Synthetic microbial flora for improving pork quality and application thereof

Abstract

The invention discloses a synthetic microbial flora for improving pork quality and application thereof. The synthetic microbial flora comprises two kinds of probiotics, namely lactobacillus plantarum WY2401 with the preservation number of CCTCC (China Center For Type Culture Collection) NO. The invention relates to ackermann muciniophilic bacteria. The synthetic microbial flora is prepared by compounding lactobacillus plantarum and ackermann mucophile according to a colony formation unit number ratio of 1: 1, concentrating and freeze-drying. Experimental results show that the synthetic microbial flora is added into the basic feed of the fattening pigs, so that the carcass traits are improved, the intramuscular fat content is increased, the conversion of muscle fiber types and the development of muscle fibers are promoted, and the meat quality is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of animal nutrition, and particularly relates to a synthetic microbial flora for improving pork quality and application thereof. BACKGROUND

[0002] With the improvement of living standards, consumers have increasingly high requirements for pork quality, and intramuscular fat content and muscle fiber type are the biological basis affecting pork quality. Intramuscular fat, as a key factor affecting pork taste and nutritional value, directly relates to the juiciness, flavor and tenderness of pork. A large number of research results show that 2% to 3% of intramuscular fat content is an ideal standard for pork, however, in the modern breeding mode pursuing growth rate and lean meat rate, excessive emphasis on lean meat rate leads to a decrease in intramuscular fat content, poor pork taste and difficulty in meeting the needs of consumers for high-quality pork. Therefore, improving intramuscular fat content has important practical significance for improving pork quality, improving edible value and meeting the interests of consumers. At the same time, muscle fiber type also has an important influence on pork quality. At present, according to the differences in contraction characteristics, structure and metabolic characteristics of muscle fibers, the muscle fiber types of pigs can be divided into four types, namely type I, type II A, type II B and type IIX. The type composition of muscle fibers is closely related to the quality indexes of pork, such as pH value, color, tenderness and intramuscular fat content. For example, muscle with high content of oxidative muscle fibers (such as type I and type II A) usually has good quality, while muscle with high content of glycolytic muscle fibers (such as type II B and type II X) has poor quality. However, muscle fiber type will change during the growth and development of pigs, and this change is affected by many factors, including nutrition and growth environment, which will eventually affect the quality of pork.

[0003] The synthetic microbial flora aims to design and combine specific functional microbial strains to construct a simplified artificial microbial community with target functions. Compared with single bacterial agents or complex natural microbial flora, the core advantage of the synthetic microbial flora is high controllability, predictable function, relatively clear action mechanism, and can realize metabolic complementation and synergistic effect. In the fields of agriculture and animal husbandry, this technology has been applied to soil remediation, crop growth promotion, feed conversion efficiency improvement and animal intestinal health regulation, and has shown significant application potential and industrialization prospect. The formation of high-quality meat traits is a systematic result of multi-dimensional and multi-point interaction between the host and microorganisms. This means that improving meat traits (such as fat synthesis, decomposition, flavor precursor metabolism, etc.) requires simultaneous regulation of multiple key biological processes. Although research has shown that single strains and their metabolites can regulate specific pathways of fat deposition or muscle fiber type, it is difficult to cover the regulation sites or pathways of multiple indicators of meat traits. By using the synthetic microbial flora technology, the modular combination design can achieve the multiplicative effect of multiple strains. SUMMARY

[0004] The present application aims to provide a synthetic microbial flora for improving pork quality and its application, that is, by adding the synthetic microbial flora in the feed during the fattening period, the intramuscular fat content is increased while the carcass traits are improved, the muscle fiber type conversion and muscle fiber development are promoted, thereby improving the meat quality and meeting the demand of high-quality pork for human beings. The applicant's unpublished previous study found that Lactobacillus plantarum WY2401 has a significant effect on muscle fiber type, Akkermansia muciniphila has a significant effect on improving pork carcass quality and intramuscular fat, and the modular 1:1 combination design is carried out by taking advantage of the complementary of the two strains, expecting that the synthetic flora has the composite effect of improving carcass quality, improving muscle fiber type and increasing intramuscular fat, thereby improving pork quality.

