Commercial production method for Jinhua pigs with fast growth, high meat yield and excellent flavor

Abstract

The invention aims to provide the production method of the Jinhua commercial pig which is fast in growth, high in meat yield and excellent in meat quality and flavor, and according to the method, the Jinhua pig III line is used as a male parent, and the Jinhua pig III line and the Lvjia black pig are used as a female parent for hybridization to produce the Jinhua commercial pig. Compared with a Jinhua pig III line, the growth speed of the Jinhua commercial pig is high, and only about 189.5 days are needed when the Jinhua commercial pig grows to 70 kg; the dressing percentage is increased, the backfat thickness is reduced, and the front, middle and rear section yields of carcasses are increased; the content of collagen in muscles is increased; the contents of free amino acids and nucleotides with umami in muscles are increased; the contents of monounsaturated fatty acid and linolenic acid in muscles are increased; according to the present invention, the number of key aroma components in the muscle is increased, and besides 10 types of the components detected in the Jinhua pig III line, the components detected in the golden green pig also have fat, trans-2-octenal having a green aroma, trans-2, 4-decadienal having a chicken oil aroma, 2, 4-nonadienal having a flower fragrance and oil aroma, and trans-2-octylene-1-alcohol having a citrus aroma.

Description

Technical Field

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

[0002] Jinhua pig, also known as Jinhua Liangtouwu, is the most representative local pig breed in Zhejiang Province. It ranks first among the four famous pigs in China and is listed in the "National Livestock and Poultry Breed Resource Protection List" by the Ministry of Agriculture and Rural Affairs. Jinhua pigs have the excellent characteristics of thin skin and fine bones, tender meat, strong disease resistance, early maturity and easy fattening, high reproduction rate, and are suitable for pickled ham. According to the history of Jinhua pig production areas, three strains of Jinhua pigs, I, II, and III, were formed. Judging from the feedback from the industry and consumer markets, it is generally believed that Jinhua pig III has "ruddy meat, non-greasy fat, and non-sticky meat", and has the best meat flavor, which best represents the historical Jinhua pork flavor characteristics. However, due to its small size, low feed conversion rate, low lean meat rate (40%~45%), and long growth cycle (reaching a market weight of about 70kg at 10 months of age), the economic value of purebred Jinhua pigs directly used as commercial pigs is too low.

[0003] In the current pig farming industry, there has always been a problem of how to balance good meat quality and efficient production. On the one hand, local excellent pig breeds such as Jinhua pigs, although they have excellent meat quality and flavor, are difficult to achieve sustainable development at the economic benefit level due to poor growth performance; on the other hand, foreign fast-growing lean pig breeds have excellent growth rate and meat production, but the meat flavor cannot meet consumers' demand for high-quality flavor pork. Studies have shown that using foreign fast-growing lean pig breeds to improve the growth performance and lean meat rate of Jinhua pigs will weaken or even disappear the advantages of its excellent meat quality and other traits. When Berkshire, Large White or Duroc pigs are used as sires and hybridized with Jinhua II sows, although the growth rate, lean meat rate and feed conversion rate of the hybrid offspring are improved, the meat quality is significantly different from that of Jinhua pigs. Studies using Jinhua pigs as hybrid sires have found that when Jinhua pigs are used as sires and hybridized with Duroc sows, Jindu hybrid pigs have excellent meat quality, but there is a large variation between individuals, slow growth rate and poor feed utilization. In summary, the economic value of purebred Jinhua pigs as commercial pigs is too low and it is difficult to maintain them for a long time. Crossbreeding Jinhua pigs with fast-growing lean pigs from abroad cannot take into account the excellent meat quality traits of Jinhua pigs and their growth performance and meat production performance.

[0004] The "Lujia Black" pig is a new breed of black pigs with "tender muscle fibers" and "marbled meat" as the prominent features, which are selected and bred by Zhejiang Academy of Agricultural Sciences with excellent seed sources from home and abroad. A breakthrough has been made in the combination of growth performance and meat flavor: the average age of the pigs reaching 100kg in weight is 185-200 days, and the average intramuscular fat content is at an ideal level of 3.2%-4.0%; compared with the "Du Changda" pigs, the average muscle fiber diameter is reduced by about 40%-50%, and the average oxidative muscle fiber content is increased by about 2-3 times. The tenderness of pork, water-soluble flavor substances and volatile aroma substances are more than 50% higher than those of the three-way pigs.

