Comprehensive aquaculture method for litopenaeus vannamei and snail composite biofloc

Abstract

The invention discloses a comprehensive aquaculture method for litopenaeus vannamei and snail composite biofloc, and belongs to the technical field of aquaculture. The breeding method comprises the following steps: carrying out composite domestication on the snails in a low-salinity-resistant water body and a high-turbidity-resistant water body, constructing a litopenaeus vannamei-snail-biofloc comprehensive breeding system, and carrying out daily breeding management. According to the method, snails are introduced into a litopenaeus vannamei biofloc culture system, redundant biofloc is efficiently utilized in an in-situ culture water body through the ingestion effect of the snails, and on one hand, additional snail culture biomass increase is obtained; on the other hand, the control level of total suspended solids in the culture water body is improved, the utilization rate of aquatic animals on nitrogen in the feed is increased, ecological synergy of litopenaeus vannamei, snails and biological floccules is achieved, and an environment-friendly technical path is provided for high-density prawn culture.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and in particular relates to a comprehensive aquaculture method of composite biological flocs of Litopenaeus vannamei and snails. Background Art

[0002] Aquaculture products provide humans with high-quality animal protein. Advances in aquaculture technology have significantly increased the unit yield of aquatic products. However, while traditional aquaculture models pursue high yields and profits, they also place a burden on the environment and pose a risk to the food safety of aquatic products.

[0003] In recent years, biofloc culture technology (BFT) has been used in practical applications, primarily using nitrifying bacteria for water purification. It has demonstrated excellent results in the aquaculture of aquatic species such as tilapia (Oreochromis niloticus) and whiteleg shrimp (Litopenaeus vannamei). Bioflocs can convert toxic nitrogenous inorganic salts into non-toxic nitrogenous substances, primarily nitrate nitrogen in the aquaculture water and biofloc biomass. Furthermore, bioflocs contain high levels of crude protein and bioactive substances, making them a valuable source of fresh feed for aquatic animals. This can reduce aquaculture costs, increase survival rates, and generate significant economic benefits for producers.

[0004] However, as the breeding cycle increases, the biomass of bioflocs in the biofloc breeding water gradually increases, and the water becomes highly turbid, that is, the biofloc concentration (total suspended solids, TSS) in the breeding water gradually increases, which affects the normal feeding and breathing of the breeding objects, and requires regular artificial regulation of the floc concentration. At present, the main methods for regulating the floc concentration include water exchange method and sedimentation collection method. The water exchange method usually discharges the breeding water containing a high concentration of flocs and then replaces it with new water, which has problems such as waste of water resources and environmental pollution. The sedimentation collection method usually discharges the breeding water containing a high concentration of flocs into another container, and after standing and settling, the supernatant is returned to the original breeding container. This method has problems such as cumbersome operation process, long time consumption, and easy stress of the breeding animals caused by drainage and water intake.

[0005] Bellamya aeruginosa and Cipangopaludina chinensis Gray are common snails and popular food items with high economic value. They are omnivorous, typically consuming phytoplankton, suspended organic debris, young aquatic plants, bacteria in the bottom mud, and humus. Bioflocs are flocs formed by microorganisms, feed residues, organic debris, and algae, providing a theoretical and material basis for snails to feed on flocs. Bellamya aeruginosa and other snails prefer to live in water environments with abundant food, clear water, and humus deposits. Their typical habitats include slow-flowing water bodies such as lakes and ponds with lush aquatic plants, rice field ditches, and slow-flowing rivers. At the same time, studies have shown that snails can adapt to salinity levels of 2.8‰ through metabolism, indicating that they have a certain range of adaptability to salinity changes. Therefore, it is theoretically feasible to apply the biological characteristics of snails that they can eat bacteria to the low-salinity biofloc culture system of Penaeus vannamei.

