A breeding method for improving the disease resistance of Pengze crucian carp myxosporeans

Abstract

The present invention provides a kind of breeding method that improves the disease resistance of Pengze crucian carp myxosporeans, comprising the following steps: S1. breeding environment treatment, S2. purchasing healthy fry, S3. fry disinfection, S4. fry delivery, S5. feeding management, S6. water quality management, S7. disease prevention and detection, S8. emergency treatment. In the fry disinfection link, Pengze crucian carp fry are soaked by using a biological disinfectant composed of tea saponin, photosensitizing component, carvacrol, artesunate, and choline-lactic acid ionic liquid, and supplemented with LED light irradiation. These disinfecting components can work together after penetrating into the inside of the myxosporeans, inhibiting their growth and reproduction, thereby achieving the effect of effectively killing the myxosporeans. In the emergency treatment link, the insecticide composed of polysaccharide-mercaptosuccinic acid conjugate, antimicrobial peptide, artesunate, nano zinc oxide, triptolide, and carvacrol is used, and through the synergistic effect between the components, multi-target efficient killing of myxosporeans is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture, and in particular to a breeding method for improving the disease resistance of Pengze crucian carp myxosporea. Background Art

[0002] Myxosporidiosis is a parasitic disease caused by pathogenic myxosporids in fish. Myxosporidiosis belongs to the kingdom Protista and is a common parasite of a wide variety of marine and freshwater fish, as well as amphibians and reptiles. It is one of the most common parasites of fish. Myxosporidiosis has no distinct seasonality and can occur year-round, but is most prevalent in late spring, early summer, late autumn, and winter, when water temperatures between 8°C and 25°C are ideal for reproduction. Myxosporidiosis poses a significant threat to fish farming. Cysts form on the body surface or parasitic sites of diseased fish, affecting their growth and, in severe cases, leading to their death. Furthermore, myxosporidiosis reduces the commercial value of diseased fish, even completely eliminating their edible value. In Pengze crucian carp farming, myxosporidiosis can cause mass mortality of both fry and adult fish, resulting in significant economic losses for farmers. The biggest difficulty in preventing and controlling myxosporidiosis during Pengze crucian carp farming is that myxosporidiosis parasitizes in the fish's body and develops into cysts with a hard chitinous shell, making it difficult for drugs to penetrate into the cysts, thus making it difficult to kill the insects. Summary of the Invention

[0003] In view of this, the present invention proposes a breeding method for improving the disease resistance of Pengze crucian carp myxosporeans to solve the above problems.

[0004] The technical solution of the present invention is achieved as follows:

[0005] A breeding method for improving the disease resistance of Pengze crucian carp myxosporea comprises the following steps:

[0006] S1. Aquaculture environment treatment: Spray the bottom and surrounding areas of the pond with quicklime. After 2-4 days, mix compound bacterial agent I into the pond mud. Then, plant aquatic plants in the pond mud.

[0007] S2. Purchase healthy fry: Purchase Pengze crucian carp fry from areas not affected by myxosporidiasis that are shiny, vibrant, and appear healthy.

[0008] S3. Fry disinfection: The purchased fry were immersed in a biological disinfectant for 25-35 min, and irradiated with LED light having a wavelength of 400-700 nm and a light intensity of 1000-3000 Lus while soaking. The biological disinfectant consisted of tea saponin, a photosensitizing component, carvacrol, artesunate, and choline-lactic acid ionic liquid.

[0009] S4. Fry release: The disinfected Pengze crucian carp fry are released into the pond, and the disinfected silver carp fry, bighead carp fry, and grass carp fry are released into the pond for polyculture;

[0010] S5. Feeding management: Pengze crucian carp are fed compound feed I during the fry stage and immune modulators every 7-10 days. Pengze crucian carp are fed compound feed II during the juvenile stage and immune modulators every 10-15 days. Pengze crucian carp are fed compound feed III during the adult stage and immune modulators every 15-20 days.

[0011] S6. Water Quality Management: Disinfect the pond with trichlorfon every 25-35 days. Change the water every 10-20 days, replacing 20-30% of the pond water each time. Maintain dissolved oxygen ≥ 5.0 mg / L, pH 7.2-8.5, ammonia nitrogen ≤ 0.2 mg / L, and nitrite ≤ 0.1 mg / L.

[0012] S7. Disease prevention and detection: Observe fish daily for any abnormal symptoms, and test fish or water samples for the pathogen causing myxosporidiasis every 30-40 days.

[0013] S8. Emergency treatment: Detect abnormal fish bodies, isolate them, and then soak and disinfect them according to the method in S1. After soaking and disinfection, take insecticides at a dose of 40-60 mg / kg based on the body weight of Pengze crucian carp for 4-6 consecutive days.

[0014] Furthermore, the amount of quicklime used in S1 is 100-150 kg / mu, the composite bacterial agent I is composed of Bacillus subtilis, Bdellovibrio, photosynthetic bacteria, and yeast, and the mass ratio of Bacillus subtilis, Bdellovibrio, photosynthetic bacteria, and yeast is (1.0-3.0):(0.4-1.0):(0.5-1.5):(2.0-4.0), and the amount of composite bacterial agent I used is 1-2 kg / mu.

[0015] Furthermore, the aquatic plant is one or a combination of Elodea, Ceratophyllum, Hydrilla verticillata, Vallisneria, and Water Fern.

[0016] Furthermore, the mass volume ratio g / L of tea saponin, photosensitizing component, carvacrol, artesunate, and choline-lactic acid ionic liquid in the S3 biological disinfectant is (1.0-2.0):(0.3-0.5):(0.5-1.5):(0.5-1.5):(4.0-6.0).

[0017] Furthermore, the photosensitizing component is one of chlorophyll a, rose bengal, and eosin Y.

[0018] Furthermore, the choline-lactic acid ionic liquid is prepared by the following method: adding choline chloride to deionized water and stirring at 300-600 r / min for 5-10 minutes to obtain a choline chloride solution, wherein the mass volume ratio of choline chloride to deionized water is (3-5) kg / L:(8-12); pouring the choline chloride solution into a container containing a hydroxide anion exchange resin, performing an ion exchange reaction for 2-4 hours, and collecting the effluent after the reaction is completed to obtain a hydroxide choline solution; adding lactic acid to the hydroxide choline solution, stirring at 100-200 r / min for 24-48 hours at 20-30° C., to obtain the choline-lactic acid ionic liquid.

[0019] Furthermore, the number of crucian carp fry released in Pengze in S4 is 1,500-2,500 per mu, and the number of silver carp fry, bighead carp fry, and grass carp fry released is 200-300 per mu in total.

[0020] Furthermore, the specifications of Pengze crucian carp fry are 30-50g / tail, the specifications of silver carp fry are 50-100g / tail, the specifications of bighead carp fry are 80-150g / tail, and the specifications of grass carp fry are 100-200g / tail.