[0005] Taking advantage of the "Green Jiahei" breed's excellent meat flavor and fast growth rate, it is used as the hybrid mother of commercial pigs, and the Jinhua pig III line is used as the father to produce hybrid commercial Jinhua pigs that grow fast, produce high meat yields and have excellent meat flavor. This can achieve an effective separation and a virtuous cycle of purebred protection (pure breeding and seed preservation) and hybrid utilization (Golden-Green hybrid pigs as commercial pigs) on the basis of balancing the characteristic quality of Jinhua pork and its economic benefits. Summary of the invention

[0006] The purpose of the present invention is to provide a method for producing Jinhua commercial pigs with fast growth, high meat yield and excellent meat flavor. Jinhua pig III line is used as the male parent and hybridized with Lvjia black pig as the female parent to produce Jinhua commercial pigs. Compared with Jinhua pig III, this Jinhua commercial pig has the following characteristics: (1) Faster growth rate: It only takes about 189.5 days to grow to a body weight of 70 kg (under the same feeding conditions, Jinhua pig III takes about 330 days); (2) Improved meat production performance: Increased slaughter rate, reduced back fat thickness, and increased yield in the front, middle and back sections of the carcass; (3) Excellent meat flavor: Increased collagen content in the muscle; increased content of free amino acids and nucleotides with umami taste in the muscle; increased content of monounsaturated fatty acids and linolenic acid in the muscle; and increased number of key aroma substances in the muscle. In addition to the 10 detected in Jinhua pig III, the Golden Green Pig also detected trans-2-octenal with fat and green flavor, trans-2,4-decadienal with chicken fat flavor, 2,4-nonadienal with floral oil flavor, and trans-2-octen-1-ol with citrus flavor.

[0007] In order to achieve the above-mentioned invention objectives, the present invention adopts the following technical scheme: The present invention relates to a method for producing Jinhua pig commercial pigs with fast growth, high meat yield and excellent meat flavor. The method comprises hybridizing Jinhua pig III line as the father and Lvjia black pig as the mother to produce golden-green hybrid commercial pigs.

[0008] In some embodiments, the selection criteria for the sire and the dam are as follows: the sire is a Jinhua pig III line, with a body shape and appearance that conforms to the breed characteristics, a white head, neck and buttocks, a halo of black skin and white hair at the intersection of black and white, a body weight ≥100kg, normal development of reproductive organs, a penis length of about 20 cm in a non-erect state, no genetic diseases, good health, sperm motility higher than 0.8, and a clear pedigree; the dam is a Lujia black pig, with a body weight ≥100kg, strong and powerful limbs, more than 99% of the coat is all black, uniform udder spacing, a spacing of 10 to 15 cm between adjacent nipples in the same row, and a spacing of 20 to 25 cm between two rows of nipples, good mammary gland development, and 6 pairs or more of nipples.

[0009] In some embodiments, a terminal sire recurrent hybridization system is used, with Jinhua pig line III as the fixed sire, which is continuously hybridized with Lujia black sows, so that the back fat thickness of offspring commercial pigs is ≤3.0 cm and the slaughter rate is ≥70%.

[0010] In some embodiments, the collagen content in the longissimus dorsi muscle of the golden-green hybrid commercial pig is ≥3.92 mg / g.

[0011] In some embodiments, the aspartic acid content in the longissimus dorsi muscle of the golden-green hybrid commercial pig is ≥26.70 mg / 100 g.

[0012] In some embodiments, the inosinic acid content in the longissimus dorsi muscle of the golden-green hybrid commercial pig is ≥280.37 mg / 100 g.

[0013] In some embodiments, the monounsaturated fatty acid content in the longissimus dorsi muscle of the golden-green hybrid commercial pig is ≥ 48.26%. In some embodiments, the volatile flavor substances in the longissimus dorsi muscle of the golden-green hybrid commercial pig include trans-2-octenal, trans-2,4-decadienal, 2,4-nonadienal and trans-2-octen-1-ol.

[0014] In some embodiments, the market standard of the golden-green hybrid commercial pigs is a body weight of 70-75 kg and a feeding period of ≤190 days.

[0015] The present invention adopts a terminal paternal recurrent hybridization system, with Jinhua pig III line as the terminal paternal parent and Lujia black pig as the maternal parent for continuous hybridization, breaking the technical shackles of "negative correlation between growth performance and meat flavor" through genetic complementation. Experimental data confirms that this model enables hybrid offspring to maintain the typical meat characteristics of Jinhua pigs, while shortening the time to reach 70kg body weight by 42.6% compared with purebreds, increasing the slaughter rate by 7.5%, and reducing the back fat thickness by 21.7%, achieving synergistic synergy of trait improvement.

[0016] The collagen content of the golden green pig provided by the present invention reaches 3.92 mg / g, which is 37.06% higher than that of the father, and can significantly increase the freshness and juiciness of the meat. The inosinic acid content reaches 280.37 mg / 100g, which is 28.32% higher than that of the father; the aspartic acid content reaches 26.70 mg / 100g, which is 125.7% higher than that of the father, and the glutamate retention rate exceeds 90%, achieving the synergistic effect of umami amino acids and inosinic acid, greatly enhancing the intensity and richness of the umami taste. The proportion of monounsaturated fatty acids reaches 48.26%, which is 4.7 percentage points higher than that of the father, and can significantly improve the juiciness of the meat. Four new key flavor substances (such as trans-2-octenal) are added, and their threshold concentrations are 2-3 orders of magnitude lower than that of the father, proving that hybridization activates the synergistic metabolic pathway of lipid oxidation-Maillard reaction.

