Feed for aquatic animal larvae

Abstract

This invention relates to aquatic animal feed containing preserved eggs and / or trochophores of dipodial crustaceans. The invention further relates to the use of preserved eggs and / or trochophores of dipodial crustaceans as feed for aquatic animal consumption, the feed being given to cultured aquatic animals 0-10 days after hatching. The invention further relates to the following steps: - Placing live diptychs in water inside a container, - Stressing and / or inducing dipodial crustaceans to release eggs, -Regarding methods for collecting eggs from dicrustaceans, including separating the eggs from water. The present invention further relates to a method for preserving dicrusted eggs and / or trochophores, comprising the following steps: - Heating seawater to 50-100 degrees Celsius, - Adding eggs and / or trochophores to seawater, - Keep the eggs and / or trochophores in seawater for 1 to 60 seconds, - Regarding methods for separating water from eggs and / or trochophores.

Description

Technical Field

[0001] The present invention relates to a feed for aquatic animals as described in the preamble of independent claim 1. The present invention also relates to a method for collecting, storing and using bivalve eggs and / or trochophores.

Background Art

[0002] Over the past few decades, there has been a strong focus on developing and identifying new resources for marine raw materials and nutritional products. The increasing fish farming activities have led to a high demand for marine raw materials suitable for use as feed. Furthermore, research has focused on the fact that there is no alternative diet suitable for feeding the initial growth stages of marine organisms such as marine larvae, particularly live prey organisms.

[0003] The high mortality, poor growth, and stunted development during the initial cultivation of marine larvae have been a major problem for the cultivation of many fish species. This is considered to be one of the main bottlenecks for the successful commercial exploitation of fish farming. The natural food of marine larvae is typically small planktonic crustaceans such as copepods. Copepods are abundant in the sea only during certain periods, and due to the difficulty of intensive cultivation for aquaculture purposes, copepods as a natural resource as live feed are rarely used in aquaculture. Since artificial feeds and abiotic feeds have been found to be inefficient or suboptimal for marine larvae, instead, selected live prey organisms have been cultured and concentrated. So far, only two families of zooplankton, namely the Artemia genus of brine shrimp and the Rotifera genus of rotifers, have been shown to be able to be produced regularly at an acceptable cost.

[0004] However, despite numerous attempts to improve the nutritional value of these organisms through various concentration techniques, it has been found that they are still insufficient to support optimal development and growth. In addition, their cultivation is labor-intensive and costly. On the other hand, artificial feeds generally reduce survival rates and larval quality. Therefore, it is clear that there is a need for new marine resources, especially high-quality alternative marine resources suitable as initial feed to replace live prey organisms.

[0005] Most aquatic organisms have a larval stage at the beginning of their life cycle. Marine fish larvae have a very simple digestive system and require a balanced diet containing adequate amounts of protein, phospholipids rich in marine polyunsaturated fatty acids, vitamins, and minerals. Phospholipids rich in polyunsaturated fatty acids are one of the essential nutrients, and it is impossible to fully satisfy this requirement when using rotifers, Artemia, or formulated dry granular feeds. Because larvae have small mouths, the size of the feed is also important. Small granular dry feeds can be manufactured, but they do not have the appropriate biochemical properties. Small granular dry feeds with a large surface area-to-volume ratio certainly have a high rate of nutrient leaching. Leaked nutrients become an excellent breeding ground for bacteria, and such an environment is ultimately deadly to fish.

[0006] Insufficient feeding during the early stages of development of marine larvae such as Atlantic cod, Atlantic halibut, and flounder can lead not only to reduced growth but also to high mortality rates, poor larval quality, pigmentation abnormalities, and developmental disorders. Furthermore, these developmental stages require small prey and have very high nutritional requirements. Marine larvae and shrimp larvae are typically planktonic organisms that inhabit the water column, relying on floating prey and food particles, and remaining in the water column until these are consumed.

