Eriocheir sinensis keep-alive method

Abstract

The invention discloses a keep-alive method for eriocheir sinensis. The keep-alive method comprises the following steps: (1) temporary rearing; (2) gradient cooling: putting the temporarily cultured eriocheir sinensis in an incubator at 22-25 DEG C, and cooling the incubator to 6-9 DEG C at a cooling rate of 2-4 DEG C / h, so that the eriocheir sinensis enters a dormant state; (3) packaging; and (4) transportation: carrying out keep-alive transportation on the packaging box. According to the method, chemical medicines are not needed, the cost is low, and the Chinese mitten crabs are kept alive for a long time.

Description

Technical Field

[0001] The invention relates to the technical field of aquatic product keeping alive, in particular to a method for keeping Chinese mitten crab alive. Background Art

[0002] The Chinese mitten crab, also known as the hairy crab, originates from the rivers along the Yellow Sea. It is one of the most important aquaculture species in Asia. In China, it has developed into a freshwater crustacean industry with great potential. In addition, crab meat is an excellent source of minerals, especially calcium, iron, zinc, potassium and phosphorus. In the Asian market, Chinese mitten crab is mostly sold as a live product. After the crab dies, protein autolysis and polyphenol oxidation in the body lead to a decrease in meat quality.

[0003] Vibration, temperature changes, hypoxia, crowding, etc. can easily cause stress in crabs, leading to death or quality degradation. The main way to deal with this is to adjust physiological functions, reduce stress responses, and improve transportation survival rate and quality. At present, the main way to keep fresh aquatic products such as crabs alive in my country is to use low temperature, anesthesia and other means to reduce the metabolism of aquatic products, reduce the oxygen consumption of aquatic products and the consumption of nutrients in the body, thereby improving the survival rate of aquatic products. Commonly used anti-stress chemicals mainly include eugenol and M-222, but the actual operation is affected by factors such as the type of aquatic products and the environment, resulting in unstable survival rate and high cost.

[0004] The Chinese patent literature discloses a "method for keeping hairy crabs alive and transporting them", and its application publication number is CN105123585A. The invention has the following anesthesia steps: (1) Anesthesia: Add a transporting agent to the temporary holding pond for hairy crabs, add 40 mg of the transporting agent per liter of water, put the hairy crabs into the temporary holding pond, and anesthetize them for 8 minutes; (2) Bundling: Wrap the legs and claws with cotton ropes to tie the hairy crabs; (3) Loading: Ship at 6°C; (4) Management during transportation: Spray the hairy crabs with clean water every hour during transportation to keep the hairy crabs moist at all times. The transportation time is 72 hours. This method has the following shortcomings: The anesthesia step requires water as a medium, and factors such as water temperature, dissolved oxygen, and water quality are variable and difficult to control. In addition, the volume and weight of water account for too large a proportion, resulting in high costs and low efficiency. Summary of the invention

[0005] The invention aims to provide a method for keeping Chinese mitten crab alive, which does not require the use of chemical drugs, is low-cost and can keep Chinese mitten crab alive for a long time.

[0006] The technical solution adopted by the present invention to solve its technical problem is: A method for keeping Chinese mitten crab alive comprises the following steps: (1) Temporary culture: tie the claws of the freshly caught Chinese mitten crab with ropes or rubber bands, place them in clean water without feeding, and aerate them continuously; (2) Gradient cooling: Place the Chinese mitten crabs in an incubator at 22-25°C and cool the incubator to 6-9°C at a cooling rate of 2-4°C / h, so that the crabs enter a dormant state. (3) Packaging: First, spread a sponge soaked with water on the bottom of the perforated packaging box, then place the dormant Chinese mitten crab on the sponge and seal the packaging box; (4) Transportation: The packaging boxes must be transported alive.

[0007] The present invention has found that the use of a specific gradient cooling method for Chinese mitten crabs can effectively alleviate the stress response of the crabs and prevent the crabs from breaking their legs or even dying due to excessive temperature differences. No chemical drugs are required, the cost is low, and the crabs can be kept alive for a long time.

[0008] When dormant, the Chinese mitten crab breathes weakly, hardly crawls, moves its feet slowly, and has unresponsiveness.

[0009] In step (1), the temperature of the temporary water is 24-26°C.

[0010] In step (1), the temporary holding time is 12 to 24 hours.

[0011] In step (4), the temperature of the live transport is controlled at 7-9°C.

[0012] In step (4), the time for live transport is 10 to 15 days.

[0013] The beneficial effects of the present invention are: The claws of live crabs are tied up to prevent them from colliding with each other, causing injury, death or broken claws, and to facilitate subsequent manual operations. The purpose of temporary rearing is to drain the excrement in the crab's body to prevent the excrement from causing massive reproduction of microorganisms during subsequent survival transportation, thereby reducing the survival rate of the crab.

[0014] Using gradient cooling on crabs can effectively alleviate the crabs' stress response and prevent the crabs from breaking their legs or even dying due to excessive temperature differences.