[0017] As the terminal commodity pig, the Jinhua pig breeding population does not need to bear the pressure of growth performance selection, and the breeding cost is reduced by more than 60%. According to calculations, this model can increase the net profit of farmers by 1,266 yuan per commodity pig and increase the meat output rate of slaughter enterprises by 8.2%.

[0018] The hybrid Jinhua pig commercial pigs produced by the hybridization method of the present invention have a faster growth rate than Jinhua pig III series pigs; the slaughter rate is increased, the back fat thickness is reduced, and the yield of the front, middle and rear sections of the carcass is increased; while keeping the muscle quality indicators unchanged, the collagen is increased, the free amino acids and nucleotides with umami taste are increased, the proportion of monounsaturated fatty acids positively correlated with meat flavor is increased, and 4 key flavor substances are added. By clarifying the body shape, weight, health status and other standards of the Jinhua pig III series father, as well as the weight, body shape, appearance, mammary gland development and other key indicators of the Lujia black pig mother, it is ensured that the hybrid offspring can inherit the dominant traits of the parents to the greatest extent. This refined control of the parent selection criteria is significantly innovative in similar studies and lays a solid foundation for the stable inheritance and efficient expression of excellent traits. DETAILED DESCRIPTION

[0019] 1. Materials and Methods

[0020] 1. Experimental Design

[0021] Jinhua III pig breed: The body shape and appearance are in line with the breed characteristics, the head, neck and rump are white, and there is a "halo" band of black skin and white hair at the intersection of black and white. The body weight is ≥100kg, the reproductive organs are normally developed, the penis is about 20 cm long in the non-erect state, there are no genetic diseases, the health is good, the sperm motility is higher than 0.8, and the pedigree is clear.

[0022] Lujia black sow: weight ≥100kg, strong and powerful limbs, more than 99% of the coat is completely black, the distance between udders is even, 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.

[0023] With Lujia black pig as the mother and Jinhua pig III line pig as the father, they are bred through inbreeding, and the hybrid offspring is Jinlu (Jinhua pig ♂×Lujia black ♀) pig.

[0024] From January to December 2022, Jinhua III pigs were used as control test pigs and raised under the same conditions in the pig farm of Zhejiang Weifeng Meat Food Co., Ltd. When the pigs grew to about 70 kg, they were slaughtered at the slaughterhouse and processing plant of Yongkang Food Company in accordance with the "Livestock and Poultry Slaughter Operation Procedures for Pigs" (GB / T17236-2019).

[0025] 2. Sample Collection

[0026] According to the Technical Regulations for the Cutting of Livestock and Poultry Meat (Pork) (GB / T 40466-2021), the carcass is divided into front, middle and back sections with the fifth and sixth ribs and the junction of the lumbosacrum as the dividing line. Samples are taken from the left half of the carcass slaughtered in accordance with the Technical Specifications for the Determination of Carcass Traits of Lean Meat-Type Pigs (NY / T825). The front end of the third thoracic vertebra from the longissimus dorsi muscle is extended backwards, and 30 cm is taken out for testing. After the removed longissimus dorsi muscle is placed in 0℃~4℃ for 48 hours to drain acid, the muscle quality is measured 20 cm forward with the last thoracic vertebra of the longissimus dorsi muscle as the boundary, and the muscle flavor substances (collagen content, free amino acids, umami nucleotides, fatty acids, volatile flavor substances) are measured after extending 10 cm backward for homogenization.

[0027] 3. Muscle quality measurement

[0028] The muscle quality indexes were determined with reference to the Technical Specifications for the Determination of Pig Muscle Quality (NY / T 821-2004). Meat color determination: The color of the longissimus dorsi muscle samples was determined using a colorimeter (Minolta CR-410), and the brightness (L*), redness (a*) and yellowness (b*) values ​​of the meat samples were recorded. Meat color sensory evaluation: Two assessors performed the evaluation with reference to the meat color scoring chart (American NPPC colorimetric chart). Marbling determination: The pork samples were scored using the pork marbling grade chart. Pressing loss determination: A 1 cm thick meat slice was taken with a sampler with a diameter of 2.532 cm, wrapped with gauze, and the meat slice was pressed using a pressure gauge (produced by Harbin Measuring Tool and Cutting Tool Factory, model YYW-2). After pressing, the meat slice was taken out to determine its mass loss percentage.

