Production method of fast-growing low-backfat commercial black pigs with excellent meat quality and flavor

Abstract

The invention aims to provide the production method of the fast-growing low-backfat commercial black pigs with excellent meat quality and flavor. Duroc pigs are used as male parents, green jaboticaba black pigs are used as female parents for hybridization, and Duroc * green commercial black pigs are produced. The commercial pig is characterized in that: (1) the hair is black; (2) growth performance and carcass traits are excellent: compared with a local pig breed and a bred black pig breed, the Duhu pig is high in growth speed, thin in backfat and large in eye muscle area; (3) the meat quality and flavor are excellent: compared with the Duroc long pig, the Duroc long pig has the advantages that the pork color score, tenderness, water holding capacity and intramuscular fat content are increased; the content of free amino acids in water-soluble taste substances, especially the content of flavor amino acids, is increased; and the activity values of the 12 key volatile flavor substances are increased.

Description

Technical Field

[0001] The invention relates to the technical field of commercial pig production methods, and in particular to a method for producing commercial black pigs with excellent meat quality and flavor. Background Art

[0002] "Du Changda" foreign three-way pig has become the leading breed of pig farming in the world because of its fast growth rate, high feed conversion rate and high lean meat rate. Since my country introduced "Du Changda" and localized breeding in the 1980s, it has ensured 90% of the pig seed supply in my country. However, the current consumer demand for pork has shifted from quantity to quality flavor, especially my country's traditional food culture and cooking habits have higher requirements for the taste and flavor of pork. The meat flavor of foreign three-way pigs can no longer meet the needs of consumers. my country's local pig breeds have good quality, good flavor and strong resistance to adversity, but due to their small size, low feed conversion rate and low lean meat rate, the scale of breeding has continued to shrink and the population has shrunk. The "National Swine Genetic Improvement Plan (2021-2035)" of the Ministry of Agriculture and Rural Affairs proposes "using local pig breeds and introduced breeds as materials to cultivate high-quality and efficient new breeds and supporting systems to meet the market demand for high-quality pork."

[0003] The production of high-quality pork should comprehensively consider the growth rate, coat color and meat flavor of pigs. Most local pig breeds in my country have black coats, so consumers are more accepting and fond of black pork, and the market price of black pork is higher than that of white pork. Meat flavor is produced by a series of chemical changes such as thermal degradation and Maillard reaction of flavor precursors during thermal processing. Flavor precursors include water-soluble components that produce flavor and lipid parts that produce volatile aroma. The muscle fiber type of pig muscle is closely related to the characteristics of meat color, tenderness and meat flavor. Muscles dominated by oxidative muscle fibers usually contain more intramuscular fat, better tenderness and meat flavor. The "Green Jia Black" pig is a new black pig breed with "tender muscle fibers" and "marbled meat" as its significant features, which was bred by Zhejiang Academy of Agricultural Sciences based on the "muscle fiber type optimization-muscle metabolism type optimization-meat flavor presentation" of pigs, through the allocation of high-quality pig resources at home and abroad. The pigs are covered with black hair, and have made breakthroughs in the combination of growth performance and meat flavor: they reach an average weight of 100kg at 185-200 days old, and the average intramuscular fat content is at an ideal level of 3.2%-4.0%; compared with the "Du Changda" pigs, the muscle fiber diameter is reduced by an average of about 40%-50%, and the content of oxidative muscle fibers is increased by an average of about 2-3 times. The tenderness of pork, water-soluble flavor substances and volatile aroma substances all surpass those of the three-way pigs by more than 50%, and are generally better than local pigs.

