A method for cultivating butter crabs

Abstract

The present invention belongs to the field of biotechnology, and specifically relates to a method for cultivating butter crabs. The present invention regulates the development process of blue crabs into butter crabs through indoor environmental factors, and provides a method for cultivating butter crabs. The method utilizes the high efficiency, convenience, and low cost of regulating indoor environmental factors, can effectively cultivate butter crabs, and can be suitable for large-scale batch production of butter crabs throughout the year. This method only takes a very short time (only 15 to 20 days) to cultivate butter crabs, and has a high conversion rate. In particular, the number of high-grade butter crabs obtained is greater than that of conventional methods. The color of its umbilicus 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.

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, a female mud crab, develops a unique golden "oil-like substance" during its growth and development. This substance gradually distributes throughout its tissues, giving its body fluids a golden hue and its joint membranes an orange-yellow hue. Due to its excellent taste and unique flavor, the butter crab enjoys high economic value and market demand in the food and aquaculture industries, occupying a significant position in my country's high-end aquatic product market. Butter crabs are found in both wild-caught mud crabs and marine ponds. Currently, large-scale production of butter crabs is concentrated in marine ponds, primarily during the month surrounding the Mid-Autumn Festival. Butter crab farming faces a number of challenges, including dependence on the weather, long breeding cycles, low catch-up rates (less than one in a thousand), and unstable yields that fall far short of meeting market demand. Consequently, efficient butter crab farming techniques and models have garnered significant attention from the government, farmers, researchers, and others. However, the mechanisms underlying the formation of butter crabs remain largely unknown, and the technology for efficiently cultivating butter crabs in artificial, controlled environments remains elusive. 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 method for cultivating butter crabs to accelerate their formation.

[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) The female blue crabs are placed 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 to 12 mg / L;

[0015] The salinity is 12‰ to 15‰;

[0016] The pH is 7.5 to 8.5;

[0017] The ammonia nitrogen and / or nitrite nitrogen concentration 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 molt, 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 mud 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 free of disease spots; there are no obvious damages on the abdomen and shell; the crab can turn over and crawl on its own when its back is facing up; it can spit out bubbles normally after adding water to cover the crab body; the eye stalks can move normally.

[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 can be selected from any one or more of silt, whetstone, ceramsite, 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 to 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 nitrite nitrogen concentration 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 further 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 body 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 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 a razor clam.

[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 daily 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 cultivation time of a single batch of 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 mud crab has a cephalothorax shadow area / cephalothorax area of ​​5 to 15% under transmitted light; and / or the female mud 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 cultured in a culture 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 to 12 mg / L;

[0058] The salinity is 12‰ to 15‰;

[0059] The pH is 7.5 to 8.5;

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

[0061] 3) Feeding and breeding;

[0062] The culture was carried out in the dark.

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

[0064] In some embodiments of the present invention, the female mud crab has a cephalothorax shadow area / cephalothorax area of ​​5-15% under transmitted light; and / or the female mud crab completes reproductive molt, 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 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 those of 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 of blue crabs into yellow crabs through indoor environmental factors, providing a method for cultivating yellow crabs. This method utilizes the high efficiency, convenience, and low cost of regulating indoor environmental factors, effectively cultivating yellow crabs, and is suitable for large-scale batch production of yellow crabs throughout the year. This method only takes a very short time (only 15 to 20 days) to cultivate yellow crabs, and has a high conversion rate. In particular, the number of high-quality yellow crabs obtained is greater than that of conventional methods. The color of the umbilicus 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, in which:

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

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

[0084] Figure 11 This is the butter crab cultivated in Example 6 of the present invention.

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

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

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

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

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

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

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

[0092] Figure 19 This is the butter crab cultivated in Example 14 of the present invention.

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

[0094] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described 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 growth and development and gradually distributed throughout the body tissues, making the body fluid appear golden and the joint membrane appear 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 part of 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 posterior 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 when a strong flashlight is pointed at the abdomen of the blue crab. It is an indicator of the degree of ovarian development in the crab.

[0101] The 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 degree of 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 method for detecting the color (yellow-blue value) of the articular membrane of the present invention refers to the "Quality Grade Assessment Rules for Butter Crabs" (group standard, T / GDNB 204-2024) issued by the Guangdong Agricultural Standardization Association.

