100 results about "Melicertus" patented technology

The invention discloses a planting and breeding integrated ecological breeding method for a large fishpond. Famous and special breeding varieties such as common carps, golden carps, grass carps, chubs, penaeus vannawei, loaches, soft-shelled turtles, river crabs and the like are put in a suitable place to breed in a breeding pond; and the stocking ratio of herbivorous fishes to forage fishes to demersal residual feed animals by weight percentage is (35-40%) to (50-55%) to (10-15%). Proper biological varieties are selected according to biological requirements of ecological niches and cooperate to build an eco-friendly environment, forage grasses are planted for feeding the herbivorous fishes, the feces of the herbivorous fishes and a water body can produce primary biological baits, the primary biological baits are supplied to shrimps and secondary nutritional fishes, and organic detritus produced by the water body sinks to the bottom of water and is ingested by the demersal loaches, crabs and the like. At the same time, lotus roots and cane shoots are planted in the breeding water body and nutritive salt in the water body is removed for purifying the water, so that a novel high-efficiency energy-saving planting and breeding integrated ecological breeding mode is formed.

The invention discloses a safe compound feed of juvenile prawn of penaeus vannamei boone, which consists of bean pulp, pea albumen powder, fish powder, blood cell albumen powder, cuttlefish powder, shrimp shell powder, double-low rapeseed meal, cotton pulp, monocalcium phosphate, No. 1 flour, gluten powder, 50% choline chloride, complex vitamin for shrimp, microelement additive for shrimp, bacillus licheniformis, decorticating element, lower polyxylose, fermented peptide for aquatic product, gene recombinant protein growth promoter, nutrition immunology aquatic product food attractant, phospholipids oil and fish oil. With the gene recombinant protein growth promoter, the nutrition immunology aquatic product food attractant, and the high antibacterial peptide-containing fermented peptide, the safe compound feed can effectively restrain various enteropathogenic bacteria, improves the digestibility of the nutrition constituent of the feed, promotes the growth of the penaeus vannamei boone, can improve the organism immunity of the penaeus vannamei boone, and can obviously improve the survival rate of the penaeus vannamei boone.

The invention discloses a wild-imitation breeding method for river eel. The method comprises the following steps: A, preparing for pond conditions and other work; B, stocking seeds, wherein the seeds include river eel, penaeus monodon, chub and bighead; C, feedstuff feeding; D, daily management: (1) aerating by adopting an aerator; (2) disinfecting a water body; (3) applying a microbial preparation; (4) changing water; (5) controlling diseases: preventing, controlling and treating diseases by using Chinese Herbal medicines; E, modifying an artificial wild-imitation environment. According to the method, river eel, penaeus monodon, chub and bighead are bred in a breeding pond in a mixed way, so that the stability of a breeding system can be improved; meanwhile, the water quality environment of the pond can be improved, and the breeding benefit of unit area is increased; a marine drug prepared by compounding natural Chinese herbal medicines has the advantages of natural property, multi-functionality, small toxic and side effects and no drug resistance, the quality of marine products is improved remarkably, and the immunologic functions of aquatic animals are improved.

The present invention discloses a new strain of Bacillus megaterium YX-7, which is screened from a water sample of a salmon circulating aquaculture sewage treating tower, and has heterotrophic and nitrification performances, and the preservation number is CCTCC (China Center For Type Culture Collection) NO:M2014275. The strain has significant degradation effect on NO2-N in water, 48h after the treatment, the NO2-N removal rate reaches 91.15%, and the Bacillus megaterium YX-7 can be used for aquaculture water and domestic sewage treatment, and can reduce water pollution; in addition, the Bacillus megaterium YX-7 can effectively improve the feed utilization rate of aquatic animals, the feed meat ratio of penaeus vannamei boone of an experimental group is decreased by 8% compared that of a control group, so that the Bacillus megaterium YX-7 can be used as feed additives for application in aquatic feeds, and is conducive to the improvement of farmer economic benefits and wide in application prospect.

