breed pigs are used as sires in the production process of high-quality pigs.

[0015] Second, in this application, the Snapshot technology is used to perform coat color SNP site genotype detection on individual pigs of this generation, and pigs with black heterozygous genotypes in the herd are eliminated, so as to effectively solve the phenomenon of obvious coat color separation in the hybridization process. That is, in this application, the homozygosity of the black hair genotype of Chuanxiang black pigs is achieved, which effectively solves the technical problem of coat color separation in the production of high-quality black pigs and improves the commercial value of Chuanxiang black pigs.

[0016] In addition, for the breeding of each generation, the present application can also use Snapshot technology to detect different SNP sites of the CAV1 gene of individual pigs of that generation, focus on selecting the GG genotype, increase the frequency of the G gene in the offspring, and achieve the purpose of increasing the intramuscular fat content (IMF); or screen the ins291 site on the VRTN gene for detection, select ins / ins individuals, and eliminate del / del individuals, in order to increase the number of ribs in the group and accelerate the realization of breeding goals.

[0017] In summary, this application provides a method for breeding a self-developed new paternal variety, Chuanxiang black pig, which has the advantages of pure black hair color, excellent meat quality, high production efficiency, etc. It can be used as a paternal parent to crossbreed with current local pig breeds to produce high-quality commercial pigs, meeting people's demand for high-quality and delicious pork consumption market; it can also be used as a terminal paternal parent to crossbreed with foreign pigs to effectively improve the meat quality of commercial pigs, which can be suitable for promotion and application in various regions, and has a very broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A flowchart of the steps of a method for breeding a new variety of Sichuan black pigs provided by an embodiment of the present invention; Figure 2 This is a flow chart of the steps of another method for breeding a new variety of Sichuan black pigs provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0020] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0021] Research has found that in order to improve pig production performance, it is necessary to crossbreed with efficient paternal breeds. Currently, the paternal breeds used for high-quality pig production generally adopt the method of introducing Duroc or Berkshire pigs, which has the following problems: First, the production process of high-quality pigs involves using foreign breed pigs as sires, and the introduction of foreign breed pigs also has the problem of high costs.

[0022] Second, these introduced pigs will have obvious coat color separation when crossbred with local pigs, seriously affecting the commercial value of high-quality pigs.

[0023] In view of the above problems, the present application proposes the following embodiments to solve the above technical problems.

[0024] See also Figure 1 , Figure 1 A method for breeding a new variety of Sichuan black pig provided in an embodiment of the present application includes: steps 101 to 104.

[0025] Step 101: Perform progressive hybridization to the hybrid F4 generation using Duroc pigs as the male parent and Tibetan pigs as the female parent.

[0026] It should be noted that before breeding a new variety of Sichuan black pigs, the breeding materials need to be screened. In the embodiment of the present application, Duroc pigs and Tibetan pigs are used for breeding.

[0027] Tibetan pigs are a plateau type of pigs with all black fur, a delicate body, fine muscle fibers, high intramuscular fat content, and excellent meat quality. We introduced 30 Tibetan pig sows and 8 boar bloodlines, and carried out continuous breeding for 4 generations. The muscle fiber diameter of 60kg body weight is about 64.35µm, and the intramuscular fat content is about 6.71%. When the body weight is 75kg, the muscle fiber diameter is about 65.54µm, and the intramuscular fat content is about 10.12%. The Tibetan pig bloodline is clear and the breed is stable.

[0028] Duroc pigs have high production efficiency and are one of the pig breeds with better meat quality among foreign pigs. They are used as the father in the examples of this application. 50 Duroc sows and 9 boar bloodlines were introduced, and generations of breeding were carried out. By the fourth generation, the body weight reached 100 kg at 164.15 days of age, with a lean meat rate of 64.22% and an intramuscular fat content of 2.88%. Duroc pigs also have clear bloodlines and stable performance.

[0029] Based on the breeding objectives, in the embodiments of the present application, Tibetan pigs and Duroc pigs are selected as breeding materials for cultivating new varieties.

[0030] Then, the Duroc pig was used as the male parent and the Tibetan pig as the female parent for progressive hybridization to the hybrid F4 generation.

[0031] In the embodiment of the present application, the progressive hybridization method adopted can be an orthogonal method, that is, specifically using Duroc pigs as the father and hybridizing with Tibetan pigs, hybridizing F1 generation, hybridizing F2 generation, hybridizing F3 generation, and then hybridizing to hybrid F4 generation.