[0005] To achieve the above purpose, the present application is realized by the following technical scheme: A synthetic microbial flora for improving pork quality, which is composed of the following two probiotics in a ratio of 1:1 according to the number of colony forming units: a) Lactobacillus plantarum WY2401 Lactobacillus plantarum WY2401), preserved in China Center for Type Culture Collection, with the preservation number CCTCC NO. M2025499 and the preservation date of March 17, 2025; b) Akkermansia muciniphila (Akkermansia muciniphila ).

[0006] The synthetic microbial flora is prepared in the form of freeze-dried powder, and the freeze-drying protectant includes 10% skimmed milk powder, 3% glycerol, 10% malt dextrin and 20% trehalose; The preparation method is as follows: (1) Prepare the freeze-drying protectant: the freeze-drying protectant is prepared by mixing sterile water with the protectant raw materials, which contains 10% skimmed milk powder, 3% glycerol, 10% malt dextrin and 20% trehalose by mass fraction; (2) Activate the probiotics: use a inoculation loop to dip the Lactobacillus plantarum WY2401 bacterial solution on the MRS solid culture medium and draw three-zone lines, then culture at 37°C under aerobic conditions for 24h, pick single colonies and inoculate into MRS liquid culture medium, and culture at 37°C under aerobic conditions for 24h, and subculture 2-3 times, finally obtain the activated Lactobacillus plantarum WY2401 bacterial solution; use a inoculation loop to dip the Akkermansia muciniphila bacterial solution on the BHI solid culture medium and draw three-zone lines, then culture at 37°C under anaerobic conditions for 48h, pick single colonies and inoculate into BHI liquid culture medium, and culture at 37°C under anaerobic conditions for 48h, and subculture 2-3 times, finally obtain the activated Akkermansia muciniphila bacterial solution; (3) Preparation of seed liquid: take the activated Lactobacillus plantarum WY2401, inoculate in MRS liquid medium at a inoculation amount of 2-4% (v / v), and culture at 37°C for 16-24h to prepare the seed liquid; take the activated Akkermansia muciniphila, inoculate in BHI liquid medium at a inoculation amount of 2-4% (v / v), and anaerobically culture at 37°C for 48h to prepare the seed liquid; (4) Centrifugal collection of bacterial slurry: centrifuge the prepared seed liquid at 12000rpm for 10min to collect the bacterial slurry, rinse 3 times with phosphate buffer solution with pH=7.0, and resuspend in 10 11 CFU / mL and freeze-dry, to obtain Lactobacillus plantarum WY2401 and Akkermansia muciniphila probiotic bacterial powders, respectively; (5) Freeze-drying: perform freeze-drying under vacuum condition (1-7 Pa), control the temperature at-40°C to-50°C, and continuously perform for 18-36h to remove water; (6) Packaging: package the freeze-dried bacterial powder in sterile aluminum foil bags and vacuum seal; Storage condition: 4°C, avoid light, and prevent moisture; Performance index: stable viable count, and the viable count after rehydration is not less than 80% of the initial viable count.

[0007] The application further discloses application of the synthetic microbial flora in feed for improving pork quality.

[0008] The improvement of pork quality includes increasing intramuscular fat content of longissimus dorsi muscle, increasing proportion of oxidative muscle fibers in muscle tissue, promoting muscle fiber development, and reducing shear force and drip loss.

[0009] The application is for finishing period Duroc-Yorkshire pigs.

[0010] The application has the following beneficial effects: By adding the synthetic microbial flora, the intramuscular fat content of pork can be significantly increased, and the content of oxidative muscle fibers in muscle tissue can be increased. Meanwhile, the preparation can promote muscle fiber development of pigs, improve tenderness and flavor of pork, and thus improve pork quality. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1A Effect of the synthetic microbial flora of the application on muscle fiber type (expression amount of muscle fiber type related genes).

[0012] Figure 1B Effect of the synthetic microbial flora of the application on muscle fiber type (expression amount of muscle development related genes).

