FI91352C - Feed for the cultivation of crayfish or equivalent and method of manufacture and use of feed for the feeding of crayfish or equivalent - Google Patents

Description

i 91352

Feed for the rearing of crabs or the like and its method of preparation and use in the feeding of crabs or the like - Foder for the production of crabs or similar feedingstuffs - the same method for the production and disposal of crabs or similar feedingstuffs for the production of crabs or the like

The invention relates to a feed for the cultivation of crabs or veal according to the preamble of claim 1. The invention also relates to a process for the preparation of feed and its use for feeding crabs or crabs.

10 Crab fishing in natural waters is increasingly based on crab populations or additions to crab populations. The crayfish pups are reared from the maturation stage to a suitable planting size under conditions arranged for rearing, in which the pups can be fed artificial feeding.

However, there are problems in crab farming that have slowed the spread of crab farming. The biggest problem is the crab-specific tendency to cannibalism. During its growth phase, the crab changes its shell ten times and every 20 times it is exposed to being eaten by its fellow species.

To prevent this, the crabs must be placed in their own compartment to grow, or the place where the crabs are reared must be provided with suitable places of refuge where the crabs can hide during the shell change.

25 Another problem with crab breeding is related to crab feeding. The nutritional needs of crabs, for example, are relatively low compared to fish. Crab chicks only need a few feedings a day, and even then crabs eat only very little at a time. Dosing the amount of food in such a way that the correct amount is obtained for each compartment is not simple. If an overdose is used to ensure adequate dosing, the deterioration of water quality 2 and the lined and algal growth of the rearing structures will be caused. It is difficult to mechanically clean up the rearing structures or Nuuk from the firmly attached algae growth, and the handling of the rearing structures nyos 5 easily damages the crabs. Surplus feed should therefore be removed from the racks after each feeding to prevent contamination of the rearing structures and water.

There are also problems associated with the feeding of crabs with artificial feed, which are not exemplified in fish farming in a similar way. The crab is an omnivorous food that uses both living and dead food in its growth environment. The way in which a crab takes advantage of food by digesting it with its scissors and canteen legs and eating it piece by piece while tasting its food is completely different from the way 15 fish use their food. The ability to digest their food and the palatability of the food are therefore very important in crab farming.

For example, FI patent publication 73578 mainly discloses dried fodder for feeding fish, which is prepared by an acid-enanti neutralization treatment. In the drying phase, a gas is introduced into the feed, for example evening or other inert gas, whereby the dried feed is made floating. In addition, a surface layer is slowly deposited on the surface of the feed, which slowly dissolves in water.

NO-A-881290 discloses a neneteln in which feed for fish is prepared by compressing the feed into a tubular compact which is cut into small pellets by a cutter. There is enough evening inside the pellets that the feed remains on the surface of the water.

The prior art fluffy feeds mentioned above, which are mainly intended for feeding fish, are not suitable for use in feeding crabs. In this way, the feed remains on the surface of the water, 3 91352, in which case the fish are to eat the feed. After some time, the partially ingested feed sinks into the water and causes the water to become dirty. The object of the invention is to provide a feed which first sinks into the water to be eaten by the crabs 5 and then, after the crab has eaten, the remaining feed can be made to rise back to a surface from which it can be easily removed. For the time allotted for the crabs to be eaten, i.e. the time during which the feed is allowed to reach the crabs or the other to be fed in the pool, the setting stage and the prevailing conditions of the animals to be reared can also be adjusted accordingly.

These objects are achieved by means of a feed according to the invention, which is characterized by what is set forth in the characterizing part of claim 1. The characteristic features of the feed production-15 method are set out in the characterizing part of claim 4 as well as the use of the feed according to the invention in the characterizing part of claim 8.

The invention also offers other noteworthy advantages: 20 - The production method according to the invention enables the use of fresh raw materials in the production of feed. Conventional feeds contain substances that are harmful to the animals. When using the feed according to the invention, no preservatives are required, nor are acidulants or neutralizers.

