Cultivation method of outdoor pond biological bait

Abstract

The invention particularly relates to a method for cultivating biological bait in an outdoor pond. According to the method, after an outdoor pond is disinfected and cleaned, a biological fertilizer source and various beneficial bacteria combination are used in a combined mode, cryptococcus ovale, composite diatom and chlorella are inoculated, a stable pond bacterium-algae system is constructed, and various cultivated microalgae are used for strengthening zooplanktons of rotifers, cladocerans and copepods in the bait pond. The breeding period of the biological bait is shortened, the survival rate of the biological bait is increased, the yield of the biological bait is increased, meanwhile, the nutritional value of the biological bait is enhanced, and opening breeding of the fry is facilitated. The breeding method is low in cost and suitable for various weathers, and sufficient bait guarantee is provided for large-scale breeding of fish fries.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture biological bait cultivation, and in particular to a method for cultivating biological bait in an outdoor pond. Background Art

[0002] In aquaculture, the feeding stage of fry is extremely important for the entire breeding process and is the key to fry cultivation. Therefore, the selection of feed and feeding method become the decisive factors affecting the survival and growth of fry. Compared with traditional commercial compound feeds, using plankton such as rotifers, cladocerans and copepods as feed has many advantages. First, in the natural environment, fry usually first come into contact with these plankton, and fry have natural adaptability and foraging instincts for them, so the use of biological feed can promote the feeding behavior of fry. Second, plankton is rich in various nutrients required for the growth and development of fry, such as high-quality protein, essential amino acids, unsaturated fatty acids, vitamins and minerals, and its nutrition is more comprehensive than compound feed. In addition, the digestive system of fry is not fully developed in the opening stage, and the digestive ability is weak. Biological bait is small in size and easy to digest. After the fry eats, the digestive burden is small and the digestion rate is high, which is more conducive to the absorption of nutrients by the fry. Therefore, the construction of large-scale cultivation technology of the above-mentioned biological bait is of great significance for the early cultivation of fry. If high-quality biological bait can be supplied on a large scale and continuously, the cultivation effect of fry will be significantly improved.

[0003] Microalgae are rich in long-chain polyunsaturated fatty acids (PUFA). Zooplankton can enrich the PUFA in microalgae and pass it to seedlings by ingesting microalgae. Among them, n-3PUFA has important biological significance for seedlings. DHA and EPA have important effects on the maintenance of normal physiological functions of seedling cell membranes, the formation and improvement of the nervous system, and the development of gonads. The use of microalgae to fortify rotifers, cladocerans and copepods can further enrich the nutrition of biological baits. In addition, microalgae can also affect the egg-laying rate and reproduction cycle of biological baits, and increase the yield of biological baits. However, the existing methods of using microalgae to fortify biological baits usually have the problems of high cost and long cultivation cycle. Therefore, there is an urgent need in the art to develop a biological bait fortification method with a short cycle and low cost. Summary of the invention

[0004] The present application provides a method for cultivating biological bait in an outdoor pond, which effectively shortens the cultivation period of the biological bait and increases the content of unsaturated fatty acids in the biological bait. The biological bait prepared by the method can enhance the immunity, antioxidant properties and growth performance of seedlings, and provide sufficient bait guarantee for large-scale cultivation of seedlings.

[0005] The present invention achieves the above technical objectives through the following technical solutions:

[0006] The present invention provides a method for cultivating biological bait in an outdoor pond, comprising the following steps:

[0007] (1) Pond cleaning and disinfection;

[0008] (2) Water injection and fertilization: Pile up decomposed and fermented biofertilizer into the pond after cleaning and disinfection, then inject new water containing rotifers, cladocerans, and copepod plankton, control the depth to between 1 / 3 and 2 / 3 of the maximum water depth, and sprinkle EM bacteria, nitrifying bacteria, and yeast paste;

[0009] (3) Algae introduction: Inoculate diatoms on the day of new water injection. After water injection, when the nitrate concentration in the pond is 8-15 mg / L, the ammonia nitrogen concentration is 20-30 mg / L, and the nitrite concentration is 7-10 mg / L, inoculate Cryptomonas ovata. Inoculate Chlorella vulgaris 5-6 days later, fill the pond with water, and start to ensure the supply of oxygen to the pond;

[0010] (4) Harvesting of biological bait: After 8-10 days, the fish are caught and separated to obtain biological bait of different specifications;

[0011] During the above cultivation process, the water temperature is 16-30°C.

