Transportation method of leopard geoffroy's wrasse fertilized eggs

Abstract

The application discloses a kind of leopard gill Cephalopholis argus fertilized egg transport methods, it is related to the field of fertilized egg transport, including the following steps: 1) transport early preparation: screening excellent fertilized egg, configuration transport packing water;2) packing and transport control: excellent fertilized egg is packed by pure oxygen bag sealing temperature control, loading packing bag, control transport time is within 12 hours;3) transport arrival processing: prepare to breed pond, balance packing bag to adhere to the water temperature of breeding pond, disinfect transition to fertilized egg, again after screening is released in breeding pond.The application reduces the density of fertilized egg, reduces the probability of adhesion, collision and hypoxia, greatly improves the survival rate of leopard gill Cephalopholis argus fertilized egg transport.

Description

Technical Field

[0001] This invention relates to a method for transporting fertilized eggs, and more particularly to a method for improving the survival rate of transported fertilized eggs of the leopard-gill spiny perch (also known as the Eastern Star Grouper). Background Technology

[0002] Leopard-gill spiny perch ( Leopard's Plectropomus The leopard-gill sea bass, also known as the Eastern Star Grouper, is a high-end marine aquaculture species highly favored by the market, standing out due to its unique biological characteristics and excellent commercial value. Firstly, this species is a mid-to-upper-level carnivorous fish with delicate flesh, rich in nutrients, high-quality protein, and unsaturated fatty acids, offering a delicate taste and unique flavor that is highly popular with consumers and possesses enormous market potential. Secondly, the leopard-gill sea bass has significant advantages in artificial breeding: it has a defined breeding season, can be artificially induced to spawn, and produces a large number of eggs with a high fertilization rate, providing a solid germplasm foundation for large-scale aquaculture. However, despite its excellent parent stock, the key bottleneck restricting the extension of the industrial chain is how to efficiently and with minimal loss transport high-quality germplasm resources from the south to northern aquaculture bases during the process of achieving large-scale production.

[0003] Currently, the low survival rate of transported fertilized eggs has become a core scientific problem restricting the industrialization of the leopard-gill sea bass. Existing transportation methods mainly rely on low-temperature oxygenation, but due to the small size of leopard-gill sea bass fertilized eggs (approximately 721±36 micrometers), thin egg membranes, and extreme sensitivity to the environment, the survival rate is less than 10% during cross-regional transportation, especially long-distance north-south transport. Specifically, current transportation faces multiple limitations: First, temperature control is a challenge. The cabin temperature fluctuates drastically during transportation, and if it cannot be maintained within a suitable low temperature range of 20-24℃, it can easily lead to premature development or embryonic death of the fertilized eggs. Second, salinity and density management are insufficient. It is difficult to maintain constant salinity, pH, and density in the transport water, and fertilized eggs are easily damaged by pressure in high-density water. In addition, due to the small size and thin egg membranes, the fertilized eggs are easily damaged by mechanical vibration and air pressure changes during transportation. It is the combined effect of these technical bottlenecks that results in an extremely low survival rate of fertilized eggs in the north-south transportation chain, seriously hindering the cross-regional chain development of the leopard-gill sea bass industry. Summary of the Invention

[0004] The purpose of this invention is to provide a method for transporting fertilized eggs of the leopard-gill spiny perch, overcoming the shortcomings of the prior art, so as to improve the survival rate of transported fertilized eggs of the red-spotted perch.