[0032] Step 102: Cross-breed the F4 generation boars and sows to form a zero-generation basic pig herd.

[0033] That is, the boars and sows of the same generation in the hybrid F4 generation are mated to form a zero-generation basic pig herd.

[0034] Step 103: Conduct closed breeding on the zero-generation basic pig herd and conduct selective breeding on each generation until the fifth generation.

[0035] Among them, the breeding methods for each generation include: breeding the pig individuals of that generation based on the value of the individual BLUP (Best Linear Unbiased Prediction) comprehensive selection index, and performing coat color SNP (Single Nucleotide Polymorphism) site genotype detection on the pig individuals of that generation through Snapshot technology to eliminate pig individuals with black heterozygous genotype in the pig herd.

[0036] It should be noted that by selecting and breeding the pig individuals of this generation based on the value of the individual BLUP comprehensive selection index, the best selection is achieved, that is, the healthy pig individuals with good development performance are selected.

[0037] It should be noted that the Snapshot technology was used to detect the genotype of the coat color SNP loci of the pig individuals of this generation, and the pig individuals with the black heterozygous genotype in the herd were eliminated. Specifically, the 708bp SNP locus of the coat color gene MC1R was detected, among which allele A determines the black coat color of the pig and is dominant.

[0038] Please refer to Table 1. It can be seen from Table 1 that after 0-4 generations of breeding, in the 5th generation of pigs, the frequency of the black dominant homozygous genotype (AA) is 1.00, which means that the non-black recessive genes in the pigs have been completely eliminated, achieving the homozygous black hair genotype in the pigs.

[0039] Table 1 Step 104: Determine the fifth generation pig individual as the paternal new breed of Chuanxiang Black Pig.

[0040] After testing the Chuanxiang black pig, it was found that the pig reached 100kg in weight at 156.60 days, had a feed efficiency of 2.54, a live back fat thickness of 10.25mm, a slaughter rate of 73.78%, a lean meat rate of 63.78%, an eye muscle area of ​​45.74cm2, and an intramuscular fat content of 3.65%, with excellent production performance and meat quality. In addition, the piglet number of Chuanxiang black pigs reached 10.36, which is equivalent to the piglet number of its parent Duroc.

[0041] In summary, the method for breeding a new variety of Sichuan black pigs provided in the embodiments of the present application has the following beneficial effects: First, in this application, Duroc pigs are used as the sire and Tibetan pigs are used as the dam for hybridization to the fourth generation (hybridized F4 generation), and the F4 generation boars and sows are cross-crossed to form a zero-generation basic pig herd, and the BLUP method and Snapshot technology are used for generational breeding to prepare a new high-quality sire variety, the Chuanxiang black pig. After testing, the Chuanxiang black pig can combine the advantages of Tibetan pigs and Duroc pigs, retain the carcass performance of the parents, such as back fat thickness, lean meat rate, intramuscular fat content, etc., and the litter size can also be maintained at the same level as that of Duroc. That is, this application proposes a self-developed new sire variety to solve the current situation in which foreign breed pigs are used as sires in the production process of high-quality pigs.

[0042] Second, in this application, the Snapshot technology is used to perform coat color SNP site genotype detection on individual pigs of this generation, and pigs with black heterozygous genotypes in the herd are eliminated, so as to effectively solve the phenomenon of obvious coat color separation in the hybridization process. That is, in this application, the homozygosity of the black hair genotype of Chuanxiang black pigs is achieved, which effectively solves the technical problem of coat color separation in the production of high-quality black pigs and improves the commercial value of Chuanxiang black pigs.

[0043] In summary, this application provides a method for breeding a self-developed new paternal variety, Chuanxiang black pig, which has the advantages of pure black hair color, excellent meat quality, high production efficiency, etc. It can be used as a paternal parent to crossbreed with current local pig breeds to produce high-quality commercial pigs, meeting people's demand for high-quality and delicious pork consumption market; it can also be used as a terminal paternal parent to crossbreed with foreign pigs to effectively improve the meat quality of commercial pigs, which can be suitable for promotion and application in various regions, and has a very broad application prospect.

[0044] See also Figure 2 Optionally, the above-mentioned progressive hybridization to the hybrid F4 generation using Duroc pig as the male parent and Tibetan pig as the female parent includes: steps 201 to 204.