[0012] According to the above cultivation method, biofertilizer is applied at a rate of 180-200 kg per mu of compost; EM bacteria is applied at a rate of 1-2 L8-10×10 8 CFU / mL of viable bacteria liquid is sprayed as standard, and nitrifying bacteria are sprayed at 0.3-0.5L per mu 15-20×10 8 The standard spraying of bacterial solution with the number of cfu / mL of viable bacteria and the standard spraying of yeast paste at 1-2kg / mu;

[0013] The inoculation amount of diatoms is 15-20L per mu 6-10×10 7 The standard inoculation of algae liquid with a density of cells / mL, Cryptomonas ovata is 30-50L per mu with 3-5×10 4 cells / mL density of algae solution, 4-6L per acre of Chlorella 5-10×10 7 cells / mL density of algal liquid.

[0014] The above-mentioned cultivation method further includes step (5), fertilizer source supplementation and plankton group rejuvenation: 3-4 days after fishing or when the number of zooplankton in the biological bait pond is significantly reduced, nitrogen source and carbon source are supplemented to the pond.

[0015] According to the above-mentioned cultivation method, the supplemented nitrogen source and carbon source are fermented bean dregs and brown sugar fertilizer paste.

[0016] According to the cultivation method described above, the amount of fermented bean dregs is 10-15 kg / mu, and the amount of brown sugar fertilizer paste is 0.8-1.2 kg / mu.

[0017] According to the above-mentioned cultivation method, in step (2), the biofertilizer is piled at the four corners of the pond.

[0018] According to the above-mentioned cultivation method, the diatom is a composite diatom dry powder, and the algae species include straight chain algae, horn algae, needle-shaped algae, nitzschia algae, strand algae and small ring algae.

[0019] Based on the cultivation method described above, the pond cleaning and disinfection method is: drain the pond water, remove the silt, debris and weeds at the bottom of the pond, disinfect each acre of pond with 50-100kg of quicklime or 10-15kg of bleaching powder, and then dry it in the sun for 10-15 days.

[0020] According to the above-mentioned cultivation method, during the algae introduction, after 2-3 days of water injection, stirring is used to promote the dissolution of biofertilizer so that the nitrate concentration in the pond reaches 8-15 mg / L, the ammonia nitrogen concentration reaches 20-30 mg / L, and the nitrite concentration reaches 7-10 mg / L.

[0021] According to the above-mentioned cultivation method, the method for expanding the cultivation of Cryptoalgae ovata is as follows: after inoculation, ensure that the water body is in a rolling state, control the water temperature at 25±5℃, the pH between 6.0-8.0, the light at 4000-6000lx, maintain 24h lighting, and add compound probiotics, brown sugar fertilizer paste, sodium nitrate, and sodium bicarbonate, and expand the cultivation until the algae density reaches 3-5×10 4 cells / mL and then sprinkle it for use.

[0022] According to the cultivation method described above, the pond area is 1-2 mu and the maximum water depth is 0.8-1.2m.

[0023] The method for cultivating outdoor pond biological bait provided by the present invention has at least the following advantages:

[0024] (1) By using chlorella, diatoms, and cryptomonads to strengthen rotifers, cladocerans, and copepod plankton bait, the cultivation cycle of biological bait can be shortened, the survival rate of biological bait can be increased, and the yield of biological bait can be improved, providing a guarantee for the large-scale cultivation of seedlings;

[0025] (2) Using biological fertilizer, yeast paste and three types of algae to cultivate biological bait in outdoor ponds, a stable balance system of bacteria, algae and plankton was established. The subsequent regular supplementation of fertilizer sources can achieve the rejuvenation of the population of rotifers, cladocerans and copepods at a low cost.