[0006] In the prior art, there is no method for integrated farming of Litopenaeus vannamei, snails, and bioflocs that improves the ability to control biofloc concentration and utilize feed sources. Summary of the Invention

[0007] To address the resource utilization problem of excess bioflocs in a biofloc aquaculture system, the present invention aims to provide an integrated aquaculture method for composite bioflocs of Litopenaeus vannamei and snails. Based on the biological characteristics of snails ingesting bacteria and humus, and a composite domestication method that tolerates low salinity and highly turbid water, snail farming is integrated into the biofloc aquaculture system of Litopenaeus vannamei. Synergistic management is achieved through simultaneous domestication, density control, and artificial sea salt preparation. This provides an integrated aquaculture method for "Litopenaeus vannamei - snails - bioflocs," thereby improving the ability to control the biofloc concentration in aquaculture water and the efficiency of in-situ feed source utilization.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides a comprehensive aquaculture method of composite bioflocs of Litopenaeus vannamei and snails, comprising the following steps:

[0010] (1) Composite domestication of snails to low salinity and high turbidity water bodies: snails are cultured in domestication ponds with a three-dimensional attachment base, baffles are added to increase the attachment area of ​​the water body for the snails to inhabit, the water depth is controlled at 0.5-1.0 m, aeration stones are installed at the bottom and sufficient aeration is provided; low salinity domestication is achieved by gradually adding artificial sea salt every day, with the salinity increasing by 0.1-0.2‰ each time until the salinity is domesticated to 2.7‰; artificial sea salt is added three times a day, in the morning, afternoon and midnight, with an interval of 8 hours between each addition, and the amount added each time is one-third of the total daily addition amount; at the same time, precipitated and concentrated bioflocs are added to the water body every day to provide a feed source, and the concentration of bioflocs in the water body is increased, so that the snails adapt to the turbidity characteristics and biological bait properties of the bioflocs, and complete the domestication of the snails to high turbidity water bodies;

[0011] (2) Construct an integrated culture system for Penaeus vannamei, snails, and bioflocs: select an indoor conical or pot-bottom culture pond with a corundum aeration stone at the bottom, connect an air pump through a gas flow meter to provide aeration and regulate its size, and use a heating rod to control the water temperature of the culture system; first, cultivate the bioflocs to maturity, and coarsely culture the Penaeus vannamei shrimp fry to an initial weight of 0.01-2.00 g, inject tap water into the culture pond that has been disinfected in advance, aerate for 24 hours to remove residual chlorine, and add artificial sea salt to the target salinity; then, inoculate the culture pond with bioflocs, and adjust the initial total suspended solids concentration of the water body to 75-150 mg / L; then, release snails into the culture pond, wait for the snails to adapt stably for at least 6 hours, and evenly attach and inhabit along the culture pond; then, release the Penaeus vannamei shrimp fry; during operation, control the water body to be evenly aerated to prevent the bioflocs from settling, control the water temperature at 25-30 ° C, and carry out routine feeding and daily maintenance management;

[0012] (3) Daily aquaculture management: After constructing the integrated aquaculture system of Penaeus vannamei, snails and biofloc, the daily feeding amount of the compound feed of Penaeus vannamei is 3-10% of the total body weight of the shrimp, and the compound feed is fed 3-12 times a day. Water quality control substances including sodium bicarbonate, calcium chloride and magnesium sulfate are added to the water body every 3-5 days. The water in the aquaculture pond is not changed during the aquaculture period, and the water lost by evaporation in the aquaculture pond is replenished every 5-10 days.

[0013] Preferably, in step (1), the snail is the copper-rust ring-edge snail and / or the Chinese round field snail.

[0014] Preferably, in step (1), the artificial sea salt is prepared according to the following composition and ratio: every 1000g of artificial sea salt contains 769.827g of sodium chloride, 96.076g of magnesium sulfate, 71.133g of magnesium chloride, 33.168g of calcium chloride, 21.076g of potassium chloride, 5.872g of sodium bicarbonate, 2.413g of sodium bromide, 0.174g of sodium silicate, 0.174g of strontium chloride, 0.029g of sodium fluoride, and 0.058g of disodium edetate.

[0015] Preferably, in step (1), the initial TSS is 0 mg / L, and the TSS is increased by 5 to 30 mg / L daily until the TSS reaches 150 mg / L or above.