[0021] Furthermore, in S5, the feeding amount of compound feed I is 1.0-1.5 kg / mu, and it is fed twice a day; the feeding amount of compound feed II is 2.0-4.0 kg / mu, and it is fed three times a day; the feeding amount of compound feed III is 5.0-10.0 kg / mu, and it is fed three times a day.

[0022] Furthermore, compound feed I includes the following raw materials in parts by weight: 20-30 parts of soybean meal, 5-15 parts of fish meal, 10-20 parts of corn gluten meal, 10-15 parts of wheat flour, 2-5 parts of yeast powder, 2-4 parts of fish oil, 1-2 parts of monocalcium phosphate, 0.5-1 parts of choline chloride, 0.5-1 parts of vitamin premix, 1-2 parts of mineral premix, 0.5-1.0 parts of amino acid additives; compound feed II includes the following raw materials in parts by weight: 30-40 parts of soybean meal, 10-15 parts of fish meal, 15-25 parts of corn flour, 5-10 parts of spirulina powder, 3-5 parts of fish oil, 1-2 parts of monocalcium phosphate, 0.5-1 part of choline chloride, 0.5-1 part of vitamin premix, 1-2 parts of mineral premix, and 0.5-1.0 part of amino acid additive. Compound feed III includes the following raw materials in parts by weight: 45-60 parts of soybean meal, 10-20 parts of fish meal, 20-25 parts of corn flour, 10-15 parts of wheat bran, 2-4 parts of phospholipid oil, 1-2 parts of monocalcium phosphate, 0.5-1 part of choline chloride, 0.5-1 part of vitamin premix, 1-2 parts of mineral premix, and 0.5-1.0 part of amino acid additive.

[0023] Furthermore, in S5, the feeding amount of Pengze crucian carp seedling immune regulator is 0.3-0.5 kg / mu, the feeding amount of Pengze crucian carp juvenile immune regulator is 0.6-1.0 kg / mu, and the feeding amount of Pengze crucian carp adult immune regulator is 1.5-2.5 kg / mu.

[0024] Furthermore, the immune modulator includes the following raw materials in parts by weight: 5-15 parts of peptidoglycan, 3-10 parts of saccharide terpenoids, 4-8 parts of garlic powder, 2-6 parts of ginger powder, 1-3 parts of astragalus powder, 1-3 parts of licorice powder, 1-3 parts of adenosine, 4-10 parts of β-glucan, 3-6 parts of mannan, 5-12 parts of Schizochytrium powder, and 3-6 parts of Clostridium butyricum fermentation broth.

[0025] Furthermore, the immune modulator is mixed into the feed or made into 1.5-2.5 mm granules and fed separately.

[0026] Furthermore, the insecticide in S8 comprises the following raw materials in parts by weight: 20-30 parts of chitosan-mercaptosuccinic acid conjugate, 5-10 parts of antimicrobial peptide, 15-25 parts of artesunate, 8-12 parts of nano zinc oxide, 5-8 parts of triptolide, and 3-5 parts of carvacrol.

[0027] Furthermore, the insecticide is prepared by the following method: antimicrobial peptide, artesunate, nano zinc oxide, triptolide, and carvacrol are mixed, and stirred at 500-1000 r / min for 10-30 min to obtain an insecticide core; chitosan-mercaptosuccinic acid conjugate is added to acetic acid with a concentration of 1.5-2.5wt%, and stirred at 500-1000 r / min for 2-4 h to obtain a chitosan-mercaptosuccinic acid conjugate solution, and then the chitosan-mercaptosuccinic acid conjugate solution is sprayed onto the surface of the insecticide core at a spray pressure of 10-20 psi, and then dried at 55-65°C for 2-4 h to obtain the insecticide.

[0028] Further, the chitosan-mercaptosuccinic acid conjugate is prepared by the following method: chitosan is added to acetic acid with a concentration of 1.5-2.5% wt, and stirred at 500-1000 / min for 2-4h to obtain a chitosan solution, wherein the mass volume ratio of chitosan to acetic acid is (0.8-1.2): (90-110) g / ml; mercaptosuccinic acid is added to deionized water, stirred at 500-1000r / min for 10-20min, and then 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added, and the mixture is stirred at 400-600r / min for activation for 25-35min at 20-30°C to obtain an activated mercaptosuccinic acid solution, wherein mercaptosuccinic acid, deionized water, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide are the mass volume ratio of chitosan to acetic acid. The volume ratio g / mL is (0.4-0.6):(30-50):(0.2-0.4):(0.1-0.3); the activated mercaptosuccinic acid solution is added dropwise to the chitosan solution, and the pH of the reaction system is adjusted to 4.9-5.1 using a 1M sodium hydroxide solution, and the reaction is stirred at 400-600r / min at 55-65°C for 18-22h to obtain a reaction solution, and the volume ratio of the activated mercaptosuccinic acid solution and the chitosan solution is (1.8-2.2):1.0; the reaction solution is transferred to a dialysis bag and dialyzed with deionized water for 70-75h, during which the water is changed every 8h to obtain a dialyzed solution; the dialyzed solution is concentrated by rotary evaporation and evaporated at an evaporation temperature of 55-65°C and an evaporation pressure of 8-12mbar for 10-12h to obtain a chitosan-mercaptosuccinic acid conjugate.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention uses a biological disinfectant composed of tea saponin, a photosensitizing component, carvacrol, artesunate, and choline-lactic acid ionic liquid to soak Pengze crucian carp fry, while supplemented with LED light irradiation. Among them, tea saponin can destroy the integrity of the cell membrane of myxosporeans, causing the substances inside to leak out, thereby achieving the killing effect. The photosensitizing component generates reactive oxygen species, which attack the β-1,4-glycosidic bonds and acetylamino groups of the chitin molecular chain of myxosporeans, causing the chemical structure of the shell to break, forming micropores or cracks, which facilitate the penetration of other ingredients. Carvacrol can interfere with the metabolic process of myxosporeans and inhibit their growth and reproduction. Artesunate has good solubility and penetrability, and can quickly enter the body of myxosporeans to inhibit their growth and reproduction. Choline-lactic acid ionic liquid causes the myxospore shell to swell and soften by destroying the intermolecular hydrogen bonds of chitin, providing favorable conditions for the penetration of other disinfectant ingredients. After penetrating into the interior of the myxosporeans, these disinfecting ingredients can work together to inhibit their growth and reproduction, thereby effectively killing the myxosporeans.