[0026] (3) The cultivation of biological bait depends on light. The algae combination population of the present invention is relatively stable. Among them, Chlorella can proliferate rapidly under sufficient light conditions, the composite diatom has a low light requirement and can grow normally in rainy weather, and the cryptoalgae can reproduce heterotrophically under insufficient light conditions. The scientific combination of the three algae can provide a steady supply of food for rotifers, cladocerans and copepods biological baits under different weather conditions, ensuring the stable cultivation of biological baits;

[0027] (4) Cryptophytes and diatoms are rich in polyunsaturated fatty acids such as EPA and DHA. These polyunsaturated fatty acids can be enriched in rotifers, cladocerans, and copepods through the food chain. The use of fortified biological baits can enhance the immunity, antioxidant properties and growth performance of seedlings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The density variation trend of biological bait in Example 1 and Example 2;

[0029] Figure 2 The effects of feeding biological bait on the growth performance of fry in Example 1, Comparative Example 1 and Comparative Example 2 are shown. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The present invention provides a method for cultivating biological bait in an outdoor pond, comprising the following steps:

[0032] (1) Pond cleaning and disinfection;

[0033] (2) Fertilization by water injection: After cleaning and disinfecting the pond, pile up decomposed biofertilizer, then inject new water containing rotifers, cladocerans, and copepod plankton, and control the depth between 1 / 3 and 2 / 3 of the highest water depth to facilitate the increase of water temperature and the reproduction of biological bait, and then spray EM bacteria, nitrifying bacteria, and yeast paste;

[0034] (3) Algae introduction: Inoculate diatoms on the day of new water injection. After water injection, when the nitrate concentration in the pond is 8-15 mg / L, the ammonia nitrogen concentration is 20-30 mg / L, and the nitrite concentration is 7-10 mg / L, inoculate Cryptomonas ovata. Inoculate Chlorella vulgaris 5-6 days later, fill the pond with water, and start to ensure the supply of oxygen to the pond;

[0035] (4) Harvesting of biological bait: After 8-10 days, the fish are caught and separated to obtain biological bait of different specifications;

[0036] During the above cultivation process, the water temperature is 16-30°C.

[0037] The method for cultivating biological bait in outdoor ponds provided by the present invention comprises the following steps: after disinfecting and cleaning the outdoor pond, a biological fertilizer source and a combination of multiple beneficial bacteria are used in combination, and ovoid cryptoalgae, composite diatoms and chlorella are inoculated to construct a stable pond bacterial-algae system, and the rotifers, cladocerans and copepod zooplankton in the bait pond are strengthened by using the cultivated multiple microalgae. Different types of microalgae are used to carry out nutritional fortification cultivation of rotifers, cladocerans and copepod biological baits in outdoor ponds, and the polyunsaturated fatty acids, proteins and other nutrients in the microalgae are enriched in the biological baits through the food chain transmission method, thereby shortening the cultivation cycle of the biological baits, increasing the survival rate of the biological baits, and improving the output of the biological baits, while enhancing the nutritional value of the biological baits, which is beneficial to the opening cultivation of seedlings. The cultivation method is low-cost, suitable for all kinds of weather, and provides sufficient bait guarantee for the large-scale cultivation of fry.

[0038] In the present invention, during water injection and fertilization, the biofertilizer is composted according to the standard of 180-220 kg per mu. The type of biofertilizer is not particularly limited, and chicken manure, pig manure, cow manure and other biofertilizers can be used. During composting, it can be piled at the four corners of the pond to avoid the nutrients in the fertilizer being released into the water body in large quantities at one time, ensuring that the fertilizer is slowly dissolved and decomposed in the water, and prolonging the fertilizer effect.

[0039] New water can be directly from water sources containing rotifers, cladocerans, and copepods, or the above-mentioned plankton can be added to water sources that do not contain them. In practical applications, outdoor ponds are usually selected from waters with flat terrain, sufficient water sources, no pollution, and good water quality, and are close to natural water sources such as rivers and lakes to facilitate water diversion and drainage. In addition, natural water sources themselves contain rotifers, cladocerans, and copepods, which are easy to introduce.

[0040] EM bacteria (Effective Microorganisms) is composed of about 80 kinds of microorganisms. EM bacteria was successfully researched by Professor Teruo Higa of the University of the Ryukyu in Japan in 1982 and was put on the market in the 1980s. EM bacteria is a microbial preparation composed of more than 80 microorganisms from 10 genera, mainly photosynthetic bacteria, lactic acid bacteria, yeast and actinomycetes. It can compete with pathogenic microorganisms for nutrients, quickly and stably form a dominant community of beneficial microorganisms, thereby controlling the reproduction of pathogenic microorganisms. EM bacteria is 1-2L per mu 8-10×10 8 Standard splashing of bacterial solution with cfu / mL viable bacterial count.

