An anti-pathogen peptide and its use in the prevention and treatment of infectious diseases in pigs

Abstract

The application discloses an anti-pathogen peptide and application thereof in prevention and treatment of pig infectious diseases, and belongs to the technical field of biological medicine. A core amino acid sequence of the polypeptide is SEQ ID NO:1 or SEQ ID NO:2, the sequence is generated by a protein language model design, is a non-natural sequence, can efficiently inhibit the proliferation of pig pathogenic viruses such as porcine reproductive and respiratory syndrome virus and porcine epidemic diarrhea virus by destroying a pathogen membrane structure mechanism, and has low toxicity to normal cells. The application also protects sequence variants of the polypeptide, a pharmaceutical composition containing the polypeptide and use of the polypeptide in preparation of a medicine for preventing or treating pig viral and bacterial diseases, for example, as a feed additive, a disinfectant or by injection, oral administration and the like. The polypeptide provided by the application solves the technical problems of insufficient activity and high toxicity of an existing anti-pig pathogen polypeptide.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, specifically relating to an antipathogenic peptide and its application in the prevention and treatment of infectious diseases in pigs. Background Technology

[0002] Antimicrobial peptides are a class of natural or synthetic polypeptides with broad-spectrum antibacterial activity, targeting a wide range of pathogens including bacteria, viruses, fungi, and parasites. Unlike traditional antibiotics, antimicrobial peptides exert their effects through mechanisms such as disrupting pathogen membrane structures, inhibiting metabolism, or interfering with viral replication. Their mechanisms of action are diverse, and resistance is unlikely to develop through a single target. However, currently disclosed natural or modified peptides for combating porcine pathogens still suffer from technical drawbacks such as insufficient efficacy (e.g., excessively high EC50 or MIC values) and / or poor safety (high cytotoxicity).

[0003] Swine farming is a vital pillar of the global agricultural economy, but viral diseases caused by viruses such as porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), porcine deltacoronavirus (PDCoV), porcine reproductive and respiratory syndrome virus (PRRSV), and rotavirus (RV) continue to pose a serious threat to the industry. These diseases spread rapidly, have high morbidity and mortality rates, and lack effective treatments, causing enormous economic losses to the global swine industry. The shortcomings of existing methods for preventing and controlling viral diseases in swine farming are as follows: For pathogens such as African swine fever virus (ASFV), there are currently no commercially available effective vaccines. PRRSV mutates rapidly, and existing vaccines have limited cross-protective capabilities, often resulting in "immunization failure" in practice. The variety of chemical antiviral drugs available for swine is very limited, and they generally suffer from problems such as drug resistance, potential liver and kidney toxicity, and drug residues, which are inconsistent with the development trend of green, antibiotic-free farming. While strict biosecurity management is fundamental to controlling disease transmission, it is a passive defense measure, costly, and difficult to completely prevent the introduction of viruses in high-risk areas.

[0004] Despite the advantages of broad-spectrum activity and low drug resistance, antipathogenic peptides still face challenges in large-scale production, cost control, and clinical translation. For example, the extraction efficiency of natural antipathogenic peptides is low, the synthesis cost is high, and some peptides may be toxic to host cells. Therefore, the development of highly effective and safe antipathogenic peptides remains a research hotspot in the current biomedical field. Summary of the Invention

[0005] The purpose of this invention is to provide an antipathogenic peptide that effectively inhibits porcine pathogens while exhibiting low cytotoxicity.

[0006] The objective of this invention is achieved through the following technical solution: An antipathogenic peptide, wherein the antipathogenic peptide is V1 or V2; the amino acid sequence of V1 is shown in SEQ ID NO:1; and the amino acid sequence of V2 is shown in SEQ ID NO:2.

[0007] As a more preferred technical solution of the present invention: the net charge of the antipathogenic peptide V1 is +2; the hydrophobicity is 0.858; the hydrophobic distance is 0.580; and the hydrophobic surface is FILLVWLYFAGP.