[0016] Preferably, in step (2), the initial stocking density of Penaeus vannamei in the culture pond is 300 to 650 tails / m 3 The initial density of snails is 300-3500g / m 3 If the stocking density of whiteleg shrimp is too high, the floc concentration in the aquaculture water will rise rapidly, increasing the oxygen consumption of the water and adversely affecting the respiration and growth of whiteleg shrimp and snails. Conversely, if the snail density is too high, they will consume the flocs too quickly, making it difficult to maintain the concentration of biological flocs in the water and reducing the water purification capacity. As the feeding amount increases in the later stage, the water quality will become uncontrollable, and the concentration of toxic substances such as ammonia nitrogen and nitrite nitrogen will rise rapidly, which is not conducive to the stability of the aquaculture water.

[0017] Preferably, in step (3), the nutritional components of the compound feed meet the following requirements: crude protein ≥ 40%, crude fat ≥ 5.0%, lysine ≥ 2.1%, total phosphorus ≥ 1.0%, crude fiber ≤ 5.0%, crude ash ≤ 18.0%, and moisture ≤ 12.0%.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention provides a "vannamei shrimp-snail-biofloc" integrated aquaculture system and method that improves the ability to control biofloc concentration and feed source utilization rate. Under this aquaculture model, vannamei shrimp can grow normally, and the feces and feed residues produced during the aquaculture process serve as a nutrient matrix for the formation and maintenance of bioflocs; the snails act as feeders of the bioflocs in the model, further utilizing the organic nutrients in the residual feed and flocs to achieve the recycling of aquaculture waste and improve the overall nutrient conversion efficiency, thereby improving the ability to control the biofloc concentration in the aquaculture water body and the efficiency of in-situ feed source utilization of bioflocs.

[0020] Second, the integrated aquaculture system constructed by this invention is simple in structure, easy to implement, and independent of complex equipment. It is applicable to a variety of aquaculture environments and has excellent prospects for promotion. By deeply transforming and recycling feed nutrients, it not only improves feed utilization but also reduces the organic load and waste accumulation in water bodies, thereby reducing water quality control and tailwater treatment costs, and improving the overall economic benefits of aquaculture.

[0021] 3. The present invention introduces snails into the biofloc culture system of Penaeus vannamei. Through the feeding action of the snails, the excess bioflocs (solid suspended matter) in the in situ culture water body are efficiently utilized. On the one hand, additional snail culture biomass is obtained, thereby improving the economic benefits per unit water body; on the other hand, the control level of floc concentration in the culture water body is improved, thereby increasing the utilization rate of nitrogen in the feed by aquatic animals.

[0022] Fourth, the present invention uses artificial sea salt with a specific formula to optimize the stocking density, and conducts a composite domestication of snails to tolerate low salinity and highly turbid water bodies, thereby achieving the ecological synergy of the vannamei shrimp, snails, and bioflocs, providing an environmentally friendly technical path for high-density shrimp farming. DETAILED DESCRIPTION

[0023] In order to more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the technical effects produced by the present invention are further described in detail and completely in conjunction with specific embodiments. Obviously, the embodiments described are only some of the embodiments of the present invention, and not all of them. It should be pointed out that for those skilled in the art, other embodiments obtained without departing from the concept of the present invention are all within the scope of protection of the present invention.

[0024] The following examples provide a method for cultivating Litopenaeus vannamei and snails in a biofloc aquaculture system, comprising the following steps:

[0025] (1) Composite domestication of snails to low salinity and high turbidity water bodies: snails are cultured in domestication ponds with a three-dimensional attachment base, the attachment area of ​​the water body is increased by adding baffles, the water depth is controlled at 0.5-1.0 m, aeration stones are installed at the bottom and sufficient aeration is provided; low salinity domestication is achieved by gradually adding artificial sea salt every day, with the salinity increasing by 0.1-0.2‰ each time until the salinity is domesticated to 2.7‰; artificial sea salt is added three times a day, in the morning, afternoon and midnight, with an interval of 8 hours between each addition, and the amount added each time is one-third of the total daily addition amount; at the same time, precipitated and concentrated bioflocs are added to the water body every day to provide a feed source, and the concentration of water flocs is increased, so that the snails adapt to the turbidity characteristics of the bioflocs and the properties of biological bait, thus completing the domestication to high turbidity water bodies;