[0041] Nitrifying bacteria are a type of aerobic bacteria, including nitrite bacteria and nitrate bacteria. The toxic substances in the pond are mainly ammonia and nitrite. Nitrifying bacteria can consume the above two toxic substances and generate non-toxic nitrates. Nitrates are the best nitrogen fertilizer for algae and can be absorbed and assimilated by algae. Nitrifying bacteria are 0.3-0.5L per mu 15-20×10 8 Standard splashing of bacterial solution with cfu / mL viable bacterial count.

[0042] Yeast paste is a product made from pure natural yeast. It is rich in nutrients such as protein, vitamins, trace elements, etc. It is a common raw material for biological culture medium and raw material in the fermentation industry. Yeast paste is sprayed at a standard of 1-2kg / mu.

[0043] The cultivation of biological bait depends on light. The algae population of the present invention is relatively stable. Chlorella can proliferate rapidly under sufficient light conditions, the composite diatom has low light requirements and can grow normally in rainy weather, and the cryptoalgae can grow heterotrophically under insufficient light conditions. The scientific combination of the three algae can provide food for rotifers, cladocerans and copepods under different weather conditions, ensuring the stable cultivation of biological bait. The inoculation amount of diatoms is 15-20L per mu, 6-10×10 7 The standard inoculation of algae liquid with a density of cells / mL, Cryptomonas ovata is inoculated at 30-50L3-5×10 cells / mL per mu. 4 cells / mL density of algae solution, 4-6L per acre of Chlorella 5-10×10 7 cells / mL density of algal liquid.

[0044] In order to ensure the stability of the population of pond biological bait and achieve continuous access to bait, the method also includes the steps of supplementing fertilizer sources and rejuvenating plankton groups. Specifically, nitrogen and carbon sources are added to the pond 3-4 days after fishing or when the number of zooplankton in the biological bait pond is significantly reduced.

[0045] There is no special restriction on the types of nitrogen source and carbon source. For example, fermented bean dregs and brown sugar fertilizer paste can be supplemented, which is low in cost.

[0046] The fermented soybean dregs in the present invention refer to the fertilizer made by stirring, grinding and fermenting soybeans or soybean meal, which is rich in lactic acid bacteria and amino acids and is mainly used as a nitrogen source supplement for algae.

[0047] The brown sugar fertilizer paste in the present invention refers to a paste-like nutrient agent whose main ingredients are brown sugar and amino acids and rich in various trace elements (such as iron, manganese, zinc, etc.), and is mainly used as a carbon source supplement for algae. For example, the brown sugar fertilizer paste purchased from Liyang Aquatic Products can be used.

[0048] The amount of fermented bean dregs (i.e. the amount to be supplemented each time) is 10-15kg / mu, and the amount of brown sugar fertilizer paste (i.e. the amount to be supplemented each time) is 0.8-1.2kg / mu. The amount can be increased by 30-40% during continuous rainy days.

[0049] The diatom used in the present invention is preferably a composite diatom, and specifically, a composite diatom dry powder can be used, and the algae species include straight chain algae, horn algae, needle algae, nitzschia algae, strand algae and small ring algae.

[0050] The method of pond cleaning and disinfection in the present invention is not specifically limited, and conventional methods in the art can be used. Generally, the pond water is drained, the silt, debris and weeds at the bottom of the pond are removed, 50-100 kg of quicklime or 10-15 kg of bleaching powder per acre of pond is evenly sprinkled on the bottom and around the pond for disinfection, and then aired for 10-15 days to kill the pathogens, parasites and wild fish in the pond.

[0051] In the present invention, 2-3 days after water injection during algae introduction, the concentrations of nitrate, ammonia nitrogen and nitrite in the pond can basically reach the above indicators. If not, the fertilizer dissolution can be accelerated by appropriately extending the time or stirring during the process to achieve the above requirements.