[0008] As a more preferred technical solution of the present invention: the net charge of the antipathogenic peptide V2 is +3; the hydrophobicity is 0.684; the hydrophobic distance is 0.525; and the hydrophobic surface is FFFFAYIYFL.

[0009] Another object of the present invention is to provide an antipathogenic peptide variant having an amino acid sequence that is at least 50% identical to SEQ ID NO: 1 or SEQ ID NO: 2; the variant having the activity of inhibiting the proliferation of porcine pathogens by disrupting the pathogen membrane structure or blocking the binding of pathogen membrane proteins to receptors.

[0010] As a preferred technical solution of the present invention: the variant comprises 1 to 10 conserved amino acid substitutions, additions, or deletions, wherein the conserved amino acid substitutions are performed within the following groups: aliphatic hydrophobic group comprises glycine, alanine, valine, leucine, and isoleucine; aromatic hydrophobic group comprises phenylalanine, tyrosine, and tryptophan; acidic group comprises aspartic acid and glutamic acid; basic group comprises lysine, arginine, and histidine; hydroxyl-containing polar group comprises serine and threonine; and amide-containing polar group comprises asparagine and glutamine.

[0011] As a preferred technical solution of the present invention: the antipathogenic peptide comprises at least one pharmaceutically acceptable modification; the modification is selected from: N-terminal acetylation, C-terminal amidation, cyclization, polyethylene glycolation, lipolation or introduction of D-amino acids.

[0012] As a preferred technical solution of the present invention: the cyclization is selected from the amide bond connection (head-tail ring) formed between the N-terminus and C-terminus of the peptide chain; or the disulfide bond connection formed between the side chains of two cysteine ​​residues in the peptide chain; or the connection formed between the side chain of one amino acid in the peptide chain and the N-terminus or C-terminus.

[0013] Another object of the present invention is to provide a pharmaceutical composition characterized by comprising the antipathogenic peptide according to any one of claims 1-6; and a pharmaceutically acceptable carrier or excipient.

[0014] As a preferred technical solution of the present invention, the dosage form is selected from feed additives, skin disinfectants, injections, oral preparations or sprays.

[0015] Another object of the present invention is to provide the use of the said antipathogenic peptide or the said pharmaceutical composition in the preparation of a medicament for the prevention or treatment of porcine pathogen infections.

[0016] As a preferred technical solution of the present invention: the porcine pathogens are coronavirus, reovirus and bacteria.

[0017] As a preferred technical solution of the present invention: the coronavirus is PEDV, TGEV, or PDCoV.

[0018] As a preferred technical solution of the present invention: the reovirus is RV.

[0019] As a preferred technical solution of the present invention, the bacteria are Escherichia coli, Staphylococcus aureus, or Pseudomonas aeruginosa.

[0020] As a more preferred technical solution of the present invention: the PEDV is of type GIIa, GIIb or GIIc.

[0021] As a preferred technical solution of the present invention: the TGEV is a h-strain.

[0022] As a preferred technical solution of the present invention: the PDCoV is of type GII.

[0023] As a preferred technical solution of the present invention: the PRRSV is NADC30 strain.

[0024] Another object of the present invention is to provide the use of the antipathogenic peptide or the pharmaceutical composition in the preparation of a medicament for use in combination with antibiotics to improve the efficacy of antibiotics.