[0004] In livestock and poultry breeding practice, there is a significant negative correlation between growth performance and meat quality and flavor traits. Rapid growth is often accompanied by thick muscle fibers, less lipid deposition, and poor meat quality and flavor. Although Chinese indigenous pig breeds have excellent meat quality, they face industrial bottlenecks such as a long growth cycle (over 300 days of age), excessive backfat thickness (generally > 35 mm), and low feed conversion rate, resulting in the long-term industrial dilemma of "tasty but difficult to raise" for high-quality black pork. The 'Duroc × Landrace × Yorkshire' white pigs produced by the commonly used hybrid system have a fast growth rate and high feed conversion rate, solving the problem of meat shortage in China, but their meat quality and flavor are gradually complained about by consumers. Other black pig hybrid systems (such as Berkshire × indigenous pig breeds) can maintain the black phenotype, but have defects such as a compensatory decrease in growth performance (a decrease in daily weight gain of more than 15%) and a 20% reduction in loin eye area. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for producing fast-growing, low-backfat commercial black pigs with excellent meat quality and flavor. Using Duroc pigs as the male parent and Lvjia black pigs as the female parent for hybridization to produce Duroc × Lvjia commercial black pigs. The characteristics of this commercial pig are: (1) black hair. (2) Excellent growth performance and carcass traits: Compared with indigenous pig breeds and cultivated black pig breeds, Duroc × Lvjia pigs have a fast growth rate, thin backfat, and a large loin eye area. (3) Excellent meat quality and flavor: Compared with Duroc × Landrace × Yorkshire pigs, the meat color score, tenderness, water-holding capacity, and intramuscular fat content of Duroc × Lvjia pork increase; the content of free amino acids, especially umami amino acids, which are water-soluble taste substances, increases; the activity values of 12 key volatile flavor substances increase.

[0006] To achieve the above invention purpose, the present invention provides the following technical solution: The present invention relates to a method for producing fast-growing, low-backfat commercial black pigs with excellent meat quality and flavor. The method includes using Duroc pigs as the male parent and Lvjia black pigs as the female parent for hybridization to produce Duroc × Lvjia commercial pigs.

[0007] The present invention uses directionally selected Lvjia black pigs as the female parent. When hybridized with a specific Duroc sire line, it can break through the trait segregation law of conventional hybridization. Especially in terms of coat color inheritance, the stable rate of black coat color in the F1 generation reaches 100%, which is significantly better than that of conventional Duroc hybrid combinations (usually more than 30% coat color segregation). In addition, this hybrid system produces heterosis: while maintaining the high-density type I oxidative muscle fibers (9.35%) of Lvjia black pigs (9.53%), it increases by 57.94% compared with Duroc × Landrace × Yorkshire commercial pigs (5.92); the muscle fiber diameter (73.06 μm) is reduced by 23.10% compared with Duroc × Landrace × Yorkshire commercial pigs (94.71 μm), and this structure innovatively realizes the simultaneous improvement of tenderness (shearing force < 44 N) and water-holding capacity (pressing loss < 28%).

[0008] Preferably, for the Duroc pigs: the age is ≥ 8 months old and the weight is ≥ 100 kg.

[0009] Preferably, the selection criteria for the body shape and appearance of the Duroc pig as the father are: chest width 45~50 cm, chest depth 35~40 cm, chest width to body length ratio ≥0.45; back and waist slightly arched, abdominal line straight, vertical height from the highest point of back and waist to the ground is 75~80 cm; limbs are strong, testicles are well developed, testicle circumference is 18~20 cm, outline is obvious, and left and right sizes are the same; sperm motility ≥0.8, deformity rate <8%.

[0010] Preferably, the Lujia black pig is: ≥8 months old, and weighs ≥100kg.

[0011] Preferably, the selection criteria for the body shape and appearance of the Lujia black pig as the mother are: strong and powerful limbs, more than 99% of the coat is completely black, the distance between udders is normal, the structure is reasonable, the distance between adjacent nipples in the same row is 10-15 cm, the distance between two rows of nipples is 20-25 cm, the mammary glands are well developed, and the number of nipples is 6 pairs or more.

[0012] The present invention utilizes the comprehensive advantages of the "Green Jia Black" pig, such as black hair, fast growth rate, and excellent meat flavor, and uses it as the maternal parent of commercial pigs. With Duroc as the paternal parent, hybridization is carried out to produce commercial black pigs with excellent growth performance, carcass traits and meat flavor, which can well meet the all-round needs of high-quality black pig operators and pig consumers.

[0013] The present invention establishes a coordinated expression system of 'muscle fiber refinement-lipid micro-deposition-flavor precursor enrichment'. Industrial verification shows that the commercial pig breeding benefits are 2.3 times higher than those of traditional black pigs, and the total amount of flavor substances is increased by more than 50%, filling the technical gap of high-quality and efficient black pig matching system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the body shape and appearance of a 6-month-old Dulu pig; Figure 2 This is a schematic diagram of the hair color of hybrid offspring pigs with Green Jiahei as the mother. DETAILED DESCRIPTION

[0015] 1. Materials and Methods 1 Experimental design

[0016] With Lujia Black Pig as the mother and Duroc Pig as the father, the hybrid offspring is Duroc (Duroc Pig♂×Lujia Black♀) Pig, please refer to Figure 1 .