[0007] Feeds rich in marine unsaturated fatty acids have been proven beneficial for the normal growth and improved nutritional value of many farmed aquatic species consumed by humans. Today, the aquaculture of many marine fish and crustacean species relies heavily on the feeding of live feed during their early growth stages.

[0008] In aquaculture, the most common feed organisms used for marine larvae are rotifers, particularly several species belonging to the family Heterocystidae, and brine shrimp of the genus Artemia (the only genus belonging to the family Artemiidae). However, the nutritional composition of rotifers and Artemia is inherently poor, and to increase their nutritional value as feed for marine larvae, they need to be fortified with marine lipids, especially omega-3 fatty acids. Despite the above fortification, however, both Artemia and rotifers are still not considered nutritionally optimal for many larval species. This is reflected in mortality rates, growth rates, pigment abnormalities, and developmental abnormalities. Therefore, it is clear that more suitable alternative feeds are needed for the early feeding larval and early life stages of many farmed aquatic animals.

[0009] European Patent No. 2916664 describes an animal feed containing stage I barnacle eggs and / or nauplius. However, barnacle eggs may be too large to feed on for the larvae of some species. Furthermore, the eggs are not readily available. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] European Patent No. 2916664 [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] the purpose One object of the present invention is to provide new biological resources for nutritional products such as animal feed, as well as new methods for utilizing marine biological resources that can be industrially applied for various purposes. Therefore, another object of the present invention is to provide new biological resources for marine-derived products, as well as methods for their utilization and production.

[0012] A further objective is to provide novel biological resources for specific pure forms of marine-derived products without mixing them with other biological materials. In particular, a further objective of the present invention is to provide optimized feeds useful for feeding aquatic animals such as fish and crustaceans, especially during their early growth stages.

[0013] Newly hatched larvae are typically 1.5–5 mm in length and weigh approximately 0.01–0.2 mg in dry weight per individual; however, these values ​​can deviate due to the vast biodiversity and early life cycle strategies of finned fish and other aquatic animals. Another objective of the present invention is to provide feed of a suitable size for larvae to eat, and more specifically, since many potential farmed species have small mouths, the feed units should not exceed 100 μm. For the larvae of some species of groupers and snappers, the preferred size of the initial feed is smaller than 100 μm, preferably 70–80 μm.

[0014] Another object of the present invention is to provide a feed for larval fish based on the readily available biological resources, and furthermore, the feed must be easily accessible to the larval fish.

[0015] Another objective of the present invention is to provide a robust and stable feed that can be introduced into aquaculture equipment for larval fish without releasing nutrients into the tank water. Nutrients released from feed become the main growth substrate for microorganisms in aquaculture.

[0016] Another objective of the present invention is to provide feed that is easy for aquaculture farmers to transport, store, handle, and feed.

[0017] Another object of the present invention is to provide a feed that has satisfactory or sufficient nutritional value. [Means for solving the problem]

[0018] The above objectives and needs are addressed by the feed, method, and use according to the feature portion of the independent claim. Further advantageous features are described in the corresponding dependent claims.

[0019] This invention relates to an aquatic animal feed containing preserved eggs and / or trochophores of dipaceous fish. The eggs and / or trochophores are preserved so as not to develop further. It is necessary to prevent further development of the eggs and trochophores because if development progresses further, they may form a calcium carbonate shell, which may be difficult for larvae to digest.

[0020] The feed may contain non-living organisms, i.e., non-living eggs and trochophores. The eggs and trochophores may be dead but still intact and may have the same or very similar biochemical contents and nutritional value as living eggs and trochophores. The eggs and / or trochophores can be fed to the larvae individually or as a composition of individual eggs / trochophores dissolved in water before or at the time of feeding.