[0005] The method for transporting fertilized eggs of the leopard-gill spiny perch provided by this invention includes the following steps: 1) Pre-transportation preparations: Step 1-1: Screening for superior fertilized eggs: Incubate the fertilized eggs in clean seawater at 27-29℃ for 6-8 hours. After they develop to the gastrula stage, use the difference in specific gravity to screen out healthy floating eggs that are vigorous, normally developed, and concentrated in the upper layer of the water. Step 1-2: Prepare transport packaging water: Use filtered clean seawater with a salinity of approximately 32‰-35‰ and add 1-2 ppm of vitamin C; 2) Packaging and transportation control: Step 2-1 Packaging high-quality fertilized eggs: The wet weight of fertilized eggs in each liter of packaging water shall not exceed 8 grams. Fill the packaging bag containing fertilized eggs and packaging water with pure oxygen until it is full and then seal it. Step 2-2 Loading the packing bags: Put the packing bags into the foam box, and place the temperature control device wrapped in oil paper above the packing bags in the air. Keep the temperature inside the box constant at about 22±1℃. Step 2-3 Transportation Time Control: The total time from the packing site to the destination pool should be within 12 hours; 3) Transportation arrival processing: Step 3-1: Preparation of the seedling pond: The seedling pond has been disinfected and sterilized, with a water temperature of 26±2℃, a salinity of 28-30‰, and dissolved oxygen greater than 5mg / L; Step 3-2 Balancing water temperature and disinfection: Float the sealed packaging bag in the seedling pond water for 20-30 minutes, then open the bag and slowly pour the fertilized eggs into a temporary container containing disinfectant solution, and let it stand for 10 minutes. Step 3-3: Re-screening and stocking: After the water has calmed down, quickly collect the healthy eggs that float to the surface again and transfer them to the prepared nursery pond for formal hatching, discarding the dead and bad eggs that sink to the bottom.

[0006] Furthermore, in the above-mentioned method for transporting fertilized eggs of the leopard-gill spiny perch: Step 3-2: Balancing water temperature and disinfection: Place the fertilized eggs in a bucket of water at about 24℃ for 10-20 minutes for disinfection, and then raise the water temperature to 26℃ for 10-20 minutes.

[0007] Furthermore, in the above-mentioned method for transporting fertilized eggs of the leopard gill spiny perch, the wet weight of the packaged fertilized eggs in water is 8 g / L.

[0008] Furthermore, in the above-mentioned method for transporting fertilized eggs of the leopard gill perch, the packaging bag is a double-layer polyethylene bag.

[0009] Furthermore, in the above-mentioned method for transporting fertilized eggs of the leopard gill perch, the temperature control device is an ice pack.

[0010] Furthermore, in the above-mentioned method for transporting fertilized eggs of the leopard gill spiny perch, during step 3-2 of balancing the water temperature and disinfection, a short-term medicated bath of 10 minutes is performed using 1-5 ppm of effective iodine.

[0011] The method for transporting fertilized eggs of the leopard-gill spiny perch provided by this invention has the following advantages compared with the prior art: 1. Select superior fertilized eggs that have developed to the gastrula stage and transport them by air to improve the overall quality of the fish eggs and their ability to resist environmental influences.

[0012] 2. Strictly controlled transport density ensures that the eggs have sufficient water space and oxygen supply, reducing the probability of fertilized eggs sticking together, colliding, and lacking oxygen, and reducing the possibility of damage and death of fertilized eggs during transportation.

[0013] 3. By balancing the water temperature and disinfecting the process, the fertilized eggs are helped to gradually adapt to the temperature, safely transitioning from the transportation state to the temperature of the nursery pond, buffering the stimulation caused by temperature differences and avoiding stress.

[0014] In summary, using the method of the present invention, the survival rate of fertilized eggs of the East Star Grouper during transportation can reach over 50%. Detailed Implementation Example

[0015] This embodiment describes the specific implementation of the method of the present invention when Rizhao Chengtai Aquatic Products purchased fertilized eggs of grouper from Sanya and transported them to the Rizhao seedling and hatching base from November 2024 to the present: 1) Pre-transportation preparations: The successful transportation of live fertilized eggs of East Star Grouper depends heavily on rigorous and scientific preparations before departure. The core is to obtain stable, healthy and pure fertilized eggs and to prepare a stable "microenvironment for the journey".

