Method for cultivating butter crabs

Abstract

The invention belongs to the technical field of biology, and particularly relates to a method for cultivating butter crabs. According to the method, the growth process of the blue crabs to the butter crabs is regulated and controlled through the indoor environment factors, the butter crabs can be effectively cultured by means of the high efficiency, convenience and low cost of regulation and control of the indoor environment factors, and the method can be suitable for large-scale batch production of the butter crabs all the year round. According to the method, the butter crabs can be cultivated within a very short time (only 15-20 days), the conversion rate is high, particularly, the number of the obtained high-grade butter crabs is larger than that of the butter crabs obtained through a conventional method, the color of abdominal navel is orange yellow, the color of articular membrane (yellow blue value) can reach 37, the content of hemolymph fat can reach 0.22 g / 100g, the content of hemolymph beta carotene can reach 396 micrograms / 100g, and the content of the butter crabs can reach 0.12 micrograms / 100g. The edible value and the economic value are extremely high.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and particularly relates to a method for cultivating butter crabs. Background Art

[0002] Scylla paramamosain is a major marine aquaculture crab in my country and one of the most expensive species among aquacultured marine crabs.

[0003] The butter crab is a female mud crab that forms a unique golden "oily substance" during its growth and development. This substance gradually spreads throughout the body tissues, making its body fluids golden and its joint membranes orange-yellow. With its high-quality taste and unique flavor, the butter crab has extremely high economic value and market demand in the food and breeding industries, and occupies an important position in my country's high-end aquatic product market. The butter crab is found in wild mud crabs caught in natural seas and mud crab seawater breeding ponds. At present, the large-scale production of butter crabs is concentrated in the seawater pond breeding model, mainly concentrated in about one month before and after the Mid-Autumn Festival. The breeding of butter crabs faces a series of problems such as "relying on the weather for food", long breeding cycle, low breeding rate (less than one thousandth), unstable production and far from meeting market demand. Therefore, the efficient breeding technology and model of butter crabs have attracted attention from the government, farmers, scientific researchers and other people from all walks of life, but the mechanism of the formation of butter crabs is still unclear, and the technology of efficiently breeding butter crabs in an artificial controllable environment is still in the exploratory stage. Summary of the invention

[0004] The first aspect of the present invention aims to provide a method for cultivating butter crabs.

[0005] The second aspect of the present invention aims to provide a cultivation method for accelerating the formation of butter crabs.

[0006] The third aspect of the present invention aims to provide a cultivation method for improving the conversion rate of butter crab.

[0007] The fourth aspect of the present invention aims to provide a method for cultivating butter crabs to improve their quality.

[0008] In order to achieve the above-mentioned purpose of the present invention, the technical solution adopted by the present invention is:

[0009] A method for cultivating butter crabs comprises the following steps:

[0010] 1) Select female blue crabs whose ovaries are in an undeveloped state;

[0011] 2) placing the female blue crab in a breeding pond with the following environmental parameters for 10 to 30 days:

[0012] The environmental parameters include water temperature, dissolved oxygen, salinity, pH, ammonia nitrogen and / or nitrite nitrogen concentration;

[0013] The water temperature is 20°C to 35°C;

[0014] The dissolved oxygen is 9-12 mg / L;

[0015] The salinity is 12‰ to 15‰;

[0016] The pH is 7.5 to 8.5;

[0017] The concentration of ammonia nitrogen and / or nitrite nitrogen is 0 to 0.05 mg / L;

[0018] 3) Feeding and breeding.

[0019] In some embodiments of the present invention, the butter crab is a species selected from the group consisting of Scylla Paramamosain, Portunidae, Decapoda.

[0020] In some embodiments of the present invention, the ovarian development status is determined by the cephalothorax shadow area / cephalothorax area under transmitted light.

[0021] In some embodiments of the present invention, the female blue crab with undeveloped ovaries has a cephalothorax shadow area / cephalothorax area of ​​5-15% under transmitted light.

[0022] In some embodiments of the present invention, the female blue crab with undeveloped ovaries has a cephalothorax shadow area / cephalothorax area of ​​8-12% under transmitted light.

[0023] In some embodiments of the present invention, the female blue crab completes reproductive molting, and the length of the abdominal skin flap bristles is 1 to 3.5 mm, preferably 2 to 3.5 mm.

[0024] In some embodiments of the present invention, the length of the bristles of the abdominal skin flap of the female blue crab is 2.5 to 3.0 mm.

[0025] In some embodiments of the present invention, the female blue crab is in a healthy state, including but not limited to the following manifestations:

[0026] The claws are healthy and have no disease spots; there are no obvious damage to the abdomen and crab shell; the crab can turn over and crawl on its own when its back is facing up; it can spit out bubbles normally after water is added to cover the crab body; the eyestalks have normal autonomous movement.

[0027] In some embodiments of the present invention, the indoor culture pond is free of space stress, and female blue crabs can move freely in the culture pond.

[0028] In some embodiments of the present invention, the spatial area of ​​the culture pond is more than 30 times larger than the total area of ​​the cephalothorax of the cultured blue crab.

[0029] In some embodiments of the present invention, a bedding material is provided at the bottom of the culture pond, and the bedding material may be selected from any one or more of silt, grindstone, expanded clay, aquatic plants, pebbles, and volcanic rocks; preferably silt.

[0030] In some embodiments of the present invention, the thickness of the litter is greater than the body height of the female blue crab.

[0031] In some embodiments of the present invention, the height of the aquaculture water body is 15 to 30 cm, preferably 20 to 25 cm.

[0032] In some embodiments of the present invention, the environmental parameters include water temperature, dissolved oxygen, salinity, pH, and ammonia nitrogen / nitrite nitrogen concentration.

[0033] In some embodiments of the present invention, the water temperature is 20°C to 35°C.