[0017] With Lujia black pig as the mother and Landrace pig as the father, the hybrid offspring is Changlu (Landrace pig ♂×Lujia black ♀) pig.

[0018] With the Lujia black pig as the mother and the Large White pig as the father, the hybrid offspring is the Large Green (Large White pig ♂×Lujia black ♀) pig.

[0019] Select healthy, well-developed breeding boars and sows with excellent genetic performance. The breeder should closely monitor the behavioral changes of the sows. When there are situations such as red and swollen vulva, mucus secretion, decreased appetite, frequent vocalization, and mounting other sows, combined with the recorded estrus cycle, arrange the first insemination within 12 - 24 hours after the sow shows the standing reflex. During the specific operation, drive the sows in estrus and the selected breeding boars into the same breeding pen, and let the boars naturally mount the sows to complete the mating process. Conduct the second insemination 8 - 12 hours after the end of the first insemination. After insemination, the sows should be strengthened in feeding management, provided with nutritionally balanced feed, ensured sufficient drinking water, and avoid the sows being affected by stress and diseases.

[0020] From January to October 2022, Lvjia black pigs and Dulv hybrid pigs were raised in Yangdu Science and Technology Ranch of the Institute of Animal Husbandry and Veterinary Medicine, Zhejiang Academy of Agricultural Sciences. The feed was formulated according to the NRC nutritional standards. The details of the basal diet are shown in Table 1, and the pigs were allowed to freely eat and drink water. Taking the "Duroc × Landrace × Yorkshire" three-way cross pigs as the control experimental pigs, slaughter determination and longissimus dorsi muscle sample collection were carried out at the Xinxing Slaughterhouse of Zhejiang Qinglian Food Co., Ltd.

[0021] The Duroc pigs mentioned above: The age is ≥ 8 months old, and the weight is ≥ 100 kg. The selection criteria for body type and appearance are as follows: chest width is 45 - 50 cm, chest depth is 35 - 40 cm, and the ratio of chest width to body length is ≥ 0.45; the back and waist are slightly arched, the ventral line is straight, and the vertical height from the highest point of the back and waist to the ground is 75 - 80 cm; the limb bones are strong, the joints are round and not swollen, the hooves are firm, of appropriate size, and the hoof shells are smooth without cracks; the testicles are well-developed, the testicular circumference is 18 - 20 cm, the outline is obvious, and the left and right sizes are the same; sperm motility ≥ 0.8, and the malformation rate < 8%.

[0022] The Lvjia black pigs mentioned above: The age is ≥ 8 months old, and the weight is ≥ 100 kg. The selection criteria for body type and appearance are as follows: the limbs are thick and strong, and they walk steadily; more than 99% of the hair is all black, the distance between the mammary glands is normal, the structure is reasonable, the distance between adjacent nipples in the same row is 10 - 15 cm, the distance between two rows of nipples is 20 - 25 cm, the mammary glands are well-developed, and the number of nipples is 6 pairs or more to ensure the normal function of subsequent lactation.

[0023] Table 1 Composition of basal diet Raw material, % Content Corn 76.00 Soybean meal 13.00 Extruded soybean 5.00 Soybean oil 2.00 Limestone powder 0.85 Calcium bicarbonate 0.85 Lysine 0.20 Sodium chloride 0.35 Wheat middlings 0.75 Premix 1.00 Total 100.00 Note: The premix provides per kilogram of diet: methionine 80 g, VA 6500 IU, VD 3 813 IU, VE 85 IU, VK 3 2 mg, VB 1 0.98 mg, VB 2 3.2 mg, VB 6 2.5 mg, VB12 26 μg, 26 mg of niacin, 19.9 mg of pantothenic acid, 1.24 mg of folic acid, 156 μg of biotin, Zn(ZnSO 4 )50 mg, Cu[Cu 2 (OH) 3 Cl]15 mg, Mn(MnSO4)10 mg, Se(Na 2 SeO 3 )0.3 mg, I(KI)0.2 mg.

