JPH11276091A - Feed for zooplankton - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a feed used for zooplankton, capable of preventing the generation of a deformity in the production of fry and capable of being simply used at a low cost by compounding an oil or fat containing docosapentaenoic acid as a constituting fatty acid in a prescribed amount or more and a microorganism. SOLUTION: This feed for zooplankton is obtained by compounding an oil or fat containing decosapentaenoic acid (C22:5, n-6) as a constituting fatty acid in an amount of >=5 wt.% and/or a microorganism such as a microorganism belonging to the Schizochyrium. sp or the Thraustochytrium. sp. The zooplankton is preferably rotifer, Artemia or Daphnia pulex.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for efficiently producing docosapentaenoic acid (C22:
5, n-6).

[0002]

2. Description of the Related Art With the recent development of artificial seedling production technology,
A variety of aquatic animals such as red sea bream, flounder, tiger pufferfish, ayu, kuruma prawn, tiger pufferfish, mako flounder, hoshi garai, yellowtail, and onioze have been cultivated, and the ratio of cultured fish to total edible fish has been increasing. Behind the increase in seed production is the development of a method for enriching the biological feed for larvae and larvae, and in particular the improvement of seed production techniques by enriching rotifers and artemia.

[0003] Fortification of biological feeds for larvae and larvae involves the use of fatty acid eicosapentaenoic acid (EPA).
In addition, n-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) have been found to be effective, and have been found to be effective in improving survival rate and vitality.

[0004] As described above, the survival rate at the production site has been greatly improved by improving the enrichment of the biological feed in the production of seeds and seedlings. However, there is no improvement in the generation of malformed fish as another problem in seed and seedling production, and this is a major issue for improving productivity in production.

[0005] Malformation in seedling production is roughly divided into abnormal body shape and abnormal body color. Abnormal body shape includes bending and loss of the spine, deformation of the head and tail, and loss of gills. Abnormal body color includes whitening and blackening. Both malformations have very low market value and seed producers have no choice but to dispose of the malformed individuals, in fact the same loss as suddenly large numbers of dead individuals.

[0006] Abnormal body shape has been confirmed in most artificial seedling production, but fish species that are particularly problematic include tiger puffer fish, red sea bream, swordfish, ayu, flounder, flounder and the like. Malformations that are particularly problematic include morphological abnormalities due to vertebral abnormalities in tiger pufferfish, red sea bream, striped horse mackerel, and ayu, and body color abnormalities called whitening, in which the body color on the ocular side is lost in heteromorphs such as flounder and flounder. .

It is known that the morphological abnormality due to the spine abnormality is an abnormality in which the fish body is curved due to the curvature of the spine, an abnormality in which the tail is shifted up and down due to the bending of the tail, and an abnormality in which the length of the body is shortened due to a spine defect. It is known that these occur from the early stage of growth, but it is difficult to discriminate them from the appearance, and their influence increases with growth. In addition, these malformed fish tend to grow slowly, and it is necessary to repeatedly sort malformed fish in order to supply good quality seedlings.

[0008] Bleaching refers to abnormal body color that occurs during the larval and fry stage of a heteromorph, in which the body color is partially or almost entirely lacking on the eye side, and has appeared in nature since ancient times Is known to be. Anomalous body color abnormalities
In addition, a double-sided color is known, in which a body color similar to that of the eye is developed on a part or the whole of the eyeless side. Unlike so-called genetic milt (albino), even a whitened individual will show a darkened body color without a pattern as it grows. In the natural world, whitening is at most a few percent or less, and the site of whitening is limited to only a small part of the body. When bleaching is included, almost all of the produced fry are bleached individuals.

[0009] In order to reduce the occurrence of malformed individuals, the breeding environment and the nutritional components of the initial feed were examined. As a result, it was found that the administration and feeding of natural plankton (copepoda) and red sea bream eggs were effective, but there was a problem in using them for commercial seed production due to the difficulty of stable supply. Feeding of particulate feed from an early stage and enrichment of fat-soluble vitamins (especially vitamin A) in rotifers were recommended, but the effect at actual seedling production sites has not been seen much at present. . Thus, a simple and specific countermeasure for preventing malformation has not been found.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an animal plankton feed that contains an effective component for preventing malformation in the production of fish seeds and can be used inexpensively and easily. is there.

