Method for shelling fairy shrimps

Abstract

The invention relates to a fairy shrimp shelling method which comprises the following steps: (1) pretreating fairy shrimps with water to obtain pretreated fairy shrimps; and (2) mixing the pretreated fairy shrimps with a shelling agent to obtain shelled fairy shrimps. According to the shelling method, egg shells and egg membranes of fairy shrimps can be fully removed, the hatching time of fairy shrimp eggs can be shortened, the fairy shrimp eggs cannot be damaged in the re-shelling process of the shelling agent, and the situation that the hatching rate and the survival rate of the fairy shrimp eggs are reduced is avoided.

Description

Technical Field

[0001] The invention belongs to the field of aquaculture and relates to a method for shelling Artemia. Background Art

[0002] Artemia is also known as fairy shrimp, brine shrimp, Artemia, etc. Artemia is a biological bait with important economic value. Its wide distribution, strong adaptability and rich nutrients make it the preferred bait source for aquatic animal breeding.

[0003] The shell of Artemia is indigestible for shrimp and fish larvae. If put into a nursery pond, the shell and unhatched eggs may cause intestinal obstruction in the seedlings, and even lead to death. The shell of Artemia may carry bacteria, fungi, viruses, algae spores, etc., and for the sake of nursery safety, it is also necessary to remove the shell. The traditional method of shelling Artemia is to use sodium hypochlorite or calcium hypochlorite solution for oxidation treatment. The above method releases a lot of heat during the operation, and the water temperature needs to be controlled to avoid the impact of high temperature on Artemia. At the same time, after the reaction is completed, it is necessary to use sodium thiosulfate for cleaning to avoid residual chlorine residue affecting the survival rate of Artemia.

[0004] Prior art CN106577408A is a method for preparing shelled Artemia eggs for improving hatching rate, wherein hawthorn juice containing organic acid and light salt water are used to hydrate Artemia eggs, bile and phospholipase C are used to decompose phospholipids and cholesterol in Artemia egg shells, and then Candida rugosa and its secreted lipoprotein lipase, active substances and papain are used to shell Artemia eggs. The above-mentioned technology requires 24-36 hours to fully hatch Artemia eggs. In order to shorten the hatching time of shelled Artemia eggs, a method for shelling Artemia is proposed. Summary of the invention

[0005] In view of this, the present invention discloses a method for shelling Artemia to solve the above problems.

[0006] The technical solution of the present invention is achieved in this way:

[0007] The method for shelling Artemia comprises the following steps:

[0008] (1) pre-treating Artemia with water to obtain pre-treated Artemia;

[0009] (2) mixing the pretreated Artemia with a shelling agent to obtain shelled Artemia;

[0010] Wherein, the shelling agent includes subtilisin, Lactococcus lactis and Trichoderma harzianum.

[0011] Furthermore, the water pretreatment of the Artemia is to wash the Artemia with fresh water to remove impurities, and then soak it in water with a salinity of 15‰-25‰ for 40-60 minutes, and aeration is used during the soaking process to allow the Artemia to fully absorb water and swell.

[0012] Furthermore, the mass ratio of the Artemia to the water with a salinity of 15‰-25‰ is 1:5-20.

[0013] Furthermore, the subtilisin accounts for 0.05%-0.08% of the total mass of the shelling agent, the Lactococcus lactis accounts for 0.05%-0.2% of the total mass of the shelling agent, and the Trichoderma harzianum accounts for 0.04%-0.06% of the total mass of the shelling agent.

[0014] Furthermore, the shelling agent also contains 3-6wt% of glucose.

[0015] Furthermore, the mass ratio of the Artemia spp. to the shelling agent is 1:15-30.

[0016] Furthermore, the pretreated Artemia and the shelling agent are mixed and reacted at 25-35°C.

[0017] Furthermore, the molted Artemia worms are soaked in a nutrient solution, wherein the nutrient solution comprises lysine, histidine, threonine, isoleucine, leucine, valine, arginine and saline.