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

[0106] The hemolymph β-carotene test was carried out in accordance with the provisions of GB5009.83-2016, and the hemolymph of the second step was 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 mud 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 the blue crab completes its reproductive molt, the ovary is not developed or develops abnormally, the expression of VTGR in the oocyte will be inhibited, which will hinder 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 mud crabs are affected by a variety of environmental factors. Continuous darkness can inhibit the development of mud crab ovaries, promote lipid absorption and production, and inhibit fat decomposition; high temperature, high dissolved oxygen, and low salt can synergistically promote the absorption and transport process of lipids in mud crabs; a large area can alleviate the spatial stress of mud crabs, 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 production of mud crab lipids. The present invention has found that comprehensive regulation of aquaculture environmental factors, such as light (intensity, cycle), water temperature, salinity, dissolved oxygen, aquaculture water size, and biological bait, can not only maintain the long-term state of ovarian agenesis or abnormal development of mud crabs, but also promote the lipid metabolism processes such as the absorption, production, storage, and transport of 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 the crabs in an indoor breeding pond and adjust the environmental parameters;

[0112] 3) Feeding and breeding.

[0113] In some embodiments of the present invention, the butter crab species is selected from the group consisting of Scylla Paramamosain, Portunidae, 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 embodiments, the female blue crab with undeveloped ovaries has a cephalothorax shadow area / cephalothorax area of ​​10-15% under transmitted light.

[0117] In some specific embodiments, when a female mud 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 mud crab is 2.5 to 3.0 mm.

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

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

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

[0121] In some specific embodiments, the area of ​​the culture pond is more than 30 times 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 can be selected from any one or more of silt, whetstone, ceramsite, 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 mud 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 the fish with bait every day.

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

[0137] In some specific embodiments, the shellfish is a fresh bivalve 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 daily is 10% to 15% of the body weight of the female blue crab.

[0140] The present invention is further described below through examples and comparative examples. The blue crab species selected in the present invention is Scylla pseudoburrowing.

[0141] Example 1

[0142] 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 is 10.5% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.6mm, the cephalothorax is (length 64mm, width 98mm), the 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 8am every day and 20g of clams were fed at 6pm. The crabs were cultured for 16 days to become butter crabs.

[0143] The belly of the crab 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, chelipeds, 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 is 9.5% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.8mm, the cephalothorax is (length 72mm, width 118mm), the 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) 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. 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 8am every day and 30g of clams were fed at 6pm. The crabs were cultured for 18 days to become butter crabs.

[0146] The belly of the crab 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, chelipeds, 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 is 10.0% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 3.0mm, the cephalothorax is 70mm long and 115mm wide, the 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) 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 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 8am every day and 30g of clams were fed at 6pm. The crabs were cultured for 18 days to become butter crabs.

[0149] The belly of the crab 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, chelipeds, 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 is 10.2% / cephalothorax area, 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 (1.8 m in diameter and 0.8 m in height) at the Longwangwan Park of Zhanjiang Bay Laboratory. During the culture period, the pool mouth was covered with black plastic film, a 5 cm sand layer was laid on the bottom of the canvas pool, and the culture water depth submerged the sand layer by 12 cm. The water temperature was 32.0-35°C, the dissolved oxygen was 9.0-9.8 mg / L, the salinity was 13.5-14.8‰, the pH was 7.5-8.3, the ammonia nitrogen concentration was 0.02-0.03 mg / L, and the nitrite nitrogen concentration was 0.01-0.02 mg / L. During the culture period, 10 g of fresh clams were fed at 8 am and 20 g of clams were fed at 6 pm every day. The crabs were cultured for 19 days to become butter crabs.

[0152] The belly of the crab 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, chelipeds, 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 is 11.0% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.7mm, the cephalothorax is (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) at 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, and 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 8am every day and 30g of clams were fed at 6pm. The crabs were cultured for 20 days to become butter crabs.

[0155] The belly of the crab 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, chelipeds, 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 is 10.2% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.7mm, the cephalothorax is (length 102mm, width 145mm), the 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) at the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid at 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 cultured for 26 days to become butter crabs.

[0158] The belly color of the butter crab 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. Figure 11 shown.

[0159] Example 7

[0160] Select female blue crabs with healthy claws, chelipeds, 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 is 10.8% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.6mm, the cephalothorax is (length 93mm, width 135mm), the 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) at the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid at 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 cultured for 26 days to become butter crabs.

[0161] The belly of the crab 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. Figure 12 shown.

[0162] Example 8

[0163] Select female blue crabs with healthy claws, chelipeds, 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 is 12.6% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.9mm, the cephalothorax is (length 104mm, width 144mm), the 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) at the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid at 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 cultured for 27 days to become butter crabs.

[0164] The belly of the crab 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. Figure 13 shown.

[0165] Example 9

[0166] 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 is 13.4% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.8mm, the cephalothorax is (length 86mm, width 133mm), the 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) at the Longwangwan Park of Zhanjiang Bay Laboratory. Natural light was used during the culture period. A 6cm sand layer was laid at 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 8am and 20g of clams were fed at 6pm every day. The crabs were cultured for 27 days to become butter crabs.

[0167] The belly of the crab 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. Figure 14 shown.