[0011]

Means for Solving the Problems The present inventors have made intensive efforts to solve these problems, and as a result, as a constituent fatty acid, 5% by weight or more of docosapentaenoic acid (C22:
By using the fats and / or microorganisms containing 5, n-6) as a feed for zooplankton, which is a biological feed, an effect of preventing the occurrence of malformed fish in the production of seeds and seeds was found, and the present invention was completed. That is, the present invention relates to docosapentaenoic acid (C
By mixing an oil and / or a microorganism containing 22: 5, n-6), a feed for zooplankton having an effect of preventing malformation can be provided, and the above-mentioned drawbacks in seed production can be solved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The fats and oils and / or microorganisms used in the present invention contain docosapentaenoic acid (C2
2: 5, n-6), and may be present in any of triglycerides, diglycerides, monoglycerides, fatty acids, fatty acid methyl esters, fatty acid ethyl esters, and complex lipids such as phospholipids and glycolipids. Good.
Naturally, docosapentaenoic acid (C22: 5, n-
As microorganisms containing 6), Schizochytrium (Sc
hizochyrium.sp), Thraustochytrium (Thrausto)
chytrium.sp), and specifically, ATCC 2
0888, 20889, 20891, 24473, 28
209, 28221, 34304, etc., but the present invention is not limited to these. When the content of docosapentaenoic acid is less than 5% by weight, the malformation rate of the test fish is 20%.
%, The effect of preventing malformation cannot be obtained.

The raw material for preparing the zooplankton feed of the present invention is not particularly limited, but a preferred example is as follows. It is preferable to use, as a raw material, a material obtained by separating only microbial cells from a culture liquid obtained by purely culturing the above-mentioned genus Schizochytrium (Schizochyrium.sp) or Thraustochytrium (Thraustochytrium.sp). Since these can be cultured in a large amount in a short period of time under relatively easy conditions, the product of the present invention can be obtained inexpensively and in large quantities.

The method of culturing the microorganism is not particularly limited, but a preferred example is as follows. In addition to the above microorganism, glucose 5 g / l, peptone 1 g / l, yeast extract 1 g / l, potassium dihydrogen phosphate 1 g / l, iron, copper, zinc,
A 50% seawater medium containing trace elements such as cobalt and manganese and thiamine and cyanocobalamin as vitamins is used as a culture solution at 5 to 40 ° C, preferably 20 to 35 ° C.
It can be obtained by shaking or aeration and stirring culture at pH 5 to 10, preferably 6 to 9, for 2 to 10 days.

The feed for zooplankton of the present invention is obtained by concentrating the microorganisms obtained as described above on fresh cells, concentrated by centrifugation or membrane filtration, dried cells by freeze-drying or spray-drying, and dried cells with a solvent. It is obtained by mixing the extracted oil or its emulsion, the extracted oil or the microorganism with other microorganisms.

The extraction of the oil component from the dried cells is not particularly limited, and a preferred example thereof is as follows. The mixture is mixed with a solvent of chloroform: methanol = 2: 1 in an amount of 3 to 10 times the dry weight, the cells are disrupted by a cell disruption apparatus, and oil is extracted. The cells and the solvent are separated by centrifugation or filtration, and the separated cells are extracted again in the same manner. The extracted solvent can be obtained by concentrating the separated solvent under reduced pressure using a rotary evaporator.

In the feed for zooplankton of the present invention, docosapentaenoic acid (C2
2: 5, n-6) The zooplankton feed that can be mixed with other than fats and oils or microorganisms containing 5% by weight or more is not particularly limited, and the raw materials used for normal zooplankton feed should be used. Can be. Examples of such other raw materials include freshwater chlorella, marine chlorella, yeast, fish oil, and phospholipid.

The zooplankton referred to in the present invention refers to a substance generally used as a biological feed in the production of seeds and seedlings, such as Rotifer, Artemia and Daphnia (freshwater daphnia and brackish water daphnia).

The method of using the feed for zooplankton according to the present invention varies depending on the zooplankton to be treated, but is usually 0.01 g to 0.4 g, preferably 0.01 g to 0.4 g of oil per liter of the zooplankton culture. 0.
It is added in the range of 03 g to 0.2 g. There is no effect when the amount is less than 0.01 g, and the effect is observed when the amount is 0.01 g to 0.4 g. Although an effect is recognized when added in excess of 0.4 g, further improvement in the amount of docosapentaenoic acid (C22: 5, n-6) in zooplankton is small and wasteful. The zooplankton grown on such a feed or the zooplankton subjected to the secondary culture is composed of docosapentaenoic acid (C22: 5, n-6) in its total fatty acids.
The content is increased or strengthened to 2-15% by weight.