The invention discloses a novel vibrio parahaemolyticus phage with a wide lysis spectrum, amplification application thereof and specific amplification primers of the phage, and the phage has a stronglysis effect on vibrio parahaemolyticus, can be specifically amplified by host bacteria, is short in proliferation time and high in fermentation product titer, and a bacteriophage source is provided for industrial production and application of the bacteriophage. The bacteriophage can be used for preparing a medicine for resisting vibrio parahaemolyticus, and a novel medicine is provided for controlling acute hepatopancreas necrosis syndrome caused by vibrio parahaemolyticus infection. After the bacteriophage is splashed on an aquaculture water body for one time, the quantity of vibrio parahaemolyticus in the water body can be obviously reduced; the phage is mixed and fed to penaeus vannamei, or the penaeus vannamei is soaked in the phage, so that infection caused by vibrio parahaemolyticuscan be effectively prevented and treated, and the survival rate of the penaeus vannamei is increased.

The invention relates to an anti-stress feed for culturing Penaeus vannamei Boone in a greenhouse. The anti-stress feed comprises 10-50% of fish meal, 5-10% of chicken powder, 3-10% of shrimp powder, 3-10% of a beer yeast, 10-30% of fermented soybean meal, 5-10% of squid powder, 10-16% of flour, 1-5% of fish oil, 1-3% of soybean phosphatide, 1-3% of betaine, 1-3% of a vitamin mixture, 2-4% of a mineral element mixture, 0.1-0.5% of Bacillus subtilis and 0.2-1% of taurine. According to the invention, the anti-stress feed selects feed raw materials having the advantages of high digestion and absorption utilization rate and strong food attraction against the growth and physiological digestion characteristics of the Penaeus vannamei Boone in the process of culturing in the greenhouse, trace nutritional elements comprising vitamins, mineral elements and the like needed by the healthy culture of the Penaeus vannamei Boone are reinforced, and simultaneously the Bacillus subtilis and the taurine are added, so shelling of the shrimps is promoted, the growth performances are improved, and the disease resistance and the stress resistance of the shrimps are enhanced. The mixed feed has the advantages of reliable sources of the raw materials, stable and safe quality, difficult water pollution, and suitableness for the large-scale culture of the Penaeus vannamei Boone in the greenhouse.

The invention belongs to the field of shrimp culture and discloses a continuous culturing method for two-year-five-crop prawns. The continuous culturing method for two-year-five-crop prawns concretely comprises steps in that during the first crop, South America prawns and fishes are mixedly cultured around the Tomb-Sweeping day; during the second crop, penaeus japonicus are stocked around the Autumn Begins day; during the third crop, South Africa prawns are stocked around the First Frost Day and cultured in a winter shed around the Light Snow day; during the fourth crop, the South Africa prawns and fishes are mixedly cultured around the Tomb-Sweeping day of the next year; and during the fifth crop, penaeus japonicus are stocked around the Autumn Begins day of the next day. The culturing mode has the great advantage of stable production. The prawn and fish mixed-culturing mode has excellent stability; the penaeus japonicus has high economic value; winter shed prawns are welcomed by farmers due to stability and high profits; three excellent culturing modes are combined, rational seedling releasing density is set out and scientific set meals matches and detailed daily management are arranged, so farmer earnings can be greatly improved; and a system solution scheme is provided for the prawn culturing industry.