[0018] Furthermore, the nutrient solution comprises 600-750 mg / 100 g of lysine, 100-150 mg / 100 g of histidine, 200-250 mg / 100 g of threonine, 180-250 mg / 100 g of isoleucine, 400-500 mg / 100 g of leucine, 300-380 mg / 100 g of valine, 70-170 mg / 100 g of arginine and saline.

[0019] Furthermore, the salinity of the brine is 15‰-25‰.

[0020] Furthermore, the shelled Artemia is soaked in a nutrient solution at 25-35° C. for 0.5-2 h.

[0021] Furthermore, the mass ratio of the shelled Artemia to the nutrient solution is 1:3-7.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention adopts subtilisin, Lactococcus lactis and Trichoderma harzianum as shelling agents, which can not only fully remove the egg shell and egg membrane of Artemia spp., but also help to shorten the hatching time of Artemia spp. eggs. More importantly, the shelling agent of the present invention does not generate a large amount of heat during the shelling process, which can reduce the damage to Artemia spp. eggs.

[0024] The artemia worm eggs of the present invention are soaked in nutrient solution, which can prolong the time of the artemia worm eggs and maintain their hatching activity. DETAILED DESCRIPTION

[0025] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0026] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0027] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0028] Subtilisin was purchased from Shanghai Yuanye Biotechnology Co., Ltd.;

[0029] Lactococcus lactis was purchased from Shandong Zhongke Jiayi Bioengineering Co., Ltd.;

[0030] Trichoderma harzianum was purchased from Wuhan Kamik Technology Co., Ltd.;

[0031] Papain Xi'an Musen Bioengineering Co., Ltd.

[0032] Embodiment 1 Artemia shelling method

[0033] (1) Artemia was washed with fresh water to remove impurities, and then soaked in water with a salinity of 15‰ for 40 minutes. Aeration was used during the soaking process to allow the Artemia to fully absorb water and swell. The Artemia was fished out with gauze to obtain the pretreated Artemia.

[0034] (2) Based on the total mass of the dehulling agent, 0.05% of subtilisin, 0.05% of Lactococcus lactis, 0.04% of Trichoderma harzianum and water were mixed to prepare a dehulling agent.

[0035] (3) Mix Artemia spp. and shelling agent in a mass ratio of 1:15, react at 25°C, observe the color of the eggs gradually change from brown to orange-yellow, sieve and collect Artemia spp. eggs, rinse the Artemia spp. eggs with fresh water, and obtain shelled Artemia spp. eggs.

[0036] Embodiment 2 Artemia shelling method

[0037] (1) Artemia was washed with fresh water to remove impurities, and then soaked in water with a salinity of 25‰ for 60 minutes. Aeration was used during the soaking process to allow the Artemia to fully absorb water and swell. The Artemia was fished out with gauze to obtain the pretreated Artemia.

[0038] (2) Based on the total mass of the dehulling agent, 0.08% of subtilisin, 0.2% of Lactococcus lactis, 0.06% of Trichoderma harzianum and water were mixed to prepare a dehulling agent.

[0039] (3) Mix Artemia spp. and shelling agent at a mass ratio of 1:30, react at 35° C., observe the color of the eggs gradually change from brown to orange-yellow, sieve and collect Artemia spp. eggs, rinse the Artemia spp. eggs with fresh water, and obtain shelled Artemia spp. eggs.

[0040] Embodiment 3 Artemia shelling method

[0041] (1) Artemia was washed with fresh water to remove impurities, and then soaked in water with a salinity of 20‰ for 50 minutes. Aeration was used during the soaking process to allow the Artemia to fully absorb water and swell. The Artemia was fished out with gauze to obtain the pretreated Artemia.

[0042] (2) Based on the total mass of the dehulling agent, 0.068% of subtilisin, 0.13% of Lactococcus lactis, 0.05% of Trichoderma harzianum and water were mixed to prepare a dehulling agent.

[0043] (3) Mix Artemia spp. and shelling agent at a mass ratio of 1:20, react at 30° C., observe the color of the eggs gradually change from brown to orange-yellow, sieve and collect Artemia spp. eggs, rinse the Artemia spp. eggs with fresh water, and obtain shelled Artemia spp. eggs.