[0021] Furthermore, the eggs must be handled carefully to prevent damage and / or leakage. This preserves their nutritional value and prevents bacterial growth in the system. Unstorage eggs begin to develop after about 20 minutes in water at approximately 10 degrees Celsius. At approximately 30 degrees Celsius, which is the normal temperature for farming tropical fish and shrimp, the eggs begin to leak out after a few seconds.

[0022] Eggs and trochophores can be preserved by direct freezing, freeze-drying, pasteurization, use of chemicals, autoclaving, low-temperature plasma, pulsed electric field, radiation, high-pressure treatment, and / or UV treatment. Chemicals that may be used include microbial inhibitors such as sodium benzoate, potassium sorbate, and sodium chloride.

[0023] The eggs and trochophores can be preserved by heating in water. The eggs and trochophores can be transferred to water at 50 - 100 degrees Celsius. The water temperature can be 50 to 75 degrees Celsius, or 55 to 65 degrees Celsius, or 62 degrees Celsius. The eggs and trochophores may be maintained at this temperature for 1 - 60 seconds, or 1 - 10 seconds.

[0024] The eggs and trochophores can be preserved by heating with electromagnetic radiation such as hot air, microwaves, or by using an autoclave.

[0025] If the heating time of the eggs is too long or the temperature is too high, the eggs may clump together to form a mass of eggs. The mass of eggs may not be edible for the larvae of aquatic animals. Furthermore, the treatment of the eggs and trochophores needs to minimize the impact on the nutritional value of the feed such as vitamins and / or proteins.

[0026] The preserved eggs have sufficient strength for handling and transportation. The stronger the eggs are, the better the biosafety.

[0027] The aquatic animals that ingest the feed can be the larvae of fish, crustaceans, coral polyps and / or mollusks. More specifically, this animal can be the larvae of cultured aquatic animals, such as the larvae of fish like barramundi, sea bass, flounder, etc. More specifically, this animal can be the larvae of crustaceans such as tropical shrimp (Litopenaeus vannamei, Penaeus monodon), lobster, squid, cuttlefish, octopus, etc., and the larvae of mollusks.

[0028] Feeds containing eggs and / or trochophores can be prepared in pellet form because it facilitates handling and distribution to aquatic animals. That is, a single pellet may contain thousands of eggs. Pellets can be 0.1–1 cm in size, and 0.3–0.6 cm in size for larvae. Pellets may be spherical, cylindrical, or other shapes, and may have the same or different lengths in different directions, or different dimensions. In this specification, the term “size” refers to the length of the longest direction or dimension of the pellet.

[0029] The pellets can be stored frozen at temperatures below 0°C. When the egg pellets are supplied to the larva tank, they dissolve quickly, and each egg is evenly distributed in the water column at the top of the tank. Another way to prepare eggs for larvae is to put water, preferably seawater or brackish water, in a bucket and add the eggs. The pellets dissolve in a few seconds to a few minutes (depending on the amount added per liter), and each egg is evenly distributed in the water column. The eggs can then be fed by hand or supplied to the tank over a long period of time using a pump.

[0030] If the eggs and / or trochophores contain some water, and the solid content of the pellets can be 1-25%, or preferably 5-12%, then manufacturing the pellets may be simpler. Furthermore, it may be advantageous to manufacture pellets containing a predetermined number of eggs and / or trochophores per gram, in which case feeding calculations may also be easier. For example, if 50 eggs should be added per milliliter of water in the container, and the feed is defined as containing 2 billion eggs / kg, then this may be easier for fish farmers. The same applies to trochophores, or combinations of eggs and trochophores.

[0031] In another aspect, the present invention relates to the use of preserved eggs and / or trochophores of diptychs as feed for aquatic animals. The nutritional value of feed is generally very important, and especially important for the larvae of aquatic animals, as mentioned above. Diptych eggs are highly nutritious and contain important omega-3 fatty acids, particularly those called HUFA-hyperunsaturated fatty acids such as DHA, EPA, and ARA fatty acids. The lipid composition of the eggs is shown in Table 1 below.

