JPH0898659A - Fish feed having improving effect on stress - Google Patents

Abstract

PURPOSE: To obtain a feed for fishes, having a reducing effect on stresses such as water temperature stress and dissolved oxygen stress and suitable for the production of cultured fishes. CONSTITUTION: This feed used for fishes and having an improving effect on stresses contains DHA or its ester and/or a phospholipid as nutrition-increasing agents. The DHA or its ester and/or the phospholipid are added in amounts of 1-2wt.% and 3-5wt.% as lipids, respectively, on the basis of the formula feed in dependence on purity, contents, feed composition, etc. The DHA ester is preferably highly pure DHA ethyl ester. The phospholipid is preferably soybean lecithin. Wheat flour, starch, water and oils are added as essential ingredients. The kinds of the target fishes are especially not restricted, but the fry of Chrysophyrys major are most suitable as revealed in the drawing wherein the good effect of the DHA ethyl ester on the body length of the Chrysophyrys major is shown.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fish feed having an improving effect on stress. More specifically, the present invention provides an effect of improving the ability to temporarily stop feeding due to strong stress associated with changes in the breeding environment, an effect of preventing reduction of vitality during transportation of live fish, an effect of enhancing resistance to environmental pollution, and prevention of disease. The present invention relates to a feed for fish having effects, and particularly to a feed for red sea bream larvae.

[0002]

2. Description of the Related Art In recent years, techniques for producing artificial seedlings of seafood have been developed, and red sea bream, stone bream, oyster oysters, flathead flounder, flounder, tiger puffer fish, flounder, striped horse mackerel, yellowtail, ayu,
It becomes possible to produce artificial seedlings of various marine products such as prawns,
A large amount of artificial seedlings are being produced for red sea bream and flounder. These depend on the mass production of fry, which is a seedling, and are affected by the growth of fry, the survival rate, and the growth of healthy seedlings without malformations.

In fish farming, including the production of artificial seedlings, resistance to stress such as changes in water temperature and lack of oxygen is a property required for healthy and efficient breeding of fish. However, no effective means has been found other than directly setting the breeding environment. Especially in the case of larvae, the survival rate drops drastically, and there is a strong demand for measures against it. The larvae of many fish species usually become capable of digesting the food within a few days after hatching, and when they are cultured, their initial food is as a first feed, such as horned rotifer, oyster larva, and fertilized sea urchin eggs. Is giving. Then, a slightly larger zooplankton is fed according to the growth of the larva. Although the breeding environment changes according to the growth of the larvae, the larvae are strongly stressed by the movement, temporarily stop feeding and stop growing, and the survival rate decreases. In the production of aquaculture seedlings, there is a strong demand for raising larvae that are resistant to stress, and for discovering substances that are effective in reducing stress in larvae.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fish feed suitable for producing a cultured seedling which is effective in reducing stress.

[0005]

[Means for solving the problems] The strong stress caused by changes in the breeding environment or movement temporarily stops feeding and stops the growth, and the survival rate declines. In addition to being kept so that it does not exist, it is necessary to be resistant to stress.
The present inventor has found that the dietary docosahexaenoic acid ethyl ester and / or phospholipids have an effect of improving stress on red sea bream larvae, and then confirmed that the same effect can be obtained with juvenile red flounder, juvenile pearl oysters, larval flounder, etc. The inventors have earnestly studied this improvement effect and completed the present invention.

The present invention is a fish feed having an improving effect on stress, which is characterized by being fortified with docosahexaenoic acid or its esters and / or phospholipids.

The target fish of the present invention is not particularly limited. Preferred examples include red sea bream, stone bream, stone pearl oyster, stone flounder, flounder, flounder, tiger puffer, stone flesh, striped horse mackerel, yellowtail, sweetfish, and prawns that artificially produce seedlings. The most preferable target fish include larvae of red sea bream, juvenile flathead flounder, larvae of red sea bream, and larval flounder.