- In the production method according to the invention, the larnpo state of the feed is not raised above 35 ° C, so that the molecular structure of the raw materials remains favorable from the point of view of food digestibility and absorption. The natural 30 enzymes of the raw materials are also preserved. The enzymes used to solidify the feed, e.g. mold enzymes, are natural food digestors in the digestion of crabs. Precipitation of feed with the help of the home enzyme is thus a very natural method of growing crabs. Also, sensitive or volatile flavors and vitamins as well as vitamins remain unchanged and flavors and flavors up to 4 are added in the process.

- The feed granules are soft so they are very suitable for even the smallest crab chicks.

- The granules of the feed according to the invention are relatively co-stable in water and withstand light mechanical treatment, in contrast to the granules of conventional feeds, which generally decompose rapidly into small flakes in water. The cohesiveness of the feed granules greatly facilitates the handling of surplus feed.

10 - The feed does not stick to the surfaces of the growing structures, so it is easier to clean the structures.

- When using the feed according to the invention, the water in the rearing ponds remains cleaner, reducing the cost of water purification and also reducing the regeneration of the water bodies.

15 - Empty crab shells and other debris can also be removed when peeling up unused feed.

- Surplus feed can be reused as feed material tax Surplus feed can be used, for example, as feed for fur animals.

The cumbersome feed of the invention can be prepared and dispensed, for example, by means of the equipment disclosed in the second patent application filed at the same time as the present application of the applicant, which relates to equipment for growing crabs or the like. In that device, crabs or 25 are placed to grow each in their own tray. In the method according to the invention, the equipment of the straws comprises means for precipitating proteins and shredding the feed mass into granules or counterparts of the straws, and means for collecting the excess feed from the pool. In addition, 30 separate or bodies connected to the device for heating unused fodder, for example by heating pool water.

The feed according to the invention can also be used in the cultivation of crabs or, for example, in ponds where 35 crabs are not placed in separate compartments but are provided with the necessary number of shelters in some other way. In order to heat the surplus fodder, for example, a warm mat can be placed on the bottom of the ground, on top of which the fodder is dispensed.

In the preparation of the feed according to the invention, almost all nutrients of animal or vegetable origin suitable for feeding on crayfish or freshly suitable can be used. However, abundant water-absorbing raw materials cannot be used without complicating the function of the invention. Crab feeds usually contain several dozen different nutrients. Milk, milk powder, egg, fish, meat, liver, honey, banana, soy flour, blueberry and brewer's yeast were used as raw materials in the experiments performed. In order to be able to raise the feed to the surface of the water at the end of the feeding, it contains a sufficient amount of precipitating proteins which form a binding fraction of the solid constituents of the feed. In the experiments performed, milk proteins, mainly casein, were precipitated, and precipitation was promoted by using rennet, i.e.

20 precipitating agents. A similar fraction can also be obtained, for example, with soy milk, milk powder mixed with water and soy flour. Milk powder and soy flour have been used e.g. for the preparation of dried fish feed, but their use in the manner according to the invention has not been previously described.

The feed according to the invention must also contain a suitable gas-generating component, for example a micro-strain, the microbial action of which results in the formation of gas in the feed granules. The rise of the feed granules at the end of the feeding 30 on the surface of the water in the rearing tank is based on the effect of the buoyancy provided by the gas. By the phrase "by the buoyancy of the gas" is meant, strictly speaking, the following type of physical event. The action of microbes or some other gas-generating component within the feed generates a gas that forms gas bubbles in the feed granule. It has been found that gas bubbles are most often formed at the interface of two different substances inside the feed. The formation of a gas bubble expands the feed grain, thus increasing the buoyancy-5 force acting on the granule. When the feed grain has expanded sufficiently, the lifting force is able to lift the grain to the surface. The feed materials used in the experiments performed contain germicidal microbes. Suitable microbes are found in, for example, brewer's yeast and milk.