[0034] In some embodiments of the present invention, the water temperature is 30-35°C.

[0035] In some embodiments of the present invention, the dissolved oxygen is greater than 9 mg / L; preferably 9 to 12 mg / L.

[0036] In some embodiments of the present invention, the salinity is 12‰ to 15‰.

[0037] In some embodiments of the present invention, the pH is 7.5-8.5.

[0038] In some embodiments of the present invention, the concentration of ammonia nitrogen and / or nitrite nitrogen is 0 to 0.05 mg / L.

[0039] In some embodiments of the present invention, the ammonia nitrogen concentration is 0 to 0.05 mg / L; preferably 0 to 0.025 mg / L.

[0040] In some embodiments of the present invention, the concentration of nitrite nitrogen is 0 to 0.05 mg / L, preferably 0 to 0.25 mg / L.

[0041] In some embodiments of the present invention, the environmental parameters also include light. Some embodiments of the present invention show that light conditions are not a decisive factor in the cultivation of butter crabs, but the quality of butter crabs is better under dark conditions, so the light conditions during the cultivation process are preferably dark-proof.

[0042] By adjusting the above-mentioned environmental parameters, the aquaculture water can be controlled to be in a clean state of continuous darkness, high temperature, low salt and high dissolved oxygen, thereby regulating the physiological ecology of hepatopancreas-ovary lipid metabolism of female blue crabs.

[0043] In some embodiments of the present invention, the farming comprises the step of feeding bait every day.

[0044] In some embodiments of the invention, the bait comprises shellfish.

[0045] In some embodiments of the present invention, the shellfish is a fresh bivalve shellfish with a thin shell and rich meat, which can be selected from any one or more of clams, mussels, razor clams, and clams.

[0046] In some embodiments of the present invention, the shellfish is razor clams.

[0047] In some embodiments of the present invention, the bait is fed once in the morning and once in the evening every day, and the total amount fed every day is 10% to 15% of the body weight of the female blue crab.

[0048] In some embodiments of the present invention, the interval between morning and evening feeding is 8 to 16 hours.

[0049] In some embodiments of the present invention, the single batch cultivation time of the butter crabs is 15 to 20 days.

[0050] The second aspect of the present invention provides a method for accelerating the formation of butter crabs, comprising the following steps:

[0051] The steps include:

[0052] 1) Select female blue crabs whose ovaries are in an undeveloped state;

[0053] The female blue crab has a cephalothorax shadow area / cephalothorax area of ​​5 to 15% under transmitted light; and / or the female blue crab has completed reproductive molting, and the length of the abdominal skin flap bristles is 1 to 3.5 mm;

[0054] 2) The female blue crabs are placed in a breeding pond with the following environmental parameters for 15 to 20 days:

[0055] The environmental parameters include water temperature, dissolved oxygen, salinity, pH, ammonia nitrogen and / or nitrite nitrogen concentration;

[0056] The water temperature is 32°C to 35°C;

[0057] The dissolved oxygen is 9-12 mg / L;

[0058] The salinity is 12‰ to 15‰;

[0059] The pH is 7.5 to 8.5;

[0060] The concentration of ammonia nitrogen and / or nitrite nitrogen is 0 to 0.05 mg / L;

[0061] 3) Feeding and breeding;

[0062] The culture was carried out under light protection.

[0063] In some embodiments of the present invention, the female mud crab is selected from the group consisting of Scylla pseudohygrophila.

[0064] In some embodiments of the present invention, the female blue crab has a cephalothorax shadow area / cephalothorax area of ​​5-15% under transmitted light; and / or the female blue crab completes reproductive molting, and the length of the abdominal skin flap bristles is 1-3.5 mm.

[0065] In some embodiments of the present invention, the spatial area of ​​the breeding pond is more than 30 times greater than the total area of ​​the cephalothorax of the female blue crab.

[0066] In some embodiments of the present invention, the breeding comprises the step of feeding bait daily;

[0067] The bait includes shellfish;

[0068] The daily feeding amount is 10-15% of the body weight of the female blue crab.

[0069] The third aspect of the present invention provides a cultivation method for improving the conversion rate of butter crabs, and the specific steps are the same as the second aspect of the present invention.

[0070] The fourth aspect of the present invention provides a cultivation method for improving the quality of butter crabs; the specific steps are the same as the third aspect of the present invention.

[0071] The beneficial effects of the present invention are:

[0072] The present invention regulates the development process of blue crab to butter crab through indoor environmental factors, and provides a method for cultivating butter crab. The method utilizes the high efficiency, convenience and low cost of indoor environmental factor regulation, can effectively cultivate butter crab, and can be suitable for large-scale batch production of butter crab throughout the year. The method only takes a very short time (only 15 to 20 days) to cultivate butter crab, and the conversion rate is high, especially the number of high-grade butter crabs obtained is more than that of conventional methods, the color of the belly navel is orange-yellow, the color of the joint membrane (yellow-blue value) can reach 37, the hemolymph fat content can reach 0.22g / 100g, and the hemolymph beta-carotene content can reach 396μg / 100g, which has extremely high edible value and economic value. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0074] Figure 1 This is the butter crab cultivated in Example 1 of the present invention.

[0075] Figure 2 This is the butter crab cultivated in Example 2 of the present invention.

[0076] Figure 3 This is the butter crab cultivated in Example 3 of the present invention.

[0077] Figure 4 This is the butter crab cultivated in Example 4 of the present invention.

[0078] Figure 5 This is the butter crab cultivated in Example 5 of the present invention.

[0079] Figure 6 This is the female blue crab bred in Comparative Example 1 of the present invention.

[0080] Figure 7 This is the female blue crab bred in Comparative Example 2 of the present invention.

[0081] Figure 8 This is the female blue crab bred in Comparative Example 3 of the present invention.

[0082] Fig. 9 This is the female blue crab bred in Comparative Example 4 of the present invention.