As the fish feed of the present invention, almost the same raw materials as conventional fish feeds can be used, and squid meal, krill meal, white meal, casein, soybean oil residue, corn used in general fish feeds. The main raw material is animal and vegetable protein sources such as gluten meal, and starch compounds such as starch and wheat flour contain other vitamin mixtures, minerals and trace metals. The above starch is used as a binder. Particularly for adult fish, it is necessary to add a large amount of lipid, and starches are preferable. However, in the fine particle feed for larvae and fry, zein is used as a binder, and thus zein is used in the examples of the present invention. When using starches, depending on the hardness of the intended fish feed, corn, wheat,
Rice, tapioca, milo, sorghum, horse mackerel, sweet potato,
Various types of starch such as sago palm can be used.

Oil can be further added to this to improve nutritionally. A high content of oil has an excellent effect on promoting the growth of fish. The oil component includes animal fats and oils and vegetable fats and oils in addition to fats derived from raw materials such as fish meal. As a fat and oil, ω of highly unsaturated fatty acid
Those containing 3 series fatty acids are preferable, and the melting point is -20 to 50.
It is preferable to use one having a temperature of ° C. Furthermore, as a food attractant, taurine, betaine, alanine, inosine-5'-
Monophosphoric acid (IMP) can be used.

Docosahexaenoic acid or its esters and / or phospholipids are used as substances that enhance the effect of improving stress.

Docosahexaenoic acid is 4,7,10,1
It is a straight-chain hexaene having 22 carbon atoms and having cis double bonds at the 3, 16 and 19 positions. Docosahexaenoic acid derived from natural products is contained in natural fats and oils, particularly marine fats and oils such as mackerel, sardines, and cod, as itself or as a derivative such as glyceride. Docosahexaenoic acid and its esters, amides, etc. are associated with thrombotic diseases, inflammatory diseases,
It is known to be useful for treatment and prevention of cancer and the like, and methods for extracting docosahexaenoic acid derived from natural fats and oils have been developed for these uses. In the present invention, docosahexaenoic acid is used as the docosahexaenoic acid ester, and the purity thereof is preferably 90% or higher.

The high-purity docosahexaenoic acid ester is obtained by, for example, rectifying a fatty acid mixture containing docosahexaenoic acid, and then forming a urea adduct to purify the mixture (JP-A-57-149400 and JP-A-58-58). No. 8037). The high-purity product obtained by this method contains other C22 highly unsaturated fatty acid ester and contaminating C20 highly unsaturated fatty acid ester in docosahexaenoic acid, and its purity is about 90%. Also, a reversed-phase partition type column supercritical fluid for separation and purification of eicosapentaenoic acid having 20 carbon atoms and 5 double bonds or its ester and docosahexaenoic acid having 22 carbon atoms and 6 double bonds or its ester It can be obtained by a method utilizing an extraction process (for example, Japanese Patent Laid-Open No. 58-88339). In this method, the concentration of docosahexaenoic acid is 30
%, It is difficult to separate docosahexaenoic acid and eicosapentaenoic acid because they contain the same amount of eicosapentaenoic acid. As a result, docosahexaenoic acid with a purity of 95% has a yield of 40%. Is obtained at a rate.

Further, the high-purity docosahexaenoic acid ester is a mixture of fatty acid esters obtained from natural fats and oils containing docosahexaenoic acid and / or its derivative, is precision distilled under high vacuum by a plurality of distillation columns, and has 2 carbon atoms.
The fraction containing the fatty acid ester of 2 as the main component is obtained, and then this fraction is subjected to contact treatment with an aqueous medium containing a silver salt, and the resulting aqueous solution is subjected to extraction treatment with a supercritical fluid to obtain a highly pure docosahexaenoic acid ester. Is obtained by the method of separating and obtaining.

Examples of the phospholipid used in the present invention include chicken egg lecithin and soybean lecithin, and soybean lecithin shows excellent effects. Lecithin is phosphatidylcholine, and often contains phosphatidylethanolamine, phosphatidylinositol, and others as impurities. Since plant-derived lecithin is available at a much lower cost than egg yolk, soybean lecithin has been produced in large quantities and has been mainly used for food since ancient times. The type and proportion of the fatty acid chain differ depending on the place of origin and feed.