[0052] In the present invention, the ovate cryptoalgae can be purchased from algae seed banks at home and abroad, or can be obtained from natural waters after enrichment, separation and culture. The ovate cryptoalgae needs to be expanded before use, and the expansion method can be used as follows: after inoculation, ensure that the water body is in a rolling state, control the water temperature at 25±5℃, pH between 6.0-8.0, and light at 4000-6000lx, and maintain 24h of light. At the same time, add compound probiotics, brown sugar fertilizer paste, sodium nitrate, and sodium bicarbonate, and expand the culture until the algae density reaches 3-5×10 4 cells / mL and then sprinkled for use. Among them, probiotics can be selected from bacterial agents that are beneficial to the growth of algae and inhibit the growth of pathogenic bacteria, such as EM bacteria.

[0053] The outdoor pond area is preferably 1-2 mu, and the maximum water depth is 0.8-1.2 m. In the present invention, the method of ensuring oxygen supply is to add an aerator by conventional methods in the art. For example, taking a pond with an area of ​​1-2 mu as an example, two 2kw tillage machines and one 3kw jet aerator are usually arranged to ensure the oxygen supply of the pond.

[0054] The present invention is described in detail below in conjunction with specific implementation modes.

[0055] Ovate cryptoalgae is obtained by enrichment, separation and culture from natural waters. Ovate cryptoalgae needs to be expanded before use. The expansion operation is as follows: pour the algae seeds into a white plastic bucket containing 200L of water. The bucket is equipped with an aeration device to keep the water body in a tumbling state. The water temperature is controlled at 25±1℃, the pH is controlled between 6.0-8.0, and the light is controlled at 4000-6000lx, and the light is maintained for 24 hours. At the same time, add 2L of compound probiotics (Liyang brand "Lijunduo"), 500g of brown sugar fertilizer paste (Liyang brand), 40g of sodium nitrate and 7g of sodium bicarbonate. After 5 days of expansion, the algae density reaches 4.2×10 4 cells / mL.

[0056] The chlorella is concentrated protein-core chlorella (Fengtian brand), which is diluted 10 times and then sprayed.

[0057] The following experiment was conducted at the rare and endemic fish breeding and release station of the Xiluodu Xiangjiaba Hydropower Station of China Three Gorges Corporation from April to July. The water temperature fluctuated between 16 and 30 °C.

[0058] Example 1

[0059] A method for cultivating biological bait in an outdoor pond comprises the following steps:

[0060] (1) Pond cleaning and disinfection: Before cultivating biological bait, the outdoor pond (area of ​​2 mu, maximum water depth of 1m) is thoroughly cleaned and disinfected. Drain the pond water and remove the silt, debris and weeds at the bottom of the pond. Use 200kg of quicklime to clean and disinfect the pond. Sprinkle the quicklime evenly on the bottom and around the pond, and then dry it in the sun for 15 days to kill the pathogens, parasites and wild fish in the pond.

[0061] (2) Water injection and fertilization: After cleaning and disinfecting the pond, pile up fermented chicken manure, pig manure, cow manure and other biofertilizers at the four corners of the pond, with a composting amount of 200 kg per mu. After composting, inject new water into the pond, and control the depth of the first water injection at 0.6 m to facilitate the increase of water temperature and the reproduction of biological bait. The outdoor pond water source is taken from the Xiluodu Xiangjiaba Reservoir of China Three Gorges Corporation. The water source itself contains rotifers, cladocerans and copepods, so there is no need to introduce the above-mentioned zooplankton during the cultivation process. After water injection, sprinkle EM bacteria (Liyang brand, viable bacteria count 8-10×10 8 cfu / mL, nitrifying bacteria (Liyang brand, viable count 15-20×10 8 cfu / mL) and yeast paste (Hongrun Baoshun brand), with dosages of 2L / mu, 0.3L / mu and 2kg / mu respectively.

[0062] (3) Algae introduction: Diatoms grow relatively slowly. On the day of water injection (recorded as day 0), composite diatoms (brand: Yuyao Technology, the main algae species are straight chain algae, horn algae, needle algae, nitzschia, strand algae and small ring algae) were inoculated. The introduction operation was to place algae powder in a large barrel and dilute it with 40L of water. The density of the algae liquid was tested to be 8×10 7 cells / mL, soaked for 3 hours, and then splashed throughout the pond). Two days after water injection, the nitrate concentration in the pond reached its peak (nitrate concentration was 8-15 mg / L, ammonia nitrogen concentration was 20-30 mg / L, and nitrite concentration was 7-10 mg / L), which was suitable for the growth of cryptoalgae. At this time, the density of 80L of expanded culture inoculated into the pond was 4.2×10 4 cells / mL of Cryptoalgae ovale, and 10L of 10-fold diluted Chlorella vulgaris (Fengtian brand, the density of the 10-fold diluted algae solution is 7×10 7 cells / mL), and fill the pond with water to a depth of 1m. At the same time, two 2kw water tillers and one 3kw jet aerator are deployed to ensure the oxygen supply of the pond.