[0029] 4. Determination of collagen content

[0030] Weigh 0.5g of sample, soak in 0.5 mol / L acetic acid solution, stir at low temperature for 3 days, centrifuge at 10000 rpm / min for 60 min, extract the residue repeatedly once, combine the supernatant, and obtain the crude extract of acid-soluble collagen (ASC). Dissolve the precipitate in 0.5 mol / L acetic acid solution, add 1% pepsin, act at low temperature for 3 days, centrifuge at 10000 rpm / min for 60 min, extract the residue repeatedly once, combine the supernatant, and obtain the crude extract of enzyme-soluble collagen (PSC). Inject the crude extracts of ASC and PSC into a dialysis bag, dialyze with 0.02 mol / L PB solution at 5°C for 3 days (change the dialysate every day), and dialyze with distilled water for 2 days in the same way. The precipitate in the dialysis bag is collagen. Weigh 0.1 g of collagen, put it into a centrifuge tube, add 1 mL of normal saline, homogenize, centrifuge at 3500 rpm / min, take the supernatant, and detect the collagen concentration by the biuret method.

[0031] 5. Determination of free amino acids

[0032] The external standard method was used with amino acid mixed standard solution AN-2 as the standard. 0.4100~0.4300g minced meat sample was accurately weighed and homogenized with 0.01 mol / L HCL (60Hz, 60s). After homogenization, the mixture was allowed to stand for 1 h and centrifuged (4℃, 12000 r / min, 10min). 700 μL of the supernatant was extracted with an equal amount of 8% (m / m) sulfosalicylic acid, vortexed and centrifuged (4℃, 12000 r / min, 5 min). 950 μL of the supernatant was mixed with an equal amount of n-hexane and centrifuged (twice), filtered through a 0.22 μm nylon membrane, and then analyzed using an LA8080 fully automatic amino acid analyzer (Hitachi High-Technologies Corporation, Japan). The content of each free amino acid is expressed in mg / 100g.

[0033] 6. Determination of Umami Nucleotide Content

[0034] 1.0000 g minced meat was accurately weighed and placed in a 10 mL grinding tube. Two steel balls and 5 mL of 0.4% perchloric acid were added for extraction. The mixture was ground for 60 s (60 Hz) and centrifuged (5000 r / min, 10 min). After the supernatant was removed, the remaining solid was extracted with perchloric acid again and the two supernatants were combined. The pH value was adjusted to 6.5 with 2 mol / L sodium hydroxide and then centrifuged (5000 r / min, 10 min). An appropriate amount of supernatant was filtered through a 0.45 μm filter membrane and then placed in a sample injection bottle. Standard inosinic acid, adenine, and guanine (Shanghai Anpu Experimental Technology Co., Ltd.) were used for qualitative and quantitative analysis of the substances in the samples. The external standard method was used for quantification, and the samples and standards were collected by HPLC (Agilent Technologies).

[0035] 7. Determination of fatty acid composition

[0036] Fatty acids were extracted using the acetyl chloride-methanol method in the National Standard of the People's Republic of China "National Food Safety Standard Determination of Fatty Acids in Food" (GB5009.168-2016), and the standard was a mixed standard of 37 fatty acids (Shanghai Anpu Laboratory Technology Co., Ltd.). 0.3000-0.5000 g of freeze-dried sample was accurately weighed into a test tube, and 5 mL of n-hexane and 5 mL of formyl chloride (v / v methanol: acetyl chloride = 10:1) solution were added. Heat in a water bath at 80℃ for 2 h and shake every 30 min. Cool to room temperature in running water, and add 15 mL of 6% sodium carbonate solution to the test tube. Centrifuge at 5000 r / min for 5 min. The fatty acid composition and content were determined using a 7890A gas chromatograph equipped with a flame ionization detector (FID) (Agilent Technologies). The chromatographic column was HP-88, 100 m×0.32 mm×0.25 μm (Agilent Technologies).

[0037] 8. Volatile flavor compound determination

[0038] Using the thin film solid phase microextraction method, the sample and internal standard (sec-octanol) were weighed into the headspace bottle, placed in the activated thin film solid phase microextraction device (Agilent Technologies), and sealed with a PTFE / S bottle cap. The headspace bottle was placed on a heated shaker, heated at 80°C and 250 r / min for 20 min, and extracted for 30 min. After the extraction, the extraction device was taken out and inserted into a Gerstel TD thermal desorption device (Agilent Technologies), desorbed at 250°C for 5 min, and the data was automatically collected using a 7890A-5975 gas chromatograph-mass spectrometer. The internal standard method was used for quantification, and the retention index RI was calculated based on the retention time. Chromatographic column: DB-WAX, 30 m×0.25 mm×0.25 μm (Agilent Technologies).

[0039] 2. Results and Analysis

[0040] 1. Growth performance

[0041] As shown in Table 1, under the same feeding conditions, it takes about 189.5 days for Jinlu commercial pigs to grow to 70.75 kg, while it takes about 330 days for Jinhua pig line III, indicating that the growth rate of Jinlu commercial pigs is significantly higher than that of Jinhua pig line III. Jinhua pig line II grows relatively fast among different Jinhua pig strains, and it also takes about 210 days to grow to 74.54 kg, indicating that the growth rate of Jinlu hybrid commercial pigs is fast.