[0044] Embodiment 4 Artemia shelling method

[0045] (1) Artemia was washed with fresh water to remove impurities, and then soaked in water with a salinity of 20‰ for 50 minutes. Aeration was used during the soaking process to allow the Artemia to fully absorb water and swell. The Artemia was fished out with gauze to obtain the pretreated Artemia.

[0046] (2) Based on the total weight of the dehulling agent, 0.068% of subtilisin, 0.13% of Lactococcus lactis, 0.05% of Trichoderma harzianum, 5% of glucose and water were mixed to prepare a dehulling agent.

[0047] (3) Mix Artemia spp. and shelling agent in a mass ratio of 1:20, react at 30° C., observe the color of the eggs gradually change from brown to orange-yellow, sieve and collect Artemia spp. eggs, and rinse the Artemia spp. eggs with fresh water to obtain Artemia spp.

[0048] Test Example 1

[0049] The Artemia eggs obtained in Examples 1-4 were subjected to hatching tests at the Yuwan Base in Fengjiawan, Huiwen Town, Wenchang City, Hainan Province. The test indicators were hatching time and hatching rate.

[0050] The incubation conditions were as follows: 10 g of Artemia eggs were added to 5 L of incubation solution with a pH value of 8.0 and a salinity of 20‰ for incubation, the light intensity was 1500 LX, and the air flow rate in the incubation bucket was controlled at 60 m 3 / (m 2 ·min), the temperature was 30° C. The pH value was adjusted by sodium carbonate.

[0051] The hatching time is the time when 90% of the Artemia eggs hatch, and the hatching time is counted in half an hour, that is, 15-45 minutes is recorded as 0.5 hours, and 46-14 minutes is recorded as 1 hour. For example, the hatching time is 2 hours and 17 minutes, which is recorded as 2.5 hours; the hatching time is 2 hours and 48 minutes, which is recorded as 3 hours.

[0052] Calculate the hatched eggs using the density method: hatching rate = number of Artemia harvested / number of hatched eggs × 100%.

[0053] Table 1 The hatching time and hatching rate of Artemia

[0054] name Example 1 Example 2 Example 3 Example 4 Incubation time (h) 13.5 12.5 13 11.5 Hatching rate (%) 97.2 96.8 97.4 98.1

[0055] The experimental results show that the shelling method of Artemia provided by the present invention can not only significantly shorten the hatching time of Artemia eggs, but also improve the hatching rate of Artemia, and the shelling rate of Artemia is as high as 98.5% or more. It can also avoid that through observation, the Artemia eggs obtained by the shelling method of Artemia provided by the present invention can be completely hatched within 16 hours.

[0056] Comparative Example 1

[0057] (1) Artemia was washed with fresh water to remove impurities, and then soaked in water with a salinity of 20‰ for 50 minutes. Aeration was used during the soaking process to allow the Artemia to fully absorb water and swell. The Artemia was fished out with gauze to obtain the pretreated Artemia.

[0058] (2) Based on the total weight of the dehulling agent, 0.068% of subtilisin, 0.13% of Lactococcus lactis, 0.05% of papain, 5% of glucose and water were mixed to prepare a dehulling agent.

[0059] (3) Mix the Artemia and the shelling agent in a mass ratio of 1:20, react at 30° C. for 14 hours, sieve, collect Artemia eggs, and rinse the Artemia eggs with fresh water to obtain Artemia eggs.

[0060] Test Example 2

[0061] The Artemia ova obtained in Comparative Example 1 were subjected to a hatching test at the Yuwan Base in Fengjiawan, Huiwen Town, Wenchang City, Hainan Province, to investigate the hatching time and hatching rate of Artemia ova.

[0062] The incubation conditions were as follows: 10 g of Artemia eggs were added to 5 L of incubation solution with a pH value of 8.0 and a salinity of 20‰ for incubation, the light intensity was 1500 LX, and the air flow rate in the incubation bucket was controlled at 60 m 3 / (m 2 ·min), the temperature was 30° C. The pH value was adjusted by sodium carbonate.