[0032] [Table 1]

[0033] The use of preserved eggs and / or trochophores of dipodial crustaceans according to the present invention may involve directly feeding the eggs to aquatic animals or incorporating them into feeds containing other components.

[0034] The use of preserved dipaceous eggs allows them to be given to aquatic animals from the time the eggs hatch or from the first day the larvae begin to eat. This means that the eggs are given as the initial food source. Depending on the animal species, the eggs may be fed to aquatic animals for several days, such as for at least the first 10 days after feeding begins. The eggs can also be given to animals during their juvenile and adult stages.

[0035] In another embodiment, the present invention relates to a method for collecting eggs from dicrustaceans. The method involves the following steps: a) Arranging live diptychs in water in a container, b) Stressing and / or inducing diaconids to release eggs, c) A method that includes separating eggs from water.

[0036] Dioscored mussels naturally spawn in the Northern Hemisphere from April to May to June, but may also spawn in the summer and autumn. In the Southern Hemisphere, spawning is often in the spring, and in some regions it can occur from September to November. However, most dioscored mussels (for example, Mytilus edulis) lay eggs continuously, so they can spawn for extended periods. Also, they usually spawn in response to stress; by placing live dioscored mussels in a container of water and applying stress, eggs are released into the water surrounding the mussels. When dioscored mussels spawn, they also release pheromones into the water, which induce other dioscored mussels of the same species to spawn. Therefore, the water in the container contains eggs and pheromones, and the eggs can be collected by separating the water from the eggs.

[0037] The eggs can be removed from the container continuously or intermittently by draining the eggs and water while the mussels are still releasing their eggs, or the eggs can be left in the container until the mussels stop laying eggs. It is better to continuously remove the eggs and water, as the eggs may be eaten by the mussels if left in the container for too long.

[0038] When removing water and eggs from a container intermittently or continuously, eggs can be separated from the water, for example, by passing the mixture over a filter, sieve, or similar device. Since eggs are typically about 70 μm in size, the mesh width of the filter should be less than 70 μm. Eggs can be fragile and may burst or leak if not handled gently when removing them from the container or separating them from the water. Filters and systems should be designed accordingly.

[0039] To remove a sufficient amount of water and, if necessary, unwanted materials such as shell fragments or debris from the eggs, the filter is arranged in multiple layers. The unwanted materials are filtered out on the first layer, while the eggs and water can pass through. On the next layer, only the water passes through the filter, leaving the eggs intact. The filter vibrates to remove even more water.

[0040] Water and eggs can be removed from the container by pumping, suction, flow, or gravity by positioning the processing equipment vertically below the container. Eggs can be fragile, and all handling must be done very gently to avoid breakage and / or leakage.

[0041] As described above, when diptychs lay eggs, they also release pheromones into the water, which can induce other diptychs of the same species to lay eggs. Removing the eggs by draining the eggs and water from the container reduces the amount of pheromones in the water, which may weaken the induction of mussel spawning. Therefore, the water separated from the eggs as described above can be circulated back into the container containing the living diptychs to induce further spawning. In this way, all of the diptychs can be released. Diptychs can lay eggs equivalent to about 4-10% of their body weight in a few days.

[0042] Dioscorea can be subjected to various stresses, such as changes in freshwater, salinity, water temperature, and mechanical influences. Furthermore, pheromones from other dioscorea can sometimes trigger spawning.

[0043] The water in the container may be replaced continuously or at intervals to maintain a healthy environment for the dipaceous crustaceans. In addition to, or in combination with, the addition of new water, the water may also be treated and recycled. Methods for water replacement and maintaining a healthy environment for organisms in the container are well known to those skilled in the art. Water separated from the eggs may be added to the container through a separate inlet, or it may be added together with the replacement water and / or recycled water.