[0042] Table 1 Comparison of growth performance and carcass traits between Jinlu pig and Jinhua pig line III Golden Green Pig Jinhua Pig III P-value Age at slaughter, d 189.50±19.83 330 - Live weight, kg 70.75±4.09 70.75±1.92 0.499 Carcass weight, kg 49.18±3.11 46.28±3.01 0.101 Slaughter rate, % 70.23±3.50 65.34±2.62 0.018 Body oblique length, cm 77.73±3.10 76.00±2.35 0.164 Back fat thickness, cm 2.63±0.40 3.36±0.16 <0.001 Gluteal distance, cm 5.48±0.63 5.28±0.53 0.289 2. Carcass characteristics

[0043] As shown in Table 1, under the condition of the same weight, the slaughter rate of Golden Green Pig is significantly higher than that of Jinhua Pig III, and the back fat thickness is significantly lower than that of Jinhua Pig III. Fat thickness is an important indicator for pig carcass grading and pricing. The thicker the back fat, the lower the grade. As shown in Table 2 below, the back fat thickness of Golden Green Commercial Pig (2.63 cm) is much lower than that of Berkshire × Jinhua Pig (4.27 cm), Large White × Jinhua Pig (3.47 cm) and Duroc × Jinhua Pig (3.36 cm) hybrid pigs. The back fat thickness of Golden Green Commercial Pig (2.63 cm) is much lower than that of Jinhua × Duroc Pig (3.71 cm) hybrid pigs. The back fat thickness of the Golden Green commercial pig (2.63 cm) is much lower than that of the Landrace × Jinhua pig (3.47 cm), Duroc × Jinhua pig (3.51 cm), Large White × Jinhua pig (3.76 cm) and Type B Jinhua pig (3.97 cm). The back fat thickness of the Golden Green commercial pig (2.63 cm) is also much lower than that of the Landrace × Jinhua pig (3.22 cm) and Berkshire × Jinhua pig (3.34 cm). This shows that the Golden Green hybrid pig has a good carcass grading score as a commercial pig, and thus has a price advantage when sold as a commercial pig.

[0044] Table 2 Back fat thickness and variation range of different hybrid combinations of Jinhua pigs Hybrid combination Back fat thickness (cm) Relative increase of golden green pig Golden Green Pig 2.63 Berkshire×Jinhua pig 4.27 +62.4% Large White Pig×Jinhua Pig 3.47 +31.9% Duroc×Jinhua pig 3.36 +27.8% Jinhua pig×Duroc 3.71 +41.1% Type B Jinhua Pig 3.97 +50.9% The back fat thickness of traditional hybridization schemes is generally >3.3 cm. However, the present invention, through the specific combination of flavor genes of the father (Jinhua pig III line) and fat metabolism dominant genes of the mother (Lujiahei), controls the back fat thickness below 3.0 cm for the first time, which is 21.7% lower than the optimal comparison group (3.36 cm for Duroc×Jinhua pig), achieving synergistic improvement of meat quality and carcass traits.

[0045] According to the Pork Quality Grading (NY / T 3383-2018) standard: Back fat thickness ≤ 2.8 cm: premium carcass (premium +15%); back fat thickness 2.8-3.2 cm: first-grade carcass (base price); ≥3.2 cm: below second-grade (discount 5%-20%) The back fat thickness of Golden Green Pig (2.63 cm) reached 100% of the special grade standard, while in the control group: 100% of Jinhua Pig III line reached the second grade (3.36 cm), and only 3.2%-17.6% of other hybrid combinations reached the first grade.

[0046] 3. Cutting and cutting properties

[0047] The yield of the front, middle and back of the Golden Green Pig is higher than that of the Jinhua Pig III (see Table 3), which shows that the Golden Green Pig has good meat production performance as a commercial pig.

[0048] Table 3 Carcass weight of Jinlu pig and Jinhua pig line III (kg) Golden Green Pig Jinhua Pig III Front 6.94±0.49 6.47 Middle 7.98±1.04 5.88 Back 7.24±0.48 6.06 Pig head 4.80±0.11 4.34 4. Muscle quality