[0083] Fig.10 This is the female blue crab bred in Comparative Example 5 of the present invention.

[0084] Fig.11 This is the butter crab cultivated according to Example 6 of the present invention.

[0085] Fig.12 This is the butter crab cultivated according to Example 7 of the present invention.

[0086] Fig.13 This is the butter crab cultivated in Example 8 of the present invention.

[0087] Fig.14 This is the butter crab cultivated in Example 9 of the present invention.

[0088] Fig.15 This is the butter crab cultivated according to Example 10 of the present invention.

[0089] Fig.16 This is the butter crab cultivated according to Example 11 of the present invention.

[0090] Fig.17 This is the butter crab cultivated according to Example 12 of the present invention.

[0091] Fig.18 This is the butter crab cultivated according to Example 13 of the present invention.

[0092] Fig.19 This is the butter crab cultivated according to Example 14 of the present invention.

[0093] Fig. 20 This is the butter crab cultivated according to Example 15 of the present invention. DETAILED DESCRIPTION

[0094] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0095] Definitions of terms related to the present invention:

[0096] The butter crab in the present invention refers to a female blue crab in which a golden "oily substance" is formed in the body during the growth and development process and gradually distributed in the whole body tissues, so that the body fluid appears golden and the joint membrane appears orange.

[0097] The arthrodial membrane is the soft texture of the claws, walking legs and swimming legs, mainly located at the connection between the basal segment and the coxa and between the wrist segment and the long segment.

[0098] The abdominal navel is the abdomen folded below the head and thorax.

[0099] Carapace length is the vertical distance from the center of the frontal edge of the carapace to the rear edge of the carapace.

[0100] The transmittance area is the percentage of the shadow area of ​​the cephalothorax to the total area of ​​the cephalothorax after a strong flashlight is shone on the abdomen of the blue crab. It is an indicator of the degree of ovarian development in the crab.

[0101] Ovary index is the percentage of the ovary mass (g) of the butter crab to its individual mass (g).

[0102] The yellowness and blueness values ​​are indicators that reflect the yellow-blue color of the joint membrane. The larger the value, the yellower the color, and the smaller the value, the bluer the color.

[0103] Description of the experimental methods related to the present invention:

[0104] The joint membrane color (yellow-blue value) detection method of the present invention refers to the "Butter Crab Quality Grade Assessment Rules" (group standard, T / GDNB 204-2024) issued by the Guangdong Agricultural Standardization Association.

[0105] The hemolymph fat test is carried out in accordance with the provisions of GB5009.6-2016, and the hemolymph of the second step foot is taken for measurement.

[0106] The hemolymph β-carotene test shall be carried out in accordance with the provisions of GB5009.83-2016, and the hemolymph of the second step shall be taken for measurement.

[0107] The relevant principles of the present invention are:

[0108] The hepatopancreas is a key site for the absorption, synthesis, storage and transport of blue crab lipids. Vitellogenin (VTG) of the blue crab is a secretory lipoprotein that is mainly synthesized and secreted in the hepatopancreas. It is the main carrier of exogenous lipid transport in the ovary. It is absorbed by the oocyte by endocytosis by binding to the vitellogenin receptor (VTGR) specifically expressed in the ovary. The inventors have found that when blue crabs complete their reproductive molting, their ovaries are not developed or develop abnormally, the expression of VTGR in oocytes is inhibited, which hinders VTGR's recognition and binding to VTG, thereby affecting the ovary's absorption of VTG by endocytosis, resulting in a large amount of VTG being transported with the hemolymph and retained in other organs in the body, thus forming butter crabs. The molting, growth, feeding, and reproduction of the mud crab are jointly affected by a variety of environmental factors. Continuous darkness can inhibit the development of the mud crab's ovaries, promote lipid absorption, generation, and inhibit fat decomposition; high temperature, high dissolved oxygen, and low salt can synergistically promote the absorption and transport process of lipids in the mud crab; a large area can alleviate the spatial stress of the mud crab, which is conducive to the feeding and absorption of exogenous biological baits; feeding biological baits with high fatty acid content is also conducive to the absorption and generation of mud crab lipids. The present invention has found that comprehensive regulation of breeding environmental factors, such as light (intensity, cycle), water temperature, salinity, dissolved oxygen, breeding water size, and biological bait, can not only maintain the long-term state of ovarian agenesis or abnormal development of the mud crab, but also promote the absorption, generation, storage, and transport of lipid metabolism processes such as VTG and lipids in the hepatopancreas, accelerate the enrichment of VTG and lipids in the body, and efficiently form butter crabs.

[0109] Specifically, the method for cultivating butter crabs of the present invention comprises the following steps:

[0110] 1) Select female blue crabs whose ovaries are in an undeveloped state;

[0111] 2) Place crabs in indoor breeding ponds and adjust environmental parameters;

[0112] 3) Feeding and breeding.

[0113] In some embodiments of the present invention, the crab species of the butter crab is selected from the genus Scylla of the family Portunidae of the order Decapoda.

[0114] In some embodiments of the present invention, the ovarian development status is determined by the cephalothorax shadow area / cephalothorax area under transmitted light.

[0115] In some specific embodiments, the female blue crab with undeveloped ovaries has a cephalothorax shadow area / cephalothorax area of ​​5-15% under transmitted light.

[0116] In some specific embodiments, for female blue crabs with undeveloped ovaries, the shadow area of ​​the cephalothorax under transmitted light is 10-15% of the cephalothorax area.

[0117] In some specific embodiments, when a female blue crab completes reproductive molt, the length of the bristles on the abdominal skin flap is 1 to 3.5 mm; in some embodiments of the present invention, it is 2 to 3.5 mm; in some embodiments of the present invention, the length of the bristles on the abdominal skin flap of the female blue crab is 2.5 to 3.0 mm.