[0031] The present invention utilizes an insecticide composed of a polysaccharide-mercaptosuccinate conjugate, antimicrobial peptides, artesunate, nano-zinc oxide, triptolide, and carvacrol. The polysaccharide-mercaptosuccinate conjugate targets and anchors to the chitinous shell of myxosporeans, disrupting the shell's dense structure. This increases the shell's porosity, thereby facilitating the infiltration of other components into the cyst. Artesunate also produces reactive oxygen species within the insect, disrupting the mitochondrial membrane potential and leading to a breakdown in energy metabolism. Artesunate also has a long half-life, maintaining an effective concentration within the insect for a long time, enhancing the therapeutic effect. Triptolide blocks insect division by inhibiting tubulin polymerization. Antimicrobial peptides inhibit insect cell membrane structure, inhibiting its growth and reproduction. Nano-zinc oxide releases zinc ions, inhibiting enzyme activity within the insect and interfering with metabolic processes, further inhibiting its growth and reproduction. Carvacrol disrupts the insect's neural conduction mechanism, affecting its normal physiological functions, thereby achieving the purpose of killing myxosporeans. Through the synergistic effect of polysaccharide-mercaptosuccinic acid conjugate, antimicrobial peptide, artesunate, nano-zinc oxide, triptolide, and carvacrol, the insecticide achieves multi-target and efficient killing of myxosporidians. DETAILED DESCRIPTION

[0032] In order to better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0033] Unless otherwise specified, the experimental methods used in the examples of the present invention are all conventional methods.

[0034] Unless otherwise specified, the materials, reagents, etc. used in the examples of the present invention can be obtained from commercial sources.

[0035] Example 1

[0036] A breeding method for improving the disease resistance of Pengze crucian carp myxosporea comprises the following steps:

[0037] S1. Aquaculture environment treatment: Use quicklime to spray the bottom and surrounding areas of the pond at a dosage of 100 kg / mu. After 2 days, mix compound bacterial agent I into the pond mud. Compound bacterial agent I is composed of Bacillus subtilis, Bdellovibrio, photosynthetic bacteria, and yeast in a mass ratio of 1.0:0.4:0.5:2.0. The dosage is 1 kg / mu. Then, plant Elodea in the pond mud.

[0038] S2. Purchase healthy fry: Purchase Pengze crucian carp fry with normal luster, vitality, normal appearance and no injuries from non-myxosporidial disease epidemic areas.

[0039] S3. Fry disinfection: The purchased fry were immersed in a biological disinfectant for 25 minutes. The biological disinfectant consisted of tea saponin, photosensitizing component, carvacrol, artesunate, and choline-lactic acid ionic liquid in a mass volume ratio of 1.0:0.3:0.5:0.5:4.0 g / L. While soaking, the fry were illuminated with LED light of 450 nm in wavelength and 1000 Lus in intensity. The photosensitizing component was chlorophyll a. The choline-lactic acid ionic liquid was prepared by the following method: adding choline chloride to the The mixture was added into deionized water and stirred at 300 r / min for 10 min to obtain a choline chloride solution, wherein the mass volume ratio of choline chloride to deionized water is 3:8 in kg / L; the choline chloride solution was poured into a container containing a hydroxide anion exchange resin to carry out an ion exchange reaction for 2 h. After the reaction was completed, the effluent was collected to obtain a hydroxide choline solution; lactic acid was added to the hydroxide choline solution, and the mixture was stirred at 100 r / min at 20°C for 48 h to obtain a choline-lactic acid ionic liquid.

[0040] S4. Stocking of Fry: 1,500 disinfected Pengze crucian carp fry will be stocked into the ponds at a rate of 200 per mu. Sterilized silver carp, bighead carp, and grass carp fry will also be stocked into the ponds for mixed culture. The weight of Pengze crucian carp fry is 30g per fry, silver carp fry is 50g per fry, silver carp fry is 80g per fry, and grass carp fry is 100g per fry.

[0041] S5. Feeding management: Pengze crucian carp are fed compound feed I during the seedling stage, with a feeding amount of 1.0 kg / mu each time and fed twice a day. Compound feed I includes the following raw materials in parts by weight: 20 parts of soybean meal, 5 parts of fish meal, 10 parts of corn gluten meal, 10 parts of wheat flour, 2 parts of yeast powder, 2 parts of fish oil, 1 part of calcium dihydrogen phosphate, 0.5 parts of choline chloride, 0.5 parts of vitamin premix, 1 part of mineral premix, and 0.5 parts of amino acid additives. Immune regulators are fed once every 7 days, with a feeding amount of 0.3 kg / mu each time. Pengze crucian carp are fed compound feed II during the juvenile stage, with a feeding amount of 2.0 kg / mu each time and fed 3 times / d. Compound feed II includes the following raw materials by weight: 30 parts of soybean meal, 10 parts of fish meal, 15 parts of corn flour, 5 parts of spirulina powder, 3 parts of fish oil, 1 part of calcium dihydrogen phosphate, 0.5 parts of choline chloride, 0.5 parts of vitamin premix, 1 part of mineral premix, and 0.5 parts of amino acid additives. Immune modulators are fed once every 10 days, with a feeding amount of 0.6 kg / mu each time. Pengze crucian carp are fed Compound Feed III during their adult stage at a rate of 5.0 kg / mu, three times daily. Compound Feed III consists of the following ingredients by weight: 45 parts soybean meal, 10 parts fish meal, 20 parts corn flour, 10 parts wheat bran, 2 parts phospholipid oil, 1 part calcium dihydrogen phosphate, 0.5-1 parts choline chloride, 0.5 parts vitamin premix, 1 part mineral premix, and 0.5 parts amino acid additive. Immunomodulators are fed every 15 days at a rate of 1.5 kg / mu. The immunomodulators consist of the following ingredients by weight: 5 parts peptidoglycan, 3 parts saccharoterpenoids, 4 parts garlic powder, 2 parts ginger powder, 1 part astragalus powder, 1 part licorice powder, 1 part adenosine, 4 parts β-glucan, 3 parts mannan, 5 parts Schizochytrium algae powder, and 3 parts Clostridium butyricum fermentation broth. The immunomodulators are mixed into the feed and fed daily.

[0042] S6. Water quality management: Spray trichlorfon into the pond for disinfection every 25 days, change the water every 10 days, and replace 20% of the water in the pond each time. Maintain the dissolved oxygen at 5.0 mg / L, the pH at 7.2, the ammonia nitrogen at 0.2 mg / L, and the nitrite at 0.1 mg / L.

[0043] S7. Disease prevention and detection: Observe fish daily for abnormal symptoms and test fish or water samples for pathogens of myxosporidiasis every 30 days.