[0025] The beneficial effects of antipathogenic peptides V1 and V2 are: they exhibit significantly lower half-maximal effective concentrations (MCCs) against major porcine pathogens such as PEDV, TGEV, PDCoV, PRRSV, RV, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Example data show that their EC50 values ​​in in vitro cell models are far lower than those of peptides reported in the prior art (such as PMAP-37 with a MIC > 20 μg / mL), achieving effective pathogen inhibition at lower doses and greatly improving antibacterial and antiviral efficiency. Within the concentration range where they exhibit high activity against pathogens, they show extremely low cytotoxicity against normal porcine cells (such as PK-15 cells), with their half-maximal cytotoxic concentrations far exceeding their EC50 values, thus exhibiting a higher therapeutic index (CC50 / EC50) and better safety for clinical application. They are not only effective against various porcine viruses (such as PRRSV and PEDV) but also have inhibitory activity against porcine pathogenic bacteria. This broad-spectrum "one-dose-multiple-effects" characteristic, compared to single-function peptides in existing technologies, enables more comprehensive control of mixed infections in pig farms, saving on medication costs and reducing the complexity of feeding management. It possesses a stable α-helical amphiphilic structure. Furthermore, it allows for pharmaceutical modifications such as N-terminal acetylation, C-terminal amidation, cyclization, or polyethylene glycol conversion, significantly enhancing its stability and half-life in vivo. This facilitates the development of various dosage forms (such as oral formulations, sprays, and long-acting injections), addressing the industry pain points of peptide drugs being easily degraded and requiring frequent administration. It exerts its effect by physically disrupting the pathogen's membrane structure; this mechanism of action differs from traditional antibiotics or antiviral drugs that target specific proteins, fundamentally reducing the risk of pathogen resistance and providing a long-term solution for sustainable livestock disease control. Attached Figure Description

[0026] Figure 1 This is a helical diagram of the antipathogenic peptide V1 of the present invention.

[0027] Figure 2 This is a helical diagram of the antipathogenic peptide V2 of the present invention.

[0028] Figure 3 This is a diagram showing the inhibitory effect of the antipathogenic peptide of the present invention on PEDV GIIa type.

[0029] Figure 4 This is a diagram showing the inhibitory effect of the antipathogenic peptide of the present invention on PEDV GIIb type.

[0030] Figure 5 This is a diagram showing the inhibitory effect of the antipathogenic peptide of the present invention on PEDV GIIc type.

[0031] Figure 6 This is a diagram showing the inhibitory effect of the antipathogenic peptide of the present invention on TGEV.

[0032] Figure 7 This diagram illustrates the inhibitory effect of the viral peptide of the present invention on PDCoV.

[0033] Figure 8 This is a diagram showing the inhibitory effect of the antipathogenic peptide of the present invention on PRRSV.

[0034] Figure 9 The diagram shows the inhibitory effects of the antipathogenic peptides of the present invention after amino acid substitution on PEDV, PDCoV, and PRRSV.

[0035] Figure 10 The diagram shows the inhibitory effects of the antipathogenic peptide cyclization of the present invention on PEDV, PDCoV, and PRRSV.

[0036] Figure 11 This is a graph showing the EC50 detection results of the antipathogenic peptide V1 of the present invention inhibiting PEDV.

[0037] Figure 12 The image shows the detection results of the half-lethal CC50 of the antipathogenic peptide V1 of the present invention on porcine intestinal epithelial cells IPEC-J2.

[0038] Figure 13 The diagram shows the inhibitory effect of the antipathogenic peptide V1 of the present invention on diarrhea in 28-day-old piglets when used as a feed additive. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the examples, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased from legitimate channels.

[0041] like Figure 1 and 2 The diagram shows the helical arrangement of antipathogenic peptides V1 and V2, illustrating the distribution of their amino acid residues on the α-helix structure. The diagram clearly shows that hydrophobic and hydrophilic / charged amino acids are clustered on one side of the helix, forming distinct hydrophobic and hydrophilic surfaces. This amphiphilic structure is the structural basis for their ability to penetrate viral envelopes or cell membranes and exert antiviral activity.

[0042] Example 1: Evaluation of the in vitro antiviral activity of antipathogenic peptides V1 and V2 against PEDV, TGEV, PDCoV and PRRSV.

[0043] V1 sequence: FWGALYKIVAKILPSLFS; V2 sequence: FYSSFYKGALKFIPKFFS.