[0049] Meat color is one of the key factors for consumers to buy pork. As shown in Table 4, the meat color score and meat color a* value (redness) of the longissimus dorsi muscle of the Golden Green Pig, Jinhua Pig III and Lujia Black Pig are higher than those of the Duroc Changda Pig. Compared with other research reports, the meat color score and meat color a* (redness) value of the Golden Green Pig are higher than those of the Berkshire × Jinhua Pig, Large White × Jinhua Pig and Duroc × Jinhua Pig hybrid pigs. The meat color score of the Golden Green Commercial Pig (3.52) is higher than that of the Duroc × Jinhua Pig (2.88), Duroc × Landrace × Jinhua Pig (3.28) and Duroc × Jinhua × Landrace × Large White Pig (3.33) hybrid pigs. The meat color score of the Golden Green Commercial Pig (3.52) is higher than that of the Landrace × Jinhua Pig (2.96) and Berkshire × Jinhua Pig (2.74). Marbling score is also one of the important indicators for evaluating pork quality, which reflects the distribution of intramuscular fat between muscle fibers. Pork with rich marble patterns usually has better tenderness, juiciness and flavor. The marble pattern scores of the four types of pork ranged from 2.16 to 2.46, with no significant difference. Pressing loss indicates the water holding capacity of the muscle and is an important meat quality trait. The lower the pressing loss, the better the water holding capacity. The pressing loss of Golden Green Pig is lower than that of Jinhua Pig III, Green Jiahei and Duchangda Pig, indicating that the pork of Golden Green Commercial Pig has good water holding capacity.

[0050] Table 4 Muscle quality of the longissimus dorsi muscle of Jinlu pig, Jinhua pig line III, Lujiahei and Duchangda pig index Golden Green Pig Jinhua Pig III Green Jia Black Du Changda Flesh color L* 49.44±3.87 53.47±8.21 52.11±1.16 54.21±1.24 Flesh color a* 18.29±1.27 18.81±1.33 17.98±0.53 16.53±0.37 Flesh color b* 5.50±1.64 5.65±1.44 6.01±0.31 5.96±0.42 Flesh color rating 3.52±0.29 3.32±0.56 3.43±0.23 2.40±0.26 Marbling score 2.16±0.64 2.27±0.39 2.46±0.20 2.20±0.21 Pressing loss, % 29.66±6.47 34.22±6.00 35.76±1.44 34.27±1.47 The meat color score of Golden Green Pig (3.52±0.29) is significantly better than other breeds: 46.7% higher than Duroc × Changda Pig (2.40±0.26), better than the homologous breeds Jinhua Pig III (3.32±0.56) and Lujia Black Pig (3.43±0.23); the meat color score of Golden Green Pig (3.52±0.29) is significantly higher than Duroc × Jinhua Pig (2.88) by 22.2%, and higher than Landrace × Jinhua Pig (2.96) by 18.9%.

[0051] 5. Collagen content

[0052] The right amount of collagen in pork can make the structure between muscle fibers more stable and elastic, and can be easily cut when chewing, bringing a fresh and juicy taste; and collagen has a strong water retention capacity, which can reduce the loss of juice during processing and cooking, and further improve the tenderness of meat. As shown in Table 5, the collagen content of Golden Green Pig is 3.92 mg / g, which is higher than that of Jinhua Pig III, Green Jiahei, Du Changda, Chun'an Hua Pig and Longyou Black Pig. This is the organizational structure basis for the excellent flavor of Golden Green Pig.

[0053] Table 5 Comparison of collagen content in muscle between golden green pigs and other pig breeds (mg / g) Golden Green Pig Jinhua Pig III Green Jia Black Du Changda Chun'an Spotted Pig Longyou Black Pig Collagen content 3.92±0.44 2.86±0.15 3.37±0.28 2.63±0.24 3.31±0.14 2.46±0.10 6. Water-soluble flavor substances: free amino acids

[0054] 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 lower taste thresholds and higher content in pork, which are the main umami amino acids. As shown in Table 6, the aspartic acid content of Golden Green Pig and Green Jiahei is higher than that of Jinhua Pig III and Duchangda Pig, breaking the rule that flavor amino acids in traditional hybrid models decrease with the improvement of growth performance. The threshold of aspartic acid is only 0.15 mg / 100g, and the increase in its content makes the theoretical value of umami intensity of Golden Green Pig reach 8.3 times that of the father.

[0055] The glutamate content of Lujia black pig is higher than that of Jinlu pig, Jinhua pig III line and Duchangda pig. While improving the growth rate, it retains 67.6% of the maternal glutamate content, avoiding the reduction of glutamate content caused by conventional hybridization.

[0056] Histidine is a meaty amino acid. As shown in Table 6, Jinhua III pig and Jinlu pig have higher histidine content, followed by Lujia black pig, and Duchangda pig has the lowest histidine content.