[0016] Step 1-1: Screening for superior fertilized eggs: At the Sanya production base, fertilized eggs are incubated in clean seawater at 27-29℃ for 6-8 hours. After developing to the gastrula stage, fertilized eggs are collected using an 80-mesh silk screen, repeatedly rinsed with clean seawater to remove excess mucus, unfertilized eggs and impurities, and then allowed to stand for separation. Only high-quality floating eggs produced on the same day, with uniform egg diameter and uniform oil globules as observed by the naked eye, are retained. Seawater temperature directly affects the metabolic rate and enzyme activity of embryonic cells. Excessively high temperatures can lead to overly rapid embryonic development, exceeding the yolk's supply capacity; conversely, excessively low temperatures can slow development and increase the risk of malformation or death. A temperature range of 27-29°C is ideal for fertilized eggs. Fertilized eggs that have stably developed to the gastrulation stage exhibit high resistance to external environmental influences and adapt to subsequent environmental changes, forming the basis for subsequent procedures.

[0017] Step 1-2: Prepare transport packaging water: Use filtered clean seawater with a salinity of approximately 32‰-35‰ and add 1-2 ppm of vitamin C; 1-2 ppm of vitamin C acts as an anti-stress agent, and its addition helps prevent stress on fertilized eggs, alleviates transport stress, and purifies water quality. The optimal salinity range is 32‰-35‰. Excessive or insufficient salinity in seawater can lead to decreased survival rate and increased mutation rate.

[0018] Packaging and transportation control: The transportation process is a concentrated test of environmental control capabilities. The core objective is to maintain a "low-speed stable" state for life activities. The method adopted in this invention is to transport the oxygen bag in a sealed and temperature-controlled manner.

[0019] Step 2-1 Packaging high-quality fertilized eggs: Fill a 10L double-layer polyethylene bag with 4L of pretreated fresh seawater, weigh out about 30g of fertilized grouper eggs, and slowly place them into the double-layer polyethylene bag. The density is calculated to be 30g / 4L≈8g / L. Slowly squeeze the bag from bottom to top to expel the air, and immediately fill it with pure oxygen to make the bag full and elastic. Finally, seal it with a rubber band or a special sealing machine.

[0020] Furthermore, in the above-mentioned method for transporting fertilized eggs of the leopard gill spiny perch, the packaging bag can also be a double-layered air bag made of other materials, such as a double-layered vinyl chloride bag, or other packaging bags with the same effect.

[0021] Furthermore, by strictly controlling the density of fish eggs to ensure that each egg has sufficient water space and oxygen supply, a high-oxygen and moist environment is created. A density of 8 g / L for packaging fertilized eggs is the optimal solution obtained through experiments. The table below shows the experimental process for obtaining the optimal solution: First, healthy and vigorous fertilized eggs of *Stellaria media* were selected and randomly divided into three experimental groups with different transport density gradients: Group A (low density group) 8 g / L, Group B (medium density group) 12 g / L, and Group C (high density group) 25 g / L. Each group had three replicates.

[0022] Then, the pre-packaged fertilized egg bags were placed on a shaker (model: Universal Shaker TS-92), and the shaker vibration frequency was set to 30 revolutions per minute to simulate the continuous bumps and vibrations generated by vehicles and airplanes during actual transportation.

[0023] Finally, after simulating vibration treatment for 12 hours, all experimental groups were removed from the shaker to simulate the recovery process after reaching the destination.

[0024] It should be noted that the fertilized egg membrane of the grouper used in this experiment is significantly thinner than that of common grouper species (such as saddle grouper and red-spotted grouper), making it more sensitive to vibration and compression. This also explains why its damage rate increases sharply under high-density conditions.

[0025] After observation, the fertilized eggs in group A (8g / L) and group B (12g / L) showed higher viability, with significantly higher egg membrane integrity and embryo survival rates than those in group C (25g / L). Details are shown in the table below: Experimental results show that under simulated transport vibration conditions, the transport density of *Symplocos edulis* fertilized eggs has a significant impact on their survival rate. Due to their thin egg membranes, excessively high density (25 g / L) directly leads to increased mechanical damage and decreased survival rate. Although groups A (8 g / L) and B (12 g / L) showed good biological characteristics, the 12 g / L density was less effective in actual transport, with a floating rate below 10%. Therefore, the preferred density is 8 g / L, which ensures a high survival rate while saving costs.