The technology belongs to the technical field of aquiculture disease prevention, in particular to the preparation method of the immune reinforcing agent for cultivating crustacean, and the applicationmethod thereof. The aquiculture composite immune reinforcing agent comprises 2-4 parts of aquiculture extractive or baicalin and 2.5-5 parts of levamisole. The composite immune reinforcing agent caneffectively enhance non-specific immunity for cultivating blue crab, improve the activity of the blood serum phenol oxidase, the superoxide dismutase and the alkalinephosphatase of the blue crab, andimproves the disease resistance of the blue crab to common pathogens such as white spot syndrome virus, vibrio, hematodinium, etc. The composite immune reinforcing agent can be applied to the cultivation of the blue crab by being injected or added into blue crab fresh fish bait and granulated feed for preventing and controlling the disease at the disease peak and reducing the disease rate and themortality rate of the blue crab. The immune reinforcing agent is added into the feed for preventing and controlling the disease of the penaeus vannamei boone and exopalaemon carinicauda.

The invention provides a compound enzyme feed additive capable of improving growth rate and non-specific immunity of prawns and application of the compound enzyme feed additive. The additive comprises mannase, xylanase, cellulase, a saccharifying enzyme, lipase, alpha-amylase, beta-amylase and neutral protease. The components are compounded and proportioned with a special carrier and are added into prawn feed by an additive amount of 0.2-0.3%. The product is environmentally friendly, can be used for industrialized production on a large scale, and a novel growth feed additive is provided for aquatic feed. The compound enzyme feed additive provided by the invention can remarkably improve growth of penaeus monodon, has the purposes of improving true nutritive value and reducing the food coefficient, and has promoting effects to different extents to activities of intestinal amylase, lipase of hepatopancreas and serum SOD (Superoxide Dismutase). Compared with additives with similar functions, the additive provided by the invention has the advantages of safety, specifity, no residues, no side effects and the like.

The invention relates to a feed additive of penaeus vannamei. The feed additive is prepared from, by weight, 10%-15% of polypeptide probiotics, 25%-30% of food-grade sodium alginate, 15%-20% of fish meal, 15%-20% of corn starch, 3%-5% of food-grade gelatin, 10%-15% of yeast hydrolysate and 5%-10% of compound vitamins, wherein a mixture of polypepti, probiotics and glucose is adopted as the polypeptide probiotics. The feed additive has the advantages that various nutrient substances such as vitamins and protein which are needed by reproduction and development of the penaeus vannamei can be met when the feed additive serves as a feed additive the penaeus vannamei; the toxicity and inflammations caused by the relatively high organic matter index in a water area to shrimp bodies can be relieved, the functions of the liver and the digestive system are improved, the wide and efficient sterilization and physical sterilization mechanism cooperates with a tissue repairing function, the comprehensive problem is solved, and great improvement is achieved from the cell tissue to the intestinal organism.

The invention relates to a primer pair, amplification reagent, amplification kit and detection method for detecting Enterocytozoon hepatopenaei of penaeus vannamei and application. The primer pair for detecting the Enterocytozoon hepatopenaei is designed and is composed of primers EHP-F and EHP-R; and a fluorescent probe EHP-P is designed. Amplification of a target gene of the Enterocytozoon hepatopenaei based on a RPA technology can be successfully achieved; the detection method disclosed by the invention is based on the RPA technology and can be used for specifically detecting the Enterocytozoon hepatopenaei; and the method is simple and convenient in operation, high in sensitivity, mild in reaction conditions and short in reaction time and can meet the primary needs of a farm on site detection.

The invention relates to a mixing breeding method for loaches and penaeus vannamei boone. The mixing breeding method comprises the following steps that a pond with the area ranging from 4.5 mu to 5.5 mu is selected as a breeding pond, the depth of sludge ranges from 10 cm to 20 cm, the bank width of the pond ranges from 1.4 m to 1.6 m, and the water depth is maintained to range from 0.8 m to 1 m; a water inlet channel and a water drainage channel are separated, and an escaping prevention facility with the height ranging from 1.15 m to 1.30 m is constructed with polyethylene meshes; in summer, loach fries and penaeus vannamei boone fries are synchronously put into the pond, wherein the put volumes are 25-35 thousands per mu for penaeus vannamei boone fries and 40-60 thousands per mu for loaches respectively fries; four-fixation, namely fixed time, fixed points, fixed quality and fixed quantity, feeding is conducted; the penaeus vannamei boone is captured after being bred for 50-65 days, and after the penaeus vannamei boone is completely captured, the loaches are successively captured after being continuously bred for 2-3 months. The mixing breeding method is reasonable in design, high in operability and obvious in breeding benefit. The ecological breeding mode of double-main-breeding of loaches and penaeus vannamei boone in the pond is achieved.