[0063] (4) Harvesting of biological bait: After 8 days, rotifers and copepods in the water body multiplied in large numbers, and the peak biomass reached 75g / m 3 , use a 300-mesh plankton net for fishing, and through graded filtration, biological baits of different specifications can be separated.

[0064] (5) Fertilizer source supplementation and plankton population rejuvenation: Three days after fishing, fermented bean dregs and brown sugar fertilizer paste (Liyang brand) are sprayed into the pond every other day to supplement the nitrogen source and carbon source for the biological bait, with the dosage of 20kg and 2kg respectively.

[0065] Example 2

[0066] The difference between Example 2 and Example 1 is that after the biological bait is harvested, fermented bean dregs and brown sugar fertilizer paste are not supplemented, and only algae photosynthesis is relied upon to supplement the carbon source.

[0067] Comparative Example 1

[0068] The difference between this comparative example and Example 1 is that no algae is used to enhance the nutrition of rotifers, cladocerans and copepods. The specific steps are as follows:

[0069] (1) Pond cleaning and disinfection: Before cultivating biological bait, the outdoor pond (area of ​​2 mu, maximum water depth of 1m) is thoroughly cleaned and disinfected. Drain the pond water and remove the silt, debris and weeds at the bottom of the pond. Use 200kg of quicklime to clean and disinfect the pond. Sprinkle the quicklime evenly on the bottom and around the pond, and then dry it in the sun for 15 days to kill the pathogens, parasites and wild fish in the pond.

[0070] (2) Water injection and fertilization: After cleaning and disinfecting the pond, pile up fermented chicken manure, pig manure, cow manure and other biofertilizers at the four corners of the pond, with a composting amount of 200 kg per mu. After composting, inject new water into the pond. The depth of the first water injection is controlled at 1 m. At the same time, two 2kw tillage machines and one 3kw jet aerator are deployed to ensure the oxygen supply of the pond. The outdoor pond water source is taken from the Xiluodu Xiangjiaba Reservoir of China Three Gorges Corporation. The water source itself contains rotifers, cladocerans and copepods. Therefore, it is not necessary to introduce the above-mentioned zooplankton during the cultivation process. After water injection, sprinkle EM bacteria (Liyang brand, viable bacteria count 8-10×10 8 cfu / mL), nitrifying bacteria (Liyang brand, viable count 15-20×10 8 cfu / mL) and yeast paste (Hongrun Baoshun brand), with dosages of 2L / mu, 0.3L / mu and 2kg / mu respectively.

[0071] (3) Harvesting of biological bait: After 12 days, rotifers and copepods will multiply in large numbers in the water body. Use a 300-mesh plankton net to catch them and harvest biological bait.

[0072] (4) Fertilizer source supplementation and plankton population rejuvenation: Three days after fishing, fermented bean dregs and brown sugar fertilizer paste (Liyang brand) are sprayed into the pond every other day to supplement the nitrogen source and carbon source for the biological bait, with the dosage of 20kg and 2kg respectively.

[0073] Comparative Example 2

[0074] The difference between this comparative example and Example 1 is that, during the algae introduction process, composite diatoms and ovate cryptomonads are not cultivated, and only Chlorella is used to enhance the nutrition of rotifers, cladocerans and copepods. The specific steps are as follows:

[0075] (1) Pond cleaning and disinfection: Before cultivating biological bait, the outdoor pond (area of ​​2 mu, maximum water depth of 1m) is thoroughly cleaned and disinfected. Drain the pond water and remove the silt, debris and weeds at the bottom of the pond. Use 200kg of quicklime to clean and disinfect the pond. Sprinkle the quicklime evenly on the bottom and around the pond, and then dry it in the sun for 15 days to kill the pathogens, parasites and wild fish in the pond.