[0063] The hatching time is the time when 90% of the Artemia eggs hatch, and the hatching time is counted in half an hour, that is, 15-45 minutes is recorded as 0.5 hours, and 46-14 minutes is recorded as 1 hour. For example, the hatching time is 2 hours and 17 minutes, which is recorded as 2.5 hours; the hatching time is 2 hours and 48 minutes, which is recorded as 3 hours.

[0064] Calculate the hatched eggs using the density method: hatching rate = number of Artemia harvested / number of hatched eggs × 100%.

[0065] Table 2 The hatching time and hatching rate of Artemia

[0066]

[0067]

[0068] Comparing the test results of Comparative Example 1 and Example 4, the shelling agent of the present invention can improve the hatching rate of Artemia worm eggs and shorten the hatching time of Artemia worm eggs. The components in the shelling agent of the present invention are reasonably proportioned, can remove the egg shell and destroy the egg membrane, do not hurt the embryonic membrane, and protect the embryo. During the hatching process, Artemia worm eggs are not bound by the egg shell and egg membrane, and can hatch successfully faster. More importantly, the components in the shelling agent attached to the surface of Artemia worm eggs can inhibit the infection of surface pathogens, and can also improve the immunity of Artemia worm eggs, thereby improving the hatching rate of Artemia worm eggs.

[0069] Example 5

[0070] (1) Mix 700 mg / 100 g of lysine, 130 mg / 100 g of histidine, 230 mg / 100 g of threonine, 1950 mg / 100 g of isoleucine, 450 mg / 100 g of leucine, 350 mg / 100 g of valine, 100 mg / 100 g of arginine and water with a salinity of 20‰ to prepare a nutrient solution.

[0071] (2) The Artemia ova obtained in Example 4 were dried at 33° C. until the moisture content of the Artemia ova was 10%.

[0072] (3) Mix the above Artemia eggs and nutrient solution in a mass ratio of 1:5 and soak them at a temperature of 30° C. for 1 h.

[0073] Comparative Example 2

[0074] (1) 400 mg / 100 g of lysine, 200 mg / 100 g of histidine, 300 mg / 100 g of threonine, 150 mg / 100 g of isoleucine, 300 mg / 100 g of leucine, 330 mg / 100 g of valine, 195 mg / 100 g of arginine and water with a salinity of 20‰ were mixed to form a nutrient solution.

[0075] (2) The Artemia ova obtained in Example 4 were dried at 33° C. until the moisture content of the Artemia ova was 10%.

[0076] (3) Mix the above Artemia eggs and nutrient solution in a mass ratio of 1:5 and soak them at a temperature of 30° C. for 1 h.

[0077] Comparative Example 3

[0078] (1) Mix 700 mg / 100 g of lysine, 130 mg / 100 g of histidine, 230 mg / 100 g of threonine, 1950 mg / 100 g of isoleucine, 450 mg / 100 g of leucine, 350 mg / 100 g of valine, 100 mg / 100 g of arginine and water with a salinity of 20‰ to prepare a nutrient solution.

[0079] (2) Mix the above Artemia eggs and nutrient solution in a mass ratio of 1:5 and soak them at a temperature of 30° C. for 1 h.

[0080] Comparative Example 4

[0081] (1) Mix 700 mg / 100 g of lysine, 130 mg / 100 g of histidine, 230 mg / 100 g of threonine, 1950 mg / 100 g of isoleucine, 450 mg / 100 g of leucine, 350 mg / 100 g of valine, 100 mg / 100 g of arginine and water with a salinity of 20‰ to prepare a nutrient solution.

[0082] (2) The Artemia ova obtained in Example 4 were dried at 33° C. until the moisture content of the Artemia ova was 10%.

[0083] (3) Mix the above Artemia eggs and nutrient solution in a mass ratio of 1:5 and soak them at a temperature of 30° C. for 5 h.

[0084] Test Example 3

[0085] The Artemia ova obtained in Example 5 and Comparative Examples 2-4 were stored at -20°C for 12 weeks to investigate the hatching time, hatching rate and survival rate of the Artemia ova.

