JP2002238396A - Method for culturing water flea - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for culturing water fleas by which the water fleas can stably be cultured at a high density. SOLUTION: Chlorella is added to a culture solution of the water fleas and the culture solution is aerated with oxygen or air having a high oxygen concentration when the water fleas are cultured. The exchange of the culture solution is carried out while leaving the water fleas in a culture solution tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for cultivating daphnia. More specifically, the present invention relates to a daphnia cultivation method capable of stably cultivating daphnia, which is useful as a biological feed for producing seeds and seedlings such as useful fish species and crustaceans.

[0002]

2. Description of the Related Art Currently, zooplankton such as rotifers and artemia are used as biological feeds for producing seeds and seedlings such as useful fish species and crustaceans.

Rotifers are small, 150-350 μm in size, and are mainly used as feed immediately after hatching. Artemia has a large size of about 600 μm when hatched, and further cultivation can produce large ones of 1000 μm or more. Therefore, it is mainly used as a biological feed for the next stage of larvae fed and fed rotifers.

Among the above-mentioned zooplankton, rotifers are used for improving the value of chlorella as a rotifer feed (Japanese Patent No. 2062476) and for improving the rotifer culture method (Japanese Patent Publication No. 4-75735). Various research results have enabled stable production.

[0005] On the other hand, Artemia hatches and cultivates natural durable eggs. Currently, the durable eggs rely on imports, and due to the recent increase in global demand and depletion of resources (durable eggs). In short, the supply of Artemia to demand is insufficient.

[0006] Therefore, there is a need for an alternative zooplankton feed that can be reproduced domestically without relying on imports. As alternative zooplankton diets, brackish water daphnia (for example, Diaphanosoma sp.) Having a size comparable to Artemia and freshwater thrips (MoMo)
ina sp.). The sizes of brackish and freshwater thrips are 400-1200 μm.

[0007] Brackish water daphnia can be artificially cultured in seawater using baker's yeast and the prasinoalga Tetraselmis. For this reason, in the 1980s, large-scale cultivation of brackish water daphnia was attempted for the purpose of use as a marine feed. However, the density of daphnia that can be cultured is several individuals / milliliter (hereinafter, milliliter is referred to as “m
L "and liters are described as" L "), and stable cultivation is difficult.

[0008] At the laboratory level, feeding the plasinoalga Tetraselmis in a culture volume of 40 mL, filtering daphnia every day with gauze, washing the daphnids, replacing the seawater and restarting the culture. Have reported that the density of daphnia has been successfully increased to 100 individuals / mL (Japanese Journal of Plankton Society, Vol. 35, No. 1, pp. 67-73, 1988). However, it is difficult to increase the scale by such a culture method that requires complicated operations, and no application to mass production of marine seedlings has been made.

[0009] On the other hand, the freshwater thrips, Daphnia magna is relatively easy to culture, and is therefore used for producing seedlings of freshwater fish. Generally, algae or bacteria grown by fertilizing chicken manure or oil cake or the like are cultured as feed or cultured using baker's yeast, but the culture density is several individuals / m
L and low.

Furthermore, Japanese Patent Application Laid-Open No. 10-113095 proposes a method of feeding chlorella and aseptically cultivating daphnia, but the cultivation density of daphnia is as low as 20 to 30 individuals / mL.

[0011] Under such circumstances, seedling facilities producing thrips are limited, and thrips are only used as supplementary zooplankton feed.

[0012]

As described above, the conventional culture of daphnia has been performed at a very low density and in a rough manner. Therefore, in order to produce daphnia in large quantities, a large amount of culture solution is required. A vast aquarium was needed. For this reason,
It was difficult to control water temperature and aeration conditions, etc., and it was difficult to culture Daphnia steadily, and the labor required to manage the culture was enormous.

The present inventors have repeatedly studied whether or not daphnia can be cultured stably and at a high density.
Adding chlorella to the culture of daphnia, aerating the culture with oxygen or air with a high oxygen concentration,
By exchanging the culture solution while leaving the daphnia in the culture solution tank, it was found that the daphnia can be cultured stably and at a high density. The present invention has been completed based on this finding.

(Object of the Invention) It is an object of the present invention to provide a method for cultivating daphnia that can stably culture daphnia at a high density.

[0015]

Means for Solving the Problems In the first invention,
Adding chlorella to the culture of daphnia, aerating the culture with oxygen or air with a high oxygen concentration,
A method of cultivating a daphnia, comprising replacing the culture solution while leaving the daphnia in the culture solution tank.

