阅读说明：本技术 一种亚临界鱼复合保活方法 (Subcritical fish composite keep-alive method ) 是由 张崟 母运龙 彭海川 李慧 钱琴 张应杰 刘文龙 白婷 于 2021-07-14 设计创作，主要内容包括：本发明公开了一种亚临界鱼复合保活方法,运输前将活鱼暂养1-5d；将鱼放入程序控温保活装置中,在水体中加入MS-222麻醉剂20-40mg/L,运输前按1-5℃/h的降温速率将水温从18-25℃调节至亚临界储藏温度1-4℃；并在运输过程中持续保持1-4℃；到达目的地后将鱼放入1-4℃养殖水中,养殖水按1-5℃/h的升温速率升温至18-25℃,结束保活。为了解决低温对鲫鱼的镇定效果较慢而且不够稳定,麻醉保活法使用较高浓度的麻醉剂存在休药期过长和有残留的问题。本发明用临界休眠温度结合较低浓度麻醉剂的保活方法,不仅能有效解决鱼类在运输过程中的高应激反应以及高死亡率,同时还能有效降低鱼肉中的血清乳酸浓度、血糖浓度,并显著提高鱼肉质构、持水性、核苷酸含量等食用品质。(The invention discloses a subcritical fish composite keep-alive method, which comprises the steps of temporarily culturing live fish for 1-5 days before transportation; putting the fish into a programmed temperature control and living device, adding 20-40mg/L of MS-222 anesthetic into a water body, and adjusting the water temperature from 18-25 ℃ to the subcritical storage temperature of 1-4 ℃ according to the cooling rate of 1-5 ℃/h before transportation; and continuously keeping the temperature of 1-4 ℃ in the transportation process; after the fish arrives at the destination, the fish is put into the aquaculture water with the temperature of 1-4 ℃, the temperature of the aquaculture water is raised to 18-25 ℃ according to the temperature raising rate of 1-5 ℃/h, and the survival is finished. In order to solve the problems that the low temperature has slow and unstable calming effect on crucian carps, and the anesthesia survival method uses anesthetic with higher concentration and has overlong drug withdrawal period and residue. The invention uses the critical dormancy temperature in combination with the keep-alive method of the anesthetic with lower concentration, which not only can effectively solve the high stress reaction and high death rate of the fish in the transportation process, but also can effectively reduce the serum lactic acid concentration and the blood sugar concentration in the fish meat, and obviously improve the eating quality of the fish meat structure, the water retention property, the nucleotide content and the like.)

1. A subcritical fish composite keep-alive method comprises the following steps:

(1) temporary culture: temporarily culturing the fishes in special temporary culture water before transportation;

(2) anesthesia: adding anesthetic into water, and placing fish into a program temperature control and survival device;

(3) controlling temperature by program: before transportation, the water temperature is gradually reduced to the subcritical storage temperature, and the subcritical storage temperature is transported at constant temperature;

(4) and (4) awakening: and after the fish reaches the destination, putting the fish into culture water, heating to 18-25 ℃, and finishing keeping alive.

2. A subcritical fish composite keep-alive method according to claim 1, wherein:

the temporary rearing time in the step (1) is 1-5 days before transportation.

3. A subcritical fish composite keep-alive method according to claim 1, wherein:

the special temporary culture water in the step (1) is prepared by the following method:

filtering and continuously aerating tap water to obtain standby water;

and adding vitamin C with the concentration of 20-30mg/L into the prepared water to obtain the special temporary culture water.

4. A subcritical fish composite keep-alive method according to claim 3, wherein:

the filtration is carried out by adopting granular activated carbon;

the continuous aeration time is 24-48 h.

5. A subcritical fish composite keep-alive method according to claim 1 or 3, wherein:

the water temperature of the temporary culture water is 18-25 ℃, the dissolved oxygen amount is 4-6mg/L, and the pH value is 7.2-7.8.

6. A subcritical fish composite keep-alive method according to claim 5, wherein:

the pH value is measured every 3-6 h.