The invention belongs to the field of feeds and relates to a preparation method of a compound feed specially used for aquacultural breeding of prawns. The invention provides a preparation method of a feed especially for high-salinity breeding of penaeus vannamei. The feed can satisfy demand on nutrition for the penaeus vannamei under high salinity (higher than 3%), is good in stability in water, has strong anti-stress capability, is high in survival rate and accelerates growth, is low in feed coefficient, and is economical and practical, thereby solving the problems of slow growth, high diseases incidence and low survival rate of the penaeus vannamei under high salinity stress breeding. The feed can promote healthy development of the aquacultural breeding of prawns.

The invention discloses a penaeus vannamei scientific feeding method. The method includes following steps: (1), treating a breeding pond; (2), feeding penaeus vannamei: selecting feed, managing feeding, observing feed intake after feeding, and adjusting the feed at proper time; (3), adjusting breeding water. Bacteria benefitting and inhibiting principles are utilized, feed conversion rate is increased, and water quality deterioration risk is controlled; natural animal bait and compound feed are feed alternately, so that quick growth of penaeus vannamei can be realized, and bait coefficient canbe lowered, water eutrophication can be avoided, and intake, digestion and absorption of penaeus vannamei are facilitated; feeding quantity, feeding time and number of times can be correspondingly adjusted according to different growth stages, and the feed can be utilized to greatest extent; feed additive is used in the adult shrimp stage, so that necessary trace element is provided for penaeus vannamei, breeding environment is improved, immunity of penaeus vannamei is enhanced, survival rate of penaeus vannamei is increased, and economic benefit is increased.

The invention discloses a feed with improved utilization rate for penaeus vannamei, and belongs to the technical field of aquaculture feeds. The feed with improved utilization rate for penaeus vannamei comprises the following components: miscellaneous fishes meal, soybean meal meal, wheat meal, corn meal, bone meal, grease, compound vitamins, compound minerals, binders, 6-12 parts of attractant, compound Chinese herbal antibacterial agents, antioxidants and mildew preventives. The feed with improved utilization rate for penaeus vannamei made with miscellaneous fishes meal, soybean meal meal, wheat meal, corn meal and bone meal as raw materials and supplemented by auxiliary materials such as compound vitamins, compound minerals and antibacterial agents can significantly enhance immunity anddisease resistance of the penaeus vannamei and effectively improve survival rate of the penaeus vannamei in aquaculture. The feed of the invention is simple in preparation process and suitable for large-scale production.

The invention discloses a penaeus vannamei culture method, including preparation of facility and equipment of a temporary-raising pond, cultivation of biological floccules in early stage of water in acultivating pond, putting-in of temporary-raised shrimp larvae, daily feeding of baits and adding of nutrients. The penaeus vannamei culture method has the advantages of short culture cycle, high yield, low cost, no adding of hormones, and being green and environmentally friendly; penaeus vannamei cultured by the method is delicious in taste and big in size.

The invention discloses a functional feed additive. The functional feed additive comprises the following components in parts by weight of 5-17 parts of paeonol, 8-20 parts of ferulic acid, 10-30 partsof curcumin and 33-77 parts of microcrystalline cellulose. The feed additive disclosed by the invention is a purely natural composition, is free from toxic and side effects, is free from drug residues, and is safe and reliable; the functional feed additive is added to a basal feed according to the mass percentage of 0.05%-0.5%, and then the basal feed containing the functional feed additive is fed to aquatic animals, so that the healthy growth of the aquatic animals including Tilapias, grass carps, megalobrama amblycephala, procambarus clarkii and penaeus vannamei can be promoted, the immunity can be enhanced, and muscle quality can be improved.