[0045] Step 201: The second generation Duroc pig S04 is used as the male parent and the Tibetan pig is used as the female parent for hybridization to obtain a hybrid F1 generation.

[0046] Here, the embodiment of the present application provides a specific paternal strain (S04) of Duroc pigs to Sichuan-Tibet black pigs. Generational breeding is performed through Duroc pigs S04. Here, the second generation of Duroc pigs S04 are used as the paternal parent and Tibetan pigs are used as the maternal parent for hybridization to obtain the hybrid F1 generation.

[0047] Step 202: Continue to hybridize the second generation Duroc pig S04 as the sire and the hybrid F1 generation sow as the maternal parent to obtain the hybrid F2 generation.

[0048] In this step, the second generation Duroc pig S04 is continued to be used as the male parent, and then hybridized with the sows of the hybrid F1 generation obtained in step 201.

[0049] Step 203: The third generation Duroc pig S04 is used as the male parent and the hybrid F2 generation sow is used as the female parent to perform hybridization to obtain the hybrid F3 generation.

[0050] In this step, the third generation S04 Duroc pigs that have been bred for generations are used as the male parent and the hybrid F2 generation sows are used as the female parent to obtain the hybrid F3 generation.

[0051] Step 204: hybridize the fourth generation of Rock pig S04 as the male parent and the hybrid F3 generation sow as the female parent to obtain the hybrid F4 generation.

[0052] In this step, the fourth generation S04 of Duroc pigs that have been bred for generations are used as the male parent and the hybrid F3 generation sows are used as the female parent for hybridization to obtain the final hybrid F4 generation.

[0053] Hybridization to the F4 generation in the above manner has the following advantages: First, it can increase genetic diversity. By using S04 strains of different generations to hybridize with Tibetan pigs, more genetic variations can be introduced, increasing the genetic diversity of the offspring. Genetic diversity helps to improve the adaptability and survival ability of the group. Second, S04 strains of different generations have different traits. Through hybridization, their respective advantageous traits can be combined, such as growth rate, meat quality, and disease resistance. Third, by optimizing the hybrid combination, the production efficiency and quality of pork can be improved, bringing higher economic benefits.

[0054] It is understandable that in step 204, Duroc pigs of other new bloodlines may also be introduced, and this application does not limit this.

[0055] Optionally, the above steps include breeding each generation, including: breeding the individual pigs of this generation includes three stages: the first stage, the second stage and the third stage.

[0056] Among them, in the first stage, the pig herd is preliminarily selected, and 1 to 2 purebred boars and 2 to 4 sows are selected from each litter.

[0057] In the examples of the present application, 1 to 2 pure black boars and 2 to 4 sows are selected from each litter based on their individual weights, and as many breeders as possible are retained in large litters, with more than 6 pairs of effective nipples.

[0058] Optionally, the first stage is when the individual pig weighs 30 kg.

[0059] In the second stage, the pig herd is selected to eliminate pigs with slow growth, disease and genetic defects.

[0060] Optionally, the second stage is when the weight of individual pigs is between 30kg and 100kg, i.e., the development period of individual pigs. This stage is mainly used to eliminate individual pigs with defects such as underdevelopment.

[0061] In the third stage, the pig herd is finally selected, and individual pigs are selected based on the value of the individual BLUP comprehensive selection index. The coat color SNP locus genotype of the pigs of this generation is tested through the Snapshot technology to eliminate the pigs with black heterozygous genotype in the herd.

[0062] Optionally, the third stage is when the individual pigs weigh 100 kg.

[0063] Optionally, the individual BLUP composite selection index is associated with the body weight at age and live backfat thickness corresponding to an individual pig weight of 100 kg.

[0064] Specifically, the BLUP method is used to estimate the breeding value of traits, and the two traits of age at 100 kg body weight and live back fat thickness are used for breeding pig selection. The correction formulas for age at 100 kg body weight, live back fat thickness and daily weight gain, the correction formula for the selection index and the sire index formula are: Correction formula: Corrected age to reach 100kg body weight = actual age + (target weight - actual weight) * (actual age - A) / actual weight; The back fat thickness of the corrected live body when the body weight reaches 100kg = actual back fat thickness + (target body weight - actual body weight) * actual back fat thickness / (actual body weight - B); 30-100kg weight-corrected daily weight gain = (70*1000) / (100kg weight-corrected age-30kg weight-corrected age); 30kg weight-corrected age = age from birth to 30kg weight + (30-actual weight measured) * b; Among them, the value of A for boars is 55.289 and for sows is 49.361; the value of B for boars is -6.240 and for sows is -4.481; and b is 1.536.