[0118] In some specific embodiments, the female blue crab is in a healthy state, including but not limited to the following manifestations:

[0119] The claws are healthy and have no disease spots; there are no obvious damage to the abdomen and crab shell; the crab can turn over and crawl on its own when its back is facing up; it can spit out bubbles normally after water is added to cover the crab body; the eye stalks have normal autonomous movement, etc.

[0120] In some specific embodiments, the indoor culture pond is free of space stress, and the female blue crabs can move freely in the culture pond.

[0121] In some specific embodiments, the spatial area of ​​the culture pond is more than 30 times larger than the total area of ​​the cephalothorax of the cultured blue crab.

[0122] In some specific embodiments, a bedding material is provided at the bottom of the culture pond, and the bedding material may be selected from any one or more of silt, whetstone, expanded clay, aquatic plants, pebbles, and volcanic rocks; preferably silt.

[0123] In some embodiments, the thickness of the litter is greater than the height of the female blue crab.

[0124] In some specific embodiments, the height of the aquaculture water body is 15 to 30 cm, preferably 20 to 25 cm.

[0125] In some embodiments, the environmental parameters include water temperature, dissolved oxygen, salinity, pH, ammonia nitrogen and / or nitrite nitrogen concentration.

[0126] In some specific embodiments, the water temperature is 20°C to 35°C.

[0127] In some specific embodiments, the water temperature is 30-35°C.

[0128] In some specific embodiments, the dissolved oxygen is greater than 9 mg / L; preferably 9 to 12 mg / L.

[0129] In some specific embodiments, the salinity is 12‰ to 15‰.

[0130] In some specific embodiments, the pH is 7.5-8.5.

[0131] In some specific embodiments, the concentration of ammonia nitrogen and / or nitrite nitrogen is 0-0.05 mg / L.

[0132] In some specific embodiments, the ammonia nitrogen concentration is 0 to 0.05 mg / L; preferably 0 to 0.025 mg / L.

[0133] In some specific embodiments, the nitrite nitrogen concentration is 0 to 0.05 mg / L, preferably 0 to 0.025 mg / L.

[0134] In some specific embodiments, the environmental parameters also include light. Some embodiments of the present invention show that light conditions are not a decisive factor in the cultivation of butter crabs, but the quality of butter crabs is better under dark conditions, so the light conditions during the cultivation process are preferably dark-proof.

[0135] In some specific embodiments, the farming comprises the step of feeding bait every day.

[0136] In some embodiments, the bait comprises shellfish.

[0137] In some specific embodiments, the shellfish is a fresh bivalve shellfish with a thin shell and rich meat, which can be selected from any one or more of clams, mussels, razor clams, and clams.

[0138] In some specific embodiments, the shellfish is razor clams.

[0139] In some specific embodiments, the bait is fed once in the morning and once in the evening every day, and the total amount fed every day is 10% to 15% of the body weight of the female blue crab.

[0140] The present invention is further described below by way of examples and comparative examples. The blue crab species selected in the present invention is the blue crab Pseudocerna pseudoburrowing.

[0141] Example 1

[0142] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 10.5%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.6mm, the cephalothorax is (length 64mm, width 98mm), the body weight is 213g, and the body height is 38mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) at the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with black plastic film, a 5cm sand layer was laid on the bottom of the canvas pool, and the culture water depth submerged the sand layer by 15cm. During the entire culture process, the water temperature was controlled at 32-34.8℃, the dissolved oxygen was 9.0-10.2mg / L, the salinity was 13.5-14.2‰, the pH was 7.5-8.2, the ammonia nitrogen concentration was 0.01-0.02mg / L, and the nitrite nitrogen concentration was 0.02-0.05mg / L. During the culture period, 10g of fresh clams were fed at 8 am every day and 20g of clams were fed at 6 pm. The crabs were cultivated for 16 days to become butter crabs.

[0143] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 24.15, the ovarian index is 0.93%, the hemolymph fat content is 0.22g / 100g, and the hemolymph beta-carotene content is 396μg / 100g. Figure 1 shown.

[0144] Example 2

[0145] Select female blue crabs with healthy claws, chelae, and swimming legs without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 9.5%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.8mm, the cephalothorax (length 72mm, width 118mm), the body weight is 326g, and the body height is 41mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with black plastic film, a 5cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 15cm, the water temperature was 32-35℃, the dissolved oxygen was 9.2-10.0mg / L, the salinity was 13.2-14.5‰, the pH was 7.5-8.0, the ammonia nitrogen concentration was 0.02-0.03mg / L, and the nitrite nitrogen concentration was 0.01-0.03mg / L. During the culture period, 15g of fresh clams were fed at 8 am and 30g of clams were fed at 6 pm every day. The crabs were cultured for 18 days and cultivated into butter crabs.

[0146] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 22.47, the ovarian index is 0.96%, the hemolymph fat content is 0.18g / 100g, and the hemolymph beta-carotene content is 381μg / 100g. Figure 2 shown.

[0147] Example 3

[0148] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing upward. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 10.0%, the reproductive molt is completed, the length of the abdominal skin flap bristles is 3.0mm, the cephalothorax is (length 70mm, width 115mm), the body weight is 302g, and the body height is 40mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with black plastic film, a 5cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 15cm, the water temperature was 32-34℃, the dissolved oxygen was 9.0-10.4mg / L, the salinity was 13.2-14.6‰, the pH was 7.6-8.4, the ammonia nitrogen concentration was 0.02-0.04mg / L, and the nitrite nitrogen concentration was 0.03-0.05mg / L. During the culture period, 15g of fresh clams were fed at 8 am and 30g of clams were fed at 6 pm every day. The crabs were cultured for 18 days and cultivated into butter crabs.