The invention belongs to the technical field of aquaculture, and particularly relates to a penaeus vannamei aquaculture method. The method comprises the following steps of (1), shrimp seed stocking, wherein high-quality penaeus vannamei larvae are selected as shrimp seeds and placed in an aquaculture pond system for stocking, the aquaculture pond system comprises a water pond unit and a greenhouse, and the greenhouse covers the entire water pond unit; (2), aquaculture temperature, salinity and dissolved oxygen control; and (3), aquaculture feeding, wherein in a penaeus vannamei aquaculture process, daphnia is adopted as the feeding bait or one of the feeding baits. By the adoption of the aquaculture method, the penaeus vannamei can be subjected to circular and high-density aquaculture allthe year round, without limitation of natural conditions. In addition, by adopting the aquaculture method, the market standards can be met only by half of the aquaculture time of a general aquaculturemethod in the prior art, and the penaeus vannamei is higher in yield and better in quality.

The invention discloses a penaeus vanmamei LvDJ-1 protein as well as a coding gene and an application thereof. The LvDJ-1 protein of the penaeus vanmamei is firstly obtained, the amino acid sequence of the LvDJ-1 protein is indicated as SEQ ID NO.2 or the LvDJ-1 protein is protein with one or more amino acid being substituted by the amino acid sequence indicated by the SEQ ID No.2, omitted and / or added and / or derived by the amino acid sequence indicated by the SEQ ID No.2 with end being modified and equal or higher activity. The experiment proves that the penaeus vanmamei LvDJ-1 protein can improve the stress resistance of the penaeus vanmamei and can be used for preparing immune preparation or feed additive related to the aquatic animals, and the application potential is wide.

The invention relates to a method for killing EHP (Enterocytozoon hepatopenaei) on Penaeus vannamei. The method comprises the steps: mixing essential oil into shrimp feed firstly, feeding Penaeus vannamei for two days or above, performing water change and pollution discharge after feeding on a culture pond two times or above in the feeding period, and performing medicated bath by using a sea saltelectrolytic solution-aqueous chlorine dioxide preparation so as to kill and eliminate EHP on Penaeus vannamei successfully. The domestic and foreign EHP treatment technology is supplemented, the economic benefits are high, the killing effect on EHP is fast, the operation is simple, and promotion is quick and convenient.

The invention relates to a compound feed for improving blue bodies of penaeus vannamei boone under industrial culture and a preparation method of the compound feed. The compound feed comprises the following components in parts by weight: 15-25 parts of fish meal, 15-25 parts of mussel meat powder, 8-10 parts of scallop meat powder, 5-10 parts of chicken meal, 3-8 parts of shrimp shell powder, 3-8parts of crab shell powder, 5-8 parts of fermented soybean meal, 5-8 parts of fermented peanut meal, 2-4 parts of chironomid larva powder, 17-20 parts of wheat flour, 2-3 parts of cuttlefish paste, 2-3 parts of shrimp paste, 2-3 parts of hydrolyzed fish soluble, 1-3 parts of soybean lecithin oil, 1-2 parts of multi-vitamin multi-mineral premix, 0.2-0.5 part of spirulina powder and 2-5 parts of haematococcus pluvialis powder. The compound feed disclosed by the invention has a remarkable improvement effect on the blue body problem of the penaeus vannamei boone under industrial culture, and experiments prove that the feed disclosed by the invention can promote the immunity and growth of the penaeus vannamei boone on the basis of improving the blue body problem of the penaeus vannamei boone.

