A method for improving the high temperature tolerance of prawns in aquaculture

Abstract

The application provides a breeding method for improving high-temperature tolerance of prawns, which comprises feeding a physical strength enhancer before high-temperature stress, wherein the physical strength enhancer comprises the following components: sea moss extract, tannic acid and astragaloside IV; the temperature is raised at a temperature raising rate of 0.5-2 DEG C per 10-14 hours, and one high-temperature stress is performed by continuously raising the temperature for 2-4 days; and the high-temperature stress is performed for 5-10 times in total during the breeding. The sea moss extract, tannic acid and astragaloside IV are used to prepare the physical strength enhancer before high-temperature stress, and the breeding method combining the high-temperature stress with a specific temperature raising rate is helpful to improve the resistance and tolerance of prawns to high-temperature environmental changes, and to improve the survival rate of prawns, and the average survival rate of prawns is more than 90%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of prawn culture, in particular to a culture method for improving high-temperature tolerance of prawn. BACKGROUND

[0002] Prawn (Penaeus orientalis), also known as Chinese prawn (Fenneropenaeus chinensis), has delicious meat and fast growth, and is an important prawn species for culture in China. Water temperature is one of the main factors affecting prawn behavior, metabolism, growth, and immune response, and other life activities. In tropical regions, and under the background of global warming, the water temperature suitable for the survival of prawn will be affected by high-temperature stress. In recent years, with the change of climate, the weather with extremely high temperature in summer shows a gradually increasing trend, and the duration of the weather is also prolonged, which causes serious damage to the culture of prawn and causes economic losses. Therefore, improving the tolerance of prawn to high temperature is one of the problems to be solved at present and is also one of the research focuses. SUMMARY

[0003] In view of this, the purpose of the present application is to provide a culture method for improving high-temperature tolerance of prawn, which solves the above problems.

[0004] The technical scheme of the present application is implemented as follows:

[0005] The culture method for improving high-temperature tolerance of prawn comprises feeding a physical strength enhancer before high-temperature stress, and the components of the physical strength enhancer comprise Gloiopeltis furcata extract, tannic acid, and astragaloside IV.

[0006] The Gloiopeltis furcata extract, tannic acid, and astragaloside IV can meet the demand of prawn body for high energy consumption required for maintaining environmental changes under high-temperature conditions, help maintain the normal physiological metabolism balance of prawn, and ensure the operation of various functions of the body.

[0007] The temperature is raised at a rate of 0.5-2℃ per 10-14h, and one high-temperature stress is performed by continuously raising the temperature for 2-5d, and 5-10 times of high-temperature stress are performed during culture.

[0008] Preferably, the components of the physical strength enhancer comprise 40-60 parts of Gloiopeltis furcata extract, 25-35 parts of tannic acid, and 12-25 parts of astragaloside IV by weight.

[0009] Preferably, the preparation method of the Gloiopeltis furcata extract comprises the following steps: drying and crushing Gloiopeltis furcata, adding distilled water, water bath oscillation, adding enzyme solution, water bath enzymolysis, centrifugation after enzyme inactivation, taking supernatant, concentration, and obtaining Gloiopeltis furcata extract.

[0010] More preferably, the ratio of sea tangle and distilled water is 1g:20-30mL, and the amount of enzyme solution added is 0.8-1.2wt% of the weight of sea tangle and distilled water; the enzyme solution is papain and cellulase, and the mass ratio of papain and cellulase is 1-2:1-2.

[0011] More preferably, the conditions of water bath oscillation are: temperature 40-50℃, oscillation frequency 200-400rpm, and time 2-3h; and the conditions of water bath enzymolysis are: temperature 40-50℃, and time 1-2h.

[0012] Preferably, the physical strength enhancer is continuously fed to the prawns 3-4 days before high temperature stress.

[0013] More preferably, the daily feeding amount of the physical strength enhancer is 30-100g / 10,000 prawns.