7. A subcritical fish composite keep-alive method according to claim 1, wherein:

the anesthetic type in the step (2) is MS-222 anesthetic, and the concentration of the anesthetic is 20-40 mg/L.

8. A subcritical fish composite keep-alive method according to claim 1, wherein:

the water temperature before transportation in the step (3) is 18-25 ℃, the cooling rate is 1-5 ℃/h, and the subcritical storage temperature is 1-4 ℃.

9. A subcritical fish composite keep-alive method according to claim 1, wherein:

the water temperature of the aquaculture water in the step (4) is 1-4 ℃, and the heating rate is 1-5 ℃/h.

10. A fish obtained by the subcritical fish composite keep-alive method according to any one of claims 1-9.

Technical Field

The invention relates to the field of aquatic product transportation, in particular to a subcritical fish composite keep-alive method.

Background

Crucian carp is one of the most common freshwater fishes in China, and is mainly a omnivorous fish taking plants as food, prefers to be gathered and grown, and prefers to be eaten and grown. The meat quality is tender, the nutritive value is high, each hundred grams of meat contains 13 grams of protein and 11 grams of fat, and contains a large amount of minerals such as calcium, phosphorus, iron and the like. The crucian has high medicinal value, is neutral in nature and sweet in taste, enters the stomach and the kidney, and has the effects of regulating the middle warmer, tonifying deficiency, removing food, warming the stomach, eating, tonifying the middle warmer and generating qi. Therefore, the crucian carp is deeply favored by consumers and has higher market value and consumption demand.

China is a large country for fish production and consumption, but the regional distribution of the fish farming industry is unbalanced, so that the fish resources in China need to meet the market demand through long-distance transportation. In the transportation process of the fishes, dealers mostly adopt a high-density loading mode so as to achieve the effects of reducing the transportation cost and improving the transportation volume. High-density transportation of live fish, if the transportation conditions are not properly controlled, causes nearly 10% of live fish to die after arriving at the destination, and seriously affects fish trade and cost control. In addition, the transport and storage conditions of the fish also have an important influence on the eating quality of the fish, and the eating quality of the live fish is generally superior to that of dead fish. Therefore, the research and development of technologies for keeping alive and reducing the death rate in the fish transportation process become the key for promoting the fish trade development. The most used keep-alive methods at present are a low-temperature keep-alive method and an anesthesia keep-alive method, but the low temperature has slow and unstable stabilization effect on crucian, and the anesthesia keep-alive method using an anesthetic with higher concentration has the problems of too long drug withdrawal period and residue. Therefore, the method of inducing the crucian to sleep by combining the critical dormancy temperature with the anesthetic is used for the keep-alive transportation.

Based on the analysis, in order to solve the problems that the low temperature has slow and unstable stabilizing effect on crucian, the anesthesia survival method uses anesthetic with higher concentration and has overlong drug withdrawal period and residue. Therefore, the survival method of the invention by combining the critical dormancy temperature with the anesthetic with lower concentration not only can effectively solve the high stress reaction and high mortality rate of the fishes in the transportation process, but also can effectively reduce the serum lactic acid concentration and the blood sugar concentration in the fish meat, and obviously improve the eating quality of the fish meat structure, the water holding capacity, the nucleotide content and the like.

Disclosure of Invention

In view of the defects, the invention aims to solve the problems that the low temperature has slow and unstable calming effect on crucian carps, and the anesthesia survival method uses high-concentration anesthetic with overlong drug withdrawal period and residue.

The invention is realized by the following technical scheme:

a subcritical fish composite keep-alive method comprises the following steps:

(1) temporary culture: temporarily culturing the fishes in special temporary culture water before transportation;

(2) anesthesia: adding anesthetic into water, and placing fish into a program temperature control and survival device;

(3) controlling temperature by program: before transportation, the water temperature is gradually reduced to the subcritical storage temperature, and the subcritical storage temperature is transported at constant temperature;

(4) and (4) awakening: and after the fish reaches the destination, putting the fish into culture water, heating to 18-25 ℃, and finishing keeping alive.