[0076] (2) Water injection and fertilization: After cleaning and disinfecting the pond, pile up fermented chicken manure, pig manure, cow manure and other biofertilizers at the four corners of the pond, with a composting amount of 200 kg per mu. After composting, fill the pond with new water (1m). The outdoor pond water source is taken from the Xiluodu Xiangjiaba Reservoir of China Three Gorges Corporation. The water source itself contains rotifers, cladocerans and copepods, so there is no need to introduce the above-mentioned zooplankton during the cultivation process. After water injection, sprinkle EM bacteria (Liyang brand, viable bacteria count 8-10×10 8 cfu / mL), nitrifying bacteria (Liyang brand, viable count 15-20×108 cfu / mL) and yeast paste (Hongrun Baoshun brand), with dosages of 2L / mu, 0.3L / mu and 2kg / mu respectively.

[0077] (3) Algae introduction: On the day of water injection, 10L of 10-fold diluted Chlorella vulgaris (Fengtian brand, the density of the 10-fold diluted algae solution is 6.5×10 7 cells / mL), and two 2kw water tillers and one 3kw jet aerator are deployed to ensure the oxygen supply to the pond.

[0078] (4) Harvesting of biological bait: After 8 days, rotifers and copepods will multiply in large numbers in the water body. Use a 300-mesh plankton net to catch them and harvest biological bait.

[0079] (5) Fertilizer source supplementation and plankton population rejuvenation: Three days after fishing, fermented bean dregs and brown sugar fertilizer paste (Liyang brand) are sprayed into the pond every other day to supplement the nitrogen source and carbon source for the biological bait, with the dosage of 20kg and 2kg respectively.

[0080] (1) After enrichment, the biological bait harvested in the first catch was wiped dry with filter paper, and then the moisture, ash, crude protein, crude fat, EPA, DHA and EAA content were tested. The test methods are as follows: moisture was determined by atmospheric pressure drying method (GT / T6435-2014), crude protein was determined by Kjeldahl nitrogen determination method (GB / T6433-2006), crude fat was determined by Soxhlet extraction method (GB / T6433-2006), and ash was determined by muffle furnace burning method (GB / T6438-2007). The wiped-dry samples were crushed and extracted, and then EPA, DHA and EAA were tested by high performance liquid chromatography. The test results are shown in Tables 1 and 2 below:

[0081] Table 1

[0082]

[0083] Table 2

[0084]

[0085] From the above results, it can be seen that the crude protein, crude fat, EPA and DHA contents in n3-PUFA of the biological bait obtained in Example 1 are significantly higher than those of the biological baits obtained in Comparative Examples 1 and 2, indicating that the biological bait cultivation method described in the present invention can enhance the nutrition of the biological bait and enrich its EPA and DHA polyunsaturated fatty acid content.

[0086] In addition, the cultivation period in Example 1 is 6-8 days, and the cultivation period in Comparative Example 1 is 12-15 days. The peak density in Example 1 is significantly higher than that in Comparative Example 1, indicating that the algae nutrition enhancement method described in the present invention can shorten the cultivation period of biological bait, increase the survival rate of biological bait, and improve the yield of biological bait.

[0087] (2) When the biological bait is harvested 30 kg per day, the decay rate of the biological bait in Example 1 is compared with the decay rate in Example 2. The results are as follows: Figure 1 shown.

[0088] As shown in 1, the decay rate of the biological bait in Example 2 is significantly slower than that in Example 2, indicating that regular supplementation of fertilizer sources can achieve population rejuvenation of rotifers and cladoceran copepods and achieve continuous production.

[0089] (3) The biological feed obtained in Example 1, Comparative Example 1 and Comparative Example 2 was graded and filtered and then fed to the same batch of thick jawed bream fry (average initial weight 0.03g), with a feeding frequency of 2 times / d, ensuring that the biological feed density in the aquaculture water was 8-10 / mL. After 15 days of feeding, the fry were sampled and their growth performance and antioxidant properties were tested. The results are as follows: Figure 2 and as shown in Table 3 below.