The amount of docosahexaenoic acid or its esters and / or phospholipids added varies depending on the purity, content, composition of feed, etc., but is 1 to 2% by weight of the former and 3 to 5% by weight of the latter. used. Usually, when the total amount of highly unsaturated fatty acids (EPA and DHA) is 4 to 5% by weight or more, growth and survival of larvae may be inhibited. Therefore, it is used at 2% by weight or less. However, other saturated fatty acids, oleic acid, linolenic acid and phospholipids can be used even at 10 to 20%.

The fish feed of the present invention may have any shape and size, but in the case of extrusion molding, the diameter is about 0.5 to 50 by changing the shape of the die or the like.
The length may be cylindrical with a length of about 0.5 to 50 mm. For larvae, use the form of fine grain feed. In the case of an adult fish feed, for example, a mixture of wheat flour and starch positively mixed with oils and fats, docosahexaenoic acid or its esters and / or phospholipids is kneaded and melted under heat and pressure and extruded to form granules. In this case, protein, starch, water and oil are contained as essential components, and the starch is composed of at least wheat flour and starch, and gluten in wheat flour is reticulated to give an oil content in the range of 5 to 30% by weight and 15 to 40%. A flexible, elastic, porous fish feed containing water in the range of wt.% In a reticulated tissue.

To produce a feed having a certain shape by extrusion molding, after adding fats and oils to a fish feed raw material fortified with docosahexaenoic acid or its esters and / or phospholipids, water is added for heating under pressure. It is manufactured by heating and kneading with an extruder. Fortification with docosahexaenoic acid or its esters and / or phospholipids can be used, but almost the same raw materials as conventional fish feeds can be used. Proteins such as fish meal, soybean oil cake, corn gluten meal, starch, Vitamin and minerals are contained in starch such as wheat flour, but after adding animal fats or vegetable fats under heating under hydro-pressure, the starch is converted into α while heating and pressurizing it into a porous solid. It is manufactured by a drying method.

For larvae, a fine grain feed is used.
The manufacturing method is as follows. Zein, which is a corn protein, is dissolved in 60% ethanol, thoroughly mixed with a mixture of feed powder materials (protein source, carbohydrate source, mineral vitamin, additives, etc.), and then freeze-dried and pulverized into zein fine particle feed. Is.

[0019]

Embodiments of the present invention will be shown below, and the structure and operation of the present invention will be described in more detail. The present invention is not limited to these examples. In the examples, as docosahexaenoic acid ester, high-purity docosahexaenoic acid ethyl ester (hereinafter,
It may be abbreviated as “DHA”. )It was used.

Example 1 Setting of test section The test section is the DHA test section, and the DHA in each test feed is
Three groups were set, a group added so that the content was 1% and 2% and a group not added with DHA as a control group. In the soybean lecithin test group, 3 groups were added, soybean lecithin was added in an amount of 3% and 5%, and a soybean lecithin-free group was set as a control group, for a total of 6 groups.

Test Feed Composition The test feed used squid meal, krill meal, white fish meal or casein as a protein source. As a lipid source, the DHA test group was soybean lecithin and 9
DHA having a purity of 2.1% was added so that the DHA content in each test feed was 0%, 1%, and 2%, and the lipid amount was adjusted with oleic acid. In the soybean lecithin test group, cod liver oil and soybean lecithin were added to 0%, 3% and 5%, and the lipid amount was adjusted with oleic acid. The vitamin mixture is a modified Halber formula, the mineral mixture is
USP XII No. 2, and Halber trace metals were used. In addition, taurine, betaine, alanine, and inosine-5'-monophosphate (IMP), which are considered to be effective for red sea bream larvae, were used as feeding attractants.
Zein was used as a binder to prepare a fine particle feed. Table 1 shows the test plots, and Table 2 shows the composition of the test feed. Table 7 shows the fish used and the breeding method. Table 8 shows the experimental results. D in Figure 1
The effect of HA on red sea bream length, FIG. 2 shows the effect of DHA on red sea bream survival rate, and FIG. 3 shows the effect of soy lecithin on red sea bream length. FIG. 4 shows the effect of soy lecithin on red sea bream survival rate.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

[0026]

[Table 5]

[0027]

[Table 6]