In the second invention, chlorella is added to a daphnia culture, oxygen or air having a high oxygen concentration is passed through the culture, and a new culture is added to the daphnia culture tank. A method for cultivating a daphnia, comprising: adding, while leaving the daphnia in the culture bath, a culture solution corresponding to the added amount from the culture bath.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The method for cultivating daphnia according to the present invention comprises adding chlorella to a culture of daphnia, aerating oxygen or air having a high oxygen concentration through the culture, and placing the daphnia in a culture tank. The replacement of the culture solution while leaving the same is included, and the order of these operations (treatments) is not particularly limited, and they can be performed simultaneously.

The present invention can be used for daphnia in general, and particularly for brackish water daphnia (eg, Diaphanosoma sp.
Etc.) and the cultivation of freshwater thrips (Moina sp.), But are not limited thereto.

The chlorella used is not particularly limited as long as it belongs to the genus Chlorella. As an example of chlorella,
Chlorella vulgaris, Chlorella pyrenoidosa, Chlorella
Chlorella saccharophila, Chlorella regularis, Chlorella sorokiniana and the like can be mentioned. These chlorellas can be easily obtained by those skilled in the art. For example, it can be obtained from the University of Tokyo IAM Culture Collection.

As a culturing method of chlorella, for example, photoautotrophic culturing, heterotrophic culturing, mixed culturing and the like are known, but the culturing method is not particularly limited.

The form of chlorella can be concentrated and refrigerated or dried powder, but from the viewpoint of excellent growth of daphnia, fresh and concentrated and refrigerated is preferable. Specifically, for example, a chlorella concentrate (trade name “Normal Chlorella-V12”, manufactured by Chlorella Industries, etc.) manufactured and sold for rotifer production can be used, but not particularly limited thereto. .

The chlorella may be fed continuously or intermittently by combining a refrigerator for storing the chlorella suspension, a feed pump, a timer, or the like, or the chlorella for one day may be fed once or once. It may be given in several portions.

The amount of chlorella fed depends on the state of the daphnia, the culture density of the daphnia, etc., but it is preferable to give about 10 to 150 mg / day in terms of dry weight of chlorella per 10,000 daphnia while observing the state of the remaining feed. preferable.

Aeration is performed during the culture of daphnia for the purpose of stirring the culture and supplying oxygen. Aeration is performed with oxygen or air having a high oxygen concentration.

The oxygen concentration when aerating the air is preferably adjusted according to the breeding density and the amount of aeration of the rotifer, for example, it can be used in the range of less than 20 to 100%. If the amount of aeration is too weak, the supply of oxygen will be insufficient, and if it is too strong, the growth of daphnia will be inhibited, so it is desirable to adjust according to the breeding density of rotifers and the oxygen concentration of the air to be aerated, practical A suitable range is 1 to 50 mL / L · min.

By exchanging the culture solution, it is possible to prevent deterioration of the water quality (deterioration of the liquid quality) of the culture solution in the culture solution tank. The culture solution may be replaced partly in the culture solution tank, or may be replaced entirely. If the amount of the culture solution to be replaced is small, the water quality deteriorates, and if the amount is large, the culture solution is wasted. Specifically, it is preferable to adjust according to the breeding density of Daphnia and the amount of feed of Chlorella,
As a practical range, it is preferable to replace the culture solution within a range of 0.4 to 2.5 L / day per 1 L of the culture solution.

The replacement of the culture solution can be performed, for example, by adding a new culture solution and discharging the old culture solution. Examples of the method of adding a culture solution include, for example, a method of adding a culture solution previously stored in a storage tank or the like by adjusting a valve or the like, a method of adding using a metering pump, and the like. It is not particularly limited to these. The addition of the culture solution to the culture solution tank may be performed continuously or intermittently.

Immediately after adding chlorella into the culture tank,
It is preferable to refrain from adding a culture solution. The reason is as follows. That is, in the case where the culture medium is not discharged together with the addition of the culture medium, if the culture medium is added immediately after the addition of the chlorella, the number of chlorella individuals per unit volume decreases, so that the frequency of daphnia contacting the chlorella is low. Become
This is because chlorella given as feed may not be used effectively. In addition, when the culture solution is discharged together with the addition of the culture solution, the added chlorella may be discharged from the culture solution tank together with the culture solution.

As a method for removing the culture solution corresponding to the newly added amount from the culture solution tank (a method for discharging the old culture solution), for example, a method using overflow, a method using a pump to drain (drain), etc. Examples of the method include, but are not particularly limited to, these methods. As an example of the overflow method, for example, a plastic container having a volume of about 120 L is used as a culture solution tank, and the volume of the culture solution is adjusted to 100 L. Then, among the side surfaces of the culture solution tank, holes or the like are opened above the liquid surface (portion where the liquid volume is 100 L), and a drainage (drainage) line such as a pipe or a tube is passed. With such a configuration, by adding a predetermined amount of culture solution to the culture solution tank,
Culture liquid exceeding 100 L is discharged from a drain (drain) line.