[0026] (2) Construction of a culture system for white shrimp, snails and biofloc: An indoor conical or pot-shaped culture pond was selected, with a corundum aeration stone at the bottom. An air pump was connected to the pond through a gas flow meter to provide aeration and regulate its size. A heating rod was used to control the water temperature of the culture system. The biofloc was first cultured to maturity, and white shrimp fry were coarsely cultured to an initial weight of 0.01-2.00 g. Tap water was injected into the culture pond that had been disinfected in advance, and the pond was aerated for 24 hours to remove residual chlorine and artificial sea salt was added to the target salinity. Subsequently, the biofloc was inoculated into the culture pond, and the initial total suspended solids concentration of the water was adjusted to 75-150 mg / L. Next, snails were added to the culture pond, and the snails were allowed to adapt stably for at least 6 hours and evenly attached along the culture pond. Then, white shrimp fry were added. During operation, the water was aerated evenly to prevent the biofloc from settling. The water temperature was controlled at 25-30 °C, and routine feeding and daily maintenance management were carried out.

[0027] (3) Daily aquaculture management: After constructing the integrated aquaculture system of Penaeus vannamei, snails and biofloc, the daily feeding amount of the compound feed of Penaeus vannamei is 3-10% of the total body weight of the shrimp, and the compound feed is fed 3-12 times a day. Water quality control substances including sodium bicarbonate, calcium chloride and magnesium sulfate are added to the water body every 3-5 days. The water in the aquaculture pond is not changed during the aquaculture period, and the water lost by evaporation in the aquaculture pond is replenished every 5-10 days.

[0028] In some embodiments, in step (1), the snails may be selected from the copper-rust ring-edge snail and / or the Chinese round field snail.

[0029] In some embodiments, in step (1), the artificial sea salt is prepared according to the following composition and ratio: every 1000g of artificial sea salt contains 769.827g of sodium chloride, 96.076g of magnesium sulfate, 71.133g of magnesium chloride, 33.168g of calcium chloride, 21.076g of potassium chloride, 5.872g of sodium bicarbonate, 2.413g of sodium bromide, 0.174g of sodium silicate, 0.174g of strontium chloride, 0.029g of sodium fluoride, and 0.058g of disodium edetate.

[0030] In some embodiments, in step (1), the initial TSS is 0 mg / L, and the TSS is increased by 5 to 30 mg / L daily until the TSS reaches 150 mg / L or more.

[0031] In some embodiments, in step (2), the initial stocking density of Penaeus vannamei in the culture pond is 300 to 650 shrimp / m 3 The initial density of snails is 300-3500g / m 3If the stocking density of whiteleg shrimp is too high, the floc concentration in the aquaculture water will rise rapidly, increasing the oxygen consumption of the water and adversely affecting the respiration and growth of whiteleg shrimp and snails. Conversely, if the snail density is too high, they will consume the flocs too quickly, making it difficult to maintain the concentration of biological flocs in the water and reducing the water purification capacity. As the feeding amount increases in the later stage, the water quality will become uncontrollable, and the concentration of toxic substances such as ammonia nitrogen and nitrite nitrogen will rise rapidly, which is not conducive to the stability of the aquaculture water.

[0032] In some embodiments, in step (3), the nutritional components of the compound feed meet the following requirements: crude protein ≥ 40%, crude fat ≥ 5.0%, lysine ≥ 2.1%, total phosphorus ≥ 1.0%, crude fiber ≤ 5.0%, crude ash ≤ 18.0%, and moisture ≤ 12.0%.

[0033] Example 1

[0034] This example uses the "L. vannamei - snails - biofloc" integrated aquaculture system and method to verify its ability to efficiently utilize resources (nitrogen in compound feed) and regulate biofloc, as follows:

[0035] Snails (initial average weight 0.92±0.03g) were acclimated to salinity using artificial sea salt before farming. The acclimation period was 12 days, during which the water salinity was increased by 0.1‰ every day, so that the salinity was steadily increased from the initial 0.5‰ to 1.7‰. 90L of tap water was injected into three pre-sterilized PVC culture barrels and aerated for 24 hours to remove residual chlorine. Subsequently, mature biological flocs mainly based on nitrification were inoculated, and the floc concentration was adjusted to 100mg / L, the aeration size was adjusted, the temperature was controlled at 27℃, the salinity was adjusted to 1.7‰, and the alkalinity was maintained at 200-250mg / L. The initial average weight of the vannamei shrimp fry with suitable salinity was 1.33±0.07g. Each culture barrel was stocked with 30 vannamei shrimp (density 440g / m3) and 100g of snails (density 1100g / m 3 ).