[0044] This embodiment aims to evaluate the inhibitory activity of V1 and V2 at the in vitro cellular level against three major porcine enteric coronaviruses: PEDV, TGEV, PDCoV, and highly pathogenic PRRSV. Simultaneously, the activity advantage and sequence specificity of the peptides of this invention are verified by comparison with positive and negative controls. The positive control used mettlein, and the negative control was a non-functional disordered peptide. All peptides were dissolved in 0.1% DMSO and stored at -80°C. PEDV included GIIa, GIIb, and GIIc types, with GIIc being the currently circulating strain; TGEV was strain h; PDCoV was type GII; and PRRSV was NADC30. Vero and ST cells were used.

[0045] Resuscitate cells to 100-mm culture dishes, maintaining approximately 80% confluence. Discard the culture medium, wash twice with 2 mL PBS, add 1 mL of 0.25% trypsin, and place in a cell culture incubator to digest the cells. Observe the digestion under a microscope. Stop the digestion with 2 mL of serum-containing culture medium, gently remove the cells using a pipette, and count them. [Further details on cell count and digestion follow.] 5 Cells were seeded at a density of 100 cells / well in 48-well plates and then cultured in a cell culture incubator.

[0046] The antipathogenic peptide was mixed with the diluted virus solution (MOI=0.1) and incubated at 37°C with 5% CO2 for 8-12 hours. After 12 hours of cell plating, when the cells adhered and formed a monolayer, the culture medium in the 48-well plates was discarded. 300 μL of a mixture of PEDV and the antipathogenic peptide (MOI=0.1) was added to each well, and the plates were incubated at 37°C with 5% CO2 for 1 hour to allow for virus adsorption to the cells. After 1 hour of virus adsorption, the medium was changed, and the unadsorbed virus solution was discarded. The cells were washed twice with PBS, and 600 μL of normal 2% FBS cell culture medium was added to each well. After 24 hours of challenge, the culture medium was discarded, the cells were washed twice with PBS, and then 300 μL of TRNzol was added. RNA was extracted, reverse transcribed, and the copy number was detected by q-PCR. The inhibition rate of the peptide against the virus was calculated. The results are as follows: Figures 3 to 8 As shown, V1 and V2 exhibited potent inhibitory activity against three major porcine enteric coronaviruses, demonstrating broad-spectrum antiviral potential.

[0047] Example 2: Activity verification of conservative substitution variants.

[0048] The first hydrophobic amino acid L in V1 was replaced with I, and chemical synthesis was commissioned to Shenlian Biotechnology. Its antiviral activity was evaluated using the same procedures as in Example 1. The results are as follows: Figure 9 As shown, the antiviral activity of the variant peptide after L to I substitution was not significantly different from that of the original peptide, proving that conservative substitution is feasible in this invention.

[0049] Example 3: Stability and activity verification of chemically modified peptides.

[0050] The N-terminus of V1 was acetylated and the C-terminus was amidated, followed by chemical synthesis; simultaneously, N- and C-terminal cyclic peptides were synthesized. Their antiviral activity was evaluated using the same procedures as in Example 1. Figure 10 As shown, the N-terminal acetylated and C-terminal amidated modified peptide 1 exhibits higher activity than the original peptide, and its half-life in porcine serum is significantly extended from 1 hour to 5 hours, demonstrating superior drug development potential.

[0051] Example 4: Therapeutic Index (SI) assessment.

[0052] V1 was serially diluted to 31.2, 15.6, 7.8, 3.9, 1.9, and 0.8 μg / ml, and its PEDV inhibition activity was evaluated in the same manner as in Example 1. The inhibition rate of the virus at each concentration was calculated based on the Ct value, and nonlinear regression analysis was performed using GraphPadPrism software to calculate the 50% effective inhibition concentration (EC50) of the peptide.

[0053] .