The species of fish that can obtain the effect of preventing malformation by producing seeds and seedlings using the zooplankton feed according to the present invention are not particularly limited. The effect is applied to things. Examples of fish species that have an effect of preventing malformation include, for example, torafugu, red sea bream, swordfish, gibberellfish, amberjack, tuna, oniokoze, red sea bream, sea bass,
For body abnormalities such as sweetfish, flounder, flounder, hoshirarei,
Flounder, flounder, Hoshigarei, Matsukawa, Turbot,
The effect is applied to an abnormal body color called whitening in which the body color on the eye side is lost in a variant such as a haribot. Hereinafter, the effects of the present invention will be clarified by showing examples of the feed for zooplankton according to the present invention.

[0021]

Example 1 About 3 kg of cells were isolated from 100 liters of a culture of Schizochytrium ATCC 20891 as a feedstock for animal plankton feed. Next, the cells were freeze-dried and then pulverized to obtain 1.2 kg of dry powder. Distilled water was added to 100 g of the dried powder to make 1 liter, and the mixture was dispersed with a homogenizer to obtain a test feed A. Next, dry powder 100
g was extracted with a solvent to obtain 30 g of test feed B. As a control, DHA algae Crypthecod
Inium cohnii ) was dispersed in distilled water in the same manner as test feed A, and control feed A was prepared. )) Was used as control feed C.
Table 1 shows the main fatty acid composition of each test feed.

For each feed, the amount shown in Table 2 was added to the zooplankton culture. Rotifer culture is 1000 individuals /
The culture solution of Artemia and Artemia was adjusted to 100 individuals / ml, and the water temperature was maintained at 25 ° C. in each case. Each animal plankton was used at least 2 hours after the addition of each feed. Table 3 shows the fatty acid composition of the rotifer reinforced as described above.
Table 4 shows the fatty acid composition of Artemia.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

[0026]

[Table 4]

A seedling production experiment was performed using red sea bream as a test fish. Red sea bream fertilized eggs collected in-house for 100
0 grains were placed in a 100 liter black polycarbonate water tank and hatched at the spawning water temperature.
° C. The hatching rate was 95% or more in each group, and rotifers enriched in the morning and evening were added from the third day after hatching to maintain 5 rotifers / ml. 8 days after hatching
Individuals were fed rotifers in the morning and evening so that 10 individuals were maintained from the 15th day, and terminated on the 20th day after hatching. Artemia was fed within 2 hours in the morning and evening from day 15 after hatching, and the feeding amount was gradually increased. Artemia feeding was terminated 30 days after hatching. From day 25, the compound feed manufactured by Kyowa Hakko Co., Ltd. was used for each group from the 25th day, and the amount of satiety was fed 5 times a day until the 60th day of the experiment, while increasing the particle size according to the growth. On the way, on the 30th day, each fish was transferred from the 100-liter black polycarbonate water tank to the 1-ton black polycarbonate water tank, and breeding was continued.

After breeding, the surviving number and body length of each red sea bream are measured, the survival rate and the average body length are calculated, the number of malformed individuals is counted as a judgment of malformation, and the bone is examined by soft radiography. Was confirmed, and the total was regarded as the number of malformed individuals. The malformation rate was calculated by dividing the number of malformed individuals by the number of surviving individuals. Table 5 shows the results of the above test. As can be seen from the test results shown in Table 5, there is no large difference in the average body length of each section, and the survival rate tends to be lower in the control feed C section. This is considered to be due to the lack of DHA in the control feed C. When the malformation rates were compared, the test group A and the test group B showed significantly lower values, indicating an excellent malformation prevention effect.

[0029]

[Table 5]

Example 2 Using a test feed and a control feed obtained in the same manner as in Example 1,
A similar experiment was carried out to fortify the seedlings to enhance the nutrition. The self-collected fertilized tiger puffer eggs were placed in a 100-liter transparent polypropylene water tank, hatched at the spawning water temperature, and the hatched larvae were transferred to a 1-ton black polycarbonate water tank and pre-bred for one week. During preliminary breeding, the water temperature was gradually raised to 22 ° C. During pre-breeding, rotifer was fortified with control feed B, and rotifers fortified in the morning and evening were added to maintain the rotifer at 5 individuals / ml. On the 7th day after hatching, 50 litters were placed in a 100-liter black polycarbonate water tank.
The tank was separated so that there were no tails, and the experiment was started. Thereafter, rotifers enriched with each feed were fed in the morning and evening, and terminated on day 25 after hatching. Artemia was fed in the amount to be eaten within 2 hours in the morning and evening from the 20th day after hatching, and the feeding amount was gradually increased. Artemia feeding was terminated 35 days after hatching. As the compound feed, a compound feed manufactured by Nisshin Flour Milling Co., Ltd. was used for each group from the 30th day, and the amount of satiety was fed 5 times a day until the 60th day of the experiment, while increasing the particle size according to the growth. On the way 4
On day 0, each fish was transferred from the 100-liter black polycarbonate aquarium to the 500-liter black polycarbonate aquarium, and breeding was continued.