Further, the temporary rearing time in the step (1) is 1-5 days before transportation.

Further, the special temporary rearing water in the step (1) is prepared by the following method:

filtering and continuously aerating tap water to obtain standby water;

and adding vitamin C with the concentration of 20-30mg/L into the prepared water to obtain the special temporary culture water.

Further, the filtration is carried out by adopting granular activated carbon; the continuous aeration time is 24-48 h.

Furthermore, the water temperature of the temporary culture water is 18-25 ℃, the dissolved oxygen amount is 4-6mg/L, and the pH value is 7.2-7.8.

Further, the pH value is measured every 3-6 h.

Further, the anesthetic type in the step (2) is MS-222 anesthetic, and the concentration of the anesthetic is 20-40 mg/L.

Further, the water temperature before transportation in the step (3) is 18-25 ℃, the cooling rate is 1-5 ℃/h, and the subcritical storage temperature is 1-4 ℃.

Further, the water temperature of the aquaculture water in the step (4) is 1-4 ℃, and the heating rate is 1-5 ℃/h.

The invention also discloses fish obtained by any one of the subcritical fish compound keep-alive methods.

The invention has the beneficial effects that:

in order to solve the problems that the low temperature has slow and unstable calming effect on crucian carps, and the anesthesia survival method uses anesthetic with higher concentration and has overlong drug withdrawal period and residue. The invention firstly uses special temporary culture water to temporarily feed the fishes before the fishes are transported, simultaneously adds 20-40mg/L MS-222 anesthetic into the water, and carries out compound keep-alive treatment by combining the critical dormancy temperature of 1-4 ℃, thereby not only effectively solving the high stress reaction and high death rate of the fishes during the transportation process, but also effectively reducing the serum lactic acid concentration and the blood sugar concentration in the fish meat, and obviously improving the eating quality of the fish meat structure, the water holding capacity, the nucleotide content and the like.

Drawings

Fig. 1 shows the breathing rate of crucian at different temperatures and the breathing rate at different times;

FIG. 2 shows the pH values of the effluent of each set of examples and comparative examples.

Detailed Description

In order to make the operational procedures and the creative features of the implementation of the invention easy to understand, the invention is further explained below by combining the specific embodiments.

Example 1

A subcritical fish composite keep-alive method comprises the following specific operation steps:

(1) temporary culture: temporarily culturing for 2 days before transportation, adding vitamin C into the temporary culture pond, wherein the concentration is 25mg/L, the water temperature is 20 ℃, and the water for temporary culture: continuously aerating tap water filtered by granular activated carbon for 24 hours for experiment; the temperature of the temporary culture water is 20 ℃, the dissolved oxygen is 5mg/L, and the pH value is 7.5;

(2) anesthesia: adding 30mg/L MS-222 anesthetic into the water body, and putting the fish into a program temperature control and survival device;

(3) temperature regulation of the program temperature control keep-alive device: before transportation, the water temperature of the program temperature-control live-keeping device for the live fish is adjusted from 20 ℃ to the subcritical storage temperature of 1.6 ℃ according to the cooling rate of firstly 5 ℃/h and then 1 ℃/h;

(4) and (3) transportation: placing the program temperature control keep-alive device on a cold chain transport vehicle for transportation, wherein the program temperature control device keeps the required temperature of 1.6 ℃ in the transportation process;

(5) and (4) awakening: taking out the fish after the fish arrives at the destination, and putting the fish into culture water with the water temperature of 1.6 ℃; the temperature rise rate of the culture water is firstly 1 ℃/h and then 5 ℃/h; raising the temperature of the culture water to 20 ℃ and finishing.