10 Feed for crabs or vast can be prepared, for example, as follows:

The solid ingredients of the feed are ground and mixed to a uniform mass in a mixing chamber. Films and long-grain fibers that may interfere with shearing are removed from the pulp at a later stage, and a liquid component containing precipitating proteins, such as milk, is added to the mixture. Fluidizing enzymes such as home enzymes and, for example, the enzyme kyraotrypsin, which precipitates egg proteins, are also added to the mixture. Thereafter, the mixture is heated for about 0.5-2 hours. During heating, the temperature of the mixture is raised to about 35 ° C. The precipitating proteins in the mixture precipitate under the influence of the enzymes and the process caused by the lamrone and the feed mixture solidifies. At the same time, the mixture separates water and the feed 25 becomes water repellent. The feed granules do not then absorb too much water and make the invention difficult to operate.

The higher the temperature, the higher the temperature of the mixture when the mixture is precipitated, the stronger the precipitation and curing of the proteins. However, at this stage the proteins are not yet completely precipitated and the precipitation is allowed to remain slightly unfinished. Thereafter, the solidified feed mixture is shredded into suitably sized granules or the like, and dispensed into the grains or the like to be fed. The size of the feed granules is selected on the basis of the size of the animals to be fed and can be, for example, 0.5 to 10 mm. During the treatment, the feed mixture must cool to the temperature of the culture water used in each case before dosing into the culture space.

5 If the feed is to be used only at a later stage, the precipitated compound feed is cooled and packaged in suitably large packages which are stored at a temperature of about 0 ° C, where the biological activity is reduced and the feed can be stored for a limited time. When cold 10 feeds are introduced, the feed is heated to approximately the temperature of the crab's rearing water before dosing, whereby the crab agrees to eat the feed immediately, unlike when the cold feed is given. When frozen, the structure of the feed decomposes slightly and the vitamin level decreases, as with other frozen-15 products.

When using the above-mentioned equipment, the dosing pump transfers the feed mixture from the mixing tank along the filling pipe to the cylindrical dosing device, where the mixture is precipitated. There is, for example, an electrical resistance for heating the mixture in the arm dosing device. The solidified feed mixture is shredded in the dispensing device with a wire cutter and dispensed into the area to be fed, preferably via adjustable feed openings / openings, or alternatively formed into granules by means of superimposed, grating holes in the dispensing step. In the dosing phase, the dosing device advances in a circumferential path in the area to be fed and the granules or counterparts are pressed into the growth compartments through the network above them.

Dosing can also be performed using rinsed feed granules 30. In this case, only about 2/3 of the volume of the dosing device is filled with the feed mixture and the mixture is allowed to solidify. Before crushing the solidified feed mass, water is added to the metering unit. This has the advantage that the feed, which has been shredded into very small granules, can be sucked out of the 8 dosing devices even before dosing into the rearing space.

After the feeding has been carried out or already during the feeding, the water circulating in the rearing tank, the temperature of which is, for example, when growing the crabs, is preferably heated to about 20 ° C. Water heating can be performed, for example, in a heater with the help of an inlet water resistor. An increase in temperature from 2 to 5 ° C above the pool water temperature, in the example case to 25 ° C, causes an increase in the microbial activity of the uneaten feed and at the same time the continuation of 10 unfinished protein precipitations.

As a result of the increase in microbial activity, gases, mainly carbon dioxide CO2, are released into the feed granules. The gas then remains, the gas impermeable to the granules due to the impermeable protein fraction. The feed thus has the same type of fermentation 15 as when the cheese is matured, creating cavities in the cheese. When a sufficient amount of gas has developed in the feed granules, the granules rise back to the surface from which they are collected due to the buoyancy caused by the gas. In some crab species, the rearing temperature is lower than in the 20 mentioned above-mentioned crabs, and in some crab species it is even higher. However, in order to achieve the function of the feed according to the invention, the temperature of the rearing water can be raised somewhat without suffering from crabs.

The above-mentioned apparatus has means for collecting the surplus feed 25 from the basin by suction by means of a suction device into the collection tanks. Excess feed can also be removed with different flow arrangements.

The rise of unused feed to the surface can be timed appropriately by starting to heat the water at a suitable time 30 and by varying the components of the feed mixture which contribute to the formation of the gas-preventing fraction. When feeding crabs, the excess feed should be removed about 1-12 hours after feeding.