[0015] The operation is convenient and the cost is low. It can greatly improve the survival rate and survival time of crabs, realize long-distance and long-time live transportation, and has significant economic benefits. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described in detail below through specific embodiments.

[0017] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, unless otherwise specified, are all conventional methods in the art.

[0018] Example 1 (1) Temporary culture: Tie the claws of the freshly caught Chinese mitten crab with ropes, place them in 24℃ clean water without feeding for 12 hours, and aerate continuously; (2) Gradient cooling: Place the live crabs in an incubator at 24°C, and cool the incubator to 7°C at a rate of 2°C / h, until the crabs enter a dormant state. (3) Packaging: First, spread a sponge soaked with water on the bottom of the perforated packaging box, then place the dormant Chinese mitten crab on the sponge and seal the packaging box; (4) Live transportation: The packaging boxes are transported. The temperature for live transportation is 7°C, the transportation time is 15 days, and the survival rate of Chinese mitten crab is 93%.

[0019] Example 2 (1) Temporary culture: tie the claws of the freshly caught Chinese mitten crab with rubber bands, place them in 25℃ clean water without feeding for 18 hours, and aerate continuously; (2) Gradient cooling: Place the live crabs in an incubator at 22°C, and cool the incubator to 6°C at a rate of 2°C / h, until the crabs enter a dormant state. (3) Packaging: First, spread a sponge soaked with water on the bottom of the perforated packaging box, then place the dormant Chinese mitten crab on the sponge and seal the packaging box; (4) Live transportation: The packaging boxes are transported. The temperature for live transportation is 8°C, the transportation time is 15 days, and the survival rate of Chinese mitten crab is 91%.

[0020] Example 3 (1) Temporary culture: Tie the claws of the freshly caught Chinese mitten crab with ropes, place them in 26℃ clean water without feeding for 24 hours, and aerate continuously; (2) Gradient cooling: Place the live crabs in an incubator at 25°C, and cool the incubator to 9°C at a rate of 4°C / h, until the crabs enter a dormant state. (3) Packaging: First, spread a sponge soaked with water on the bottom of the perforated packaging box, then place the dormant Chinese mitten crab on the sponge and seal the packaging box; (4) Live transportation: The packaging boxes are transported. The temperature for live transportation is 9°C, the transportation time is 15 days, and the survival rate of Chinese mitten crab is 87%.

[0021] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that there is no gradient cooling step, and the cells are directly transported alive after temporary storage, the temperature is 7° C., and the time is 15 days. The other process steps are exactly the same.

[0022] Comparative Example 2 The difference between Comparative Example 1 and Example 1 is that there is no gradient cooling step, and the cells are directly transported alive after temporary storage at a temperature of 4° C. for 15 days, and the other process steps are exactly the same.

[0023] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the temperature is gradually lowered to 4°C, the temperature for transportation is 7°C, and the time is 15 days. The other process steps are exactly the same.

[0024] The partial transportation processes and the survival rates of crabs of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1: Table 1. Partial transportation process and crab survival rate of Examples 1-3 and Comparative Examples 1-3 As can be seen from Table 1, gradient cooling is crucial to the survival rate of Chinese mitten crabs during live transportation. Comparing Example 1 with Comparative Examples 1 and 2, it can be seen that without gradient cooling treatment, the survival rate of crabs will be reduced. This is because crabs are extremely sensitive to temperature; the death of live crabs during the logistics process is mostly due to the strong stress response caused by environmental changes. Using gradient cooling for crabs can effectively alleviate the stress response of crabs and avoid the phenomenon of crabs breaking their legs or even dying due to excessive temperature differences. Comparing Example 1 with Comparative Example 3, it can be seen that the gradient cooling treatment is not within the specific scope of the present invention, and the survival rate of crabs is also significantly reduced.

[0025] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A method for keeping Chinese mitten crab alive, characterized in that: The following steps are involved: (1) Temporary culture: tie the claws of the freshly caught Chinese mitten crab with ropes or rubber bands, place them in clean water without feeding, and aerate them continuously; (2) Gradient cooling: Place the Chinese mitten crabs in an incubator at 22-25°C and cool the incubator to 6-9°C at a cooling rate of 2-4°C / h, so that the crabs enter a dormant state. (3) Packaging: First, spread a sponge soaked with water on the bottom of the perforated packaging box, then place the dormant Chinese mitten crab on the sponge and seal the packaging box; (4) Transportation: The packaging boxes must be transported alive.

2. The method for keeping alive according to claim 1, characterized in that: In step (1), the temperature of the temporary water is 24-26°C.

3. The method for keeping alive according to claim 1, characterized in that: In step (1), the temporary holding time is 12 to 24 hours.

4. The method for keeping alive according to claim 1, characterized in that: In step (4), the temperature of the live transport is controlled at 7-9°C.

5. The method for keeping alive according to claim 1, characterized in that: In step (4), the time for live transport is 10 to 15 days.

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