Example 2

A subcritical fish composite keep-alive method comprises the following specific operation steps:

(1) temporary culture: temporarily culturing for 2 days before transportation, adding vitamin C into the temporary culture pond, wherein the concentration is 25mg/L, the water temperature is 20 ℃, and the water for temporary culture: continuously aerating tap water filtered by granular activated carbon for 24 hours for experiment; the temperature of the temporary culture water is 20 ℃, the dissolved oxygen is 4mg/L, and the pH value is 7.2;

(2) anesthesia: adding 30mg/L MS-222 anesthetic into the water body, and putting the fish into a program temperature control and survival device;

(3) temperature regulation of the program temperature control keep-alive device: before transportation, the water temperature of the program temperature-control live-keeping device for the live fish is adjusted from 20 ℃ to the subcritical storage temperature of 1.6 ℃ according to the cooling rate of firstly 3 ℃/h and then 1 ℃/h;

(4) and (3) transportation: placing the program temperature control keep-alive device on a cold chain transport vehicle for transportation, wherein the program temperature control device keeps the required temperature of 1.6 ℃ in the transportation process;

(5) and (4) awakening: taking out the fish after the fish arrives at the destination, and putting the fish into culture water with the water temperature of 1.6 ℃; the temperature rise rate of the culture water is 1 ℃/h firstly and then 3 ℃/h later; raising the temperature of the culture water to 20 ℃ and finishing.

Example 3

A subcritical fish composite keep-alive method comprises the following specific operation steps:

(1) temporary culture: temporarily culturing for 2 days before transportation, adding vitamin C into the temporary culture pond, wherein the concentration is 25mg/L, the water temperature is 20 ℃, and the water for temporary culture: continuously aerating tap water filtered by granular activated carbon for 24 hours for experiment; the temperature of the temporary culture water is 20 ℃, the dissolved oxygen is 6mg/L, and the pH value is 7.5;

(2) anesthesia: adding 30mg/L MS-222 anesthetic into the water body, and putting the fish into a program temperature control and survival device;

(3) temperature regulation of the program temperature control keep-alive device: before transportation, the water temperature of the program temperature-control live-keeping device for the live fish is adjusted from 20 ℃ to the subcritical storage temperature of 1.6 ℃ according to the cooling rate of firstly 2 ℃/h and then 1 ℃/h;

(4) and (3) transportation: placing the program temperature control keep-alive device on a cold chain transport vehicle for transportation, wherein the program temperature control device keeps the required temperature of 1.6 ℃ in the transportation process;

(5) and (4) awakening: taking out the fish after the fish arrives at the destination, and putting the fish into culture water with the water temperature of 1.6 ℃; the temperature rise rate of the culture water is 1 ℃/h firstly and then 2 ℃/h later; raising the temperature of the culture water to 20 ℃ and finishing.

Example 4

A subcritical fish composite keep-alive method comprises the following specific operation steps:

(1) temporary culture: temporarily culturing for 2 days before transportation, adding vitamin C into the temporary culture pond, wherein the concentration is 25mg/L, the water temperature is 20 ℃, and the water for temporary culture: continuously aerating tap water filtered by granular activated carbon for 24 hours for experiment; the temperature of the temporary culture water is 20 ℃, the dissolved oxygen is 5mg/L, and the pH value is 7.7;

(2) anesthesia: adding 20mg/L MS-222 anesthetic into water, and placing the fish into a program temperature control and survival device;

(3) temperature regulation of the program temperature control keep-alive device: before transportation, the water temperature of the program temperature-control live-keeping device for the live fish is adjusted from 20 ℃ to the subcritical storage temperature of 1.6 ℃ according to the cooling rate of firstly 2 ℃/h and then 1 ℃/h;

(4) and (3) transportation: placing the program temperature control keep-alive device on a cold chain transport vehicle for transportation, wherein the program temperature control device keeps the required temperature of 1.6 ℃ in the transportation process;

(5) and (4) awakening: taking out the fish after the fish arrives at the destination, and putting the fish into culture water with the water temperature of 1.6 ℃; the temperature rise rate of the culture water is 1 ℃/h firstly and then 2 ℃/h later; raising the temperature of the culture water to 20 ℃ and finishing.