[0036] During the culture period, the shrimp were fed at a daily rate of 5% in four feeding sessions (8:00, 12:00, 16:00, and 20:00) for a total of 35 days. The main ingredients of the shrimp feed were: lysine ≥ 2.8%, crude protein ≥ 43.0%, crude fat ≥ 7.5%, crude ash ≤ 15.0%, total phosphorus 1.0%-2.0%, crude fiber ≤ 3.0%, and moisture ≤ 10.0%.

[0037] Ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, active phosphate, floc concentration, alkalinity, temperature, pH, salinity, and dissolved oxygen in the water were monitored and managed every five days. Crude protein, crude ash, and nitrogen and phosphorus nutrients were measured in the water, feed, flocs, snails, and Litopenaeus vannamei at the beginning and end of the culture period. After the culture period, the shrimp and snails were weighed, and the specific growth rate and survival rate of the cultured animals were calculated.

[0038] Aquaculture management focuses on maintaining stable aquaculture water quality. The relevant control values ​​are: pH maintained at around 8, dissolved oxygen concentration ≥6 mg / L, and alkalinity maintained at around 200 mg / L. Water quality testing is conducted every five days, and aquaculture management measures are adjusted based on water conditions. Ammonia nitrogen and nitrite nitrogen should be controlled at ≤1.5 mg / L and ≤0.5 mg / L, respectively. These data are regulated in accordance with the national standards GB 11607-89 and GB 3838-2002, which stipulate fishery water quality standards of: pH (6.5-8.5); DO (≥5 mg / L); total ammonia nitrogen (<1.6 mg / L); and alkalinity (20 mg / L-250 mg / L), which are Class III water standards.

[0039] After 35 days of culture, growth indicators, feed nitrogen utilization, and floc concentration are shown in Table 1. The survival rate of white shrimp (Penaeus vannamei) was 93.33%, with an average harvest of 166.7 g / barrel. The average harvest of snails was 169 g / barrel, with a survival rate of 97.33%. The biomass nitrogen retention rate of white shrimp (Penaeus vannamei), the biomass nitrogen retention rate of snails (Penaeus vannamei), and the feed nitrogen utilization rate of aquatic animals were 25.78%. Throughout the culture period, the integrated "white shrimp-snail-biofloc" culture system maintained excellent water quality control, particularly with floc concentration kept below 218 mg / L.

[0040] Table 1

[0041]

[0042] Example 2

[0043] This example uses a "Lopenaeus vannamei - snails - biofloc" integrated aquaculture system and method to verify the stability and aquaculture efficiency of the system under conditions of a longer aquaculture time, a higher snail density, and a larger water body, as follows:

[0044] Before culture, the snails (initial average weight 0.92±0.03g) were first acclimated with artificial sea salt. The acclimation period was 20 days, during which the salinity was increased by 0.1‰ every day, so that it could be steadily increased from the initial 0.5‰ to 2.5‰, so as to adapt to the salinity environment of the target culture water. 10m3 of water was injected into three pre-sterilized pot-bottom cement culture ponds. 3Tap water was aerated for 24 hours to remove residual chlorine. Subsequently, mature bioflocs with nitrification as the main component were inoculated and the floc concentration was adjusted to 75 mg / L. The aeration size was adjusted, the temperature was controlled at 27°C, the salinity was adjusted to 2.5‰, and the alkalinity was maintained at 200-250 mg / L. The initial average weight of the shrimp fry in the suitable salinity environment was 1.33±0.07g. About 3,300 shrimp fry were stocked in each culture pond (density of about 440g / m 3 ) and 33kg snails (density is about 3300g / m 3 ).

[0045] During the culture period, the daily feeding rate for Litopenaeus vannamei is 5%, divided into four feeding sessions (8:00, 12:00, 16:00, and 20:00) for a total of 60 days. The main ingredients of the Litopenaeus vannamei feed are: lysine ≥ 2.8%, crude protein ≥ 43.0%, crude fat ≥ 7.5%, crude ash ≤ 15.0%, total phosphorus 1.0%-2.0%, crude fiber ≤ 3.0%, and moisture ≤ 10.0%.