[0014] More preferably, when the prawn larvae are less than 2cm in length, the feeding amount of the physical strength enhancer is 30-50g / 10,000 prawns, and when the prawn larvae are more than 2cm in length, the feeding amount of the physical strength enhancer is 80-100g / 10,000 prawns.

[0015] Preferably, when the prawn larvae are less than 3cm in length, the temperature is raised at a rate of 0.5℃ per 10-14h, and the temperature is raised for 4 days as one high temperature stress; when the prawn larvae are 4-6cm in length, the temperature is raised at a rate of 1℃ per 10-14h, and the temperature is raised for 5 days as one high temperature stress; and when the prawn larvae are more than 8cm in length, the temperature is raised at a rate of 2℃ per 10-14h, and the temperature is raised for 3 days as one high temperature stress.

[0016] Preferably, the initial temperature of cultivation is 23-24℃, and after one high temperature stress is completed, the temperature is stopped from rising, and the water temperature is naturally decreased until the initial temperature 23-24℃ is restored.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] The present application selects sea tangle extract, tannic acid and astragaloside to prepare the physical strength enhancer before high temperature stress, which helps to improve the resistance and tolerance of prawns to high temperature environmental changes, and improves the survival rate of prawns, and the average survival rate of prawns reaches more than 90%.

[0019] In addition, through the cultivation mode of step-by-step high temperature stress, the activities of intestinal lipase and trypsin of prawns are improved to different degrees, and the prawns will be more advantageous in subsequent growth and development, reproduction and quality. DETAILED DESCRIPTION

[0020] In order to better understand the technical content of the present application, the following specific examples are provided to further illustrate the present application.

[0021] The experimental methods used in the embodiments of the present application are all conventional methods unless otherwise specified.

[0022] The materials, reagents, etc. used in the embodiments of the present application can be obtained from commercial channels unless otherwise specified.

[0023] Example 1

[0024] The preparation method of the sea moss extract 1 is as follows: the sea moss is dried, crushed and passed through a 60-mesh sieve, then 1 g of the crushed sea moss is added to 25 mL of distilled water according to a solid-liquid ratio of 1 g:25 mL, and the mixture is subjected to water bath oscillation extraction at 45°C with a shaking frequency of 300 rpm for 3 h, then 1 wt% of enzyme solution (papain and cellulase in a mass ratio of 1:1) is added, the oscillation is stopped, and the mixture is subjected to enzymolysis in a water bath at 45°C for 2 h, after which the enzyme is inactivated, the mixture is centrifuged at 4000 rpm for 10 min, the supernatant is taken, and the sea moss extract 1 is obtained after concentration.

[0025] The preparation method of the sea moss extract 2 is as follows: the sea moss is dried, crushed and passed through a 60-mesh sieve, then 1 g of the crushed sea moss is added to 25 mL of distilled water according to a solid-liquid ratio of 1 g:25 mL, and the mixture is subjected to water bath oscillation extraction at 45°C with a shaking frequency of 300 rpm for 3 h, then 1 wt% of enzyme solution (papain and cellulase in a mass ratio of 1:2) is added, the oscillation is stopped, and the mixture is subjected to enzymolysis in a water bath at 45°C for 2 h, after which the enzyme is inactivated, the mixture is centrifuged at 4000 rpm for 10 min, the supernatant is taken, and the sea moss extract 2 is obtained after concentration.

[0026] The preparation method of the sea moss extract 3 is as follows: the sea moss is dried, crushed and passed through a 60-mesh sieve, then 1 g of the crushed sea moss is added to 20 mL of distilled water according to a solid-liquid ratio of 1 g:20 mL, and the mixture is subjected to water bath oscillation extraction at 45°C with a shaking frequency of 300 rpm for 3 h, then 0.8 wt% of enzyme solution (papain and cellulase in a mass ratio of 2:1) is added, the oscillation is stopped, and the mixture is subjected to enzymolysis in a water bath at 45°C for 2 h, after which the enzyme is inactivated, the mixture is centrifuged at 4000 rpm for 10 min, the supernatant is taken, and the sea moss extract 3 is obtained after concentration.