[0024] 2 Sample collection and determination

[0025] Determine the body weight at 180 days of age in accordance with the "Regulations for Determining the Production Performance of Breeding Pigs" (NY / T 822-2019). Take samples from the left half carcass slaughtered in accordance with the provisions of the "Technical Specification for Determining the Carcass Traits of Lean-Type Pigs" (NY / T 825). Extend backward from the front end of the third thoracic vertebra from the back of the longissimus dorsi muscle and take out 30 cm for the test. Average backfat thickness at three points: The backfat thickness at the thickest part of the shoulder at the dorsal midline of the carcass after slaughter, the junction of the thoracic and lumbar vertebrae, and the junction of the lumbar and sacral vertebrae. Calculate the average backfat thickness. Eye muscle area: The cross-sectional area of the longissimus dorsi muscle. Calculation formula: Eye muscle area (cm 2 ) = Eye muscle height (cm) × Eye muscle width (cm) × 0.7.

[0026] Refer to the "Technical Specification for Determining the Muscle Quality of Pigs" (NY / T 821-2004) to determine the muscle quality indicators. Sensory evaluation of meat color: Evaluated by two appraisers with reference to the meat color scoring chart (American NPPC colorimetric plate). Shear force determination: Take a 3 cm thick meat block, after steaming and cooking, take a 1 cm × 1 cm × 2 cm cuboid meat block along the direction of muscle fibers, keep the muscle fibers of the meat block perpendicular to the shear instrument, and determine the shear force. Determination of intramuscular fat content: Accurately weigh about 2 g of air-dried muscle samples and determine the crude fat content by the Soxhlet extraction method. Determination of pressing loss: Take a 1 cm thick muscle sample, sample with a sampler with a diameter of 2 cm, weigh (m1), wrap it with gauze, place 18 layers of filter paper on the top and bottom, use a pressure tester to keep it for 3 minutes and then quickly remove and weigh (m2), and calculate the pressing loss = (m1 - m2) / m1 × 100%.

[0027] 3 Determination of free amino acid content

[0028] The external standard method was used with the amino acid mixed standard solution AN-2 type as the standard. Accurately weigh 0.4100 - 0.4300 g of the meat paste sample, add 0.01 mol / L HCL and homogenize (60 Hz, 60 s). After homogenization, let it stand for 1 h and centrifuge (4°C, 12000 r / min, 10 min). Extract 700 μL of the supernatant with an equal volume of 8% (m / m) sulfosalicylic acid, vortex and then centrifuge (4°C, 12000 r / min, 5 min). Mix 950 μL of the supernatant with an equal volume of n-hexane, mix well and centrifuge (twice), filter through a 0.22 μm nylon membrane, and then analyze using an LA8080 automatic amino acid analyzer. The content of each free amino acid is expressed in mg / kg.

[0029] 4 Determination of Volatile Flavor Compounds

[0030] The thin film solid-phase microextraction method was adopted. Weigh the sample and internal standard (2-octanol) into a headspace vial, place it into the activated thin film solid-phase microextraction device, and seal it with a PTFE / S bottle cap. Put the headspace vial into a heating shaker, heat it at 80°C and 250 r / min for 20 min, and extract for 30 min. After the extraction is completed, take out the extraction device, insert the extraction device into a Gerstel TD type thermal desorption device, desorb it at 250°C for 5 min, use a 7890A-5975 type gas chromatography-mass spectrometry instrument to automatically collect data, use the internal standard method for quantification, calculate the retention index according to the retention time, and select the data with a difference of within 20 from the standard retention index. Chromatographic column: DB-WAX, 30 m × 0.25 mm × 0.25 μm (Agilent Technologies Co., Ltd.).

[0031] II. Results 1 Coat Color of Hybrid Pig Offspring

[0032] Coat color is an important genetic trait of pigs. Most local pig breeds in China have black hair, so Chinese consumers are more recognized and fond of black pork, and the market price of black pork is higher than that of white pork. As Figure 2 shown, with Lvjia black pigs as the female parent, all the commercial pigs of the Duroc × Lvjia cross are black, all the commercial pigs of the Landrace × Lvjia cross are white, and the commercial pigs of the Yorkshire × Lvjia cross have white hair with black spots. This shows that the cross between Duroc and Lvjia black pigs has specificity in coat color inheritance, breaking through the regular coat color segregation law of conventional crosses and meeting the market demand for black pork.