[0028]

[Table 7]

[0029]

[Table 8]

Example 2 Water Temperature Stress Test Test Method A 54 liter square water tank with a 100 W heater set therein was used as a constant temperature water tank, and 1 liter beaker was set for each test.
Then, 6 test fish were housed in each test plot. The water temperature rise in the beaker was set as follows. Period A 2
2.5 ° C to 26.5 ° C, B period 24.5 ° C to 28.5
C, C period 28.5 to 32.5 ° C, D period 32.5 ° C
In the period A to 33.5 ° C., the temperature was raised by 0.5 ° C. per hour and left at 26.5 ° C. for 24 hours. In the period B, half of the water in the beaker was replaced, the temperature was raised by 0.5 ° C per hour, and the beaker was left at 28.5 ° C for 12 hours. In the period C, the temperature was increased by 1.0 ° C. per hour and left at 32.5 ° C. for 4 hours. In period D, the temperature was increased by 0.5 ° C. per hour and left at 33.5 ° C. for 3 hours. After confirming dead fish in each period, it was removed and used as the survival rate. The stress test was performed with a double set.

Water temperature setting A period 22.5 ° C. to 26.5 (increased by 0.5 ° C. per hour, left at 26.5 ° C. for 24 hours) B period 24.5 ° C. to 28.5 ° C. (After half the seawater was replaced, the temperature was raised 0.5 ° C per hour and left at 28.5 ° C for 12 hours.) C period 28.5 ° C to 32.5 ° C (1.0 ° C per hour) The temperature was raised and left at 32.5 ° C for 4 hours.) D period 32.5 ° C to 33.5 ° C (increase by 1.0 ° C per hour and left at 33.5 ° C for 3 hours)

[0032]

[Table 9]

Table 9 shows the results of these tests. As is clear from Table 9, the red sea bream larvae in each test group fed with the DHA ethyl ester-enriched feed were:
The growth rate (body length), survival rate, and vitality test all showed excellent results as compared with the larvae of the control group.

Example 3 Dissolved Oxygen Stress Test Test Method Six test fish were placed in a 2.5 l plastic container for each test section, and the dissolved oxygen in the container was lowered by using nitrogen gas for about 2 hours. It was The plastic container containing the test fish was immersed in a constant temperature water bath to eliminate changes in measured values due to changes in water temperature. Then, the DO when the first fish tumbled, the DO when half tumbled, and the time when half tumbled were measured. The stress test was performed with a double set.

[0035]

[Table 10]

[0036]

EFFECTS OF THE INVENTION It is possible to grow cultured fish that are strong against stress. It is possible to provide a feed for fish suitable for producing cultured seedlings that is effective in reducing stress such as temperature change stress and dissolved oxygen stress. Fishes that have the effect of improving the ability to temporarily stop eating due to strong stress associated with changes in the breeding environment, the effect of preventing a decrease in vitality during the transportation of live fish, the effect of strengthening resistance to environmental pollution, the effect of preventing diseases, etc. Forage can be provided.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the influence of DHA on the total length of red sea bream.

FIG. 2 is a diagram illustrating the influence of DHA on the survival rate of red sea bream.

FIG. 3 is a drawing explaining the effect of soybean lecithin on the red sea bream length.

FIG. 4 is a drawing explaining the influence of soybean lecithin on the survival rate of red sea bream.

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[Procedure amendment]

[Submission date] October 1, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

FIG.

[Fig. 2]

[Figure 3]

[Figure 4]

Claims (5)

[Claims] 1. A feed for fish having an improving effect on stress, which is characterized by being fortified with docosahexaenoic acid or its esters and / or phospholipids. 2. The feed for fish having the effect of improving stress according to claim 1, wherein the docosahexaenoic acid esters are docosahexaenoic acid ethyl ester. 3. The phospholipid is soybean lecithin.
Alternatively, a fish feed having a stress-improving effect of 2. 4. A fish feed having an effect of improving stress according to any one of claims 1 to 3, which contains wheat flour, starch, water and oil as essential components. 5. The fish feed having the effect of improving stress according to claim 1, wherein the fish feed is a red sea bream feed.