[0149] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 24.52, the ovarian index is 0.98%, the hemolymph fat content is 0.12g / 100g, and the hemolymph beta-carotene content is 323μg / 100g. Figure 3 shown.

[0150] Example 4

[0151] Select female blue crabs with healthy claws, chelae, and swimming legs without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 10.2%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.3mm, the cephalothorax is (length 72mm, width 102mm), the weight is 226g, and the body height is 40mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) at the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with black plastic film, a 5cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 12cm, the water temperature was 32.0-35℃, the dissolved oxygen was 9.0-9.8mg / L, the salinity was 13.5-14.8‰, the pH was 7.5-8.3, the ammonia nitrogen concentration was 0.02-0.03mg / L, and the nitrite nitrogen concentration was 0.01-0.02mg / L. During the culture period, 10g of fresh clams were fed at 8am every day and 20g of clams were fed at 6pm. The crabs were cultivated for 19 days to become butter crabs.

[0152] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 37.0, the ovarian index is 0.93%, the hemolymph fat content is 0.18g / 100g, and the hemolymph beta-carotene content is 372μg / 100g. Figure 4 shown.

[0153] Example 5

[0154] Select female blue crabs with healthy claws, chelae and swimming legs without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 11.0%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.7mm, the cephalothorax (length 75mm, width 118mm), the weight is 349g, and the body height is 43mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with black plastic film, a 6cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 15cm, the water temperature was 32.2-34.2℃, the dissolved oxygen was 9.2-10.6mg / L, the salinity was 13.06-14.5‰, the pH was 7.5-8.4, the ammonia nitrogen concentration was 0.01-0.03mg / L, and the nitrite nitrogen concentration was 0.02-0.04mg / L. During the culture period, 15g of fresh clams were fed at 8 am every day and 30g of clams were fed at 6 pm. The crabs were cultivated for 20 days to become butter crabs.

[0155] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 26.47, the ovarian index is 0.95%, the hemolymph fat content is 0.14g / 100g, and the hemolymph beta-carotene content is 332μg / 100g. Figure 5 shown.

[0156] Example 6

[0157] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 10.2%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.7mm, the cephalothorax is (length 102mm, width 145mm), the body weight is 512g, and the body height is 46mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid on the bottom of the canvas pool. The culture water depth submerged the sand layer by 15cm. The water temperature was 32-35℃, the dissolved oxygen was 9.1-9.8mg / L, the salinity was 13.4-14.5‰, the pH was 7.6-7.8, the ammonia nitrogen concentration was 0.04-0.05mg / L, and the nitrite nitrogen concentration was 0.03-0.05mg / L. During the culture period, 20g of fresh clams were fed at 8am and 35g of clams were fed at 6pm every day. The crabs were cultivated for 26 days to become butter crabs.

[0158] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 16.21, the ovarian index is 1.12%, the hemolymph fat content is 0.18g / 100g, and the hemolymph beta-carotene content is 351μg / 100g. Fig.11 shown.

[0159] Example 7

[0160] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 10.8%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.6mm, the cephalothorax is (length 93mm, width 135mm), the body weight is 423g, and the body height is 45mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid on the bottom of the canvas pool. The culture water depth submerged the sand layer by 15cm. The water temperature was 32.8-34.2℃, the dissolved oxygen was 9.03-10.2mg / L, the salinity was 13.1-13.9‰, the pH was 7.6-7.9, the ammonia nitrogen concentration was 0.01-0.03mg / L, and the nitrite nitrogen concentration was 0.03-0.04mg / L. During the culture period, 20g of fresh clams were fed at 8am and 25g of clams were fed at 6pm every day. The crabs were cultivated for 26 days to become butter crabs.

[0161] The color of the crab belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 18.65, the ovarian index is 1.34%, the hemolymph fat content is 0.24g / 100g, and the hemolymph beta-carotene content is 326μg / 100g. Fig.12 shown.

[0162] Example 8

[0163] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 12.6%, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.9mm, the cephalothorax is (length 104mm, width 144mm), the body weight is 519g, and the body height is 47mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid on the bottom of the canvas pool. The culture water depth submerged the sand layer by 15cm. The water temperature was 32.1-33.9℃, the dissolved oxygen was 9.2-10.1mg / L, the salinity was 14.1-14.9‰, the pH was 7.5-7.9, the ammonia nitrogen concentration was 0.03-0.05mg / L, and the nitrite nitrogen concentration was 0.02-0.05mg / L. During the culture period, 20g of fresh clams were fed at 8am and 35g of clams were fed at 6pm every day. The crabs were cultivated for 27 days to become butter crabs.

[0164] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 19.42, the ovarian index is 1.41%, the hemolymph fat content is 0.16g / 100g, and the hemolymph beta-carotene content is 342μg / 100g. Fig.13 shown.

[0165] Example 9

[0166] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 13.4%, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.8mm, the cephalothorax is (length 86mm, width 133mm), the body weight is 376g, and the body height is 45mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid on the bottom of the canvas pool. The culture water depth submerged the sand layer by 15cm. The water temperature was 32.9-34.8℃, the dissolved oxygen was 9.8-10.5mg / L, the salinity was 12.3-13.6‰, the pH was 7.5-8.1, the ammonia nitrogen concentration was 0.04-0.05mg / L, and the nitrite nitrogen concentration was 0.03-0.04mg / L. During the culture period, 20g of fresh clams were fed at 8 am and 20g of clams were fed at 6 pm every day. The crabs were cultured for 27 days to cultivate into butter crabs.

[0167] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 17.66, the ovarian index is 1.29%, the hemolymph fat content is 0.19g / 100g, and the hemolymph beta-carotene content is 339μg / 100g. Fig.14 shown.