9 91352

The suitability of the feed according to the invention for feeding crab fry was investigated in an experiment in which fish feed commonly used in crab farming was used as a reference feed. In the experiments, feed was prepared for each feeding 5 times separately. Crabs were plated in a 0.3 m2 basin at different densities and fed twice a day.

At the start of the experiment, freshly peeled crabs with a mean length of 9.6 mm and a mean weight of 24 mg were placed in the ponds. The experiment was continued for 44 days. During this time, 10 crabs changed their shells four times. The fourth shell change of the crabs fed the feed according to the invention started 35 days after the start of the experiment and ended 42 days later. The fourth shell change of the crabs fed the comparative feed started five days later and lasted 15 significantly longer. In the feed test, two different feeds according to the invention were used, carbohydrate-containing feed (feed 1) and normal feed (feed 2).

The following tables show the average length of the crabs 20 as well as the average weight after the second and fourth shell changes.

Table 1. Second shell change

Average length (1) Average weight mm g

Feed 1 7.3 / 14.8 0.08 25 Feed 2 7.3 / 14.8 0.08

Reference feed 6.6 / 13.4 0.05

Table 2. Fourth shell change

Average length (l) Average weight mm g 30 Feed 1 9.3 / 18.6 0.17

Feed 2 9.5 / 19.3 0.18

Reference feed 8.7 / 17.7 0.14 (1) Lobster back length / total length 10

At the end of the experiment, it was found that the crab chicks had grown and the bark changes had taken place normally or even at a slightly faster pace. The test mixtures thus show that the feed is suitable for feeding crabs, especially well for the rearing of the 5 start stages of crabs.

The invention is not limited to the embodiment described above, but can be modified within the scope of the appended claims. The feed according to the invention is also suitable as a feed for other aquaculture species such as fish.

Claims (10)

91352 A feed for the cultivation of crabs or the like, consisting of raw materials from animals and / or plants, which feed is formed into granules or the like of suitable size, the gas formation of which is the result of the action of microbes in the granules to be obtained, whereby the gas said granules being raised to the surface of the water in the culture tank, characterized in that the feed comprises a gas-impermeable fraction consisting of 10 precipitated proteins which binds the solid constituents of the feed, whereby gas-filled cavities can be formed under the action of microbes. Feed according to Claim 1, characterized in that the protein fraction is formed by proteins which, when precipitated, cause water to be released from the feed. Feed according to Claim 1, characterized in that the protein fraction consists of milk proteins, in particular casein. Process for preparing a feed according to Claim 1, characterized in that the proteins contained in the feed are precipitated to obtain a gas-impermeable fraction which binds the solid constituents of the feed and at the same time a solid feed mass by using a rennet for less than 0.5 hours. At a temperature of 36 ° C, after which the feed mass is formed into granules or the like for dosing. A method for preparing a feed according to claim 4, characterized in that proteins are used in the feed mixture which, when precipitated, cause the release of water from the feed. A method for preparing a feed according to claim 4, characterized in that milk is added to the feed mixture and that milk proteins, mainly casein, are precipitated from the feed mixture. A method of preparing a feed according to claim 4, characterized in that the precipitated feed is cooled to about 0 ° C and packed in suitably sized packages for intermediate storage and in which temperature the feed is stored for a limited time, after which the feed is preferably heated or heated for 10 hours. and that the feed granules or the like are formed before the feed is packaged in said packages or that the feed granules or the like are formed during the feeding of the feed to the crabs or the like. Use of a feed according to claim 1 for feeding crabs or the like, wherein the crabs or the like formed from the feed when feeding the crabs or the like land in the rearing space within the reach of the crabs or the like is characterized in that the or the like by heating them and that the unused feed granules or the like are allowed to rise to the surface of the water in the growing tank under the effect of the 25 buoyancy produced by the gas and removed from the growing tank. The use of feed according to claim 8, characterized in that the unused feed granules or the like are heated by heating the water in the rearing tank, wherein the temperature of the water in the rearing tank is raised to about 2-5 to 30 ° C above the normal water temperature. Use of fodder according to Claim 8, characterized in that a heating mat is placed in the rearing tank, on which the fodder is dispensed, and which, by heating the mat 91352,