Example 5

A subcritical fish composite keep-alive method comprises the following specific operation steps:

(1) temporary culture: temporarily culturing for 2 days before transportation, adding vitamin C into the temporary culture pond, wherein the concentration is 25mg/L, the water temperature is 20 ℃, and the water for temporary culture: continuously aerating tap water filtered by granular activated carbon for 24 hours for experiment; the temperature of the temporary culture water is 20 ℃, the dissolved oxygen is 4.5mg/L, and the pH value is 7.6;

(2) anesthesia: adding 40mg/L MS-222 anesthetic into the water body, and putting the fish into a program temperature control and survival device;

(3) temperature regulation of the program temperature control keep-alive device: before transportation, the water temperature of the program temperature-control live-keeping device for the live fish is adjusted from 20 ℃ to the subcritical storage temperature of 1.6 ℃ according to the cooling rate of firstly 2 ℃/h and then 1 ℃/h;

(4) and (3) transportation: placing the program temperature control keep-alive device on a cold chain transport vehicle for transportation, wherein the program temperature control device keeps the required temperature of 1.6 ℃ in the transportation process;

(5) and (4) awakening: taking out the fish after the fish arrives at the destination, and putting the fish into culture water with the water temperature of 1.6 ℃; the temperature rise rate of the culture water is 1 ℃/h firstly and then 2 ℃/h later; raising the temperature of the culture water to 20 ℃ and finishing.

Comparative example 1

Compared with the embodiment 3, the temporary culture water is not professionally treated, and the rest of the operation is the same as the embodiment 3, and the specific steps are as follows:

(1) temporary culture: temporary culture for 2d before transportation, temporary culture water: continuously aerating tap water filtered by granular activated carbon for 24 hours for experiment; the temperature of the temporary culture water is 20 ℃, and the dissolved oxygen is 6 mg/L;

(2) anesthesia: adding 30mg/L MS-222 anesthetic into the water body, and putting the fish into a program temperature control and survival device;

(3) temperature regulation of the program temperature control keep-alive device: before transportation, the water temperature of the program temperature-control live-keeping device for the live fish is adjusted from 20 ℃ to the subcritical storage temperature of 1.6 ℃ according to the cooling rate of firstly 2 ℃/h and then 1 ℃/h;

(4) and (3) transportation: placing the program temperature control keep-alive device on a cold chain transport vehicle for transportation, wherein the program temperature control device keeps the required temperature of 1.6 ℃ in the transportation process;

(5) and (4) awakening: taking out the fish after the fish arrives at the destination, and putting the fish into culture water with the water temperature of 1.6 ℃; the temperature rise rate of the culture water is 1 ℃/h firstly and then 2 ℃/h later; raising the temperature of the culture water to 20 ℃ and finishing.

Comparative example 2

Compared with the example 3, the operation is the same as the example 3 except that the fish is not anesthetized, and the following concrete steps are carried out:

(1) temporary culture: temporarily culturing for 2 days before transportation, adding vitamin C into the temporary culture pond, wherein the concentration is 25mg/L, the water temperature is 20 ℃, and the water for temporary culture: continuously aerating tap water filtered by granular activated carbon for 24 hours for experiment; the temperature of the temporary culture water is 20 ℃, the dissolved oxygen is 6mg/L, and the pH value is 7.5;

(2) temperature regulation of the program temperature control keep-alive device: before transportation, the water temperature of the program temperature-control live-keeping device for the live fish is adjusted from 20 ℃ to the subcritical storage temperature of 1.6 ℃ according to the cooling rate of firstly 2 ℃/h and then 1 ℃/h;

(3) and (3) transportation: placing the program temperature control keep-alive device on a cold chain transport vehicle for transportation, wherein the program temperature control device keeps the required temperature of 1.6 ℃ in the transportation process;

(4) and (4) awakening: taking out the fish after the fish arrives at the destination, and putting the fish into culture water with the water temperature of 1.6 ℃; the temperature rise rate of the culture water is 1 ℃/h firstly and then 2 ℃/h later; raising the temperature of the culture water to 20 ℃ and finishing.