[0027] Example 2

[0028] The prawn seedlings are placed in a clean and disinfected indoor aquaculture pond, and filtered seawater is used for aquaculture. The water temperature for aquaculture is adjusted to 23-24°C, the pH value is 7.5±0.1, the ammonia nitrogen is ≤0.1 mg / L, the nitrite is ≤0.005 mg / L, and the dissolved oxygen is ≥5.0 mg / L. The prawn feed (Tangshan Jin Fengshou Feed Co., Ltd.) is used for daily feeding, and the formula of the physical strength enhancer is as follows:

[0029] Table 1 Formula of the physical strength enhancer

[0030] Components (parts by weight) Hizikia fusiformis extract 1 Hizikia fusiformis powder Tannic acid Astragalus glycoside Herbal powder Body strength enhancer 1 52 - 30 17 - Body strength enhancer 2 60 - 25 12 - Body strength enhancer 3 40 - 35 25 - Body strength enhancer 4 - 52 30 17 - Body strength enhancer 5 - - 30 17 52 Body strength enhancer 6 20 - 30 - 52

[0031] Note: The sea algae powder is obtained by drying sea algae, crushing and passing through 60 mesh; the herbal medicine powder is obtained by mixing Astragalus, honeysuckle and radix isatidis at a mass ratio of 1:1:1, and then crushing.

[0032] The feeding method of the constitution enhancer is as follows: 3 days before the high temperature stress, the constitution enhancer is continuously fed, and when the body length of the shrimp seedlings is less than 2 cm, the feeding amount of the constitution enhancer is 30-50 g / 10,000 shrimps, and when the body length of the shrimp seedlings is greater than 2 cm, the feeding amount of the constitution enhancer is 80-100 g / 10,000 shrimps.

[0033] The breeding method for improving the high temperature tolerance of prawns is as follows: the water temperature is continuously increased at a rate of 1 °C per 12 h for 5 days, and then the water temperature is naturally decreased until the initial temperature of 23-24 °C is restored after the water temperature reaches 33-34 °C, and the continuous temperature increase for 5 days is one high temperature stress, and the high temperature stress is performed 6, 8 and 10 times during the breeding.

[0034] Table 2 Survival of prawns under different constitution enhancer formulations

[0035]

[0036] As shown in the above table, the average survival rate of prawns in the constitution enhancer 1 and 2 groups is more than 90% during the 6, 8 and 10 times of high temperature stress, and the average survival rate of prawns in the constitution enhancer 3 group is more than 93% during the 6 and 8 times of high temperature stress. The average survival rate of prawns in the constitution enhancer 4-6 groups is less than 90%. The use of sea algae extract, tannic acid and astragaloside for preparing the constitution enhancer before the high temperature stress helps to improve the resistance and tolerance of prawns to environmental changes under high temperature conditions, and to improve the survival rate of prawns. The use of sea algae extract, tannic acid and astragaloside can meet the high energy consumption demand of prawn body for maintaining environmental changes under high temperature conditions, and helps to maintain the normal physiological metabolism balance of prawns and ensure the operation of various functions of the prawn body.

[0037] Example 3

[0038] The breeding method for improving the high temperature tolerance of prawns is adjusted as follows:

[0039] When the body length of the shrimp seedlings is less than 3 cm, the water temperature is continuously increased at a rate of 0.5 °C per 12 h for 4 days, and then the water temperature is naturally decreased until the initial temperature of 23-24 °C is restored after the water temperature reaches 27-28 °C, and the high temperature stress is performed 2 times.