[0033] 2 Growth Performance and Carcass Traits

[0034] Table 2 Growth Performance and Carcass Traits of Some Local Pigs and Hybrid Black Pigs

[0035] Index Dulv pig Lüjia black pig Jinhua pig Chenghua pig Songliao black pig New Jilin black pig Tianfu black pig No. 1 black pig Xidu black pig Age, days 180 180 330 300 - - 182 235.8 - Body weight, kg 101.11 94.06 72.60 102.3 126.75 117.14 98.40 125.68 99.58 Average backfat thickness, mm 30.00 33.91 33.60 31.32 32.47 35.58 29.58 49.70 36.61 <![CDATA[Eye muscle area, mm 2 > 37.31 35.76 22.72 28.51 25.68 30.34 32.97 27.10 32.70 The growth rate of pigs is generally expressed by the weight at 180 days of age or the number of days to reach the market weight. As shown in Table 2, local pig breeds such as Jinhua pigs and Chenghua pigs grow slowly. The Jinhua pig reaches a market weight of 72.60 kg at 330 days of age, and the Chenghua pig reaches 102.3 kg after being raised for 300 days. The Dulv pig grows fast. After being raised for 180 days, its weight can reach 101.11 kg, which is higher not only than local pig breeds but also than the hybrid female parent Lvjia Black Pig and the cultivated pig breeds Tianfu Black Pig (Berkshire × Chenghua pig) and No. 1 Black Pig.

[0036] Backfat refers to the fat layer between the back muscles and the skin of an animal. The backfat thickness is an important indicator for pig carcass grading and pricing. The thicker the backfat, the lower the grade. The backfat thickness of the Dulv pig is much lower than that of Xin Jilin Black Pig (Berkshire × Min pig), No. 1 Black Pig, and Se Du Black Pig, and is comparable to that of Tianfu Black Pig and Chenghua pig. The eye muscle area refers to the cross-sectional area of the longissimus dorsi muscle at the last rib of a pig, and has a strong positive correlation with meat production performance. It can be seen from Table 2 that the eye muscle area of the Dulv pig is larger than that of the hybrid female parent Lvjia Black Pig, local pig breeds (Jinhua pig, Chenghua pig, Songliao Black Pig), and cultivated pig breeds (Xin Jilin Black Pig, Tianfu Black Pig, No. 1 Black Pig, and Se Du Black Pig).

[0037] The Dulv pig has excellent growth performance and carcass traits: compared with local pig breeds and cultivated black pig breeds, the Dulv pig grows fast, has thin backfat, and a large eye muscle area.

[0038] 3 Muscle Quality

[0039] Meat color is one of the key factors for consumers to choose pork. As can be seen from Table 3, the Lvjia Black Pig has the highest meat color score, followed by the Dulv pig, and the Duroc × Landrace × Yorkshire pig has the lowest. Shear force is one of the indicators to evaluate muscle tenderness. The lower the shear force, the tenderer the muscle. The Dulv pig has the best tenderness. The intramuscular fat content is strongly correlated with the flavor of pork and directly affects the juiciness of the meat. When the intramuscular fat content reaches 2.5% or more, the flavor and juiciness of the pork are significantly improved. As can be seen from Table 3, the Lvjia Black Pig has the highest, followed by the Dulv pig, and the Duroc × Landrace × Yorkshire pig has the lowest. Pressing loss represents the water-holding capacity of muscle and is an important meat quality trait. The lower the pressing loss, the better the water-holding ability. The pressing losses of the Dulv pig and the Lvjia Black Pig are much lower than that of the Duroc × Landrace × Yorkshire pig.

[0040] Compared with the Duroc × Landrace × Yorkshire pig, the Dulv pig has increased meat color score, tenderness, water-holding ability, and intramuscular fat content.