[0013] Figure 2This is an HE staining result of the effect of the synthetic microbial flora of the present invention on the intramuscular fat of the longissimus dorsi muscle. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Experimental strain: Lactobacillus plantarum ( Lactobacillus plantarum WY2401, Akermansia myxophila (Akkermansia muciniphila ) Lactobacillus plantarum ( Lactobacillus plantarum WY2401 is deposited at the China Center for Type Culture Collection (CCTCC), accession number CCTCC NO. M2025499.

[0016] Akkermansia myxophilus (Akkermansia muciniphila (Provided by Shanghai Yuanyan Biotechnology Co., Ltd.)

[0017] Preparation of freeze-dried powder: (1) Preparation of freeze-drying protectant: The freeze-drying protectant is prepared by mixing sterile water with the protectant raw materials, and contains 10% skim milk powder, 3% glycerol, 10% maltodextrin and 20% trehalose by mass fraction.

[0018] (2) Activation of probiotics: Using an inoculation loop, a small amount of Lactobacillus plantarum WY2401 bacterial solution was inoculated onto an MRS solid. Streak the culture medium in three zones, then incubate upside down at 37°C under aerobic conditions for 24 hours; pick a single colony and inoculate it into MRS liquid. In the culture medium, the bacteria were incubated upside down at 37°C under aerobic conditions for 24 hours, and then passaged 2-3 times to obtain activated bacterial suspension. A small amount of *Ackermania viridis* suspension was taken with an inoculation loop and streaked in three zones on BHI solid medium, and then anaerobically incubated upside down at 37°C for 48 hours. A single colony was picked and inoculated into BHI liquid medium, and then anaerobically incubated upside down at 37°C for 48 hours, and passaged 2-3 times to obtain activated bacterial suspension.

[0019] (3) Preparation of seed culture: Take activated Lactobacillus plantarum WY2401 and inoculate it into MRS liquid medium at an inoculation amount of 2-4% (v / v) and culture it at 37℃ for 16-24h to prepare seed culture; take activated Akkermansia myxophilus and inoculate it into BHI liquid medium at an inoculation amount of 2-4% (v / v) and culture it anaerobically at 37℃ for 48h to prepare seed culture.

[0020] (4) Centrifugal collection of bacterial slurry: The seed liquid prepared is centrifuged at 12000 rpm for 10 min to collect the bacterial slurry, which is then rinsed three times with a phosphate buffer at pH = 7.0, resuspended to 10 11 CFU / mL with the freeze-drying protective agent described in step (1), and freeze-dried to obtain Lactobacillus plantarum WY2401 and mucinophilic Akkermansia muciniphila probiotic bacterial powder.

[0021] (5) Freeze-drying: Freeze-drying is performed under vacuum (1-7 Pa) at a temperature of -40 to -50°C for 18-36 hours to remove water.

[0022] (6) Packaging: The freeze-dried bacterial powder is divided into sterile aluminum foil bags and vacuum sealed.

[0023] Experimental animals: 36 healthy Duroc × Landrace × Yorkshire pigs with an initial weight of about 121 kg. The pigs were allowed to freely eat and drink during the feeding period, and the feeding period was 40 days.

[0024] Example 1: Adding synthetic microbial flora to the feed during the fattening stage to improve meat quality 1. Experimental design Thirty-six Duroc × Landrace × Yorkshire pigs of the same batch, with an initial weight of about 121 kg and good health, were randomly divided into two groups of 18 pigs each, which were fed with basal feed and basal feed supplemented with synthetic microbial flora, respectively. During the experiment, the pigs were allowed to freely eat and drink, and were managed according to the conventional feeding method of the pig farm. The experimental period was 40 days. The pigs were fasted for 24 hours before slaughter, and growth performance and meat quality traits were detected before slaughter. The meat quality traits detected included intramuscular fat content, pH (45 min, 24 h), drip loss (24 h, 48 h), shear force, meat color, meat color score, and marbling score.