[0168] Example 10

[0169] Select female blue crabs with healthy claws, chelipeds, 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 is 9.7% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.5mm, the cephalothorax is 79mm long and 127mm wide, the 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. Natural light was used during the culture period. A 6cm sand layer was laid at 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 8am and 20g of clams were fed at 6pm every day. The crabs were cultured for 28 days to become butter crabs.

[0170] The belly of the crab 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. Figure 15 shown.

[0171] Example 11

[0172] 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 is 12.1% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.7mm, the cephalothorax is 75mm long and 108mm wide, the 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) at 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, and 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 8am and 15g of clams were fed at 6pm every day. The crabs were cultured for 30 days to become butter crabs.

[0173] The belly of the crab 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. Figure 16 shown.

[0174] Example 12

[0175] 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 is 11.6% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.9mm, the cephalothorax is (length 76mm, width 107mm), the 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) at 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, and 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 8am and 15g of clams were fed at 6pm every day. The crabs were cultured for 31 days to become butter crabs.

[0176] The belly of the crab 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. Figure 17 shown.

[0177] Example 13

[0178] Select female blue crabs with healthy claws, chelipeds, 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 is 13.9% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.8mm, the cephalothorax is (length 82mm, width 125mm), the 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) at 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, and 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 8am every day and 15g of clams were fed at 6pm. The crabs were cultured for 31 days to become butter crabs.

[0179] The belly of the crab 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. Figure 18 shown.

[0180] Example 14

[0181] Select female blue crabs with healthy claws, chelipeds, 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 is 14.1% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.7mm, the cephalothorax is (length 84mm, width 127mm), the 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) at 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, and 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 8am every day and 15g of clams were fed at 6pm. The crabs were cultured for 33 days to become butter crabs.

[0182] The belly of the crab 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. Figure 19 shown.

[0183] Example 15

[0184] Select female blue crabs with healthy claws, chelipeds, 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 is 11.3% / cephalothorax area, the reproductive molt is completed, the length of the abdominal skin flap bristles is 2.9mm, the cephalothorax is (length 81mm, width 123mm), the 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) at 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, and 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 8am every day and 15g of clams were fed at 6pm. The crabs were cultured for 35 days to become butter crabs.

[0185] The belly of the crab 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. Figure 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, chelipeds, and swimming legs without disease spots, no damage to the abdomen and crab shell, and the ability of female blue crabs to flip over and crawl on their 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 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. 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 8am every day and 20g of clams were fed at 6pm. After 20 days of culture, the crabs were still roe crabs and could not be cultivated into butter crabs.

[0190] The crab's belly is white, its synovial color (yellow-blue value) is 3.07, its ovarian index is 12.2%, its hemolymph fat content is 0.08g / 100g, and its 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 legs without disease spots, no damage to the abdomen and crab shell, and the ability of female blue crabs 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 46.1% (the gonads are fully developed), the cephalothorax is 78mm long and 118mm wide, the 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) in 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, the crabs were still roe crabs and could not be cultivated into butter crabs.

[0195] The crab's belly is white, its synovial color (yellow-blue value) is 2.34, its ovarian index is 13.4%, its hemolymph fat content is 0.05g / 100g, and its 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 legs without disease spots, no damage to the abdomen and crab shell, and the ability of female blue crabs 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 47.4% (the gonads are fully developed), the cephalothorax is 72mm long and 118mm wide, the 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) in the Longwangwan Park of Zhanjiang Bay Laboratory. The pool mouth was covered with black plastic film during the culture period. The water temperature was 32.4-33.8℃, 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 culture period, 10g of fresh clams were fed at 8am every day and 15g of clams were fed at 6pm. After 20 days of culture, they were still roe crabs and could not be cultivated into butter crabs.

[0200] The crab's belly is white, its joint membrane color (yellow-blue value) is 1.46, its ovarian index is 13.8%, its hemolymph fat content is 0.03g / 100g, and its 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 legs without disease spots, no damage to the abdomen and crab shell, and the ability of female blue crabs to flip over and crawl on their own when the back is facing up. The shadow area of ​​the cephalothorax under transmitted light / the cephalothorax area is 48.2% (the gonads are fully developed), the cephalothorax is 85mm long and 121mm wide, the 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) in 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 8am every day and 20g of clams were fed at 6pm. After 20 days of culture, the crabs were still roe crabs and could not be cultivated into butter crabs.

[0205] The crab's belly is white, its synovial color (yellow-blue value) is 4.06, its ovarian index is 14.1%, its hemolymph fat content is 0.09g / 100g, and its hemolymph beta-carotene content is 171μg / 100g. Figure 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, chelipeds, and swimming legs without disease spots, no damage to the abdomen and crab shell, and the ability of female blue crabs to flip over and crawl on their own when their backs are facing up. The shadow area of ​​the cephalothorax under transmitted light / cephalothorax area is 49.5% (the gonads are fully developed), the cephalothorax is 79mm long and 123mm wide, the 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) in 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, the crabs were still roe crabs and could not be cultivated into butter crabs.