At this time, a filter cloth such as a plankton net can be provided in a drain (drain) line in order to leave the daphnia in the culture solution. If the size of the filter cloth to be used is too small, clogging is likely to occur, and if it is too large, daphnia tends to flow out.

[0031]

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 A culture experiment of brackish water daphnia (Diaphanosoma sp.) Was performed by feeding chlorella. A 50 L Artemia hatch tank filled with seawater was maintained at a culture temperature of 25 ° C., and cultivation of brackish daphnia was started at 5 individuals / mL.
Culture is performed at 7.5 mL / L
This was performed while ventilating at a flow rate of 1 minute.

As the seawater, artificial seawater (manufactured by Kyushu Sekisui Kogyo Co., Ltd.) whose salt concentration was adjusted to 10 ° was used. Further, a predetermined amount of seawater was added to the Artemia hatching tank using a metering pump, and seawater corresponding to the added amount was drained from the Artemia hatching tank by overflow. A plankton net (mesh size: 150 μm) was installed in the drainage line of the Artemia hatching tank to prevent the outflow of daphnia.

The chlorella used was "raw chlorella-V12" (trade name, manufactured by Chlorella Industry Co., Ltd.), and the daily feed amount was 2 parts.
They were fed once or three times. In addition, "raw chlorella-
One liter of V12 contains 145 g of chlorella in terms of dry weight.

Under the above conditions, daphnia cultivation was performed, and changes in the number of daphnia were examined. The cultivation was performed for a total of 20 days, and daphnia was harvested on the twelfth day of cultivation, and a second cultivation was performed using the harvested portion (15 individuals / mL) as a seed, following the same procedure.

Table 1 below shows the number of days of culture, the amount of seawater added to the Artemia hatching tank, the oxygen concentration of the aerated air, the amount of chlorella fed, and the density of daphnia. FIG. 1 is a graph showing the number of days of culture and the density of daphnia.

[0037]

[Table 1]

From the results shown in Table 1 and FIG.
It was revealed that the daphnia could be grown to individual / mL or more, and high-density production of daphnia was possible without complicated culture work.

[Example 2] A culture experiment of freshwater daphnia (Moina sp.) Was conducted by feeding chlorella. A 50 L Artemia hatchery tank filled with seawater was maintained at a culture temperature of 25 ° C., and culture of freshwater daphnia was started at 5 individuals / mL for 9 days. The other culturing conditions are almost the same as those in Example 1, and the description is omitted.

Table 2 below shows the number of days of culture, the amount of seawater added to the Artemia hatching tank, the oxygen concentration of the aerated air, the amount of chlorella fed, and the density of daphnia. FIG. 2 is a graph showing the number of days of culture and the density of daphnia.

[0041]

[Table 2]

From the results shown in Table 2 and FIG.
It was revealed that the daphnia could be grown to individual / mL or more, and high-density production of daphnia was possible without complicated culture work.

The terms and expressions used in the present specification are for explanation only, are not restrictive, and do not exclude terms and expressions equivalent to the above-mentioned terms and expressions.

[0044]

According to the method for cultivating daphnia according to the present invention, daphnia can be cultured stably at high density. Therefore, it is possible to intensively culture daphnia in a small-sized culture solution tank. Therefore, unlike cultivation in a vast culture solution tank, control of water temperature, aeration conditions, and the like becomes easy, and planned production of daphnia, which was conventionally difficult, is possible. In addition, compared with the conventional method, it becomes possible to culture daphnia of the same production amount in a small-sized culture broth, so that a great deal of labor is not required for culture management.
Production costs can be kept low.

[0045]

[Brief description of the drawings]

FIG. 1 is a graph showing the time-dependent changes in the number of daphnia when brackish water daphnia is cultured.

FIG. 2 is a graph showing a time-dependent change in the number of daphnia when freshwater daphnia is cultured.

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Claims (2)

[Claims] 1. adding chlorella to a culture of daphnia, aerating oxygen or air having a high oxygen concentration to the culture, and replacing the culture with the daphnia remaining in the culture tank. A method for cultivating a daphnia, comprising: 2. Addition of chlorella to a culture of daphnia, aeration of oxygen or air having a high oxygen concentration to the culture, addition of a new culture to a culture tank of daphnia, Removing the culture solution corresponding to the added amount from the culture solution tank while remaining in the tank.