[0044] Not only eggs, but also trochophores or a combination of eggs and trochophores can be used as feed. To collect trochophores, eggs can be transferred to a pool of water at a concentration of, for example, 1 to 50 grams of eggs per liter of water. This water may contain some of the water separated from the eggs as described above, and such water may contain sperm capable of fertilizing the eggs. The water temperature should be between 5 and 25 degrees Celsius. The water should be agitated with a pump or air should be bubbled to prevent the eggs from sinking. The eggs are kept in the water for 1 to 24 hours until a desired proportion of the eggs have developed into trochophores. The required time depends, in particular, on the temperature. The trochophores are separated from the water in the same manner as described above for separating the eggs, preferably by using a 25 μm filter, and are processed in the same manner as the eggs.

[0045] Once the eggs and / or trochophores are separated, they must be preserved before they can be used as feed for aquatic organisms. Another aspect of the present invention relates to a method for preserving dicrusted eggs and / or trochophores, comprising the following steps: i) Adding eggs and / or trochophores to seawater, ii) Heating seawater to 50-100 degrees Celsius, iii) Keep the eggs and / or trochophores submerged in water for 1 to 60 seconds, iv) A method comprising removing eggs and / or trochophores from water.

[0046] Steps i) and ii) can be carried out by adding eggs and / or trochophores to seawater at ambient temperature and then heating the mixture to 50-100 degrees Celsius, or by heating seawater to 50-100 degrees Celsius and then adding eggs and / or trochophores.

[0047] As described above, eggs and / or trochophores must be preserved to prevent some larvae from progressing to developmental stages that are difficult to digest. Furthermore, preserving the eggs makes them less prone to breakage and more resistant to rougher handling and processing. When preserved eggs are used as feed for aquatic animals, they will not break and leak into the surrounding water. Because the eggs are whole and relatively stable, there is little to no leakage of nutrients into the water surrounding the aquatic animals compared to using other feeds (both live and dry), and the growth of bacteria in the tank is also suppressed. When preserving eggs and / or trochophores according to the method described above, in step II, the water may be heated to a temperature of 50-75 degrees Celsius, or 55-65 degrees Celsius, or even 62 degrees Celsius. The eggs and / or trochophores may be maintained at this temperature for 1-60 seconds, or 1-10 seconds. Once the eggs and / or trochophores are sufficiently heated, they can be removed from the water by filtration, for example, as described above.

[0048] Another aspect of the present invention relates to a method for producing pelletized feed for aquatic animals, comprising dicrusted eggs and / or trochophores. By producing pellets of eggs and / or trochophores, aquaculture farmers can more easily measure and handle the feed. The method involves the following steps: v) Adding a small amount of water to the eggs and / or trochophores collected and preserved by the above method, vi) Manufacturing pellets and vii) A method comprising freezing the pellets containing eggs and / or trochophores until use.

[0049] Pellets can be produced by adding larger units, such as droplets or eggs / seawater, to a cryogenic medium such as liquid nitrogen.

[0050] Water can be added to the eggs and / or trochophores, for example, in equal volume ratios of water and eggs and / or trochophores, until the mixture becomes fluid. This mixture can then be dripped into fluid nitrogen at a temperature of -196 degrees Celsius to produce small pellets. The pellets may be spherical, having a diameter of 0.1–1 cm, more preferably 0.3–0.6 cm. The pellets are stored at this temperature until use.

[0051] Further ingredients may be added to the feed and / or pellets.

[0052] Another aspect of the present invention relates to a method for preparing a diet for aquatic animals, comprising dicrusted eggs and / or trochophores. The method comprises the following steps: viii) A method comprising placing frozen pellets containing eggs produced by the above method into a container filled with water at 0 degrees Celsius or higher.

[0053] The water may contain seawater, and preferably, the amount is less than the amount of seawater in the tank of the aquatic animal receiving the feed. The pellets will melt during thawing and become individual eggs.