[0054] V1 was serially diluted to 249.6, 124.8, 62.4, 31.2, 15.6, and 7.8 μg / ml. Cell culture was performed as in Example 1. Vero cells in logarithmic growth phase were digested, counted, and cultured at 2 × 10⁻⁶ cells / ml. 4 The cells were seeded at a density of 100 μL per well in 96-well cell culture plates and incubated at 37°C with 5% CO2 for 12–24 hours until the cells adhered and grew to approximately 80% confluence. The culture medium was discarded, and different concentrations of the test peptide were added to the plates. Control wells containing only culture medium were also included. Each concentration was repeated in triplicate. Cell morphology was observed after another 24 hours of incubation. The assay was performed according to the CCK-8 manual from Tongren Chemical. Cell viability was calculated.

[0055] Cell viability (%) = (OD value of example wells / OD value of cell control wells) × 100%. Selectivity index (SI) was calculated as CC50 / EC50. Results are as follows... Figure 11As shown, the EC50 of V1 of the present invention is in the low micromolar concentration range, while the cytotoxic CC50 is much higher than the EC50, and the obtained SI reaches 30, which has significant application potential.

[0056] Example 5: Preparation of veterinary drug composition.

[0057] The core polypeptide of this invention has excellent drug-like properties and can be prepared into various veterinary compositions suitable for different clinical scenarios, aiming to improve administration convenience, bioavailability, and drug stability. The long-acting injectable formulation is used for rapid and precise treatment of individual animals already suffering from the disease; the long-acting design reduces the frequency of administration and minimizes stress.

[0058] A clear, slightly viscous, sterile liquid injection was prepared by using a standard formula containing 5 mg sodium carboxymethyl cellulose, 1881 mg poloxamer, 9 mg benzyl alcohol, appropriate amounts of citrate / sodium citrate, and 20 mg polypeptide, with water for injection added to a final volume of 1 ml. After intramuscular injection, the drug is slowly released locally, maintaining an effective blood concentration for over 48 hours, achieving a single-dose, multi-day therapeutic effect.

[0059] Oral concentrate for drinking water administration: Used for large-scale, emergency prevention or treatment of the entire pig herd when an epidemic occurs in a pig farm. Administering the medication through the drinking water system is time-saving and labor-saving.

[0060] The standard formula consists of 300mg propylene glycol, 10mg citric acid, 2mg sucralose, 2mg potassium sorbate, and 100mg vitamin C, with purified water added to a volume of 1ml to obtain a high-concentration, clear liquid. This liquid can be easily added to the central drinking water system of a pig farm at a ratio (e.g., 1:4000). The product disperses well in water, does not clog water lines, and has excellent palatability, ensuring that pigs ingest sufficient medication and quickly control the spread of disease.

[0061] Enteric-coated microcapsules added to feed are used for long-term, large-scale disease prevention or treatment in pig farms, especially in the nursery and finishing stages. By formulating the drug into a stable premix, it can be added directly to the feed, achieving stress-free administration and making the operation extremely simple.

[0062] The standard formulation consists of 200g stearic acid, 100g L-type methacrylic acid copolymer, 630g microcrystalline cellulose, 20g talc, and 50g peptides. The resulting enteric-coated microspheres possess sufficient mechanical strength and thermal stability to withstand conventional feed pelleting without rupture. After feeding, the microspheres remain intact in the acidic environment of the pig's stomach, with the enteric coating effectively protecting the peptides from degradation by gastric acid and pepsin. When the microspheres enter the small intestine with the higher pH of the digestive tract, the enteric coating rapidly dissolves, releasing a high concentration of peptides, allowing them to exert maximum local antiviral activity at the intestinal site where the virus primarily infects and replicates. This microsphere premix can be directly mixed into complete feed by feed mills at the recommended ratio (e.g., 200g per ton of feed) for precise and continuous administration to the entire pig herd. Data on V1's inhibitory effect on diarrhea are as follows: Figure 13 As shown.