[0026] Step 2-2: Loading the packing bags: Place the sealed double-layer polyethylene bags into a custom foam box with a 2cm thick insulation layer. Depending on the temperature, place an appropriate amount of ice packs wrapped in oil paper above the bags to ensure they do not directly contact the bags. Keep the temperature inside the box constant at around 22±1℃. Tightly close the foam box lid and seal the outer layer of the box with tape.

[0027] Furthermore, existing technologies with the same effect, such as popsicles, dry ice, or constant temperature boxes, can be used. Wrapping the fish in oil paper not only protects them from damage and external environmental pollution, but also keeps them warm and waterproof. It also helps maintain the internal temperature of the foam insulated box at around 22±1℃. Too high a temperature accelerates oxygen consumption, while too low a temperature inhibits metabolism. This temperature is the optimal temperature for transporting grouper or red snapper. Any drastic temperature fluctuations may affect the survival rate.

[0028] Steps 2-3 Transportation Time Control: Long-distance transportation adopts land-air combined transport. Each batch transports 3kg of high-quality fertilized eggs. The packaging boxes are moved to refrigerated trucks and transported from Sanya to Sanya Airport Cargo Terminal. Cargo procedures are completed, and the goods are transported to the destination airport on the next available flight. After arriving at the destination airport, a special vehicle is arranged to pick up the goods quickly and transport them to the designated seedling incubation base. The total time from the packaging site to the destination for incubation should be controlled within 12 hours as much as possible. The shorter the transportation time, the better the survival rate of fertilized eggs. The entire transportation process should be as efficient as possible. Exceeding the time limit will significantly reduce the hatching rate and seedling quality. During handling and driving, it is necessary to handle the eggs gently and drive smoothly to minimize the mechanical damage to the fragile embryos caused by physical vibration.

[0029] 3) Handling upon arrival: After the fertilized eggs arrive at their destination, they are not directly poured into the pool. Instead, a meticulous "awakening" and "transition" procedure is required to help them safely recover from their transportation state. During this process, the personnel can perform mild oxygenation treatment according to the local environmental conditions to reduce the impact of the environment on the survival rate of the fertilized eggs.

[0030] Step 3-1: Preparation of the seedling bed: The seedling bed should be disinfected and sterilized, with a water temperature of 26±2℃, a salinity of 28-30‰, and dissolved oxygen greater than 5mg / L. All the indicators of the seedling bed should meet the optimal environment for the development of fertilized eggs, which is conducive to the development of fertilized eggs into seedlings.

[0031] Step 3-2: Balancing water temperature and disinfection: Place the arrived packaging bags in the seedling pond water for 20-30 minutes to allow the water temperature inside the bags to gradually approach the temperature of the hatching pond water, avoiding temperature stress. Then, open the double-layered polyethylene bag and slowly pour the fertilized eggs into a large beaker or plastic basin containing disinfectant solution, and let it stand for 10 minutes.

[0032] Furthermore, in the above-mentioned method for transporting fertilized eggs of the leopard-gill sea bass, step 3-2 can also employ another method for balancing water temperature and disinfection: the fertilized eggs are placed in a bucket of water at approximately 24°C for disinfection for 10-20 minutes, then the water temperature is increased to 26°C and maintained for 10-20 minutes, simultaneously performing disinfection while minimizing the impact of temperature stress. Those skilled in the art can select an appropriate method for balancing water temperature and disinfection based on specific circumstances.

[0033] Furthermore, in the above-mentioned method for transporting fertilized eggs of the leopard gill spiny perch, when balancing the water temperature and disinfecting in step 3-2, a short-term medicated bath of 1-5 ppm of effective iodine for 10 minutes can be used to prevent the spread of pathogens that may be carried.

[0034] Step 3-3: Re-screening and stocking: After the water has calmed down, observe the stratification and collect the floating eggs (live / high-quality eggs) and sinking eggs (dead / low-quality eggs) separately, and calculate the floating rate. The calculation formula is: Floating rate (%) = [Floating egg weight (g) / Total egg weight (g)] × 100%. The separated floating eggs are placed into the nursery pond prepared in Step 3-1 at an appropriate density, for example, 0.2-0.3 kg / pond, for formal hatching. After calculation, the sinking eggs are discarded to ensure the cleanliness of the hatching water.