Comparative example 3

Compared with the embodiment 3, the program temperature control, keep-alive and temperature regulation treatment is not carried out on the fishes, and the rest of the operation is the same as the embodiment 3, which specifically comprises the following steps:

the subcritical keep-alive storage temperature has great influence on keep-alive. When the keep-alive transportation temperature of the crucian is maintained at the subcritical storage temperature, the keep-alive time can be prolonged to the maximum extent, the stress response is reduced, and the fish meat eating quality is improved. To determine the optimum temperature of the crucian during transportation, we monitored the breathing rate of the crucian at 1-20 ℃. As shown in fig. 1, the breathing times of the crucian carp in one hour are recorded at each temperature, and the time for the crucian carp to adapt to the water temperature at each temperature can be obtained by recording every 10 min. In conclusion, the time for the crucian to adapt to the water temperature is 40 min.

As can be seen from fig. 1, when the temperature is in the range of 1-2 ℃, the crucian is in a calm state and the respiratory frequency is below 20 times/min. The lowest breathing rate of crucian when the temperature reached 1.6 ℃, i.e., the subcritical storage temperature was 1.6 ℃, so the transport temperature set in this comparative example was 1.6 ℃.

(1) Determination of subcritical storage temperature: cooling the fish placed in the program temperature control keep-alive device at a cooling rate of 5 ℃/h and then 1 ℃/h, and determining the subcritical storage temperature of the fish to be 1.6 ℃ according to the respiratory state and the physiological state of the fish;

(2) temporary culture: temporarily culturing for 2 days before transportation, adding vitamin C into the temporary culture pond with concentration of 25mg/L and water temperature of 20 deg.C, and testing pH value every 3 hr. Temporary culture water: continuously aerating tap water filtered by granular activated carbon for 24 hours for experiment; the temperature of the temporary culture water is 20 ℃, the dissolved oxygen is 6mg/L, and the pH value is 7.5;

(3) anesthesia: adding 30mg/L MS-222 anesthetic into the water body, and putting the fish into a program temperature control and survival device;

(4) and (3) transportation: transporting at normal temperature of 18-25 deg.C;

(5) and (4) awakening: and taking out the fish after the fish arrives at the destination, and putting the fish into the aquaculture water.

Test example 1

The pH values of the temporary culture water of each group of examples and comparative examples were monitored

The concentration of vitamin C determines the pH value of the temporary water, and the pH value is too high or too low, so that the fish body is not adaptive and the stress response is strong. As can be seen from FIG. 2, comparative example 1, which had a lower pH than the other groups due to the absence of vitamin C, further demonstrated that fish survival was not facilitated at a pH < 7. Therefore, the concentration of the vitamin C in the temporary culture water is adjusted to be 20-30mg/L according to the pH range of 7.2-7.8.

Test example 2

Monitoring blood index and tissue index of crucian in each group of examples and comparative examples

In the process of compound keep-alive transportation, the concentration of lactic acid and blood sugar in the crucian serum can reflect the stress reaction degree of the crucian. The content of blood sugar can be increased in the whole keep-alive process, and as can be seen from table 1, the blood sugar value is reduced after the keep-alive process disclosed by the invention is used, so that the transport stress of crucian carp is reduced. Lactic acid is a product of glucose glycolysis under anaerobic conditions to provide energy, most of the lactic acid produced by muscle enters blood, and the increase of the content of lactic acid affects the oxygen transport capacity of hemoglobin in blood, so that the maximum oxygen binding capacity of blood is reduced. The content of lactic acid is obviously reduced after the keep-alive process is used, and the keep-alive transportation is facilitated. The water retention capacity refers to the capacity of keeping original water content when the muscle is under the action of external force, is influenced by the deformation and degradation of the structure of myofibrillar protein, and the water retention capacity can influence the tenderness, juiciness, nutritional ingredients, taste and the like of the meat, so that the water retention capacity is a simple and convenient index for measuring the change condition of the fish meat quality. After the keep-alive process is used, the water retention is improved.