After breeding, the survival number and body length of each puffer fish are measured, the survival rate and average body length are calculated, the number of malformed individuals of appearance is counted as a judgment of malformation, and the soft X
Abnormal bones were confirmed by radiographs, and the total was determined as the number of malformed individuals. The malformation rate was calculated by dividing the number of malformed individuals by the number of surviving individuals. Table 6 shows the results of the above test. As can be seen from the test results shown in Table 6, the malformation rates of the test section A and the test section B showed significantly lower values, indicating that there was an excellent deformity preventing effect.

[0032]

[Table 6]

Example 3 Using a test feed and a control feed obtained in the same manner as in Example 1,
A similar experiment was carried out to enhance the nutrition, and a flounder seedling production experiment was conducted.
Self-collected flounder fertilized eggs were placed in a 1-ton black polycarbonate water tank and reared for 10 days. During preliminary breeding,
The water temperature was gradually raised to 24 ° C. During pre-breeding, rotifer was fortified with control feed B, and rotifers fortified in the morning and evening were added to maintain the rotifer at 5 individuals / ml. On the 10th day after hatching, the cells were divided into 100-liter black polycarbonate water tanks so as to have 500 cells in each section, and the experiment was started. Thereafter, rotifers enriched with each feed were fed in the morning and evening, and 1 day after hatching.
It ended on the fifth day. Artemia was fed within 2 hours in the morning and evening from day 12 after hatching, and the feeding amount was gradually increased. Artemia feeding was continued until day 35 at the end of the experiment.

After the rearing, the surviving number and body length of each flounder were measured, the survival rate and the average body length were calculated, and the number of whitened individuals was counted as a judgment of malformation, which was regarded as the number of whitened individuals.
The bleaching rate was calculated by dividing the number of bleaching individuals by the number of surviving individuals. Table 7 shows the results of the above test. As can be seen from the test results shown in Table 7, the whitening rates of the test plots A and B were significantly lower, indicating an excellent whitening prevention effect.

[0035]

[Table 7]

Example 4 Using a test feed and a control feed obtained in the same manner as in Example 1,
The same nutrient fortification was performed, and an experiment on the production of a moss sole was conducted. The self-collected fern eggs of the flathead flounder were placed in a 1-ton black polycarbonate aquarium and reared for 14 days. During preliminary breeding, the water temperature was gradually raised to 14 ° C. During preliminary breeding, control feed B was used to fortify rotifers, and 5 rotifers / m
rotifers were added in the morning and evening to maintain the liter. On the 14th day after hatching, the cells were divided into 100-liter black polycarbonate water tanks so as to have 500 cells in each section, and the experiment was started. Thereafter, rotifers enriched with each feed were fed in the morning and evening, and terminated on day 20 after hatching. Artemia after hatching 1
From the 5th day, the amount to be eaten was fed within 2 hours in the morning and evening, and the feeding amount was gradually increased. Feeding of Artemia was performed until the 50th day at the end of the experiment.

After breeding, the number of surviving and body lengths of each flat plaice were measured, the survival rate and average body length were calculated, and the number of whitened individuals was counted as a determination of malformation, and the number was determined as the number of whitened individuals. The bleaching rate was calculated by dividing the number of bleaching individuals by the number of surviving individuals. Table 8 shows the results of the above test. As can be seen from the test results shown in Table 8, the whitening ratio of the test plot A and the test plot B showed a significantly low value, indicating that there was an excellent whitening prevention effect.

[0038]

[Table 8]

[0039]

According to the present invention, zooplankton can efficiently enhance zooplankton with docosapentaenoic acid (C22: 5, n-6) and prevent malformation during seedling production. Feed can be provided.

Claims (3)

[Claims] 1. An animal plankton feed containing a fat and / or microorganism containing 5% by weight or more of docosapentaenoic acid (C22: 5, n-6) as a constituent fatty acid. 2. The microorganism is of the genus Schizochyrium.
ium.sp), Thraustochytriu
The feed for zooplankton according to claim 1, which belongs to m.sp). 3. The feed for zooplankton according to claim 1, wherein the zooplankton is rotifer, artemia or daphnia.