[0035] The above series of post-harvest operations are the ultimate guarantee for ensuring a high hatching rate and obtaining healthy fry.

[0036] After the larvae hatch, the number of healthy larvae in the hatching tank is counted. This is usually estimated using a sampling count method. The formula is: Hatching rate (%) = (Number of healthy larvae hatched / Total number of eggs released to the surface) × 100%. The statistical results of the surface rate (%) and hatching rate (%) are shown in the table below: Statistical results show that the method of the present invention can ensure unit transportation efficiency without causing devastating losses, meet the timeliness and temperature control requirements of fertilized eggs of the Oriental Star Spot, control physical damage within an acceptable range, and realize the cross-regional transfer of fertilized eggs of the Oriental Star Spot.

[0037] Based on this embodiment and statistical results, compared with the previous 10% survival rate during transportation, the floating rate of fertilized eggs after transportation using the method of this invention is 50%, which is a significant improvement. Furthermore, with a hatching rate of over 85% for floating eggs, a large number of healthy fry can be obtained to meet the seedling needs of large-scale production. Compared with existing technologies, this method has the value of being promoted and applied to the large-scale seedling production of grouper.

Claims

1. A method for transporting fertilized eggs of the leopard-gill spiny perch, characterized in that, Includes the following steps: 1) Pre-transportation preparations: Step 1-1: Screening for superior fertilized eggs: Incubate the fertilized eggs in clean seawater at 27-29℃ for 6-8 hours. After they develop to the gastrula stage, use the difference in specific gravity to screen out healthy floating eggs that are vigorous, normally developed, and concentrated in the upper layer of the water. Step 1-2: Prepare transport packaging water: Use filtered clean seawater with a salinity of approximately 32‰-35‰ and add 1-2 ppm of vitamin C; 2) Packaging and transportation control: Step 2-1 Packaging high-quality fertilized eggs: The wet weight of fertilized eggs in each liter of packaged water shall not exceed 8g. Fill the packaging bag containing fertilized eggs and packaged water with pure oxygen until it is full and then seal it. Step 2-2 Loading the packing bags: Put the packing bags into the foam box, and place the temperature control device wrapped in oil paper above the packing bags in the air. Keep the temperature inside the box constant at about 22±1℃. Step 2-3 Transportation Time Control: The total time from the packing site to the destination pool should be within 12 hours; 3) Transportation arrival processing: Step 3-1: Preparation of the seedling pond: The seedling pond has been disinfected and sterilized, with a water temperature of 26±2℃, a salinity of 28-30‰, and dissolved oxygen greater than 5mg / L; Step 3-2 Balancing water temperature and disinfection: Float the sealed packaging bag in the seedling pond water for 20-30 minutes, then open the bag and slowly pour the fertilized eggs into a temporary container containing disinfectant solution, and let it stand for 10 minutes. Step 3-3: Re-screening and stocking: After the water has calmed down, quickly collect the healthy eggs that float to the surface again and transfer them to the prepared nursery pond for formal hatching, discarding the dead and bad eggs that sink to the bottom.

2. The method for transporting fertilized eggs of the leopard-gill spiny perch according to claim 1, characterized in that: Step 3-2: Balancing water temperature and disinfection: Place the fertilized eggs in a bucket of water at about 24℃ for 10-20 minutes for disinfection, and then raise the water temperature to 26℃ for 10-20 minutes.

3. The method for transporting fertilized eggs of the leopard-gill spiny perch according to claim 1 or 2, characterized in that: The wet weight of the fertilized eggs in the packaged water was 8 g / L.

4. The method for transporting fertilized eggs of the leopard-gill spiny perch according to claim 3, characterized in that: The packaging bag is a double-layer polyethylene bag.

5. The method for transporting fertilized eggs of the leopard-gill spiny perch according to claim 4, characterized in that: The temperature control device is an ice pack.

6. The method for transporting fertilized eggs of the leopard-gill spiny perch according to claim 1 or 2, characterized in that: In step 3-2, when balancing the water temperature and disinfecting, use 1-5 ppm of effective iodine for a short 10-minute medicated bath.