[0044] S8. Emergency treatment: Detect abnormal fish bodies, isolate them, and then soak and disinfect them according to the method in S1. After soaking and disinfection, take insecticide at a dose of 40 mg / kg based on the body weight of Pengze crucian carp for 6 consecutive days. The insecticide comprises the following raw materials in parts by weight: 20 parts of chitosan-mercaptosuccinic acid conjugate, 5 parts of antimicrobial peptide, 15 parts of artesunate, 8 parts of nano zinc oxide, 5 parts of triptolide, and 3 parts of carvacrol. The insecticide is prepared by the following method: antimicrobial peptide, artesunate, nano zinc oxide, triptolide, and carvacrol are mixed, and stirred at 500 r / min for 30 minutes to obtain an insecticide core; chitosan-mercaptosuccinic acid conjugate is added to acetic acid with a concentration of 1.5wt%, and stirred at 500 r / min for 4 hours to obtain a chitosan-mercaptosuccinic acid conjugate solution; and then the chitosan-mercaptosuccinic acid conjugate solution is sprayed onto the surface of the insecticide core at a spray pressure of 10 psi, and then dried at 55°C for 4 hours to obtain the insecticide. The chitosan-mercaptosuccinic acid conjugate is prepared by the following method: chitosan is added to acetic acid with a concentration of 1.5% wt, and stirred at 500 / min for 4 hours to obtain a chitosan solution, wherein the mass volume ratio of chitosan to acetic acid is 0.8:90 g / ml; mercaptosuccinic acid is added to deionized water, and stirred at 500r / min for 20 minutes, and then 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added, and the mixture is stirred at 400r / min for 35 minutes at 20°C to obtain an activated mercaptosuccinic acid solution, mercaptosuccinic acid, deionized water, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide, and the like. The mass-to-volume ratio of amber imide is g / mL of 0.4:30:0.2:0.1; the activated mercaptosuccinic acid solution is added dropwise to the chitosan solution, and the pH of the reaction system is adjusted to 4.9 using a 1M sodium hydroxide solution. The reaction is stirred at 400 r / min at 55°C for 22 hours to obtain a reaction solution, and the volume ratio of the activated mercaptosuccinic acid solution to the chitosan solution is 1.8:1.0; the reaction solution is transferred to a dialysis bag and dialyzed with deionized water for 70 hours, during which the water is changed every 8 hours to obtain a dialyzed solution; the dialyzed solution is concentrated by rotary evaporation and evaporated at an evaporation temperature of 55°C and an evaporation pressure of 8 mbar for 12 hours to obtain a chitosan-mercaptosuccinic acid conjugate.

[0045] Example 2

[0046] A breeding method for improving the disease resistance of Pengze crucian carp myxosporea comprises the following steps:

[0047] S1. Aquaculture environment treatment: Use quicklime to spray the bottom and around the pond, the usage amount is 125Kg / mu, and after 3 days, mix the compound bacterial agent I into the pond mud. The compound bacterial agent I is composed of Bacillus subtilis, Bdellovibrio, photosynthetic bacteria and yeast in a mass ratio of 2.0:0.7:1.0:3.0, and the usage amount is 1.5Kg / mu. Then, plant duckweed, black algae and Vallisneria in the pond mud.

[0048] S2. Purchase healthy fry: Purchase Pengze crucian carp fry with normal luster, vitality, normal appearance and no injuries from non-myxosporidial disease epidemic areas.

[0049] S3. Fry disinfection: The purchased fry were immersed in a biological disinfectant for 30 minutes. The biological disinfectant consisted of tea saponin, a photosensitizing component, carvacrol, artesunate, and choline-lactic acid ionic liquid in a mass volume ratio of 1.5:0.4:1.0:1.0:5.0 g / L. While soaking, the fry were illuminated with LED light of a wavelength of 550nm and a light intensity of 2000Lus. The photosensitizing component was rose bengal. The choline-lactic acid ionic liquid was prepared by the following method: adding choline chloride to the The mixture was stirred in deionized water at 450 r / min for 7.5 min to obtain a choline chloride solution, wherein the mass volume ratio of choline chloride to deionized water was 4:10 (kg / L); the choline chloride solution was poured into a container containing a hydroxide anion exchange resin to carry out an ion exchange reaction for 3 h. After the reaction was completed, the effluent was collected to obtain a hydroxide choline solution; lactic acid was added to the hydroxide choline solution, and the mixture was stirred at 150 r / min at 25°C for 36 h to obtain a choline-lactic acid ionic liquid.

[0050] S4. Stocking of fry: Stock the Pengze crucian carp fry after disinfection into the pond at a rate of 2,000 per mu. Stock the pond with disinfected silver carp fry, bighead carp fry, and grass carp fry for mixed culture at a rate of 250 per mu. The Pengze crucian carp fry are 40g / fry, silver carp fry are 80g / fry, silver carp fry are 120g / fry, and grass carp fry are 150g / fry.

[0051] S5. Feeding management: Pengze crucian carp are fed compound feed I during the seedling stage, with a feeding amount of 1.2 kg / mu each time and fed twice a day. Compound feed I includes the following raw materials in parts by weight: 25 parts of soybean meal, 10 parts of fish meal, 15 parts of corn gluten meal, 12.5 parts of wheat flour, 3.5 parts of yeast powder, 3 parts of fish oil, 1.5 parts of calcium dihydrogen phosphate, 0.8 parts of choline chloride, 0.8 parts of vitamin premix, 1.5 parts of mineral premix, and 0.8 parts of amino acid additives. Immune modulators are fed once every 8 days, with a feeding amount of 0.4 kg / mu each time. Pengze crucian carp are fed compound feed II during the juvenile stage, with each feeding amount of 3.0 kg / mu, and fed 3 times / d. Compound feed II includes the following raw materials by weight: 35 parts of soybean meal, 12.5 parts of fish meal, 20 parts of corn flour, 7.5 parts of spirulina powder, 4 parts of fish oil, 1.5 parts of calcium dihydrogen phosphate, 0.8 parts of choline chloride, 0.8 parts of vitamin premix, 1.5 parts of mineral premix, and 0.8 parts of amino acid additives. Immune modulators are fed once every 10-15 days, with each feeding amount of 0.8 kg / mu. Pengze crucian carp were fed a compound feed III at a rate of 7.5 kg / mu three times daily during the adult stage. The compound feed III consisted of the following ingredients by weight: 52.5 parts soybean meal, 15 parts fish meal, 22.5 parts corn flour, 12.5 parts wheat bran, 3 parts phospholipid oil, 1.5 parts calcium dihydrogen phosphate, 0.8 parts choline chloride, 0.8 parts vitamin premix, 1.5 parts mineral premix, and 0.8 parts amino acid additive. An immune modulator was also fed every 18 days at a rate of 2.0 kg / mu. The immune modulator consisted of the following ingredients by weight: 10 parts peptidoglycan, 6.5 parts saccharoterpenoids, 6 parts garlic powder, 4 parts ginger powder, 2 parts astragalus powder, 2 parts licorice powder, 2 parts adenosine, 7 parts β-glucan, 4.5 parts mannan, 8.5 parts Schizochytrium powder, and 4.5 parts Clostridium butyricum fermentation broth. The immune modulator was prepared into 2.0 mm granules and fed separately.

[0052] S6. Water quality management: Spray trichlorfon into the pond for disinfection every 30 days, change the water every 15 days, and replace 25% of the water in the pond each time. Maintain the dissolved oxygen at 5.5 mg / L, the pH at 7.9, the ammonia nitrogen at 0.1 mg / L, and the nitrite at 0.05 mg / L.