[0025] 2. Intramuscular fat content The intramuscular fat content was determined by the Soxhlet extraction method according to the national standard. About 50 g of longissimus dorsi muscle was taken, the tendon membrane was removed, and the meat was ground using a meat grinder. After being placed in a freezer at -80°C for 24 hours, the meat sample was dried in a drying machine for 48 hours. The sample was then weighed and subjected to Soxhlet extraction.

[0026] 3. pH (45 min, 24 h) pH 45min : The pH value was measured within 45 minutes after the pig was slaughtered; pH 24h : The pH value was measured 24 hours after the pig was slaughtered. The determination steps were as follows: the pH meter was calibrated using a standard pH buffer. A small piece of meat sample was cut from the longissimus dorsi muscle of the pig. The electrode was inserted into the meat sample, and the pH value was recorded.

[0027] 4. Drip loss One hour post-slaughter, the longissimus dorsi muscle from the 3rd-4th thoracic vertebrae (from the bottom) of the carcass was harvested. The peripheral myofascia was removed, and the meat was trimmed into 2×2×2cm pieces along the muscle fiber direction. The weight of each piece was weighed using an analytical balance and recorded. The pieces were then placed in sample bags with the muscle fiber direction facing down. The sample bags were labeled, and the samples were placed in a 4℃ refrigerator. Their weights were recorded after 24 and 48 hours. The calculation formula for drip loss (%) was: [(W1 - W2) / W1] × 100%, where W1 is the initial weight of the meat piece, and W2 is the weight of the meat piece after storage.

[0028] 5. Shear force Take a cooked meat sample and let it stand at room temperature for 15 minutes. Take a piece that is 4-6 cm long and has a cross-sectional area of ​​1×1 cm. 2 The meat sample was placed on the groove of the tenderness meter, and the shearing blade was made to pass through the meat sample at a constant speed perpendicular to the direction of the muscle fibers. The shearing force of the muscle was recorded.

[0029] 6. Flesh-colored One to two hours after slaughter, the longissimus dorsi muscle at the thoracolumbar junction was measured using a fully automatic colorimeter. The values ​​of L* (brightness), a* (redness), and b* (yellowness) were read. Each sample was measured three times and the average value was taken.

[0030] 7. Flesh color rating The longissimus dorsi muscle at the thoracic-lumbar junction was placed in a 4°C environment for 24 hours. Fresh meat samples were cut with a knife and scored using a standard color chart of the fresh meat surface.

[0031] 8. Marble Pattern Rating The longissimus dorsi muscle at the thoracolumbar junction was placed in a 4°C environment for 24 hours. Fresh meat samples were cut with a knife and scored against a marbled scoring chart.

[0032] 9. Experimental Results: As shown in Table 1, there were no significant differences between the two groups in initial body weight, final body weight, average daily weight gain, average daily feed intake, and feed conversion ratio in this experiment. P＞0.05）， This indicates that adding synthetic microbial flora to the diet during the fattening stage has no effect on the growth performance of pigs.

[0033] Table 1. Effects of adding synthetic microbial inoculants to the diet during the fattening stage on pig growth performance.

[0034] As shown in Table 2, compared with the control group, the addition of synthetic microbial flora to the diet significantly increased the ocular muscle area of ​​fattening pigs ( P <0.05), indicating that adding synthetic microbial flora to the diet during the fattening stage can improve the carcass quality of pigs.

[0035] Table 2 Effects of adding synthetic microbial flora in the fattening stage feed on pork quality Item Control group Test group Value Live weight (kg) 164.0±1.21 164.9±0.96 0.61 Carcase weight (kg) 131.46±1.67 132.78±1.35 0.58 Dressing percentage (%) 80.00±0.00 81.00±0.00 0.60 Thickest part of shoulder (mm) 43.23±1.22 40.51±1.98 0.30 Chest-lumbar joint (mm) 21.17±1.55 23.63±1.54 0.34 Lumbar-sacral joint (mm) 22.13±1.96 19.70±1.87 0.45 Average back fat thickness (mm) 30.29±1.32 26.89±1.10 0.29 Straight length of carcase (cm) 118.33±1.26 118.33±1.69 1 Inclined length of carcase (cm) 103.67±0.90 103.67±1.61 1 Eye muscle area (cm 2 )]> 77.97±4.79 96.93±5.02 0.04 As shown in Table 3, compared with the control group, the intramuscular fat content of the test group added with synthetic microbial flora in the diet was significantly improved ( P< 0.05 )、 , the drip loss was significantly reduced ( P< 0.05 ） , the shear force was significantly reduced ( P < 0.05), the meat color score was significantly improved ( P< 0.05 P< 0.05 ） , indicating that adding synthetic microbial flora in the fattening stage feed can significantly improve pork quality.