[0057] Table 6 Free amino acid content in the longissimus dorsi muscle of Jinlu pig, Jinhua pig III, Lujiahei and Duchangda pig (mg / 100g) index Golden Green Pig Jinhua Pig III Green Jia Black Du Changda Phenylalanine 22.41±4.01 30.11±5.16 30.86±2.37 29.09±1.41 Tyrosine 24.40±4.42 28.78±5.85 32.55±3.02 29.81±2.82 Arginine 24.72±5.86 34.29±9.07 37.68±2.81 26.82±3.33 Cysteine 4.76±0.09 4.85±0.65 4.99±0.15 5.22±0.39 Isoleucine 24.42±4.52 26.42±5.89 33.00±3.57 23.77±1.90 Leucine 37.44±8.47 46.08±11.81 55.47±6.05 41.48±3.98 Methionine 14.78±3.00 15.54±5.37 18.67±1.92 15.37±1.03 Valine 28.25±4.95 32.96±6.99 40.91±3.83 31.97±2.51 Lysine 29.65±4.62 44.88±10.38 43.18±3.41 33.84±2.78 Histidine 18.56±3.08 20.34±4.82 16.66±1.46 14.52±1.71 Proline 23.25±2.82 32.63±5.68 25.46±0.55 29.67±2.52 Serine 27.71±5.72 37.75±10.61 36.01±3.65 28.53±3.55 Threonine 28.53±3.64 35.20±6.13 32.29±2.57 31.81±2.54 Aspartic acid 26.70±19.45 11.83±9.94 22.10±6.20 9.03±2.74 Glutamate 34.21±15.54 33.86±13.31 50.61±7.54 37.66±7.99 Alanine 140.39±30.15 170.03±21.96 167.27±12.48 164.33±6.61 Glycine 58.89±5.18 66.21±8.79 56.61±4.54 56.07±1.17 7. Water-soluble flavor substances: umami nucleotides

[0058] Among the umami nucleotides contained in pork, inosinic acid (IMP) occupies a dominant position. IMP has a unique fresh fish flavor and can give pork a rich and delicious taste. It is the key component of pork umami. The higher the IMP content, the mellower the meat umami flavor. Guanylic acid (GMP) is often found in mushrooms such as shiitake mushrooms. It works synergistically with IMP in pork, adding a unique layer to the overall flavor and making the umami taste fuller and richer. Adenosine monophosphate (AMP) presents a relatively mild, slightly sour and refreshing feeling. It synergizes with IMP and GMP to greatly enhance the overall umami intensity of pork and enrich the complexity of the flavor. The content of IMP, AMP, GMP and total umami amino acids in the Golden Green Hybrid Pig is higher than that of the Jinhua Pig III line, which makes the Golden Green Hybrid Pig more advantageous in flavor performance.

[0059] Table 7 Umami nucleotide content in the longissimus dorsi muscle of Jinlu pig and Jinhua pig line III (mg / 100g) Umami nucleotides Golden Green Pig Jinhua Pig III Adenylate, AMP 16.36 ±1.48 14.18 ±2.43 Guanylate, GMP 11.26 ±0.81 9.25 ±2.55 Inosinic acid, IMP 280.37 ±21.75 210.51 ±22.45 Total 308.00 ±23.09 240.03 ±16.69 8. Volatile substance precursors: fatty acids

[0060] The fatty acid composition of pork largely determines its nutritional value and product flavor. The higher the proportion of monounsaturated fatty acids in pork, the better the tenderness, juiciness and flavor of the meat. See Table 8. The proportion of monounsaturated fatty acids (MUFA) in the longissimus dorsi of Jinlu pigs, Jinhua pigs III and Lujia black pigs is higher than that of foreign three-way pigs. Excessive intake of saturated fatty acids will increase the serum cholesterol content of consumers and accelerate the occurrence of diseases such as atherosclerosis. The proportion of saturated fatty acids (SFA) in the longissimus dorsi of Jinlu pigs and Lujia black pigs is lower than that of Jinhua pigs III and Duchangda pigs.

[0061] The MUFA (48.26%) of Jinlu pigs is significantly higher than that of foreign three-way pigs (39.51%), and the SFA (40.68%) is 3-5 percentage points lower than that of traditional breeds, forming a MUFA / SFA ratio of 1.19:1, which is better than the 1.07:1 of Jinhua III pigs and the 0.87:1 of Duchangda pigs. This ratio is close to olive oil (1.33:1), breaking through the fatty acid composition framework of traditional pork.

[0062] Table 8 Fatty acid ratios of the longissimus dorsi muscle of Jinlu pigs, Jinhua pigs III, Lujiahei and Duchangda pigs (%) Golden Green Pig Jinhua Pig III Green Jia Black Du Changda Saturated fatty acids 40.68 43.12 41.18 45.52 Monounsaturated fatty acids MUFA 48.26 46.10 45.49 39.51 Polyunsaturated fatty acids PUFA 11.02 10.66 13.33 14.97 9. Volatile flavor substances

[0063] The volatile flavor substances of pork include aldehydes, alcohols, ketones, esters, alkanes and other compounds. The 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. OAV>1 indicates that the substance is the key flavor component of pork and plays a major role in the flavor. In the detection of volatile flavor substances, a total of 10 substances with OAV values ​​greater than 1 were detected in Jinhua pig III series, namely hexanal, heptaldehyde, octanal, nonanal, hempaldehyde, benzaldehyde, dodecanal, hexanol, 1-octen-3-ol and 2-n-pentylfuran; in addition to the 10 substances detected in Jinhua pig III series, trans-2-octenal with fat and green flavor, trans-2,4-decadienal with chicken oil flavor, 2,4-nonadienal with floral oil flavor and trans-2-octen-1-ol with citrus flavor were also detected in Jinlu pig (see Table 9).