[0053] S7. Disease prevention and detection: Observe fish daily for abnormal symptoms and test fish or water samples for myxosporidial pathogens every 35 days.

[0054] S8. Emergency treatment: Detect abnormal fish bodies, isolate them, and then soak and disinfect them according to the method in S1. After soaking and disinfection, take insecticide at a dose of 50 mg / kg based on the body weight of Pengze crucian carp for 5 consecutive days. The insecticide comprises the following raw materials in parts by weight: 25 parts of chitosan-mercaptosuccinic acid conjugate, 7.5 parts of antimicrobial peptide, 20 parts of artesunate, 10 parts of nano zinc oxide, 6.5 parts of triptolide, and 4 parts of carvacrol. The insecticide is prepared by the following method: antimicrobial peptide, artesunate, nano zinc oxide, triptolide, and carvacrol are mixed, and stirred at 750 r / min for 20 minutes to obtain an insecticide core; chitosan-mercaptosuccinic acid conjugate is added to acetic acid with a concentration of 2.0wt%, and stirred at 750 r / min for 3 hours to obtain a chitosan-mercaptosuccinic acid conjugate solution; and then the chitosan-mercaptosuccinic acid conjugate solution is sprayed onto the surface of the insecticide core at a spray pressure of 15 psi, and then dried at 60°C for 3 hours to obtain the insecticide. The chitosan-mercaptosuccinic acid conjugate is prepared by the following method: chitosan is added to acetic acid with a concentration of 2.0% wt, and stirred at 750 / min for 3 hours to obtain a chitosan solution, wherein the mass volume ratio of chitosan to acetic acid is 1.0:100 g / ml; mercaptosuccinic acid is added to deionized water, and stirred at 750r / min for 15 minutes, and then 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added, and the mixture is stirred at 500r / min for 30 minutes at 25°C to obtain an activated mercaptosuccinic acid solution, mercaptosuccinic acid, deionized water, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide, etc. The mass-to-volume ratio of amber imide is 0.5:45:0.3:0.2 g / mL; the activated mercaptosuccinic acid solution is added dropwise to the chitosan solution, and the pH of the reaction system is adjusted to 5.0 using a 1 M sodium hydroxide solution. The reaction is stirred at 500 r / min at 60°C for 20 hours to obtain a reaction solution, and the volume ratio of the activated mercaptosuccinic acid solution to the chitosan solution is 2.0:1.0; the reaction solution is transferred to a dialysis bag and dialyzed with deionized water for 72 hours, during which the water is changed every 8 hours to obtain a dialyzed solution; the dialyzed solution is concentrated by rotary evaporation and evaporated at an evaporation temperature of 60°C and an evaporation pressure of 10 mbar for 11 hours to obtain a chitosan-mercaptosuccinic acid conjugate.

[0055] Example 3

[0056] A breeding method for improving the disease resistance of Pengze crucian carp myxosporea comprises the following steps:

[0057] S1. Treatment of aquaculture environment: Use quicklime to spray the bottom and surrounding areas of the pond at a dosage of 150 kg / mu. After 4 days, mix compound bacterial agent I into the pond mud. Compound bacterial agent I is composed of Bacillus subtilis, Bdellovibrio, photosynthetic bacteria, and yeast in a mass ratio of 3.0:1.0:1.5:4.0. The dosage is 2 kg / mu. Then, combine duckweed, black algae, and water fern to plant in the pond mud.

[0058] S2. Purchase healthy fry: Purchase Pengze crucian carp fry with normal luster, vitality, normal appearance and no injuries from non-myxosporidial disease epidemic areas.

[0059] S3. Fry disinfection: The purchased fry were immersed in a biological disinfectant for 35 minutes. The biological disinfectant consisted of tea saponin, photosensitizing component, carvacrol, artesunate, and choline-lactic acid ionic liquid in a mass volume ratio of 2.0:0.5:1.5:1.5:6.0 g / L. While soaking, LED light with a wavelength of 700 nm and a light intensity of 3000 Lus was used for irradiation. The photosensitizing component was eosin Y. The choline-lactic acid ionic liquid was prepared by the following method: adding choline chloride to The mixture was added into deionized water and stirred at 600 r / min for 5 minutes to obtain a choline chloride solution, wherein the mass volume ratio of choline chloride to deionized water was 5:12 in kg / L; the choline chloride solution was poured into a container containing a hydroxide anion exchange resin to carry out an ion exchange reaction for 2 hours. After the reaction was completed, the effluent was collected to obtain a hydroxide choline solution; lactic acid was added to the hydroxide choline solution, and the mixture was stirred at 200 r / min at 30°C for 24 hours to obtain a choline-lactic acid ionic liquid.

[0060] S4. Stocking of Fry: 2,500 disinfected Pengze crucian carp fry will be stocked into the ponds at a rate of 300 per mu. The Pengze crucian carp fry, silver carp fry, and grass carp fry will also be stocked into the ponds for mixed culture. The total weight of these fry is 300 per mu. The Pengze crucian carp fry should be 50g per fry, the silver carp fry should be 100g per fry, the silver carp fry should be 150g per fry, and the grass carp fry should be 200g per fry.

[0061] S5. Feeding management: Pengze crucian carp are fed compound feed I during the seedling stage, with a feeding amount of 1.5 kg / mu each time and fed twice a day. Compound feed I includes the following raw materials by weight: 30 parts of soybean meal, 15 parts of fish meal, 20 parts of corn gluten meal, 15 parts of wheat flour, 5 parts of yeast powder, 4 parts of fish oil, 2 parts of calcium dihydrogen phosphate, 1 part of choline chloride, 1 part of vitamin premix, 2 parts of mineral premix, and 1.0 part of amino acid additive. Immune modulators are fed once every 10 days, with a feeding amount of 0.5 kg / mu each time. Pengze crucian carp are fed compound feed II during the juvenile stage, with each feeding amount of 24.0 kg / mu, and fed 3 times / d. Compound feed II includes the following raw materials by weight: 40 parts of soybean meal, 15 parts of fish meal, 25 parts of corn flour, 10 parts of spirulina powder, 5 parts of fish oil, 2 parts of calcium dihydrogen phosphate, 1 part of choline chloride, 1 part of vitamin premix, 2 parts of mineral premix, and 1.0 part of amino acid additive. Immune modulators are fed once every 15 days, with each feeding amount of 1.0 kg / mu. Pengze crucian carp were fed Compound Feed III during their adult stage at a rate of 10.0 kg / mu, three times daily. Compound Feed III consisted of the following ingredients by weight: 60 parts soybean meal, 20 parts fish meal, 25 parts corn flour, 15 parts wheat bran, 4 parts phospholipid oil, 2 parts monocalcium phosphate, 1 part choline chloride, 1 part vitamin premix, 2 parts mineral premix, and 1 part amino acid additive. Immunomodulators were also fed every 20 days at a rate of 2.5 kg / mu. The immunomodulators consisted of the following ingredients by weight: 15 parts peptidoglycan, 10 parts saccharoterpenoids, 8 parts garlic powder, 6 parts ginger powder, 3 parts astragalus powder, 3 parts licorice powder, 3 parts adenosine, 10 parts β-glucan, 6 parts mannan, 12 parts Schizochytrium algae powder, and 6 parts Clostridium butyricum fermentation broth. The immunomodulators were fed separately in 2.5 mm pellets.