[0036] Table 3 Effects of adding synthetic microbial flora in the fattening stage feed on pork quality Item Control group Test group Value Intramuscular fat content (%) 2.84±0.14 4.5±0.39 0.01 pH 45min ]]> 6.26±0.11 6.36±0.08 0.51 pH 24h ]]> 5.45±0.03 5.52±0.04 0.22 Drip loss (%) 2.20±0.19 1.64±0.21 0.03 Shear force (kg / cm 2 ) 40.08±0.85 36.30±0.91 0.04 Brightness (L*) 35.15±0.32 34.99±0.42 0.78 Redness (a*) 2.45±0.14 2.59±0.12 0.45 Yellowness (b*) 21.03±0.21 21.70±0.24 0.09 Meat color score 2.37±0.14 3.37±0.20 0.03 Marbling score 1.17±0.08 2.31±0.29 0.04 Example 2: Adding synthetic microbial flora in the fattening stage feed to improve the content of oxidative muscle fibers and promote muscle fiber development.

[0037] 1. Tissue sample collection The longissimus dorsi muscle at the 5-6 ribs from the left half carcass of the fattening pigs in Example 1 was taken, the upper 1 / 3 near the back fat was removed, the lower 1 / 3 near the spine was removed, and the middle 1 / 3 was reserved. The muscle was cut into thin strips perpendicular to the muscle fibers and placed in a fixing solution for hematoxylin-eosin (HE) staining. Another part of the sample was placed in a cryogenic tube, immediately frozen in liquid nitrogen and transferred to a -80°C refrigerator for further analysis.

[0038] 2. Extraction of total muscle RNA 2.1 An appropriate amount of ground tissue sample was taken in an RNAase free 1.5 mL EP tube, then 1 mL of RNAio plus was added, followed by 200 μL of pre-cooled chloroform (RNAio plus: chloroform = 5:1). After mixing, it was incubated at room temperature for 5 min.

[0039] 2.2 4°C, 12000 g centrifugation for 20 min, the supernatant was taken into an RNAase free 1.5 mL EP tube, and then an equal volume of pre-cooled isopropanol was added. After mixing, it was incubated overnight.

[0040] 2.3 4°C, 12000 g centrifugation for 20 min, the supernatant was discarded, and 1 mL of pre-cooled 75% ethanol was added to wash the precipitate. The operation was repeated 3 times.

[0041] 2.4 4°C, 12000 g centrifugation for 10 min, discard the supernatant, after the precipitate is dried, add an appropriate amount of DEPC water, and blow repeatedly with a pipette to fully dissolve.

[0042] 2.5 Take 1 μL of solution in each tube to determine the experimental results on the nucleic acid / protein analyzer.

[0043] 3. Reverse transcription and real-time fluorescent quantitative PCR 3.1 Add each component to the RNase-free PCR tube on ice according to Table 4, mix and centrifuge momentarily, and let the real-time fluorescent quantitative PCR instrument perform amplification. The amplification conditions are: 37°C, 2 min; 55°C, 15 min; 85°C, 15 min; 85°C, 5 min, 4°C cycle.

[0044] Table 4 Reverse transcription reaction system Component Added amount 5X ABScript IIIRT Mix 4 μL 20X gDNA Remover Mix 1 μL Total RNA 1µg Nuclease-free H2O Supplemented to 20 μL 3.2 According to the following Table 5 system, point SYBR Green Mix dye, primer of the gene to be tested and sample into the 96-well quantitative PCR plate, and then machine on the fluorescent quantitative PCR instrument.