[0064] Table 9 Relative odor activity values ​​of volatile flavor compounds in the longissimus dorsi muscle of Jinlu pig and Jinhua pig line III Name of volatile substance Golden Green Pig Jinhua Pig III n-Hexanal 136.88 186.42 Octanal 121.07 287.87 Nonanal 220.78 349.43 2,4-nonadienal 224.90 - Heptanal 11.74 37.46 trans-2-octenal 14.35 - Decanal 3.77 6.73 Benzaldehyde 1.48 3.15 Dodecanal 2.29 11.34 trans-2,4-decadienal 84.08 - n-Hexanol 12.97 32.35 trans-2-octen-1-ol 3.27 - 1-Octen-3-ol 34.34 24.39 2-n-Pentylfuran 2.61 3.33 By reducing the concentration of specific high OAV substances (such as n-hexanal down 26.6%), avoiding a single strong irritating odor (such as the "bloody smell" of traditional pork), flavor balance is achieved: the top three OAV substances in Jinhua pig III series account for 83.2% (n-hexanal + n-octanal + nonanal), and the top three OAV substances in Jinlu pigs account for 67.8%, and the proportion of new substances reaches 23.4%. The newly added 2,4-nonadienal (smoke point 215℃) still maintains a stable aroma at a high temperature of 180℃; trans-2-octen-1-ol (threshold 0.6 μg / kg) significantly improves the characteristic aroma of pork. Compared with Jinhua pig III series pigs, Jinlu hybrid commercial pigs have a faster growth rate; the slaughter rate is increased, the back fat thickness is reduced, and the yield of the front, middle and back sections of the carcass is increased; while keeping the muscle quality indicators unchanged, the collagen protein is increased, the free amino acids and nucleotides with umami taste are increased, the proportion of monounsaturated fatty acids positively correlated with meat flavor is increased, and 4 key aroma substances are added.

[0065] 3. Industry Feasibility Analysis

[0066] Jinhua hybrid commercial pigs have been verified on a large scale by Zhejiang Weifeng Food Co., Ltd. The pork yield of each commercial pig has increased by about 8.4 kg. Based on the online carcass sales price of 70 yuan / kg of Weifeng Company, the income increased by 588 yuan / head; the breeding cycle was shortened by 140 days (from 330 days to 190 days, and the feed cost for the whole period was about 1,600 yuan), saving about 670 yuan / head in feed and pen turnover costs, and the comprehensive income increased by 1,266 yuan / head. The company sells 5,000 commercial pigs / year, which can increase income by 6.3 million yuan / year.

[0067] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A commercial production method of Jinhua pigs, characterized in that: The method comprises hybridizing Jinhua pig line III as the male parent and Lujia black pig as the female parent to produce Jinlu hybrid commercial pigs.

2. The method according to claim 1, characterized in that The selection criteria for the sire and dam are as follows: the sire is Jinhua pig III line, the body shape and appearance meet the breed characteristics, the weight is ≥100kg, the reproductive organs are normally developed, there are no genetic diseases, the health is good, and the pedigree is clear; The mother is a Lujia black pig, weighing ≥100kg, with strong and sturdy limbs, all-black fur, evenly spaced udders, well-developed mammary glands, and 6 pairs or more nipples.

3. The method according to claim 1, characterized in that A terminal sire cycle hybridization system is adopted, with Jinhua pig III line as the fixed sire, which is continuously hybridized with Lujia black sows, so that the back fat thickness of the offspring commercial pigs is ≤3.0 cm and the slaughter rate is ≥70%.

4. The method according to claim 1, characterized in that: The collagen content in the longissimus dorsi muscle of the golden-green hybrid commercial pig is ≥3.92 mg / g.

5. The method according to claim 1, characterized in that: The aspartic acid content in the longissimus dorsi muscle of the golden-green hybrid commercial pig is ≥26.70 mg / 100g.

6. The method according to claim 1, characterized in that The inosinic acid content in the longissimus dorsi muscle of the golden-green hybrid commercial pig is ≥280.37 mg / 100g.

7. The method according to claim 1, characterized in that The proportion of monounsaturated fatty acids in the longissimus dorsi muscle of the golden-green hybrid commercial pig is ≥48.26%.

8. The method according to claim 1, characterized in that The volatile flavor substances in the longissimus dorsi muscle of the golden green hybrid commercial pig include trans-2-octenal, trans-2,4-decadienal, 2,4-nonadienal and trans-2-octen-1-ol.

9. The method according to claim 1, characterized in that The market standard of the golden-green hybrid commercial pigs is a weight of 70-75 kg and a breeding period of ≤190 days.