[0062] S6. Water quality management: Spray trichlorfon into the pond for disinfection every 35 days, change the water every 20 days, and replace 30% of the water in the pond each time. Maintain the dissolved oxygen at 6.0 mg / L, the pH at 8.5, the ammonia nitrogen at 0.1 mg / L, and the nitrite at 0.1 mg / L.

[0063] S7. Disease prevention and detection: Observe fish daily for abnormal symptoms and test fish or water samples for myxosporidial pathogens every 40 days.

[0064] S8. Emergency treatment: Detect abnormal fish bodies, isolate them, and then soak and disinfect them according to the method in S1. After soaking and disinfection, take insecticide at a dose of 60 mg / kg based on the body weight of Pengze crucian carp for 4 consecutive days. The insecticide comprises the following raw materials in parts by weight: 30 parts of chitosan-mercaptosuccinic acid conjugate, 10 parts of antimicrobial peptide, 25 parts of artesunate, 12 parts of nano zinc oxide, 8 parts of triptolide, and 5 parts of carvacrol. The insecticide is prepared by the following method: antimicrobial peptide, artesunate, nano zinc oxide, triptolide, and carvacrol are mixed, and stirred at 1000 r / min for 10 minutes to obtain an insecticide core; chitosan-mercaptosuccinic acid conjugate is added to acetic acid with a concentration of 2.5wt%, and stirred at 1000 r / min for 2 hours to obtain a chitosan-mercaptosuccinic acid conjugate solution; and then the chitosan-mercaptosuccinic acid conjugate solution is sprayed onto the surface of the insecticide core at a spray pressure of 20 psi, and then dried at 65°C for 2 hours to obtain the insecticide. The chitosan-mercaptosuccinic acid conjugate is prepared by the following method: chitosan is added to acetic acid with a concentration of 2.5% wt, and stirred at 1000 / min for 2 hours to obtain a chitosan solution, wherein the mass volume ratio of chitosan to acetic acid is 1.2:110 g / ml; mercaptosuccinic acid is added to deionized water, and stirred at 1000 r / min for 10 minutes, and then 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide are added, and the mixture is stirred at 600 r / min for 25 minutes at 30°C to obtain an activated mercaptosuccinic acid solution, mercaptosuccinic acid, deionized water, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide, and the like. The mass-to-volume ratio of succinimide g / mL is 0.6:50:0.4:0.3; the activated mercaptosuccinic acid solution is added dropwise to the chitosan solution, and the pH of the reaction system is adjusted to 5.1 using a 1M sodium hydroxide solution. The reaction is stirred at 600 r / min at 65°C for 22 hours to obtain a reaction solution, and the volume ratio of the activated mercaptosuccinic acid solution to the chitosan solution is 2.2:1.0; the reaction solution is transferred to a dialysis bag and dialyzed with deionized water for 75 hours, during which the water is changed every 8 hours to obtain a dialyzed solution; the dialyzed solution is concentrated by rotary evaporation and evaporated at an evaporation temperature of 65°C and an evaporation pressure of 12 mbar for 10 hours to obtain a chitosan-mercaptosuccinic acid conjugate.

[0065] Comparative Example 1

[0066] This comparative example is compared with Example 2, except that an equal volume of deionized water is used in the biological disinfectant in step S3 instead of the choline-lactic acid ionic liquid.

[0067] Comparative Example 2

[0068] Compared with Example 2, this comparative example differs in that the biological disinfectant in step S3 does not contain any photosensitive components, and LED light is not used for irradiation while soaking in the biological disinfectant.

[0069] Comparative Example 3

[0070] This comparative example is different from Example 2 in that no immune modulator is fed in step S5.

[0071] Comparative Example 4

[0072] Compared with Example 2, this comparative example differs in that the insecticide in step S8 does not contain chitosan-mercaptosuccinic acid conjugate.

[0073] Comparative Example 5

[0074] This comparative example is compared with Example 2, except that the insecticide in step S8 uses chitosan of equal mass instead of chitosan-mercaptosuccinic acid conjugate.

[0075] Effect verification

[0076] Set up 8 ponds of 1 mu with the same length, width and height, inject equal amounts of water, and culture according to the culture methods of Examples 1-3 and Comparative Examples 1-5, respectively, for 200 days. Record the initial total weight of the Pengze crucian carp put in each pond before the fry are put in, record the number of Pengze crucian carp infected with myxosporidiosis in each pond during the culture process, and record the number of Pengze crucian carp cured when treating Pengze crucian carp infected with myxosporidiosis. After the culture is completed, weigh and record the final total weight of the Pengze crucian carp. Statistics of the infection rate of myxosporidiosis, cure rate of myxosporidiosis and weight gain rate of Pengze crucian carp in each pond are shown in Table 1. Calculate according to the following formula:

[0077] Myxosporidiosis infection rate = (number of fish infected with myxosporidiosis / total number of fish released) × 100%;

[0078] Myxosporidiosis cure rate = (number of fish cured of myxosporidiosis / number of fish infected with myxosporidiosis) × 100%;

[0079] Weight gain rate = (final total weight / initial total weight) × 100%.

[0080] Table 1

[0081] Myxosporidiosis infection rate / % Myxosporidiosis cure rate / % Weight gain rate / % Example 1 2.3 95 231 Example 2 2.0 98 235 Example 3 2.1 96 229 Comparative Example 1 11.4 65 187 Comparative Example 2 11.2 67 182 Comparative Example 3 10.9 80 163 Comparative Example 4 2.2 61 190 Comparative Example 5 2.1 77 201

[0082] As can be seen from Table 1, the breeding methods of Examples 1-3 of the present invention have low myxosporean infection rates, high cure rates, and high weight gain rates, among which Example 2 has the best effect.

[0083] By comparing Example 2 with Comparative Example 1, there are a large number of hydrogen bonds between the chitin shell molecular chains of myxosporeans, and the choline cation and lactate anion contained in the choline-lactic acid ionic liquid can be combined with the hydroxyl and acetylamino groups on the chitin shell molecular chains of myxosporeans to form competitive hydrogen bonds, which destroys the hydrogen bond network between the original chitin molecular chains, causing the shell structure to loosen, which is conducive to the choline-lactic acid ionic liquid to penetrate into the chitin shell. And after penetrating into the chitin shell, the distance between the chitin molecular chains is increased by solvation. The hydrogen bond network destruction and the increase in the distance between the molecular chains of the chitin shell cause the shell to form micropores, which provide channels for the penetration of tea saponin, photosensitizing ingredients, carvacrol, and artesunate, thereby effectively eliminating myxosporeans, thereby reducing the infection rate of myxosporean disease and improving the cure rate of myxosporean disease. Due to the reduction in the infection rate of myxosporean disease and the improvement in the cure rate of myxosporean disease, Pengze crucian carp can better grow and develop during the breeding process. The fish's growth rate is accelerated and the feed conversion rate is improved, so that within the same breeding cycle, the total weight of Pengze crucian carp increases more. Therefore, at the end of the breeding period, the harvested Pengze crucian carp has a higher growth rate and the breeding efficiency is significantly improved.