[0046] Ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, active phosphate, floc concentration, alkalinity, temperature, pH, salinity, and dissolved oxygen in the water were monitored and managed every five days. Crude protein, crude ash, and nitrogen and phosphorus nutrients were measured in the water, feed, flocs, snails, and Litopenaeus vannamei at the beginning and end of the culture period. After the culture period, the shrimp and snails were weighed, and the specific growth rate and survival rate of the cultured animals were calculated.

[0047] Aquaculture management focuses on maintaining stable aquaculture water quality. The relevant control values ​​are: pH around 8, dissolved oxygen concentration ≥6 mg / L, and alkalinity around 200 mg / L. Water quality testing is conducted every five days, and aquaculture management measures are adjusted based on water conditions. Ammonia nitrogen and nitrite nitrogen should be controlled at ≤1.5 mg / L and ≤0.5 mg / L, respectively. These data are regulated in accordance with the national standards GB 11607-89 and GB 3838-2002, which stipulate fishery water quality standards of: pH (6.5-8.5); DO (≥5 mg / L); total ammonia nitrogen (<1.6 mg / L); and alkalinity (20 mg / L-250 mg / L), which are Class III water standards.

[0048] After 60 days of culture, growth indicators, feed nitrogen utilization, and floc concentration are shown in Table 2. The survival rate of white shrimp (L. vannamei) was 87.55%, and that of snails was 97.53%. The biomass-to-feed nitrogen retention rate of white shrimp (L. vannamei) was 21.96%, while that of snails was 4.90%. The feed nitrogen utilization rate of aquatic animals was 26.86%. On days 30 and 45, 10.2 kg and 19.8 kg of snails were harvested, respectively. Throughout the culture period, the integrated "L. vannamei-snail-biofloc" culture system maintained excellent water quality control, with floc concentrations maintained at ≤396 mg / L.

[0049] Table 2

[0050]

[0051]

[0052] Comparative Example 1

[0053] This comparative example uses the "L. vannamei-biofloc" culture system, without the introduction of snails, as a control for the integrated culture system, as follows:

[0054] 90L of tap water was poured into three pre-sterilized PVC buckets and aerated for 24 hours to remove residual chlorine. Then, mature bioflocs with nitrification as the main component were inoculated and the floc concentration was adjusted to 100mg / L. The aeration size was adjusted, the temperature was controlled at 27℃, the salinity was adjusted to 1.7‰, and the alkalinity was controlled at 200-250mg / L. Each bucket was filled with shrimp fry (initial average weight was 1.33±0.07g) in an environment with suitable salinity. The stocking density was 30 per bucket (about 440g / m 3 ). Do not raise snails.

[0055] During the culture period, the shrimp were fed at a daily rate of 5% in four feeding sessions (8:00, 12:00, 16:00, and 20:00) for a total of 35 days. The main ingredients of the shrimp feed were: lysine ≥ 2.8%, crude protein ≥ 43.0%, crude fat ≥ 7.5%, crude ash ≤ 15.0%, total phosphorus 1.0%-2.0%, crude fiber ≤ 3.0%, and moisture ≤ 10.0%.

[0056] Ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, active phosphate, floc concentration, alkalinity, temperature, pH, salinity, and dissolved oxygen in the water are monitored and managed every five days. Crude protein, crude ash, and nitrogen and phosphorus nutrients in the water, feed, flocs, and Litopenaeus vannamei are measured at the beginning and end of the culture period. After the culture period, the harvested Litopenaeus vannamei are weighed, and the specific growth rate and survival rate of the cultured animals are calculated.

[0057] Aquaculture management primarily focuses on maintaining aquaculture water stability, with the following numerical controls: pH maintained at approximately 8, dissolved oxygen concentration ≥6 mg / L, and alkalinity controlled at approximately 200 mg / L. Water quality testing is conducted every five days, and aquaculture management measures are adjusted based on water conditions. Ammonia nitrogen and nitrite nitrogen should be controlled at ≤1.5 mg / L and ≤0.5 mg / L, respectively. These values ​​are regulated in accordance with national standards GB 11607-89 and GB 3838-2002, which stipulate fishery water quality standards of pH (6.5-8.5), DO (≥5 mg / L), total ammonia nitrogen (<1.6 mg / L), and alkalinity (20 mg / L-250 mg / L), consistent with Class III water standards.