[0065] The expression of individual BLUP comprehensive selection index is: ; in, ; It indicates the EBV at the age of 100 kg body weight; It indicates the back fat thickness EBV of a live animal with a body weight of 100 kg; It is expressed as the standard deviation of EBV of all individuals participating in this genetic evaluation who reached 100 kg body weight at the age of 24 hours; It is expressed as the standard deviation of the backfat thickness EBV of all individuals participating in this genetic evaluation at a body weight of 100 kg; Expressed as the standard deviation of the index before normalization; Expressed as the mean of the unnormalized exponentials.

[0066] It should be noted that in the embodiments of the present application, the above-mentioned screening method is used to effectively select excellent pig individuals, and the selection logic is mainly based on the quality trait coat color, and the quantitative traits are the age at which the pig reaches 100 kg in weight and the back fat thickness, while taking into account the number of piglets.

[0067] Optionally, the individual pigs of this generation are selected based on the values ​​of the individual BLUP comprehensive selection index, including: for each family, selecting sows whose individual BLUP comprehensive selection index is within the top 60%, and selecting boars whose individual BLUP comprehensive selection index is within the top 30%.

[0068] In the embodiments of the present application, selecting sows whose individual BLUP comprehensive selection index is within the top 60%, and selecting boars whose individual BLUP comprehensive selection index is within the top 30% can improve genetic gain and improve the production performance of the entire population. The selection index usually takes into account multiple traits, which can ensure that the selected individuals have better performance as a whole, which helps to quickly improve the population level. At the same time, by setting the selection parameters of 60% and 30%, the decline in genetic diversity caused by excessive concentrated selection can be avoided. Maintaining a certain degree of genetic diversity is crucial for long-term breeding plans and responding to environmental changes.

[0069] Optionally, the method of breeding each generation further includes: detecting different SNP sites of the CAV1 gene of the pig individuals of that generation by using the Snapshot technology, and breeding pig individuals with the GG genotype.

[0070] It should be noted that the Snapshot technology was used to detect different SNP sites of the CAV1 gene of individual S06, with a focus on selecting the GG genotype to increase the frequency of the G gene in the offspring and achieve the purpose of increasing the intramuscular fat content (IMF).

[0071] Intramuscular fat has an important influence on the pleasantness of the mouthfeel, juiciness, tenderness and taste. Not only is it a precursor of flavor, but the volatile compounds produced by the heating of lipids can also produce different types of characteristic flavors. During the cooking process, the fat-soluble components that form the aroma of the lean meat will dissolve in the fat, and the triglycerides and phospholipids in the intramuscular fat can also undergo thermal and oxidative degradation to form aldehyde aromatic substances with very low thresholds. Their content and composition directly determine the flavor intensity after heating. In addition, the lipid degradation products can also interact with the early products of the Maillard reaction and the degradation products of sulfur-containing amino acids at high temperatures to produce a complex flavor combination. It can be seen that IMF is the most important indicator for evaluating pork flavor.

[0072] Please refer to Table 2. After assisted selection to the 5th generation, the measured IMF content was 3.51, which was 0.36 percentage points higher than the 3.15 of the 0th generation without selection.

[0073] Table 2 Optionally, the method of breeding each generation also includes: detecting the VRTN gene of the pig individuals of that generation by PCR technology, and breeding pig individuals with the ins / ins genotype.

[0074] It should be noted that pigs are vertebrates. The vertebrae of pigs are divided into cervical vertebrae, thoracic vertebrae, lumbar vertebrae, sacral vertebrae and caudal vertebrae. The number of cervical vertebrae, sacral vertebrae and caudal vertebrae of pigs is relatively fixed, while the number of thoracic vertebrae and lumbar vertebrae varies. The thoracic vertebrae, also known as ribs, are important economic traits. Studies have shown that the number of vertebrae in pigs is a trait with high heritability, with a heritability of 0.60-0.62, and there is a positive correlation between the number of thoracic vertebrae and carcass length. For every additional rib, the carcass grows 10-30mm and the carcass weight increases 1%. Studies have shown that an increase in the number of thoracic vertebrae can lead to an increase in body length, an expansion of the chest cavity, an increase in chest circumference, and a corresponding increase in carcass growth, which in turn increases the meat production of pigs.