[0084] By comparing Example 2 with Comparative Example 2, the photosensitive component absorbs LED light energy of a specific wavelength and transitions from a ground state to an excited state. The excited state photosensitizer transfers energy to the surrounding oxygen molecules to generate highly reactive singlet oxygen or generates reactive oxygen species such as superoxide anions and hydroxyl radicals through electron transfer. The generated reactive oxygen species attack the β-1,4-glycosidic bonds and acetylamino groups of the chitin molecular chain, causing the chemical structure of the shell to break and form micropores or cracks, thereby facilitating the penetration of other components, thereby effectively eliminating myxosporidiosis, thereby reducing the infection rate of myxosporidiosis and improving the cure rate of myxosporidiosis.

[0085] By comparing Example 2 with Comparative Example 3, the peptidoglycan, saccharide terpenoid, garlic powder, ginger powder, astragalus powder, and ginger powder in the immunomodulator can stimulate the nonspecific immune system of Pengze crucian carp and enhance its bactericidal and antiviral capabilities. β-glucan, mannan, and adenosine can stimulate the specific immune system of Pengze crucian carp, promote its proliferation and differentiation, produce more antibodies and cytokines, and improve the disease resistance of Pengze crucian carp. The beneficial substances in the Clostridium butyricum fermentation liquid can regulate the intestinal flora of Pengze crucian carp, inhibit the growth of harmful bacteria, and promote the reproduction of beneficial bacteria, thereby enhancing the digestive ability and immunity of Pengze crucian carp. By enhancing the immunity of Pengze crucian carp, the immunomodulator can enable Pengze crucian carp to better resist the infection of myxosporeans. The enhancement of the immune system can more effectively identify and eliminate pathogens, thereby reducing the infection rate. When Pengze crucian carp is infected with myxosporeans, the enhanced immune system can initiate an immune response faster, produce more antibodies and cytokines, accelerate the removal of pathogens and the repair of tissues, thereby improving the cure rate. The Schizochytrium algae powder in the immune modulator is rich in polyunsaturated fatty acids, which can promote the growth and development of Pengze crucian carp. Furthermore, the enhanced immune system enables the fish to better utilize nutrients in the feed, improving feed conversion efficiency and thus increasing weight gain. Through the synergistic effects of multi-target immune activation, anti-inflammatory repair, intestinal health regulation, and metabolic stimulation, the immune modulator significantly enhances the immunity of Pengze crucian carp, achieving the triple goals of reducing infection rates, increasing cure rates, and boosting weight gain.

[0086] Comparing Example 2 with Comparative Example 4, the amino groups contained in the chitosan-mercaptosuccinic acid conjugate form hydrogen bonds with the acetyl groups of chitin in myxosporeans, anchoring them to the cyst surface. The sulfhydryl groups contained in the chitosan-mercaptosuccinic acid conjugate undergo an exchange reaction with the disulfide bonds of the chitin coat protein, forming covalent bonds, further enhancing adsorption. The simultaneously formed hydrogen and covalent bonds can disrupt the original hydrogen bond network and protein structure of the shell, thereby destroying the shell's compactness and increasing the shell's porosity. This allows antimicrobial peptides, artesunate, nano-zinc oxide, triptolide, and carvacrol to enter the cysts smoothly, effectively killing myxosporeans.

[0087] By comparing Example 2 with Comparative Example 5, the chitosan-mercaptosuccinic acid conjugate further enhances the targeting effect and penetration effect through the exchange reaction between the thiol group and the disulfide bond of the chitin coat protein. Therefore, compared with chitosan, the chitosan-mercaptosuccinic acid conjugate has a better effect.

[0088] The above description is only a preferred embodiment of the present invention and is 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 scope of protection of the present invention.

Claims

1. A method for improving the disease resistance of Pengze crucian carp myxosporeans, characterized in that: The following steps are involved: S1. Aquaculture environment treatment: Spray the bottom and surrounding areas of the pond with quicklime. After 2-4 days, mix compound bacterial agent I into the pond mud. Then, plant aquatic plants in the pond mud. S2. Purchase healthy fry: Purchase Pengze crucian carp fry from areas not affected by myxosporidiasis that are shiny, vibrant, and appear healthy. S3. Fry disinfection: The purchased fry were immersed in a biological disinfectant for 25-35 min, and irradiated with LED light having a wavelength of 400-700 nm and a light intensity of 1000-3000 Lus while soaking. The biological disinfectant consisted of tea saponin, a photosensitizing component, carvacrol, artesunate, and choline-lactic acid ionic liquid. S4. Fry release: The disinfected Pengze crucian carp fry are released into the pond, and the disinfected silver carp fry, bighead carp fry, and grass carp fry are released into the pond for polyculture; S5. Feeding management: Pengze crucian carp are fed compound feed I during the fry stage and immune modulators every 7-10 days. Pengze crucian carp are fed compound feed II during the juvenile stage and immune modulators every 10-15 days. Pengze crucian carp are fed compound feed III during the adult stage and immune modulators every 15-20 days. S6. Water Quality Management: Disinfect the pond with trichlorfon every 25-35 days, perform water changes every 10-20 days, and replace 20-30% of the pond water each time. Maintain dissolved oxygen ≥ 5.0 mg / L, pH 7.2-8.5, ammonia nitrogen ≤ 0.2 mg / L, and nitrite ≤ 0.1 mg / L. S7. Disease prevention and detection: Observe fish daily for any abnormal symptoms, and test fish or water samples for the pathogen causing myxosporidiasis every 30-40 days. S8. Emergency treatment: Detect abnormal fish, isolate them, and then disinfect them by soaking according to the method in S1. After the disinfection, administer an insecticide at a dose of 40-60 mg / kg of Pengze crucian carp body weight for 4-6 days. The insecticide in S8 comprises the following raw materials in parts by weight: 20-30 parts of chitosan-mercaptosuccinic acid conjugate, 5-10 parts of antimicrobial peptide, 15-25 parts of artesunate, 8-12 parts of nano zinc oxide, 5-8 parts of triptolide, and 3-5 parts of carvacrol; The chitosan-mercaptosuccinic acid conjugate is prepared by the following method: adding chitosan to acetic acid with a concentration of 1.5-2.5%wt, stirring at 500-1000 / min for 2-4h to obtain a chitosan solution, wherein the mass volume ratio of the chitosan to the acetic acid is (0.8-1.2): (90-110) g / ml; adding mercaptosuccinic acid to deionized water, stirring at 500-1000r / min for 10-20min, then adding 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, stirring at 400-600r / min for activation at 20-30°C for 25-35min, to obtain an activated mercaptosuccinic acid solution, wherein the mass volume ratio of the mercaptosuccinic acid, deionized water, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is (0.8-1.2): (90-110) g / ml; The ratio g / mL is (0.4-0.6):(30-50):(0.2-0.4):(0.1-0.3); the activated mercaptosuccinic acid solution is added dropwise to the chitosan solution, and the pH of the reaction system is adjusted to 4.9-5.1 using a 1M sodium hydroxide solution, and the reaction is stirred at 400-600r / min at 55-65°C for 18-22h to obtain a reaction solution, wherein the volume ratio of the activated mercaptosuccinic acid solution to the chitosan solution is (1.8-2.2):1.0; the reaction solution is transferred to a dialysis bag and dialyzed with deionized water for 70-75h, during which the water is changed every 8h to obtain a dialyzed solution; the dialyzed solution is concentrated by rotary evaporation and evaporated at an evaporation temperature of 55-65°C and an evaporation pressure of 8-12mbar for 10-12h to obtain a chitosan-mercaptosuccinic acid conjugate.