The invention discloses a penaeus vannamei larva desalting culture method, including preparation of facility and equipment for production workshops, preparation of artificial sea water, cultivation ofbiological floccules, putting-in of penaeus vannamei larvae, daily feeding of baits and management on desalting process. The penaeus vannamei larva desalting culture method has the advantages of realizing desalting treatment on penaeus vannamei larvae within a short desalting cycle; the penaeus vannamei desalted has the advantages of short culture cycle, high yield, low cost, no adding of hormones, being green and environmentally friendly, and being delicious in taste and big in size.

The invention discloses a fresh water aquaculture method for penaeus vannamei. The fresh water aquaculture method comprises the following steps of: preparing a penaeus vannamei pond; desalting penaeus vannamei larvae; improving the immunity of the penaeus vannamei by using Chinese herbal medicines; regulating and controlling the water quality; biologically preventing and controlling; and daily managing and harvesting the penaeus vannamei. The fresh water aquaculture method is characterized by comprising the following steps of: artificially enclosing colored cloth at corners of a fish pond to form a desalination box; artificially configuring chemical raw materials into sea water in the desalination box and gradually desalting the sea water to form fresh water; enabling the penaeus vannameilarvae to gradually adapt to the growth in the fresh water; carrying out health care in the growth process by adopting the Chinese herbal medicines researched by Zhongshan University; and controllingthe water body by using a clarias leather or grass carp to prevent pests from being spread. Under the condition of sufficient feed, the penaeus vannamei can quickly and healthily grow. The fresh water aquaculture method is simple, easy in operation and convenient in popularization and application; according to the breeding demonstration of 68 popularizing demonstration sites with 2000mu in Li county of Hunan Province, 400-600 kilos of penaeus vannamei are produced in each mu, the production value is 12800-19200yuan, the profit is 8000-12000yuan of each mu and the cultivation success rate reaches 100 percent; and the fresh water aquaculture method is deeply favored by local farmers.

The invention belongs to the technical field of aquaculture, and particularly relates to a penaeus vannamei phagostimulant as well as a preparation method and a use method thereof. The phagostimulantis prepared from the following components in percentage by mass: 35 to 45% of Chinese herbal medicine extracts, 15 to 25% of animal extracts, 20 to 30% of compound amino acids, 5 to 10% of allicin and5 to 10% of vitamin C. According to the invention, a plurality of Chinese herbal medicine extracts, animal extracts, compound amino acids, allicin and vitamin C are compounded and mixed according toa certain ratio; the prepared phagostimulant can stimulate smell, taste, vision and the like of penaeus vannamei; the penaeus vannamei phagostimulant can attract penaeus vannamei to the periphery of feed, improve appetite, accelerate food intake, improve feed intake and feed utilization rate, reduce dissolution loss waste of feed in water, and reduce pollution of residual feed decay to water quality, so that the growth rate of penaeus vannamei is improved, and the compound amino acids, allicin and vitamin C can also promote penaeus vannamei resistance improvement and reduce diseases.

The invention belongs to the technical field of aquaculture, and particularly relates to a penaeus vannamei feeding method. According to the method, in a penaeus vannamei culture process, cladocera isadopted as feed or one of feed. Penaeus vannamei cultured by adopting the special feeding method is larger than commonly-cultured penaeus vannamei in specification, and the body weight of each penaeus vannamei is three times or above that of each commonly-cultured penaeus vannamei. Moreover, by adopting the special feed and the feeding method, a yield of the penaeus vannamei is comprehensively raised, and the yield per mu is up to 1000 kg or above; and the quality of the penaeus vannamei is optimized, the penaeus vannamei bodies are smooth in surface, and the penaeus vannamei has good activity, does not have off-odour, pasts drug tests, are uniform in specification, and reach the specifications completely.