[0086] Thaw the frozen Artemia eggs naturally at 25℃ to room temperature before hatching.

[0087] The incubation conditions were as follows: 10 g of Artemia eggs were added to 5 L of incubation solution with a pH value of 8.0 and a salinity of 20‰ for incubation, the light intensity was 1500 LX, and the air flow rate in the incubation bucket was controlled at 60 m 3 / (m 2 ·min), the temperature was 30° C. The pH value was adjusted by sodium carbonate.

[0088] The hatching time is the time when 90% of the Artemia eggs hatch, and the hatching time is counted in half an hour, that is, 15-45 minutes is recorded as 0.5 hours, and 46-14 minutes is recorded as 1 hour. For example, the hatching time is 2 hours and 17 minutes, which is recorded as 2.5 hours; the hatching time is 2 hours and 48 minutes, which is recorded as 3 hours.

[0089] Calculate the hatched eggs using the density method: hatching rate = number of Artemia harvested / number of hatched eggs × 100%.

[0090] Survival rate detection method: randomly sample the obtained Artemia three times, with a sampling size of 1g each time. Place 1g of Artemia in seawater and observe its movement state. Those that can swim in the seawater are defined as living worms. Take out the Artemia nauplii that sink to the bottom and cannot swim, and observe under a microscope. Those that can move are alive, and those that cannot swim or are motionless are dead.

[0091] Survival rate = number of surviving Artemia / number of Artemia per gram × 100%

[0092] Table 3 Results of hatching time, survival rate and hatching rate of Artemia

[0093] name Example 5 Comparative Example 2 Comparative Example 3 Comparative Example 4 Incubation time (h) 12 14 15.5 14.5 Hatching rate (%) 95.4 90.3 84.8 91.7 Survival rate (%) 94.8 88.9 85.1 90.6

[0094] Experimental results show that the Artemia ova obtained by the Artemia ova shelling method provided by the present invention can maintain a good hatching rate and survival rate under conditions of frozen storage after being soaked in a nutrient solution.

[0095] The artemia eggs obtained by the artemia shelling method provided by the present invention effectively remove the egg shell of the artemia and destroy the egg membrane structure, so that the amino acid components in the nutrient solution can penetrate the embryonic membrane, provide effective components such as amino acids to the embryo, and reduce the loss of the artemia during the dormancy period.

[0096] The experimental results of Example 5 and Comparative Example 2 show that the nutrient solution of the present invention has a reasonable ratio and can improve the hatching rate and survival rate of Artemia eggs.

[0097] The experimental results of Example 5 and Comparative Example 3 show that the present invention dries the Artemia eggs at 33°C until the water content of the Artemia eggs is 10%, and then soaks them in nutrient solution to allow the Artemia eggs to fully absorb the nutrient solution. At the same time, the water content of the Artemia eggs can be controlled to avoid damage to the embryos during cryopreservation, resulting in a decrease in hatching rate and survival rate.

[0098] The experimental results of Example 4 and Comparative Example 4 show that the present invention reasonably controls the parameters such as the immersion time and temperature of the nutrient solution, can control the water content of Artemia eggs, avoid damage to the embryos during cryopreservation, and lead to a decrease in the hatching rate and survival rate.

[0099] Comparative Example 5

[0100] (1) Mix 700 mg / 100 g of lysine, 130 mg / 100 g of histidine, 230 mg / 100 g of threonine, 1950 mg / 100 g of isoleucine, 450 mg / 100 g of leucine, 350 mg / 100 g of valine, 100 mg / 100 g of arginine and water with a salinity of 20‰ to prepare a nutrient solution.

[0101] (2) The Artemia ova obtained in Comparative Example 1 were dried at 33° C. until the moisture content of the Artemia ova was 10%.

[0102] (3) Mix the above Artemia eggs and nutrient solution in a mass ratio of 1:5 and soak them at a temperature of 30° C. for 1 h.

[0103] Test Example 3

[0104] The Artemia nauplii eggs obtained in 5 were stored at -20°C for 12 weeks to investigate the hatching time, hatching rate and survival rate of the Artemia nauplii eggs.