[0058] After 35 days of culture, growth indicators, feed nitrogen utilization, and floc concentration are shown in Table 3. The survival rate of L. vannamei was 86.66%, the average harvest was 156.52 g / barrel, and the biomass-to-feed nitrogen conservation rate of L. vannamei was 22.62%. Throughout the culture period, the "L. vannamei-biofloc" culture system demonstrated excellent water quality control, with a maximum floc concentration of 336 mg / L.

[0059] Table 3

[0060]

[0061] Comparative Example 2

[0062] This comparative example uses a "Lopenaeus vannamei - biofloc" aquaculture system without the introduction of snails to verify the water quality control and aquaculture effects under the same conditions of a larger aquaculture water scale and extended aquaculture cycle. The details are as follows:

[0063] Pour 10m3 of water into three pre-sterilized pot-bottom cement aquaculture ponds. 3 Tap water was aerated for 24 hours to remove residual chlorine, and then mature bioflocs with nitrification as the main function were inoculated. The floc concentration was adjusted to 75 mg / L, and the aeration size was adjusted. The temperature was controlled at 27 °C, the salinity was adjusted to 2.5‰, and the alkalinity was controlled at 200-250 mg / L. Vannamei shrimp fry were added under suitable salinity conditions. The initial average weight was 1.33±0.07 g. About 3,300 vannamei shrimp were stocked in each culture pond (density of about 440 g / m 3 ), do not raise snails.

[0064] During the culture period, the daily feeding rate for Litopenaeus vannamei is 5%, divided into four feeding sessions (8:00, 12:00, 16:00, and 20:00) for a total of 60 days. The main ingredients of the Litopenaeus vannamei feed are: lysine ≥ 2.8%, crude protein ≥ 43.0%, crude fat ≥ 7.5%, crude ash ≤ 15.0%, total phosphorus 1.0%-2.0%, crude fiber ≤ 3.0%, and moisture ≤ 10.0%.

[0065] Ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, active phosphate, total suspended solids concentration, alkalinity, temperature, pH, salinity, and dissolved oxygen in the water are monitored and managed every five days. Crude protein, crude ash, and nitrogen and phosphorus nutrients in the water, feed, flocs, and Litopenaeus vannamei are measured at the beginning and end of the culture period. After the culture period, the harvested Litopenaeus vannamei are weighed, and the specific growth rate and survival rate of the cultured animals are calculated.

[0066] Aquaculture management primarily involves maintaining the stability of the aquaculture water. The relevant numerical control values ​​are: pH maintained at around 8, dissolved oxygen concentration ≥6 mg / L, and alkalinity around 200 mg / L. Water quality testing is conducted every five days, and aquaculture management measures are adjusted based on water conditions. Ammonia nitrogen and nitrite nitrogen should be controlled at ≤1.5 mg / L and ≤0.5 mg / L, respectively. These data are regulated in accordance with the national standards GB 11607-89 and GB 3838-2002, which stipulate fishery water quality standards of: pH (6.5-8.5); DO (≥5 mg / L); total ammonia nitrogen (<1.6 mg / L); and alkalinity (20 mg / L-250 mg / L), which are Class III water standards.

[0067] After 60 days of culture, growth indicators, feed nitrogen utilization, and floc concentration are shown in Table 4. The survival rate of L. vannamei was 85.6%, and the biomass-to-feed nitrogen conservation rate was 21.96%. The "L. vannamei-biofloc" culture system maintained good water quality throughout the culture period. However, the maximum floc concentration reached 972 mg / L, indicating significant accumulation of suspended particulate matter.