2. A method for cultivating the myxosporeans of Pengze crucian carp to improve disease resistance as claimed in claim 1, characterized in that: The amount of quicklime used in S1 is 100-150 kg / mu, the composite bacterial agent I is composed of Bacillus subtilis, Bdellovibrio, photosynthetic bacteria, and yeast, and the mass ratio of Bacillus subtilis, Bdellovibrio, photosynthetic bacteria, and yeast is (1.0-3.0):(0.4-1.0):(0.5-1.5):(2.0-4.0), and the amount of composite bacterial agent I used is 1-2 kg / mu.

3. A method for cultivating the myxosporeans of Pengze crucian carp to improve its disease resistance as claimed in claim 1, characterized in that: The mass volume ratio g / L of tea saponin, photosensitizing component, carvacrol, artesunate and choline-lactic acid ionic liquid in the S3 biological disinfectant is (1.0-2.0):(0.3-0.5):(0.5-1.5):(0.5-1.5):(4.0-6.0).

4. A method for cultivating the myxosporeans of Pengze crucian carp to improve its disease resistance as claimed in claim 3, characterized in that: The photosensitive component is one of chlorophyll a, rose bengal and eosin Y.

5. A method for cultivating the myxosporeans of Pengze crucian carp to improve its disease resistance as claimed in claim 3, characterized in that: The choline-lactic acid ionic liquid is prepared by the following method: adding choline chloride to deionized water, stirring at 300-600 r / min for 5-10 minutes to obtain a choline chloride solution, wherein the mass volume ratio of choline chloride to deionized water is (3-5) to (8-12) in kg / L; pouring the choline chloride solution into a container containing a hydroxide anion exchange resin, performing an ion exchange reaction for 2-4 hours, and collecting the effluent after the reaction is completed to obtain a hydroxide choline solution; adding lactic acid to the hydroxide choline solution, stirring at 100-200 r / min for 24-48 hours at 20-30° C., to obtain the choline-lactic acid ionic liquid.

6. A method for cultivating the myxosporeans of Pengze crucian carp to improve its disease resistance as claimed in claim 1, characterized in that: The compound feed I in S5 is fed at a rate of 1.0-1.5 kg / mu each time and is fed twice a day; the compound feed II is fed at a rate of 2.0-4.0 kg / mu each time and is fed three times a day; the compound feed III is fed at a rate of 5.0-10.0 kg / mu each time and is fed three times a day; the compound feed I comprises the following raw materials in parts by weight: 20-30 parts of soybean meal, 5-15 parts of fish meal, 10-20 parts of corn gluten meal, 10-15 parts of wheat flour, 2-5 parts of yeast powder, 2-4 parts of fish oil, 1-2 parts of calcium dihydrogen phosphate, 0.5-1 parts of choline chloride, 0.5-1 parts of vitamin premix, 1-2 parts of mineral premix, 0.5-1.0 parts of amino acid additives, and the compound feed II contains The compound feed III comprises the following raw materials in parts by weight: 30-40 parts of soybean meal, 10-15 parts of fish meal, 15-25 parts of corn flour, 5-10 parts of spirulina powder, 3-5 parts of fish oil, 1-2 parts of monocalcium phosphate, 0.5-1 parts of choline chloride, 0.5-1 parts of vitamin premix, 1-2 parts of mineral premix, and 0.5-1.0 parts of amino acid additives. The compound feed III comprises the following raw materials in parts by weight: 45-60 parts of soybean meal, 10-20 parts of fish meal, 20-25 parts of corn flour, 10-15 parts of wheat bran, 2-4 parts of phospholipid oil, 1-2 parts of monocalcium phosphate, 0.5-1 parts of choline chloride, 0.5-1 parts of vitamin premix, 1-2 parts of mineral premix, and 0.5-1.0 parts of amino acid additives.

7. A method for cultivating the myxosporeans of Pengze crucian carp to improve its disease resistance as claimed in claim 1, characterized in that: The feeding amount of the Pengze crucian carp fry immune regulator in S5 is 0.3-0.5 kg / mu, the feeding amount of the Pengze crucian carp juvenile immune regulator is 0.6-1.0 kg / mu, and the feeding amount of the Pengze crucian carp adult immune regulator is 1.5-2.5 kg / mu. The immune regulator includes the following raw materials in parts by weight: 5-15 parts of peptidoglycan, 3-10 parts of saccharide terpenoids, 4-8 parts of garlic powder, 2-6 parts of ginger powder, 1-3 parts of astragalus powder, 1-3 parts of licorice powder, 1-3 parts of adenosine, 4-10 parts of β-glucan, 3-6 parts of mannan, 5-12 parts of Schizochytrium powder, and 3-6 parts of Clostridium butyricum fermentation broth.

8. A method for cultivating the myxosporeans of Pengze crucian carp to improve its disease resistance as claimed in claim 1, characterized in that: The insecticide is prepared by the following method: antimicrobial peptide, artesunate, nano zinc oxide, triptolide and carvacrol are mixed, and the mixture is stirred at 500-1000 r / min for 10-30 minutes to obtain an insecticide core; chitosan-mercaptosuccinic acid conjugate is added to acetic acid with a concentration of 1.5-2.5wt%, and the mixture is stirred at 500-1000 r / min for 2-4 hours to obtain a chitosan-mercaptosuccinic acid conjugate solution; the chitosan-mercaptosuccinic acid conjugate solution is then sprayed onto the surface of the insecticide core at a spray pressure of 10-20 psi, and the mixture is subsequently dried at 55-65°C for 2-4 hours to obtain the insecticide.