[0045] Table 5 Real-time fluorescent quantitative PCR reaction system Component Volume SYBR Green Mix 5 μL cDNA 4 μL Forward primer 0.5 μL Reverse primer 0.5 μL 4. Experimental results: from Figure 1A It can be seen that compared with the control group, the expression of MyHCI in the longissimus dorsi muscle of the test group was significantly increased (P<0.05), and the expression of MyHCⅡb was significantly reduced (P<0.05), indicating that the addition of synthetic microbial flora in the feed during the fattening stage significantly increased the content of oxidative muscle fibers in the longissimus dorsi muscle of pigs. P<0.05 P< It can be seen that compared with the control group, the expression of MyHCI in the longissimus dorsi muscle of the test group was significantly increased (P<0.05), and the expression of MyHCⅡb was significantly reduced (P<0.05), indicating that the addition of synthetic microbial flora in the feed during the fattening stage significantly increased the content of oxidative muscle fibers in the longissimus dorsi muscle of pigs. Figure 1B P< It can be seen that compared with the control group, the expression of MyHCI in the longissimus dorsi muscle of the test group was significantly increased (P<0.05), and the expression of MyHCⅡb was significantly reduced (P<0.05), indicating that the addition of synthetic microbial flora in the feed during the fattening stage significantly increased the content of oxidative muscle fibers in the longissimus dorsi muscle of pigs.

[0046] Example 3: Addition of synthetic microbial flora in the feed during the fattening stage promotes intramuscular fat deposition in the longissimus dorsi muscle 1. Take the muscle samples in Example 2 for hematoxylin-eosin (HE) staining, the specific steps are as follows: 1.1 Trim the fixed muscle sample, then wash it in water for 24 h to remove formalin. After that, perform a dehydration step, i.e. gradually immerse in increasing concentrations of alcohol (0%, 80%, 85%, 90%, 95% alcohol and absolute alcohol) for 2 h, to gradually dehydrate the tissue sample.

[0047] ​​1.2 After dehydration, the muscle samples were placed in xylene for 1–2 minutes until transparent, then immersed in paraffin to allow for permeation, so that they could be sliced ​​into thin sections in subsequent steps. Paraffin was used as the permeation medium. The tissue samples were immersed in paraffin for a period of time to ensure complete saturation. Then, the tissue samples were placed in a specimen mold, and molten paraffin was gradually poured in to completely embed them.

[0048] 1.3 The embedded tissue samples were fixed on a microtome and cut into sections, typically 4-6 micrometers thick. These sections were then transferred onto glass slides.

[0049] 1.4 Soak the sections in a dewaxing agent (xylene I, II, etc.), then place them sequentially in a mixed solution (ethanol and xylene in a 1:1 ratio), ethanol (100%, 95%, 90%, 80%, and 70%) for 15 minutes each, and make the tissue samples transparent.

[0050] 1.5 Immerse the sections in hematoxylin staining solution for 5-10 minutes, then rinse 9-10 times with tap water; then phenolize the sections with hydrochloric acid-alcohol solution for 3 seconds, rinse again, and maintain blue staining in water for 10 minutes. After staining, immerse the sections sequentially in 80% ethanol, 95% ethanol, and anhydrous ethanol for dehydration. Finally, stain in xylene solution for 20 minutes.

[0051] 1.6 Cover the stained sections with coverslips and dry them in an oven (37°C) for storage.

[0052] 1.7 Muscle images were acquired using a photomicrography system.

[0053] 2. Experimental Results: From Figure 2 It can be seen that, compared with the control group, the experimental group had an increased number of fat cells in the longissimus dorsi muscle, indicating that the addition of synthetic microbial flora to the diet during the fattening stage promotes fat deposition in the longissimus dorsi muscle.