[0168] Example 10

[0169] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 9.7%, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.5mm, the cephalothorax is (length 79mm, width 127mm), the body weight is 362g, and the body height is 43mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid on the bottom of the canvas pool. The culture water depth submerged the sand layer by 15cm. The water temperature was 32.6-34.4℃, the dissolved oxygen was 9.4-10.2mg / L, the salinity was 12.7-14.2‰, the pH was 7.6-8.0, the ammonia nitrogen concentration was 0.01-0.03mg / L, and the nitrite nitrogen concentration was 0.03-0.05mg / L. During the culture period, 20g of fresh clams were fed at 8 am and 20g of clams were fed at 6 pm every day. The crabs were cultivated for 28 days to become butter crabs.

[0170] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 18.63, the ovarian index is 1.36%, the hemolymph fat content is 0.17g / 100g, and the hemolymph beta-carotene content is 367μg / 100g. Fig.15 shown.

[0171] Embodiment 11

[0172] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 12.1%, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.7mm, the cephalothorax (length 75mm, width 108mm), the body weight is 286g, and the body height is 40mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with a black plastic film, a 6cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 15cm, the water temperature was 22.9-24.6℃, the dissolved oxygen was 9.6-10.3mg / L, the salinity was 12.6-14.6‰, the pH was 7.6-8.1, the ammonia nitrogen concentration was 0.03-0.05mg / L, and the nitrite nitrogen concentration was 0.01-0.03mg / L. During the culture period, 15g of fresh clams were fed at 8 am and 15g of clams were fed at 6 pm every day. The crabs were cultured for 30 days and cultivated into butter crabs.

[0173] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 18.76, the ovarian index is 1.13%, the hemolymph fat content is 0.19g / 100g, and the hemolymph beta-carotene content is 374μg / 100g. Fig.16 shown.

[0174] Example 12

[0175] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 11.6%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.9mm, the cephalothorax is (length 76mm, width 107mm), the body weight is 265g, and the body height is 39mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with black plastic film, a 6cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 15cm, the water temperature was 21.6-23.8℃, the dissolved oxygen was 9.3-10.0mg / L, the salinity was 12.1-13.9‰, the pH was 7.6-8.0, the ammonia nitrogen concentration was 0.02-0.04mg / L, and the nitrite nitrogen concentration was 0.03-0.05mg / L. During the culture period, 15g of fresh clams were fed at 8 am and 15g of clams were fed at 6 pm every day. The crabs were cultured for 31 days and cultivated into butter crabs.

[0176] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 19.73, the ovarian index is 1.48%, the hemolymph fat content is 0.21g / 100g, and the hemolymph beta-carotene content is 310μg / 100g. Fig.17 shown.

[0177] Embodiment 13

[0178] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 13.9%, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.8mm, the cephalothorax is (length 82mm, width 125mm), the body weight is 349g, and the body height is 41mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with black plastic film, a 6cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 15cm, the water temperature was 22.9-24.8℃, the dissolved oxygen was 9.6-10.2mg / L, the salinity was 12.3-14.8‰, the pH was 7.5-8.1, the ammonia nitrogen concentration was 0.03-0.05mg / L, and the nitrite nitrogen concentration was 0.01-0.03mg / L. During the culture period, 20g of fresh clams were fed at 8 am every day and 15g of clams were fed at 6 pm. The crabs were cultivated for 31 days to become butter crabs.

[0179] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 17.98, the ovarian index is 1.23%, the hemolymph fat content is 0.17g / 100g, and the hemolymph beta-carotene content is 307μg / 100g. Fig.18 shown.

[0180] Embodiment 14

[0181] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 14.1%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.7mm, the cephalothorax is (length 84mm, width 127mm), the body weight is 358g, and the body height is 41mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with a black plastic film, a 6cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 15cm, the water temperature was 21.8-24.9℃, the dissolved oxygen was 9.6-10.1mg / L, the salinity was 13.2-14.6‰, the pH was 7.6-7.9, the ammonia nitrogen concentration was 0.02-0.03mg / L, and the nitrite nitrogen concentration was 0.03-0.05mg / L. During the culture period, 20g of fresh clams were fed at 8 am every day and 15g of clams were fed at 6 pm. The crabs were cultured for 33 days and cultivated into butter crabs.

[0182] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 19.34, the ovarian index is 1.36%, the hemolymph fat content is 0.23g / 100g, and the hemolymph beta-carotene content is 312μg / 100g. Fig.19 shown.

[0183] Embodiment 15

[0184] Select female blue crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the ability to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 11.3%, and the reproductive molt is completed. The length of the abdominal skin flap bristles is 2.9mm, the cephalothorax (length 81mm, width 123mm), the body weight is 321g, and the body height is 40mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) in the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with a black plastic film, a 6cm sand layer was laid on the bottom of the canvas pool, the culture water depth submerged the sand layer by 15cm, the water temperature was 22.3-24.1℃, the dissolved oxygen was 9.2-10.1mg / L, the salinity was 12.8-14.6‰, the pH was 7.6-7.9, the ammonia nitrogen concentration was 0.03-0.05mg / L, and the nitrite nitrogen concentration was 0.03-0.04mg / L. During the culture period, 20g of fresh clams were fed at 8 am every day and 15g of clams were fed at 6 pm. The crabs were cultivated for 35 days to become butter crabs.

[0185] The color of the crab's belly is orange-yellow, the color of the joint membrane (yellow-blue value) is 18.42, the ovarian index is 1.29%, the hemolymph fat content is 0.18g / 100g, and the hemolymph beta-carotene content is 364μg / 100g. Fig. 20 shown.

[0186] Comparative Example 1

[0187] The difference between this comparative example and Example 1 is that the status of the female blue crab is different.