[0075] The VRTN gene can be used as a molecular standard auxiliary gene for the number of ribs. Studies have shown that VRTN is a candidate QTG (Quantitative Trait Gene) on SSC7 that affects the number of thoracic vertebrae. There are two polymorphic sites on the VRTN gene that are candidate QTNs that affect the number of thoracic vertebrae. They are significantly correlated with the number of thoracic vertebrae in pig breeds. By detecting any of these two sites using modern molecular biological technology and using marker-assisted selection of individuals with favorable genotypes for breeding, the number of ribs in the population can be effectively increased, and the individual body length and meat production can be increased.

[0076] Therefore, during the process of generational breeding, the ins291 site on the VRTN gene was screened for testing, ins / ins individuals were selected, and del / del individuals were eliminated, in order to increase the number of ribs in the group and accelerate the realization of our breeding goals.

[0077] Please refer to Table 3 and Table 4. By selecting individuals with favorable genotypes from generation to generation, the frequency of the ins gene was gradually increased. By the fifth generation, the recessive homozygous was completely eliminated. Through breeding, by the fifth generation, the homozygous advantageous genotype had reached 0.58 and the ins gene frequency was 0.79. From the first generation to the fifth generation, the number of ribs increased by 0.74 and the carcass length increased by 1.16 cm.

[0078] Table 3 Table 4 Optionally, the number of sows in the zero-generation basic pig herd is M; the number of boars is N; and the number of different bloodlines is P; wherein the range of M is 150-160; the range of N is 20-30; The range of P is greater than or equal to 10.

[0079] In the embodiment of the present application, a sufficient number of boars, sows, and blood types can ensure that the bloodline within the group is closed during mating, and no boars outside the group are introduced, so as to improve the homozygosity of the group genes, so that the genes within the group can be randomly matched, in order to obtain a better gene combination. This approach helps to fix and accumulate the excellent characteristics of specific individuals, and is also convenient for maintaining and improving the bloodline of pigs.

[0080] Optionally, the same feeding conditions are used in the selection and breeding process of each generation, and a breeding model is adopted in which sows are bred in autumn and piglets are farrowed in spring.

[0081] Specifically, feed formulas can be formulated for various types of pigs, including growing pigs, pregnant sows, lactating sows, boars, suckling piglets, and weaned piglets, to ensure consistent nutritional levels in different generations.

[0082] Each generation adopts the method of sows being bred in autumn, piglets being born in spring, and growth and development pigs being tested in summer and autumn, so as to maintain relatively consistent environmental conditions, minimize environmental variance and improve selection accuracy.

[0083] Finally, the test results are used to illustrate the breed characteristics and performance of the Chuanxiang black pig bred by the method of the embodiment of the present application.

[0084] 1. Appearance: The Chuanxiang Black Pig has black fur all over its body, a medium-sized head, a medium-length and straight mouth, medium-sized ears that lean forward, a straight back and waist, a well-connected waist and sacrum, a long, deep and broad body, well-developed legs and buttocks, strong limbs, and more than 6 pairs of nipples.

[0085] 2. Reproduction performance: The total number of piglets born in the first litter of Chuanxiang Black Pig is 9.15; the total number of piglets born in the second litter is 10.21; the total number of piglets born in the third litter is 11.73; the total number of piglets born in mixed litters is 10.36, and the number of piglets born alive is 9.75.

[0086] 3. Growth and development performance: The corrected age of male and female Chuanxiang black pigs reaching 100kg body weight is 156.79 days and 157.76 days respectively; the corrected fat thickness of male and female pigs is 9.92mm and 10.76mm respectively.

[0087] 4. Fattening performance: The corrected daily weight gain, live corrected fat thickness, feed conversion rate and corrected age at reaching 100kg of Chuanxiang black pigs from 30 to 100kg are 885.78g, 10.25mm, 2.54 and 156.60 days respectively.

[0088] 5. Carcass and meat quality performance: The slaughter rate of Chuanxiang black pig is 73.78%, the proportion of hind legs is 34.38%, the lean meat rate is 63.78%, pH1, meat color and drip loss are all within the normal range, the muscle fiber diameter is 90.19µm, the tenderness is 5222.34g, the intramuscular fat content is 3.65%, and the meat quality is excellent.