[0068] Table 4

[0069]

[0070] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A comprehensive aquaculture method of composite biofloc of Litopenaeus vannamei and snails, characterized in that: The following steps are involved: (1) Composite domestication of snails to low salinity and high turbidity water bodies: snails are cultured in domestication ponds with a three-dimensional attachment base, baffles are added to increase the attachment area of ​​the water body for the snails to inhabit, the water depth is controlled at 0.5-1.0 m, aeration stones are installed at the bottom and sufficient aeration is provided; low salinity domestication is achieved by gradually adding artificial sea salt every day, with the salinity increasing by 0.1-0.2‰ each time until the salinity is domesticated to 2.7‰; artificial sea salt is added three times a day, in the morning, afternoon and midnight, with an interval of 8 hours between each addition, and the amount added each time is one-third of the total daily addition amount; at the same time, precipitated and concentrated bioflocs are added to the water body every day to provide a feed source, and the concentration of bioflocs in the water body is increased, so that the snails adapt to the turbidity characteristics and biological bait properties of the bioflocs, and complete the domestication of the snails to high turbidity water bodies; (2) Construct an integrated culture system for Penaeus vannamei, snails, and bioflocs: select an indoor conical or pot-bottom culture pond with a corundum aeration stone at the bottom, connect an air pump through a gas flow meter to provide aeration and regulate its size, and use a heating rod to control the water temperature of the culture system; first, cultivate the bioflocs to maturity, and coarsely culture the Penaeus vannamei shrimp fry to an initial weight of 0.01-2.00 g, inject tap water into the culture pond that has been disinfected in advance, aerate for 24 hours to remove residual chlorine, and add artificial sea salt to the target salinity; then, inoculate the culture pond with bioflocs, and adjust the initial total suspended solids concentration of the water body to 75-150 mg / L; then, put snails into the culture pond, wait for the snails to adapt stably for at least 6 hours, and evenly attach and inhabit along the culture pond; then, put the Penaeus vannamei shrimp fry; during operation, control the water body to be evenly aerated to prevent the bioflocs from settling, control the water temperature at 25-30 ° C, and carry out routine feeding and daily maintenance management; (3) Daily aquaculture management: After constructing the integrated aquaculture system of Penaeus vannamei, snails and biofloc, the daily feeding amount of the compound feed of Penaeus vannamei is 3-10% of the total body weight of the shrimp, and the compound feed is fed 3-12 times a day. Water quality control substances including sodium bicarbonate, calcium chloride and magnesium sulfate are added to the water body every 3-5 days. The water in the aquaculture pond is not changed during the aquaculture period, and the water lost by evaporation in the aquaculture pond is replenished every 5-10 days.

2. The integrated aquaculture method of the composite biofloc of Penaeus vannamei and snails according to claim 1, characterized in that: In step (1), the snails are Copper Rust Ring Edge Snail and / or Chinese Round Field Snail.

3. The integrated aquaculture method of the composite biofloc of Penaeus vannamei and snails according to claim 1, characterized in that: In step (1), the artificial sea salt is prepared according to the following composition and ratio: every 1000g of artificial sea salt contains 769.827g of sodium chloride, 96.076g of magnesium sulfate, 71.133g of magnesium chloride, 33.168g of calcium chloride, 21.076g of potassium chloride, 5.872g of sodium bicarbonate, 2.413g of sodium bromide, 0.174g of sodium silicate, 0.174g of strontium chloride, 0.029g of sodium fluoride, and 0.058g of disodium edetate.

4. The integrated aquaculture method of the composite biofloc of Penaeus vannamei and snails according to claim 1, characterized in that: In step (1), the initial biofloc concentration is 0 mg / L, and the concentration is increased by 5 to 30 mg / L every day until the biofloc concentration reaches 150 mg / L or more.

5. The integrated aquaculture method of the composite biofloc of Litopenaeus vannamei and snails according to claim 1, characterized in that: In step (2), the initial stocking density of Penaeus vannamei in the culture pond is 300 to 650 tails / m 3 The initial density of snails is 300-3500g / m 3 .

6. The integrated aquaculture method of the composite biofloc of Litopenaeus vannamei and snails according to claim 1, characterized in that: In step (3), the nutritional components of the compound feed meet the following requirements: crude protein ≥ 40%, crude fat ≥ 5.0%, lysine ≥ 2.1%, total phosphorus ≥ 1.0%, crude fiber ≤ 5.0%, crude ash ≤ 18.0%, and moisture ≤ 12.0%.

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