[0063] Example 6: Evaluation of the inhibitory effects of V1 and V2 on piglet diarrhea.

[0064] In this embodiment, 60 healthy Duroc-Landrace-Large White crossbred weaned piglets, 21 days old, with an average weight of (6.5 ± 0.5) kg, were selected, with half males and half females. They were housed in isolated, disinfected pig pens with free access to water, fed three times daily, and kept at an ambient temperature of 26-28℃. PEDV GIIc modeling was used.

[0065] Sixty healthy piglets were randomly divided into 5 groups of 12 each. The blank control group was fed a basal diet without virus challenge or V1 supplementation; upon virus challenge, they were orally administered an equal volume (3 mL) of sterile PBS buffer. The model control group was fed a basal diet and orally challenged with PEDV. The V1 medium-dose group... Feed a basal diet supplemented with 300 mg / kg V1 and administer an oral PEDV test; High dose V1: Feed a basal diet supplemented with 500 mg / kg V1 and administer an oral PEDV test.

[0066] The calculated dosage of antipathogenic peptide V1 powder was enteric-coated to a particle size of 200-800 μm and uniformly mixed into the basal diet at two doses of 300 mg / kg and 500 mg / kg. The feed was administered three times daily, 100 g each time. On day 8 of the experiment (i.e., 7 days after pre-feeding), except for the blank control group, piglets in all other groups were fasted for 4 hours and then orally administered 3 mL of PEDV virus suspension with a virus titer of 10. 5 TCID 50 / mL. Feed 150g three times daily. Control group piglets were gavaged with an equal volume of sterile PBS. The experiment ended on day 14 post-viral challenge.

[0067] Observation and testing indicators: Diarrhea rate. The fecal condition of each group of piglets was observed and recorded daily at 8:00 AM and 4:00 PM. Fecal scoring criteria: 0 points = formed feces, normal; 1 point = pasty soft feces; 2 points = watery loose feces; 3 points = projectile watery loose feces. A pig with a fecal score ≥ 2 points was considered to have diarrhea.

[0068] Diarrhea rate (%) = (Number of pigs with diarrhea per day in the group / Total number of pigs in the group) × 100% Average daily weight gain was calculated by weighing the patient on an empty stomach in the mornings of Day 1, Day 8 (attack day), and Day 22 (end of the trial). Data on the inhibition of diarrhea by V1 are as follows: Figure 13 As shown.

[0069] The effects of the antipathogenic peptide V1 of the present invention on the average daily weight gain and mortality rate of 28-day-old diarrheal piglets when used as a feed additive are shown in Table 1.

[0070] All experimental data were analyzed and plotted using Prism10 software. Quantitative data are expressed as mean ± standard deviation (Mean ± SD). One-way ANOVA was used for comparisons among multiple groups. If differences were significant, pairwise comparisons were further performed using Duncan's method or Tukey's HSD method. A p < 0.05 was considered statistically significant, and a p < 0.01 was considered highly significant.

[0071] Example 7: Broad-spectrum antibacterial activity of antipathogenic peptide V1 In this embodiment, *Escherichia coli* ATCC 25922, *Staphylococcus aureus* ATCC 29213, and *Pseudomonas aeruginosa* ATCC 27853 were selected for detection. These bacteria were cultured in Müller-Shinton broth (MHB) and Müller-Shinton agar (MHA). MIC values ​​were determined using the microbroth dilution method recommended by the Clinical and Laboratory Standards Institute (CLSI), followed by MBC values ​​determined by plate culture.

[0072] Activate each bacterial strain on its corresponding agar plate. Pick a single colony and inoculate it into 5 mL of liquid culture medium, incubating at 37°C with shaking for 12–18 hours. Adjust the bacterial concentration to 1.5 × 10⁻⁶ with sterile culture medium. 8 The concentration of the bacterial culture was CFU / mL, and then diluted 100 times with culture medium to make the final bacterial concentration used in the example approximately 1.5 × 10⁻⁶. 6 CFU / mL.