[0090] Table 3

[0091]

[0092] From the above results, it can be seen that the fry fed with the biological bait in Example 1 are significantly better than the fry fed with the comparative examples 1 and 2 in terms of weight gain rate and liver antioxidant performance, indicating that the enhanced biological bait of the present invention has the advantages of enhancing the immunity, antioxidant performance and growth performance of the fry.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for cultivating biological bait in an outdoor pond, characterized in that: The following steps are involved: (1) Pond cleaning and disinfection; (2) Water injection and fertilization: Pile up decomposed and fermented biofertilizer into the pond after cleaning and disinfection, then inject new water containing rotifers, cladocerans, and copepod plankton, control the depth to between 1 / 3 and 2 / 3 of the maximum water depth, and sprinkle EM bacteria, nitrifying bacteria, and yeast paste; (3) Algae introduction: Inoculate diatoms on the day of new water injection. After water injection, when the nitrate concentration in the pond is 8-15 mg / L, the ammonia nitrogen concentration is 20-30 mg / L, and the nitrite concentration is 7-10 mg / L, inoculate Cryptomonas ovata. Inoculate Chlorella vulgaris 5-6 days later, fill the pond with water, and start to ensure the supply of oxygen to the pond; (4) Harvesting of biological bait: After 8-10 days, the fish are caught and separated to obtain biological bait of different specifications; During the above cultivation process, the water temperature is 16-30°C.

2. The method for cultivating outdoor pond biological bait according to claim 1, characterized in that: Biofertilizer is applied at a rate of 180-200kg of compost per acre; EM bacteria is 1-2L per mu, 8-10×10 8 CFU / mL of viable bacteria liquid is sprayed as standard, and nitrifying bacteria are sprayed at 0.3-0.5L per mu 15-20×10 8 The standard spraying of bacterial solution with the number of cfu / mL of viable bacteria and the standard spraying of yeast paste at 1-2kg / mu; The inoculation amount of diatoms is 15-20L per mu 6-10×10 7 The standard inoculation of algae liquid with a density of cells / mL, Cryptomonas ovata is 30-50L per mu with 3-5×10 4 cells / mL density of algae solution, 4-6L per acre of Chlorella 5-10×10 7 cells / mL density of algal liquid.

3. The method for cultivating outdoor pond biological bait according to claim 1 or 2, characterized in that: The method also includes step (5), supplementing fertilizer sources and rejuvenating the plankton community: 3-4 days after fishing or when the number of zooplankton in the biological bait pond is significantly reduced, supplementing nitrogen and carbon sources to the pond.

4. The method for cultivating outdoor pond biological bait according to claim 3, characterized in that: The supplementary nitrogen and carbon sources are fermented bean dregs and brown sugar fertilizer paste; and / or The dosage of fermented bean dregs is 10-15kg / mu, and the dosage of brown sugar fertilizer paste is 0.8-1.2kg / mu.

5. The method for cultivating outdoor pond biological bait according to claim 1 or 2, characterized in that: In step (2), biofertilizer is piled at the four corners of the pond.

6. The method for cultivating outdoor pond biological bait according to claim 1 or 2, characterized in that: The diatom is a composite diatom dry powder, and the algae species include straight chain algae, horn algae, needle-shaped algae, nitzschia algae, strand algae and small ring algae.

7. The method for cultivating outdoor pond biological bait according to claim 1 or 2, characterized in that: The method for pond cleaning and disinfection is: drain the pond water, remove the silt, debris and weeds at the bottom of the pond, disinfect each acre of pond with 50-100kg of quicklime or 10-15kg of bleaching powder, and then dry it in the sun for 10-15 days.

8. The method for cultivating outdoor pond biological bait according to claim 1 or 2, characterized in that: During the algae introduction, after 2-3 days of water injection, stirring is used to promote the dissolution of biofertilizer so that the nitrate concentration in the pond reaches 8-15 mg / L, the ammonia nitrogen concentration reaches 20-30 mg / L, and the nitrite concentration reaches 7-10 mg / L.

9. The method for cultivating outdoor pond biological bait according to claim 1 or 2, characterized in that: The method of propagating Cryptoalgae ovata is as follows: after inoculation, ensure that the water body is in a rolling state, control the water temperature at 25±5℃, pH between 6.0-8.0, light at 4000-6000lx, maintain 24h lighting, and add compound probiotics, brown sugar fertilizer paste, sodium nitrate, and sodium bicarbonate, and propagate until the algae density reaches 3-5×10 4 cells / mL and then sprinkle it for use.

10. The method for cultivating outdoor pond biological bait according to claim 1 or 2, characterized in that: The pond area is 1-2 acres, and the maximum water depth is 0.8-1.2m.

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