[0188] The specific method steps in this comparative example are:

[0189] Select crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the female blue crab can flip over and crawl on its own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / the cephalothorax area is 45.8% (the gonads are fully developed), the cephalothorax is 79mm long and 126mm wide, the body weight is 362g, and the body height is 43mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) at the Longwangwan Park of Zhanjiang Bay Laboratory. The pool mouth was covered with black plastic film during the culture period. The water temperature was 32.0-33.2℃, the dissolved oxygen was 9.0-10.2mg / L, the salinity was 13.1-14.0‰, the pH was 7.5-8.2, the ammonia nitrogen concentration was 0.01-0.03mg / L, and the nitrite nitrogen concentration was 0.02-0.04mg / L. During the culture period, 15g of fresh clams were fed at 8 am every day and 20g of clams were fed at 6 pm. After 20 days of culture, they were still roe crabs and could not be cultivated into butter crabs.

[0190] The crab's belly is white, the color of the joint membrane (yellow-blue value) is 3.07, the ovarian index is 12.2%, the hemolymph fat content is 0.08g / 100g, and the hemolymph beta-carotene content is 142μg / 100g. Figure 6 shown.

[0191] Comparative Example 2

[0192] The difference between this comparative example and Example 1 is that the status of the female blue crab is different.

[0193] The specific method steps in this comparative example are:

[0194] Select crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the female blue crab can flip over and crawl on its own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / the cephalothorax area is 46.1% (the gonads are fully developed), the cephalothorax is (78mm long, 118mm wide), the body weight is 306g, and the body height is 41mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) at the Longwangwan Park of Zhanjiang Bay Laboratory. The pool mouth was covered with black plastic film during the culture period. The water temperature was 32.2-33.4℃, the dissolved oxygen was 9.3-10.1mg / L, the salinity was 13.3-14.3‰, the pH was 7.6-8.3, the ammonia nitrogen concentration was 0.04-0.05mg / L, and the nitrite nitrogen concentration was 0.02-0.04mg / L. During the culture period, 10g of fresh clams were fed at 8am every day and 20g of clams were fed at 6pm. After 20 days of culture, they were still roe crabs and could not be cultivated into butter crabs.

[0195] The crab's belly is white, the color of the joint membrane (yellow-blue value) is 2.34, the ovarian index is 13.4%, the hemolymph fat content is 0.05g / 100g, and the hemolymph beta-carotene content is 127μg / 100g. Figure 7 shown.

[0196] Comparative Example 3

[0197] The difference between this comparative example and Example 1 is that the status of the female blue crab is different.

[0198] The specific method steps in this comparative example are:

[0199] Select crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the female blue crab can flip over and crawl on its own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / the cephalothorax area is 47.4% (the gonads are fully developed), the cephalothorax is 72mm long and 118mm wide, the body weight is 269g, and the body height is 38mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) at the Longwangwan Park of Zhanjiang Bay Laboratory. The pool mouth was covered with black plastic film during the breeding period. The water temperature was 32.4-33.8℃, the dissolved oxygen was 9.0-10.0mg / L, the salinity was 13.1-13.9‰, the pH was 7.6-8.2, the ammonia nitrogen concentration was 0.01-0.04mg / L, and the nitrite nitrogen concentration was 0.02-0.05mg / L. During the breeding period, 10g of fresh clams were fed at 8 am every day and 15g of clams were fed at 6 pm. After 20 days of breeding, the crabs were still roe crabs and could not be cultivated into butter crabs.

[0200] The crab's belly is white, the color of the joint membrane (yellow-blue value) is 1.46, the ovarian index is 13.8%, the hemolymph fat content is 0.03g / 100g, and the hemolymph beta-carotene content is 94μg / 100g. Figure 8 shown.

[0201] Comparative Example 4

[0202] The difference between this comparative example and Example 1 is that the status of the female blue crab is different.

[0203] The specific method steps in this comparative example are:

[0204] Select crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the female blue crab can flip over and crawl on its own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 48.2% (gonads are fully developed), the cephalothorax is (85mm long, 121mm wide), the body weight is 329g, and the body height is 42mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) at the Longwangwan Park of Zhanjiang Bay Laboratory. The pool mouth was covered with black plastic film during the culture period. The water temperature was 32.0-33.0℃, the dissolved oxygen was 9.2-10.2mg / L, the salinity was 13.0-14.0‰, the pH was 7.6-8.0, the ammonia nitrogen concentration was 0.03-0.05mg / L, and the nitrite nitrogen concentration was 0.04-0.05mg / L. During the culture period, 15g of fresh clams were fed at 8 am every day and 20g of clams were fed at 6 pm. After 20 days of culture, they were still roe crabs and could not be cultivated into butter crabs.

[0205] The crab's belly is white, the color of the joint membrane (yellow-blue value) is 4.06, the ovarian index is 14.1%, the hemolymph fat content is 0.09g / 100g, and the hemolymph beta-carotene content is 171μg / 100g. Fig. 9 shown.

[0206] Comparative Example 5

[0207] The difference between this comparative example and Example 1 is that the status of the female blue crab is different.

[0208] The specific method steps in this comparative example are:

[0209] Select crabs with healthy claws, chelae, and swimming feet without disease spots, no damage to the abdomen and crab shell, and the female blue crab can flip over and crawl on its own when its back is facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 49.5% (gonads are fully developed), the cephalothorax is 79mm long and 123mm wide, the body weight is 303g, and the body height is 40mm. The crabs were cultured in an indoor plastic canvas pool (1.8m in diameter and 0.8m in height) at the Longwangwan Park of Zhanjiang Bay Laboratory. The pool mouth was covered with black plastic film during the culture period. The water temperature was 32.3-34.4℃, the dissolved oxygen was 9.1-10.5mg / L, the salinity was 13.2-14.4‰, the pH was 7.6-8.3, the ammonia nitrogen concentration was 0.03-0.05mg / L, and the nitrite nitrogen concentration was 0.03-0.04mg / L. During the culture period, 10g of fresh clams were fed at 8am every day and 20g of clams were fed at 6pm. After 20 days of culture, they were still roe crabs and could not be cultivated into butter crabs.