[0041] Table 3 Muscle Quality of the Longissimus Dorsi Muscle of Dulv Pig, Lvjia Black Pig, and Duroc × Landrace × Yorkshire Pig Index Dulv pig Lüjia black pig Duroc×Landrace×Yorkshire pig Meat color score 2.55 3.43 2.40 Shear force, N 43.11 47.12 47.11 Intramuscular fat, % 2.82 3.55 2.24 Press loss, % 27.99 27.29 34.27 Proportion of type I muscle fibers, % 9.35 9.53 5.92 Muscle fiber diameter μm 73.06 53.15 94.71 4 Flavor Substances in Muscle 4.1 Water-Soluble Taste Substances - Free Amino Acids

[0042] Free amino acids are the main water-soluble flavor substances in meat. Amino acids with umami taste include glutamic acid, aspartic acid, phenylalanine, alanine, glycine, and tyrosine. Among them, glutamic acid and aspartic acid have relatively low taste thresholds and relatively high contents in pork, being the main umami amino acids. In terms of the total content of free amino acids in muscle, Lvjia Black pigs are the highest, Dulv pigs are the second, and Duroc×Landrace×Yorkshire pigs are the lowest. In terms of the total amount of umami amino acids among free amino acids, Lvjia Black pigs and Dulv pigs are comparable and higher than Duroc×Landrace×Yorkshire pigs. The contents of alanine and aspartic acid in umami amino acids in Lvjia Black pigs and Dulv pigs are higher than those in Duroc×Landrace×Yorkshire pigs.

[0043] The content of free amino acids in Dulv pigs, especially the content of umami amino acids, is higher than that in Duroc×Landrace×Yorkshire pigs.

[0044] Table 4 Comparison of the contents of free amino acids in the longissimus dorsi muscle of Dulv pigs, Duroc×Landrace×Yorkshire pigs, and Lvjia Black pigs, mg / kg Dulv pig Lüjia black pig Duroc×Landrace×Yorkshire pig Total free amino acids 612.76 678.24 586.72 Total umami amino acids 289.83 288.31 263.08 Alanine 182.55 167.27 164.33 Aspartic acid 23.24 22.10 9.03 4.2 Volatile flavor substances

[0045] The volatile flavor substances in pork include compounds such as aldehydes, alcohols, ketones, esters, alkanes, etc. The relative odor activity value (OAV) is the ratio of the content of each volatile substance in the sample to its threshold value under the sample matrix, revealing the contribution of odor components to the food flavor system from two dimensions of concentration and threshold. OAV>1 indicates that the substance is a key flavor component and plays a major role in the flavor. In the three kinds of pork of Dulv pigs, Lvjia Black pigs, and Duroc×Landrace×Yorkshire pigs, the OAV values of 16 compounds such as hexanal (with the fragrance of grease, grass, and apple), 2,4-nonadienal (with the fragrance of flowers, fruits, and grease), octanal (with the fragrance of fat and citrus), nonanal (with the fragrance of citrus, rose, and grease), E,E-2,4-decadienal (with the fragrance of fat), 1-octen-3-ol (with the fragrance of mushroom), heptanal (with the fragrance of fat and grass), hexanol (with the fragrance of wine, fruit, and fat), (E)-2-octenal (with the fragrance of green and fat), decanal (with the fragrance of green and fat), benzaldehyde (with the fragrance of bitter almond), 2-pentylfuran (with the fragrance of soil and green), dodecanal (with the fragrance of fat), trans-2-octen-1-ol (with the fragrance of citrus), ethyl caprate (with the fragrance of grape), and ethyl hexanoate (with the fragrance of wine and fruit) are greater than 1 (see Table 5), and they are considered the flavor components with major contributions in pork.

[0046] Compared with Duroc×Landrace×Yorkshire pigs, the contents of 12 volatile flavor substances with OAV values greater than 1, such as hexanal, 2,4-nonadienal, octanal, nonanal, E,E-2,4-decadienal, 1-octen-3-ol, heptanal, hexanol, (E)-2-octenal, 2-pentylfuran, trans-2-octen-1-ol, and ethyl caprate, in the longissimus dorsi muscle of Dulv pigs and Lvjia Black pigs increase. Among them, the OAV value of 2,4-nonadienal with the fragrance of flowers, fruits, and grease in the muscle of Dulv pigs is higher than that of Lvjia Black pigs and Duroc×Landrace×Yorkshire pigs.

[0047] It can be seen from this that the 12 key volatile flavor substances in the muscles of Dulv pigs are higher than those in Duroc×Landrace×Yorkshire pigs.