TABLE 1 comparison of blood index and tissue index of each group of crucian carp

。

Test example 3

Monitoring fish texture of each group of crucian carps in examples and comparative examples

The fish meat quality is an important index for measuring the change of the fish meat tissue characteristics and reflecting the fish meat quality. The texture parameters mainly investigated in this test are hardness, cohesiveness, chewiness, elasticity and cohesiveness. As can be seen from table 2, comparative example 3, which was not subjected to the gradient cooling treatment, had significantly reduced fish meat hardness, chewiness and elasticity as compared with the other groups, and comparative example 2, which was not subjected to the anesthetic treatment, had significantly reduced fish meat hardness, chewiness and elasticity as compared with the examples.

TABLE 2 comparison of meat texture of crucian carp in each group

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Test example 4

Monitoring nucleotide indexes of various groups of crucian carps in examples and comparative examples

In aquatic products, disodium 5 ' -Adenylate (AMP), disodium 5 ' -Cytidylate (CMP), disodium 5 ' -Inosinate (IMP), disodium 5 ' -Guanylate (GMP) and disodium 5 ' -Uridylate (UMP) play a strong umami role and also determine the mouthfeel, flavor and freshness of meat products. The flavor-developing nucleotide compound has rich content in aquatic products, not only has remarkable freshness-increasing effect, but also has certain increase and decrease effect on various flavors of the aquatic products. As can be seen from Table 3, the test method can keep the contents of AMP and IMP which are main components of crucian at high levels, and can improve the water retention property and meat texture of crucian.

TABLE 3 nucleotide comparison of various groups of crucian carps

。

According to the indexes, the blood indexes and the tissue indexes of the crucian after being transported for five days show that the temperature reduction rate and the temperature rise rate have great influence on the keeping alive and the relative influence on the anesthetic concentration is small. Therefore, in the keep-alive process, attention should be paid to effective control of the cooling rate. The temperature reduction rate and the temperature rise rate have great influence on the keep-alive. The slower the cooling rate and the heating rate, the better the keep-alive effect of the fish body. However, due to the excessively slow cooling rate and heating rate, the keep-alive transportation time is too long, so that the investment time in the production process of enterprises is too long, and therefore, it is very important to reasonably select the appropriate cooling rate and heating rate. The temperature reduction rate is 1-5 ℃/h, the temperature rise rate is 1-5 ℃/h, namely, the rate of 2-5 ℃/h is adopted in the temperature range of 20-6 ℃, and the rate of l ℃/h is adopted in the temperature range of 6-1.6 ℃, so that a good keep-alive transportation effect can be obtained. The concentration of the anesthetic is also influential, when the concentration of the anesthetic is less than 20mg/L, the anesthetic effect is small, the fish body is greatly stimulated, the stress response is aggravated, and the survival is not facilitated. When the concentration of the anesthetic is more than 40mg/L, the anesthetic effect is too strong, the crucian can enter a deep anesthetic state and can not perform normal physiological activities, and the keep-alive rate is reduced. Experiments show that when the proper concentration of the anesthetic MS-222 is 20-40mg/L, the anesthetic effect is most proper, and the crucian can enter a deep calm state and can keep normal physiological activities.

After the crucian carp is treated by the keep-alive method, the blood sugar and lactic acid concentration of the crucian carp can be effectively reduced, the stress reaction of the crucian carp is reduced, the normal physiological state of the crucian carp is maintained, and the fish texture, the water holding capacity and the nucleotide content of the crucian carp can be improved to a certain extent. The invention has high survival rate after the live-keeping transportation and can greatly reduce the transportation cost. Therefore, the method has important significance for keep-alive transportation.

The above embodiments are illustrative of the principles of the present invention and its efficacy, and are not to be construed as limiting the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.