[0105] Thaw the frozen Artemia eggs naturally at 25℃ to room temperature before hatching.

[0106] The incubation conditions were as follows: 10 g of Artemia eggs were added to 5 L of incubation solution with a pH value of 8.0 and a salinity of 20‰ for incubation, the light intensity was 1500 LX, and the air flow rate in the incubation bucket was controlled at 60 m 3 / (m 2 ·min), the temperature was 30° C. The pH value was adjusted by sodium carbonate.

[0107] The hatching time is the time when 90% of the Artemia eggs hatch, and the hatching time is counted in half an hour, that is, 15-45 minutes is recorded as 0.5 hours, and 46-14 minutes is recorded as 1 hour. For example, the hatching time is 2 hours and 17 minutes, which is recorded as 2.5 hours; the hatching time is 2 hours and 48 minutes, which is recorded as 3 hours.

[0108] Calculate the hatched eggs using the density method: hatching rate = number of Artemia harvested / number of hatched eggs × 100%.

[0109] Survival rate detection method: randomly sample the obtained Artemia three times, with a sampling size of 1g each time. Place 1g of Artemia in seawater and observe its movement state. Those that can swim in the seawater are defined as living worms. Take out the Artemia nauplii that sink to the bottom and cannot swim, and observe under a microscope. Those that can move are alive, and those that cannot swim or are motionless are dead.

[0110] Survival rate = number of surviving Artemia / number of Artemia per gram × 100%.

[0111] Table 4 Results of hatching time, survival rate and hatching rate of Artemia

[0112] name Comparative Example 5 Example 5 Incubation time (h) 14 12 Hatching rate (%) 90.8 95.4 Survival rate (%) 91.3 94.8

[0113] The test results of Comparative Example 5 and Example 5 show that the Artemia larvae obtained by soaking in the shelling agent of the present invention can still obtain Artemia larvae with high hatching rate and survival rate after being soaked in nutrient solution and stored at -20°C for 12 weeks.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for shelling Artemia, characterized in that: The following steps are involved: (1) pre-treating Artemia with water to obtain pre-treated Artemia; (2) mixing the pretreated Artemia spp. and a shelling agent to obtain shelled Artemia spp.; Wherein, the shelling agent includes subtilisin, Lactococcus lactis and Trichoderma harzianum.

2. The method for shelling Artemia according to claim 1, characterized in that: The subtilisin accounts for 0.05%-0.08% of the total mass of the shelling agent, the lactococcus lactis accounts for 0.05%-0.2% of the total mass of the shelling agent, and the trichoderma harzianum accounts for 0.04%-0.06% of the total mass of the shelling agent.

3. The method for shelling Artemia according to claim 1, characterized in that: The shelling agent also contains 3-6 wt % of glucose.

4. The method for dehulling Artemia according to claim 1, characterized in that: The mass ratio of the Artemia spp. to the shelling agent is 1:15-30.

5. The method for dehulling Artemia according to claim 1, characterized in that: The pretreated Artemia and the shelling agent are mixed and reacted at 25-35°C.

6. The method for shelling Artemia according to claim 1, characterized in that: The method also includes soaking the molted Artemia in a nutrient solution, wherein the nutrient solution includes lysine, histidine, threonine, isoleucine, leucine, valine, arginine and saline.

7. The method for dehulling Artemia according to claim 6, characterized in that: The nutrient solution comprises 600-750 mg / 100 g of lysine, 100-150 mg / 100 g of histidine, 200-250 mg / 100 g of threonine, 180-250 mg / 100 g of isoleucine, 400-500 mg / 100 g of leucine, 300-380 mg / 100 g of valine, 70-170 mg / 100 g of arginine and saline.

8. The method for shelling Artemia according to claim 7, characterized in that: The salinity of the brine is 15‰-25‰.

9. The method for dehulling Artemia according to claim 7, characterized in that: The shelled Artemia is soaked in a nutrient solution at 25-35° C. for 0.5-2 hours.

10. The method for shelling Artemia according to claim 7, characterized in that: The mass ratio of the shelled Artemia to the nutrient solution is 1:3-7.

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