[0048] Table 5 Activity values of volatile flavor substances in the longissimus dorsi muscle of Dulv pigs, Duroc×Landrace×Yorkshire pigs and Lvjia black pigs Dulv pig Lüjia black pig Duroc×Landrace×Yorkshire pig n-Hexanal 488.59 698.73 177.47 2,4-Nonadienal 1141.80 936.55 568.20 n-Octanal 287.14 350.63 141.04 Nonanal 495.32 514.64 337.38 E,E-2,4-Decadienal 264.13 289.64 101.04 1-Octen-3-ol 135.73 134.14 34.51 Heptanal 23.35 79.98 20.91 n-Hexanol 23.78 34.33 8.87 (E)-2-Octenal 21.29 16.23 6.43 Decanal 7.47 10.45 12.14 Benzaldehyde 2.73 4.55 3.76 2-N-Amylfuran 9.80 21.39 3.65 Dodecanal 8.70 8.72 9.20 Trans-2-octen-1-ol 4.28 3.50 1.32 Ethyl caprate 3.05 3.90 0.92 Ethyl caproate 2.70 0.74 0.64 III. Conclusion

[0049] Taking Duroc pigs as the male parent and Lvjia black pigs as the female parent for hybridization, the commercial Duroc×Lvjia black pigs are produced. The characteristics of this commercial pig are as follows: (1) The hair is black. (2) It has excellent growth performance and carcass traits: Compared with local pig breeds and cultivated black pig breeds, Dulv pigs have a fast growth rate, thin backfat, and a large loin eye area. (3) It has excellent meat quality and flavor: Compared with Duroc×Landrace×Yorkshire pigs, the meat color score, tenderness, water-holding capacity and intramuscular fat content of Dulv pork increase; the content of free amino acids, especially umami amino acids, which are water-soluble taste substances, increases; the activity values of 12 key volatile flavor substances increase.

[0050] IV. Analysis of industrialization feasibility

[0051] Taking a certain breeding base in Zhejiang as an example, 500 "Dulv" hybrid commercial pigs are sold annually. The feeding cycle and body weight are basically the same as those of the "Duroc×Landrace×Yorkshire" (outer three-way cross white pigs). The market live pig selling price of Dulv hybrid pigs is on average 3 yuan / kg higher than that of Duroc×Landrace×Yorkshire pigs. Calculated based on the slaughter weight of 120 kg, the income per black pig increases by 360 yuan, and the total annual income from live pigs can be increased by 1.8 million yuan. If high-quality pork is sold in the form of fine cutting after slaughter, the yield rate of its fresh cut products for sale is about 85% of that of Duroc×Landrace×Yorkshire pigs, and the product selling price is about 1.5 times that of Duroc×Landrace×Yorkshire pork. The comprehensive output value increases by more than 20% compared with raising the "Duroc×Landrace×Yorkshire" (outer three-way cross white pigs).

[0052] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for producing fast-growing, low-backfat commercial black pigs with excellent meat flavor, characterized in that: The method comprises hybridizing Duroc pig as the father and Lujia black pig as the mother to produce Duroc×Lujia commercial pig.

2. The commercial black pig production method according to claim 1, characterized in that: The Duroc pigs are ≥8 months old and weigh ≥100kg.

3. The commercial black pig production method according to claim 1, characterized in that: The selection criteria for the body shape and appearance of the Duroc pig as the father are as follows: chest width 45-50 cm, chest depth 35-40 cm, chest width to body length ratio ≥0.45; back and waist slightly arched, abdominal line straight, vertical height from the highest point of back and waist to the ground is 75-80 cm; limbs are strong, testicles are well developed, testicle circumference is 18-20 cm, outline is obvious, and left and right sizes are the same; sperm motility is ≥0.8, and deformity rate is <8%.

4. The commercial black pig production method according to claim 1, characterized in that: The Lujia black pig is ≥8 months old and weighs ≥100kg.

5. The commercial black pig production method according to claim 1, characterized in that: The selection criteria for the body shape and appearance of the Lujia black pig as the mother are: strong and powerful limbs, more than 99% of the coat is completely black, the distance between the udders is normal, the structure is reasonable, the distance between adjacent nipples in the same row is 10~15 cm, the distance between two rows of nipples is 20~25 cm, the mammary glands are well developed, and the number of nipples is 6 pairs or more.

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