The invention provides an efficient polyculture method for penaeus vannamei and loaches. The efficient polyculture method comprises the following specific steps of 1, desalination culture of the penaeus vannamei, specifically, 1) selecting and treating a desalination culture pond, 2) putting penaeus vannamei seeds, 3) desalinating culture water, and 4) feeding baits; 2, selecting and treating a polyculture pond; 3, mixed stocking of the seeds; and 4, breeding management. According to the method, the polyculture manner of the penaeus vannamei and the loaches is adopted, the loaches and the penaeus vannamei do not kill each other, the loaches can also eat excrement of the penaeus vannamei, and therefore the effect of purifying water is achieved; and plankton cultured in an arrowhead plantingpool can serve as food for the penaeus vannamei, the physique of the penaeus vannamei can be enhanced, the growth speed is increased, and diseases are reduced.

The invention discloses a penaeus vannamei seed breeding feed and a preparation process and a preparation device thereof, and relates to the technical field of feeds. The penaeus vannamei seed breeding feed is prepared from the following raw materials in parts by weight: 8 to 16.5 parts of fish bone meal, 1.8 to 2.2 parts of cod liver oil, 11 to 16 parts of rapeseed soybean meal, 1.2 to 2.3 parts of radix astragali seu hedysari, 0.6 to 1.3 parts of herba leonuri, 1.2 to 2.3 parts of herba menthae, 4 to 7 parts of flos lonicerae, 3 to 7 parts of radix et rhizoma rhei, 0.5 to 1.5 parts of vegetable oil, 0.5 to 1 part of calcium hydrogen phosphate, 0.01 to 0.03 part of erucyl amide, 0.5 to 1.5 parts of yeast powder, 1 to 2.2 parts of photosynthetic bacteria, 0.5 to 1.3 parts of bacillus, 2.1 to 3.2 parts of phagostimulant, and 1.7 to 1.9 parts of an antioxidant; the penaeus vannamei seed breeding feed can improve the disease resistance of penaeus vannamei in the middle stage, protect the liver, promote digestion, strengthen absorption, accelerate stable growth of the penaeus vannamei and avoid pathological changes, meanwhile, the device is convenient for multi-point detection, and the accuracy of detection data is ensured.

The invention belongs to the technical field of aquatic feed, and particularly relates to expanded feed for penaeus vannamei boone and an expanding method of the expanded feed. By replacing existing expensive fish meal with a fish meal substitute and newly adding a phagostimulant and a stabilizer in water, the produced feed can well meet the growth requirements of the penaeus vannamei boone, and the feed is good in stability in water, sufficient in ingestion and not prone to waste. In addition, the expanding method has the advantages of being good in expanding effect and thorough in expanding,an improved double-screw expanding machine has the two flexible and selectable modes of direct discharging before expanding or steam-assisted hardening and tempering, the selection action of the twomodes is simple and efficient, residual feed powder is easily accumulated in the overall structure of a feeding pipe, a steam-assisted hardening and tempering structure is simple and reliable, and thefeeding pipe on the expanding machine has the advantages of being high in overall structural stability and convenient to disassemble, assemble and maintain.

The invention belongs to the technical field of aquatic product preservation, and particularly relates to a natural preservative as well as a preparation method and application thereof. The natural preservative comprises the following components in percentage by mass: 3-6% of a protamine complex liquid, 1-3% of tea polyphenol, 1-2% of a chitosan solution, 0.5-1% of a kojic acid solution and the balance of water. According to the preparation method, the protamine complex liquid, the chitosan solution and the kojic acid solution are prepared respectively, and uniformly mixing the protamine complex liquid, the chitosan solution and the kojic acid solution with tea polyphenol and water is carried out to obtain the natural preservative. The invention further relates to application of the prepared natural preservative to preservation of the penaeus vannamei, the fresh penaeus vannamei is soaked in the natural preservative, fished out after soaking and rapidly blow-dried with low-temperaturesterile wind, and the blow-dried penaeus vannamei is put into a preservation bag for low-temperature storage. The preservative prepared by the invention is a pure natural preservative, can effectivelyinhibit blackening of the penaeus vannamei when being applied to preservation of the penaeus vannamei, and can prolong the low-temperature storage time of the penaeus vannamei by 8 days.