[0054] If the water in which the pellets are thawed contains less seawater than the seawater surrounding the aquatic animals, the thawed eggs will remain in the upper water column of the seawater surrounding the animals. The animals will have easier access to feed, and most of the eggs will be eaten. This improves the economics of aquaculture. Furthermore, because the pellets are preserved and remain suspended in the upper water column, fewer nutrients are released into the water of the aquaculture tank, and less sediment settles at the bottom of the tank. With fewer nutrients and less sediment, the water in the tank becomes cleaner, and less cleaning of the tank walls and bottom is required.

[0055] The specific features, structures, or properties described above can be combined in any suitable manner in one or more embodiments. [Examples]

[0056] Embodiments of the present invention will be described in detail below. The examples are provided to clarify the present invention and should not be used to interpret them as limiting the present invention. Egg collection

[0057] In this experiment, we used the mussel *Mytilus edulis*, but any bipodial organism may be used. We fed the mussel eggs to the larvae of fish, but the eggs can be fed to the larvae of any aquatic animal.

[0058] Live mussels were placed in a container filled with seawater. While various methods can be used to induce spawning simultaneously, in this experiment, heated freshwater was used to raise the temperature to approximately 15-20 degrees Celsius and lower the salinity from 1 / 1000 to approximately 15. Once the first mussels began spawning, the water was recirculated and then treated with pheromones sufficient to induce spawning in the remaining mussels without using freshwater.

[0059] Seawater was poured over mussels in a container, and water and eggs were continuously collected from the container's outlet. The water and eggs were spread over filters arranged in multiple stages, with the upstream filter having a mesh width larger than the eggs (e.g., 90 micrometers) and the final filter having a mesh width less than 70 micrometers (e.g., 20 micrometers). In this way, eggs with a diameter of approximately 70 micrometers were collected in the final filter. Particles larger than the eggs, such as shell fragments and debris, were removed by the upstream filter, while particles smaller than the eggs were removed by the water.

[0060] A tank was placed below the filter to collect the water flowing through it. The water was then returned to the container along with the mussels for reuse, and the pheromones in the water further stimulated spawning in the mussels.

[0061] The eggs were removed from the filter and transferred to a container filled with heated seawater. The eggs were then heated to 62 degrees Celsius for 1 to 10 seconds for storage.

[0062] After preserving the eggs, they were removed from the water and sterile or disinfected seawater was added to prepare them for pellet production. The pellets were approximately 0.3–0.6 mm in size and had a solid content of approximately 5–12% by dry weight. The pellets were frozen on liquid nitrogen at approximately -196 degrees Celsius.

[0063] When eggs were used, they were thawed in water with a lower seawater content than the water in which the larvae were raised. In this experiment, the seawater content of the water in which the eggs were thawed was approximately 0.5-2%, while the seawater content of the water in which the larvae were raised was approximately 2.5-4.0%.

[0064] Baranbera Eggs were fed to larvae of the Barambera fish in two different experiments, according to the table below.

[0065] [Table 2]

[0066] The larvae in the tank showed a significant increase in weight and survival rate compared to the tank fed only concentrated rotifers, which is the usual diet. Since young larvae cannot survive without food for three full days, this experiment clearly indicates that the larvae ate the eggs of the mussel (Mytilus edulis).

[0067] Furthermore, tanks containing larvae fed with mussel (M. edulis) eggs were far cleaner than tanks containing larvae fed with concentrated rotifers. While tanks normally need to be cleaned daily, the tanks using mussel (M. edulis) eggs as feed did not require cleaning. This is because the eggs were robust and did not break, resulting in fewer nutrients accessible to the bacteria in the tank.

[0068] Furthermore, because the eggs do not sink as quickly as regular food, food does not accumulate at the bottom of the tank, and this does not cause bacterial growth. The eggs were either eaten or washed away by the water flowing through the tank.

[0069] Red sea bream: An industrial-scale trial was conducted at a fish farm in Greece. The trial involved approximately 1.5 million larval red sea bream. They were fed only preserved mussel (M. edulis) eggs from day one. The larvae were removed and examined to see if they consumed the feed and how much they ultimately ate.