[0073] Using a 96-well plate, add 100 µL of V1 peptide stock solution with a concentration of 1024 µg / mL to the wells in column 1, mix well, and then add 100 µL of this solution to the wells in column 2. Continue this 2-fold serial dilution until column 10. After mixing in column 10, discard the 100 µL solution. At this point, the concentrations of V1 peptide in columns 1-10 are 512, 256, 128, 64, 32, 16, 8, 4, 2, and 1 µg / mL, respectively. Positive control (column 11): 100 µL of culture medium + 10 µL of bacterial suspension (peptide-free); negative control (column 12): 100 µL of culture medium (sterile and peptide-free). Add 10 µL of the prepared bacterial suspension to each well in columns 1-11. Incubate for 18-24 hours and observe the results. The lowest drug concentration that completely inhibits visible bacterial growth is taken as the MIC value of the peptide for that bacterial strain.

[0074] After the MIC determination, select all clear wells with MIC values ​​or higher. Thoroughly mix the bacterial suspension in each well using a pipette, and evenly spread 10 µL of the suspension onto the corresponding drug-free agar plate. Incubate the plates at the appropriate temperature for 24-48 hours. Observe the colony growth on the plates. The lowest drug concentration capable of killing more than 99.9% of the original inoculum is used as the MBC value. The results are shown in Table 2.

[0075] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An antipathogenic peptide, characterized in that, The antipathogenic peptide is V1 or V2; the amino acid sequence of V1 is shown in SEQ ID NO: 1; the amino acid sequence of V2 is shown in SEQ ID NO:

2.

2. The antipathogenic peptide according to claim 1, characterized in that: The antipathogenic peptide V1 has a net charge of +2; a hydrophobicity of 0.858; a hydrophobic distance of 0.580; and a hydrophobic surface of FILLVWLYFAGP. The antipathogenic peptide V2 has a net charge of +3; a hydrophobicity of 0.684; a hydrophobic distance of 0.525; and a hydrophobic surface of FFFFAYIYFL.

3. A variant of antipathogenic peptide V1, characterized in that: The variant is to replace the first hydrophobic amino acid L in the antipathogenic peptide V1 of claim 1 with I.

4. A modified antipathogenic peptide V1, characterized in that: It includes pharmaceutically acceptable modifications, said modifications being the N-terminal acetylation and C-terminal amidation of the antipathogenic peptide V1 of claim 1.

5. A pharmaceutical composition, characterized in that, It comprises the antipathogenic peptide of claim 1 or 2, or the variant of claim 3, or the modified antipathogenic peptide V1 of claim 4; and a pharmaceutically acceptable excipient.

6. The pharmaceutical composition according to claim 5, characterized in that, Its dosage form is selected from feed additives, skin disinfectants, injections, oral preparations, or sprays.

7. Use of the antipathogenic peptide of claim 1 or 2 in the preparation of a medicament for the prevention or treatment of PEDV, TGEV, PDCoV, or PRRSV infection; use of a variant of the antipathogenic peptide V1 of claim 3 in the preparation of a medicament for the prevention or treatment of PEDV, PDCoV, or PRRSV infection; use of the modified antipathogenic peptide V1 of claim 4 in the preparation of a medicament for the prevention or treatment of PEDV, PDCoV, or PRRSV infection; use of the antipathogenic peptide V1 of claim 1 in the preparation of a medicament for the prevention or treatment of Escherichia coli, Staphylococcus aureus, or Pseudomonas aeruginosa infection.

8. The use according to claim 7, characterized in that, The PRRSV was strain NADC30.

9. The use according to claim 7, characterized in that, The PEDV is of type GIIa, GIIb, or GIIc.

10. The use according to claim 7, characterized in that, The TGEV mentioned is strain h.

11. The use according to claim 7, characterized in that, The PDCoV mentioned is of type GII.

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