[0210] The crab's belly was white, the color of the joint membrane (yellow-blue value) was 4.92, the ovarian index was 15.0%, the hemolymph fat content was 0.09g / 100g, and the hemolymph beta-carotene content was 196μg / 100g. Fig.10 shown.

[0211] Effect example

[0212] The experimental data of Examples 1 to 15 and Comparative Examples 1 to 5 are summarized. The trait data of female blue crabs before culture are shown in Table 1, the culture conditions are shown in Table 2, and the culture results are shown in Table 3.

[0213] Table 1 Trait data of female mud crab before culture

[0214]

[0215] Table 2 Culture conditions

[0216]

[0217]

[0218] Table 3 Culture results

[0219]

[0220] Based on the appearance of the female crabs in Table 3, it is preliminarily determined whether they are butter crabs. From the results, it can be seen that the ovarian development state of female blue crabs before breeding is the key to the formation of butter crabs. Only female blue crabs with incomplete ovarian development and a cephalothorax shadow area / cephalothorax area of ​​less than 15% under transmitted light can subsequently develop into butter crabs. Although Examples 6 to 15 can also form butter crabs, they require a culture time of more than 25 days, which is not as good as Examples 1 to 5 in terms of breeding cycle. It can be seen that light and water temperature will affect the cultivation time required to form butter crabs.

[0221] According to the "Butter Crab Quality Grade Assessment Rules" (Group Standard, T / GDNB 204-2024) issued by the Guangdong Agricultural Standardization Association, the grade identification rules for butter crabs (Table 4) were used to determine the breeding results of Examples 1 to 15 and Comparative Examples 1 to 5 of the present invention.

[0222] Table 4 Rules for determining the grade of butter crab

[0223]

[0224] It can be seen that Examples 1 to 5 of the present invention are all top-grade products, and the yellow-blue values ​​are all above 22, and some can even be as high as 37. Examples 6 to 10 and Examples 11 to 15 can also form butter crabs, although their appearance is not as good as Examples 1 to 5, they are also top-grade products. Comparative Examples 1 to 5 cannot form butter crabs. It can be seen that light and water temperature can affect the grade of butter crabs.

[0225] Further, referring to the culture conditions of Examples 1 to 5, 5 batch experiments were conducted, and the results are shown in Table 5.

[0226] Table 5

[0227]

[0228] In summary, the present invention provides a method for large-scale continuous cultivation of butter crabs by regulating relevant environmental factors. The method has a short cultivation cycle, is simple and convenient to operate, has low cost, and has a good cultivation effect. The method can achieve an overall conversion rate of butter crabs of more than 80%. The color of the belly navel of the obtained butter crab is orange-yellow, the color of the joint membrane (yellow-blue value) can reach 37, the hemolymph fat content can reach more than 0.22g / 100g, and the hemolymph beta-carotene content can reach 396μg / 100g, which can achieve 20% of female blue crabs converted into top-grade butter crabs.

Claims

1. A method for cultivating butter crabs, comprising the following steps: 1) Select female blue crabs whose ovaries are in an undeveloped state; 2) placing the female blue crab in a breeding pond with the following environmental parameters for 10 to 30 days: The environmental parameters include water temperature, dissolved oxygen, salinity, pH, ammonia nitrogen and / or nitrite nitrogen concentration; The water temperature is 20°C to 35°C; The dissolved oxygen is 9-12 mg / L; The salinity is 12‰ to 15‰; The pH is 7.5 to 8.5; The concentration of ammonia nitrogen and / or nitrite nitrogen is 0 to 0.05 mg / L; 3) Feeding and breeding.

2. The method according to claim 1, characterized in that: The female blue crab is a blue crab.

3. The method according to claim 1, characterized in that: The female blue crab has a cephalothorax shadow area / cephalothorax area of ​​5-15% under transmitted light; and / or the female blue crab has completed reproductive molting, and the length of the abdominal skin flap bristles is 1-3.5 mm.

4. The method according to claim 1, characterized in that: The spatial area of ​​the breeding pond is more than 30 times greater than the total area of ​​the cephalothorax of the female blue crab.

5. The method according to claim 1, characterized in that: The female blue crabs are cultured in the culture pond for 15 to 20 days.

6. The method according to claim 5, characterized in that: The temperature is 32-35°C.

7. The method according to claim 6, characterized in that: The culture was carried out under light protection.

8. The method according to claim 1, characterized in that: The breeding comprises the steps of feeding bait every day; The bait includes shellfish; The daily feeding amount is 10-15% of the body weight of the female blue crab.

9. Any of the methods a) to c) comprising the following steps: a) a cultivation method for accelerating the formation of butter crab; b) a cultivation method for improving the conversion rate of butter crab; c) a cultivation method for improving the quality of butter crab; The steps include: 1) Select female blue crabs whose ovaries are in an undeveloped state; The female blue crab has a cephalothorax shadow area / cephalothorax area of ​​5 to 15% under transmitted light; and / or the female blue crab has completed reproductive molting, and the length of the abdominal skin flap bristles is 1 to 3.5 mm; 2) The female blue crabs are placed in a breeding pond with the following environmental parameters for 15 to 20 days: The environmental parameters include water temperature, dissolved oxygen, salinity, pH, and ammonia nitrogen / nitrite nitrogen concentration; The water temperature is 32°C to 35°C; The dissolved oxygen is 9-12 mg / L; The salinity is 12‰ to 15‰; The pH is 7.5 to 8.5; The concentration of ammonia nitrogen and / or nitrite nitrogen is 0 to 0.05 mg / L; 3) Feeding and breeding; The culture was carried out under light protection.

10. Use of the method according to claim 9 in accelerating the formation of butter crabs, improving the conversion rate of butter crabs, and improving the quality of butter crabs.

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