[0070] 80% of the larvae studied fed on the first day, but only 20% fed when given concentrated rotifers. Larvae fed with mussel (M. edulis) eggs grew considerably better than those fed only concentrated rotifers. Larvae fed with diptych (M. edulis) eggs grew approximately two days faster in the first 10 days after hatching and had a very low mortality rate. Digestion and satiety in the stomach and intestines were good throughout the entire period. This difference is sensational and will have a significant impact, as feed and feed intake are known to limit development from egg to juvenile.

[0071] Madara We conducted an attraction test by feeding Pacific cod larvae with eggs from the Mytilus edulis mussel. The Pacific cod larvae ate and digested the eggs very well, and based on the results for the Baranbera and Pacific cod described above, we expect that the growth and survival rate of the Pacific cod larvae will also improve.

[0072] In another experiment, Atlantic cod juveniles were fed mussel (M. edulis) eggs on their first feeding day and compared to Pacific cod fed concentrated rotifers. Nine 400-liter flow-through tanks containing newly hatched Atlantic cod (100 individuals per liter) were used, with a control and two treatments (all in sets of three). In the control treatment, rotifers were fed from the first feeding day. In one of the treatments, mussel (M. edulis) eggs were used for feeding for the first five days.

[0073] Histological analysis was performed at the University of Patra in Greece. Atlantic cod fed with Mytilus edulis eggs had improved intestinal and liver quality, which can be interpreted as a healthy gut that can utilize ingested feed and assimilate it for growth. The eyes and gills of Pacific cod fed with Mytilus edulis eggs were also of better quality compared to the control. At the end of the study, Atlantic cod fed with Mytilus edulis eggs had an individual weight approximately 10% higher than the control, and their survival rate was 35%, compared to 25% for the control. From this study, it is clear that Mytilus edulis eggs provide marine larvae with nutrients that are limited in rotifers.

Claims

1. Aquatic animal feed characterized by containing preserved eggs and / or trochophores, rather than live eggs and / or trochophores of dipaceous crustaceans.

2. The feed according to claim 1, characterized in that the aquatic animal is a fish larva, a crustacean, and / or a mollusk larva.

3. The feed according to any one of claims 2 to 3, characterized in that the aquatic animal is a larval fish.

4. The feed according to claim 1, characterized in that the eggs and / or trochophores are preserved by direct freezing, freeze-drying, pasteurization, use of chemicals, autoclaving, low-temperature plasma, pulsed electric field, radiation, high-pressure treatment and / or UV treatment.

5. The feed according to claim 4, characterized in that the eggs and / or trochophores are preserved by heating in water.

6. The feed according to claim 4 or 5, characterized in that the eggs and / or trochophores are preserved by heating them to a temperature of 50 to 100 degrees Celsius and holding the eggs and / or trochophores at this temperature for 1 to 60 seconds.

7. The use of preserved eggs and / or trochophores as feed for aquatic animals, characterized in that the feed is given to the cultured aquatic animals 0 to 10 days after hatching.

8. A method for collecting eggs from dipaceous crustaceans, consisting of the following steps: 1) Placing live diptychs in water inside a container, 2) Stressing and / or inducing stress on the dipodial crustaceans in order to release eggs, 3) Separating the eggs from the water, 4) A method characterized by comprising introducing the water from step 3 into the container.

9. The method according to claim 8, characterized in that while the dipodial crustacean is releasing its eggs, the eggs and water are intermittently or continuously removed from the container.

10. A method for preserving dipodial eggs and / or trochophores used as feed according to claim 1 or 2, - Heating seawater to 50-100 degrees Celsius, - Adding eggs and / or trochophores to seawater, - Holding the eggs and / or trochophores in the water for 1 to 60 seconds, - A method comprising separating water from the egg and / or trochophore.

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