[0089] It should be noted that, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0090] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0091] In the description of the embodiments of the present invention, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0092] In the description of the embodiments of the present invention, it should be understood that "-" and "~" represent the range between two values, and the range includes the endpoints. For example, "AB" represents a range greater than or equal to A and less than or equal to B. "A~B" represents a range greater than or equal to A and less than or equal to B.

[0093] In the description of the embodiments of the present invention, the term "and / or" herein is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " herein generally indicates that the associated objects before and after are in an "or" relationship.

[0094] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for breeding a new variety of Sichuan black pigs, characterized in that: include: The Duroc pig was used as the male parent and the Tibetan pig as the female parent for progressive crossbreeding to the hybrid F4 generation; Crossbreed F4 generation boars and sows to form a zero-generation basic pig herd; The zero-generation basic pig herd is bred in a closed manner, and each generation is selected until the fifth generation; the selection method for each generation includes: selecting the pig individuals of this generation based on the value of the individual BLUP comprehensive selection index, and performing coat color SNP site genotype detection on the pig individuals of this generation through the Snapshot technology to eliminate the black heterozygous genotype pig individuals in the pig herd; The fifth generation of pigs was identified as the paternal new breed of Chuanxiang Black Pig; The breeding method for each generation also includes: detecting different SNP sites of the CAV1 gene of the pig individuals of that generation by using the Snapshot technology to breed pig individuals with the GG genotype, or detecting the VRTN gene of the pig individuals of that generation by using the PCR technology to breed pig individuals with the ins / ins genotype; The method of carrying out progressive hybridization to the hybrid F4 generation with Duroc pig as the sire and Tibetan pig as the maternal parent includes: hybridizing with Duroc pig second generation S04 as the sire and Tibetan pig as the maternal parent to obtain the hybrid F1 generation; continuing to hybridize with Duroc pig second generation S04 as the sire and sow of hybrid F1 generation as the maternal parent to obtain the hybrid F2 generation; hybridizing with Duroc pig third generation S04 as the sire and sow of hybrid F2 generation as the maternal parent to obtain the hybrid F3 generation; hybridizing with Duroc pig fourth generation S04 as the sire and sow of hybrid F3 generation as the maternal parent to obtain the hybrid F4 generation.

2. The method for breeding a new variety of Chuanxiang black pig according to claim 1, characterized in that: The selective breeding of each generation includes: The selection of individual pigs for this generation consists of three stages: In the first stage, the herd is preliminarily selected, and 1 to 2 purebred boars and 2 to 4 sows are selected from each litter; In the second stage, the herd is subjected to secondary selection to eliminate individuals with slow growth, disease and genetic defects; In the third stage, the pig herd is finally selected, and individual pigs are selected based on the value of the individual BLUP comprehensive selection index. The coat color SNP locus genotype of the pigs of this generation is tested through the Snapshot technology to eliminate the pigs with black heterozygous genotype in the herd.

3. The method for breeding a new variety of Chuanxiang black pig according to claim 2, characterized in that: The first stage is when the individual pig weight is 30kg; The second stage is when the individual pig weight is between 30kg and 100kg; The third stage is when the individual pig weight is 100 kg.

4. The method for breeding a new variety of Chuanxiang black pig according to claim 3, characterized in that: The individual BLUP comprehensive selection index was associated with the body weight at age and live backfat thickness corresponding to an individual pig weight of 100 kg.

5. The method for breeding a new variety of Chuanxiang black pig according to claim 2, characterized in that: The pigs of this generation are selected based on the value of the individual BLUP comprehensive selection index, including: For each family, sows whose individual BLUP comprehensive selection index is within the top 60%, and boars whose individual BLUP comprehensive selection index is within the top 30% are selected.

6. The method for breeding a new variety of Chuanxiang black pig according to claim 1, characterized in that: The number of sows in the zero-generation basic pig herd is M; the number of boars is N; the number of different blood types is P; Among them, the range of M is 150~160; N ranges from 20 to 30; The range of P is greater than or equal to 10.

7. The method for breeding a new variety of Chuanxiang black pig according to claim 1, characterized in that: The same feeding conditions are used in the selection and breeding process of each generation, and the breeding model of sows being bred in autumn and farrowing in spring is adopted.

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