[0210] The crab's belly is white, its synovial color (yellow-blue value) is 4.92, its ovarian index is 15.0%, its hemolymph fat content is 0.09g / 100g, and its hemolymph beta-carotene content is 196μg / 100g. Figure 10 shown.

[0211] Effect Examples

[0212] The experimental data of Examples 1 to 15 and Comparative Examples 1 to 5 were summarized. The characteristic data of the female mud 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 Characteristic data of female mud crab before culture

[0214]

[0215] Table 2 Culture conditions

[0216]

[0217]

[0218] Table 3 Breeding results

[0219]

[0220] Based on the appearance of the female crabs in Table 3, a preliminary assessment of whether they are butter crabs was made. The results indicate that the ovarian development of female mud crabs prior to culture is crucial for the development of butter crabs. Only female mud crabs with incomplete ovarian development (i.e., a carapace shadow area / carapace area ratio of less than 15% under transmitted light) can subsequently develop into butter crabs. While Examples 6-15 also produced butter crabs, they required a culture time of over 25 days, which is inferior to Examples 1-5 in terms of the culture cycle. This indicates that light intensity and water temperature affect the cultivation time required to develop 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 breeding results of Examples 1 to 15 of the present invention and Comparative Examples 1 to 5 were judged for the grade identification rules of butter crab (Table 4).

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

[0223]

[0224] As can be seen, Examples 1-5 of the present invention are all top-quality, with yellow-blue values ​​exceeding 22, and some even reaching as high as 37. Examples 6-10 and Examples 11-15 also produced butter crabs, and while their appearance was inferior to that of Examples 1-5, they were still considered top-quality. Comparative Examples 1-5 failed to produce butter crabs. This shows that light and water temperature can affect the quality of butter crabs.

[0225] Furthermore, referring to the culture conditions of Examples 1 to 5, five 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 and sustainable cultivation of butter crabs by regulating relevant environmental factors. The method has a short cultivation cycle, is simple and convenient to operate, is low in cost, and has a good cultivation effect. The method can achieve an overall conversion rate of butter crabs exceeding 80%. The obtained butter crabs have an orange-yellow belly navel color, a synovial membrane color (yellow-blue value) of 37, a hemolymph fat content of 0.22 g / 100 g or more, and a hemolymph beta-carotene content of 396 μg / 100 g. 20% of female blue crabs can be converted into top-quality butter crabs.

Claims

1. A method for cultivating butter crabs, comprising the following steps: 1) Select female blue crabs whose ovaries are not yet developed; 2) The female blue crabs are cultured in a culture 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 32°C to 35°C; The dissolved oxygen is 9-12 mg / L; The salinity is 12‰~15‰; The pH is 7.5 to 8.5; The ammonia nitrogen and / or nitrite nitrogen concentration is 0-0.05 mg / L; 3) Feeding and breeding; The female blue crab has a cephalothorax shadow area / cephalothorax area of ​​5-15% under transmitted light; The female mud crab completes reproductive molting, and the length of the abdominal skin flap bristles is 1 to 3.5 mm.

2. The method according to claim 1, wherein: The female blue crab is the blue crab Parasitoid.

3. The method according to claim 1, wherein: 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.

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

5. The method according to claim 1, wherein: The culture was carried out in the dark.

6. The method according to claim 1, wherein: The breeding comprises the steps of feeding bait every day; The bait includes shellfish; The daily feeding amount is 10-15% of the female mud crab's body weight.

7. Any of methods a) to c) a) A method for accelerating the formation of butter crabs; b) A method for increasing the conversion rate of butter crabs; c) A method for cultivating butter crabs to improve their quality; The following steps are involved: 1) Select female blue crabs whose ovaries are not yet developed; The female blue crab has a cephalothorax shadow area / cephalothorax area of ​​5-15% under transmitted light; The female mud crab completes reproductive molt, and the length of the abdominal skin flap bristles is 1 to 3.5 mm; 2) The female blue crabs were cultured in a culture pond with the following environmental parameters for 15 to 20 days: The environmental parameters include water temperature, dissolved oxygen, salinity, pH, ammonia nitrogen and / or nitrite nitrogen concentration; The water temperature is 32°C to 35°C; The dissolved oxygen is 9-12 mg / L; The salinity is 12‰~15‰; The pH is 7.5 to 8.5; The ammonia nitrogen and / or nitrite nitrogen concentration is 0-0.05 mg / L; 3) Feeding and breeding; The culture was carried out in the dark.

8. Use of the method according to claim 7 in accelerating the formation of butter crab, increasing the conversion rate of butter crab or improving the quality of butter crab.

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