[0054] In summary, the addition of synthetic microbial flora to the diet of Duroc, Landrace, and Large White pigs during the fattening period can improve carcass quality by increasing intramuscular fat content in the longissimus dorsi muscle, meat color score, marbling score, oxidized muscle fiber content, and promoting muscle fiber development. At the same time, it can improve the meat quality of Duroc, Landrace, and Large White pigs during the fattening stage by reducing shear force and drip loss.

[0055] The embodiments described above can be further combined or replaced, and these embodiments are merely descriptions of preferred embodiments of the present invention, not limitations on the concept and scope of the present invention. Various changes and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the design concept of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is given by the appended claims and any equivalent technical solutions.

Claims

1. A synthetic microbial flora for improving pork quality, characterized in that, It is composed of two types of probiotics in a 1:1 ratio of colony-forming units: a) Lactobacillus plantarum ( Lactobacillus plantarum WY2401, deposited at the China Center for Type Culture Collection, accession number CCTCC NO. M2025499; b) Akkermansia myxophila (Akkermansia muciniphila ).

2. The synthetic microbial community according to claim 1, characterized in that, The synthetic microbial community is prepared in the form of lyophilized powder, and the lyophilization protectant includes 10% skim milk powder, 3% glycerol, 10% maltodextrin, and 20% trehalose. The preparation method is as follows: 1) Preparation of freeze-drying protectant: The freeze-drying protectant is prepared by mixing sterile water with the protectant raw materials, and it contains 10% skim milk powder, 3% glycerol, 10% maltodextrin, and 20% trehalose by mass fraction. 2) Activation of probiotics: Using an inoculation loop, streak Lactobacillus plantarum WY2401 culture onto three zones of MRS solid medium, then incubate upside down at 37°C under aerobic conditions for 24 hours. Single colonies are then picked and inoculated into MRS liquid medium, and incubated upside down at 37°C under aerobic conditions for 24 hours. This process is repeated 2-3 times to obtain activated Lactobacillus plantarum WY2401 culture. Similarly, using an inoculation loop, streak Ackermania muscaria culture onto three zones of BHI solid medium, then incubate anaerobically at 37°C upside down for 48 hours. Single colonies are then picked and inoculated into BHI liquid medium, and incubated anaerobically at 37°C upside down for 48 hours. This process is repeated 2-3 times to obtain activated Ackermania muscaria culture. 3) Preparation of seed culture: Take activated Lactobacillus plantarum WY2401 and inoculate it into MRS liquid medium at an inoculation rate of 2-4% (v / v), and culture it at 37℃ for 16-24h to prepare seed culture; take activated Akkermansia myxophilus and inoculate it into BHI liquid medium at an inoculation rate of 2-4% (v / v), and culture it anaerobically at 37℃ for 48h to prepare seed culture; 4) Centrifugation to collect bacterial sludge: The prepared seed culture was centrifuged at 12000 rpm for 10 min to collect bacterial sludge, and then washed three times with phosphate buffer solution at pH 7.

0. The sludge was then resuspended in the lyophilization protectant described in step (1) to 10 mL. 11 CFU / mL and freeze-dried to obtain probiotic powders of Lactobacillus plantarum WY2401 and Akkermansia muciniphila, respectively; 5) Freeze-drying: Freeze-dry under vacuum conditions at 1-7 Pa, with the temperature controlled at -40℃ to -50℃, for 18-36 hours to remove moisture; 6) Packaging: The freeze-dried bacterial powder is dispensed into sterile aluminum foil bags and vacuum sealed; Storage conditions: 4℃, protected from light and moisture; Performance indicators: The number of viable bacteria is stable, and the number of viable bacteria after rehydration is not less than 80% of the initial number of viable bacteria.

3. The application of the synthetic microbial flora as described in claim 1 or 2 in feed for improving pork quality.

4. The application according to claim 3, characterized in that, The improvements in pork quality include increasing the intramuscular fat content of the longissimus dorsi muscle; increasing the proportion of oxidized muscle fibers in the muscle tissue; promoting muscle fiber development; and reducing shear force and drip loss.

5. The application according to claim 4, characterized in that, The application is for Duroc Landrace Large White pigs during the fattening period.

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