[0040] When the body length of the shrimp seed is 4-6 cm, the water temperature is raised at a rate of 1 DEG C per 12 hours for 5 days, reaches 33-34 DEG C, then stops raising the temperature, and the water temperature is naturally decreased until the initial temperature of 23-24 DEG C is recovered, and the high temperature stress is performed for 3 times;

[0041] When the body length of the shrimp seed is greater than 8 cm, the water temperature is raised at a rate of 2 DEG C per 12 hours for 3 days, reaches 35-36 DEG C, then stops raising the temperature, and the water temperature is naturally decreased until the initial temperature of 23-24 DEG C is recovered, and the high temperature stress is performed for 3 times.

[0042] At the end of the experiment, 100 shrimps are randomly selected, the intestinal tracts are collected, and PBS is added for homogenization, 8 min of centrifugation at 10,000 rpm and 4 DEG C is performed, and the enzyme activity is determined by using a kit of Nanjing Jiancheng Biological Engineering Research Co., Ltd.

[0043] Table 3 Enzyme activity of shrimps under different high temperature stress modes

[0044]

[0045] Note: Body strength enhancers 1 and 6 are high temperature stress modes of example 2, and both are 8 times of high temperature stress.

[0046] As shown in the above table, the step-by-step high temperature stress improves the activities of intestinal lipase and trypsin, and the shrimps decompose macromolecular nutrients into small molecular substances through the digestion and decomposition of protease, lipase, amylase and sucrase, and the improvement of the activities of intestinal digestive enzymes indicates the improvement of the digestion capacity of shrimps, and the shrimps will be more superior in growth and development and product quality.

[0047] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for improving the high temperature tolerance of shrimp in aquaculture, characterized by, The constitution enhancer comprises sea tangle extract, tannic acid and astragalus glycoside, and is fed before high temperature stress. The temperature is raised by 0.5-2 ℃ per 10-14 h, and the temperature is kept rising for 2-5 days as one high temperature stress, and the high temperature stress is performed 5-10 times during the cultivation. When the body length of the shrimp seedlings is less than 3 cm, the temperature is raised by 0.5 ℃ per 10-14 h, and the temperature is kept rising for 4 days as one high temperature stress; when the body length of the shrimp seedlings is 4-6 cm, the temperature is raised by 1 ℃ per 10-14 h, and the temperature is kept rising for 5 days as one high temperature stress; when the body length of the shrimp seedlings is more than 8 cm, the temperature is raised by 2 ℃ per 10-14 h, and the temperature is kept rising for 3 days as one high temperature stress. The initial temperature is 23-24 ℃, and after one high temperature stress, the temperature is kept constant, and the temperature is naturally decreased until the initial temperature 23-24 ℃ is recovered. The constitution enhancer comprises sea tangle extract, tannic acid and astragalus glycoside, and is fed before high temperature stress. The preparation method of the sea tangle extract comprises the following steps: drying and crushing sea tangle, adding distilled water, water bath oscillation, adding enzyme solution, water bath enzymolysis, centrifugation, taking supernatant, concentration, and obtaining sea tangle extract. The ratio of sea tangle to distilled water is 1 g:20-30 mL, and the amount of enzyme solution is 0.8-1.2 wt% of the weight of sea tangle and distilled water; the enzyme solution is papain and cellulase, and the mass ratio of papain to cellulase is 1-2:1-2. The water bath oscillation is performed at a temperature of 40-50 ℃, an oscillation frequency of 200-400 rpm, and for 2-3 h; and the water bath enzymolysis is performed at a temperature of 40-50 ℃ for 1-2 h.

2. The farming method according to claim 1, characterized in that, The constitution enhancer is continuously fed for 3-4 days before high temperature stress.

3. The farming method according to claim 1 or 2, characterized in that, The feeding amount of the constitution enhancer is 30-100 g / 10,000 shrimps per day.

4. The farming method according to claim 2, characterized by, When the body length of the shrimp seedlings is less than 2 cm, the feeding amount of the constitution enhancer is 30-50 g / 10,000 shrimps; and when the body length of the shrimp seedlings is more than 2 cm, the feeding amount of the constitution enhancer is 80-100 g / 10,000 shrimps.

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