JP2668107B2 - High-density mass-culture method for rotifers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to continuous mass culture of rotifers such as S-type rotifer, L-type rotifer and freshwater rotifer, which are multicellular microorganisms of seawater / freshwater, at a high density of several thousand to 10,000 individuals per ml. Culture method.

[0002]

BACKGROUND ART Rotifers are known as excellent culture feeds for larvae, and are expected to be important feeds in fish cultivation, and there is a demand for establishment of a large-scale culture method. The conventional method for cultivating rotifers is to culture Nannochloropsis in an aquarium and use this as the main feed to supplementally supplement the feed with fresh water chlorella, baker's yeast, etc. while culturing while supplementing air. Met.
In this conventional culture method, the culture density is about 50 to 5
The growth rate is low at about 20 to 30% in the range of 00 individuals (N) / ml, and a practical large-scale cultivation of rotifers requires several hundred tons of rotifer culture tank and several times the Nannochloropsis culture tank. Becomes Rotifer culture was unstable because Nannochloropsis culture was affected by the weather.

[0003]

According to the conventional method for cultivating rotifers, even if the temperature condition and the air aeration amount are set appropriately, the value of 50 to 50 can be obtained.
500 individuals (N) / ml were limited. The problem to be solved by the present invention is to investigate the cause of the problem of the conventional culture method, to solve the conventional problem based on new findings, and to obtain several thousands to 10,000 individuals (N) / ml. It is an object of the present invention to provide a high-density, large-scale cultivation method for rotifers that enables stable and large-scale cultivation at a high density.

[0004]

The gist of the present invention which has solved the above-mentioned problems is as follows: 1) Rotifer which is fed in a water tank to culture rotifers.
Feed concentrated feed in open-system culture
And, by passing an oxygen-dissolved oxygen aquarium water at all times 2ppm or more, the addition dense rotifers, characterized in that the pH adjusted to maintain the range of constantly 5 to 7.5 and the pH of the aquarium water Mass culture method 2) High-density mass culture method of rotifers according to the above 1) using hydrochloric acid as a pH adjuster 3) The above 1) or 2) wherein the feed is concentrated freshwater chlorella
In the method for high-density mass culture of rotifers described above.

[0005]

[Action] The present inventors have conducted an experimental study on the reasons why conventional rotifers cannot be cultured at a high density. As a result, the essential inhibition of the high-density cultivation is not due to water temperature and food, but to the high density cultivation. It was found that there was an oxygen deficiency due to the consumption of oxygen by rotifers and their feed, and an increase in non-dissociated ammonia produced from rotifers. The present invention has solved the conventional problems and solved the problems based on such knowledge. That is,
In the present invention, the required feed is sufficiently fed to the aquarium according to the number of individuals, the dissolved oxygen DO in the aquarium water is maintained at 2 ppm or more, and the dissolved oxygen necessary for culturing high-density rotifers is aerated by oxygen aeration. Supply. And the increase of non-dissociated ammonia caused by the growth of rotifers can suppress non-dissociated ammonia NH ₃ -N to 4 ppm or less by adding an acid to maintain the tank water at a pH of 5 to 7.5, This prevents rotifers from being killed or reduced in number due to oxygen deficiency and toxicity of non-dissociated ammonia, which are responsible for suppressing growth from 50 to 500 individuals (N) / ml, and prevents thousands to one.
Even at a high density of 10,000 (N) / ml, rotifers could be stably and continuously mass-cultured.

[0006]

Embodiments of the present invention will be described below with reference to the drawings and experiments. The rotifer cultivated in this example is an S-type rotifer, Brachionus Plicati.
lis) (hereinafter simply abbreviated as rotifer), and freshwater chlorella (vitamin B ₁₂ 1 mg /
l, cell density about 1.5 × 10 ¹⁰ cells / m
1) and seawater was used as the tank water, and dilute hydrochloric acid was used as a pH adjuster.

FIG. 1 shows the culture apparatus of this embodiment. In FIG. 1, reference numeral 1 denotes a culture water tank using an Artemia hatcher, 2 denotes culture water using filtered seawater (pH 8.2) in the water tank, 3 denotes an oxygen disperser that releases oxygen in the form of small bubbles, 4 air ejectors to release air bubbles, 5 small oxygen generator for providing oxygen to the oxygen distributor 3, 6 the air inlet tube of the air ejector 4, 7 was concentrated B ₁₂ addition of fresh water Chlorella, 8 is a missing number, 9 is a 50-liter freshwater chlorella container, 1
Reference numeral 0 denotes a metering pump for supplying the concentrated freshwater chlorella to the culture tank 1, reference numeral 11 denotes a titanium heater provided in the tank 1, reference numeral 12 denotes a control unit of the titanium heater, reference numeral 13 denotes a suspension in the culture tank 1, and suspension of feces and the like. Nylon special processing mat (trademark "Vilene mat") for removing turbid matter, 14 is a dilute hydrochloric acid solution of a pH adjuster, 15 is a dilute hydrochloric acid container, and 16 is a dilute hydrochloric acid solution 14.
Is a metering pump for feeding the water into the water tank 1.

[0010] Using the culture apparatus of FIG. 1, a culture example in which only air ventilation is performed without pH adjustment (see FIG. 2) and a culture example in which air ventilation and oxygen ventilation are performed without pH adjustment (see FIG. 3). A description will be given in comparison with an embodiment of the present invention in which the pH is adjusted and oxygen is ventilated (see FIG. 4). : Example of culture with air ventilation (see FIG. 2) The drawing in FIG. 2 is a 1 kiloliter culture water tank 1 shown in FIG.
The concentrated fresh water chlorella 7 is not used in the culture device of the above, but using the diluted hydrochloric acid solution 14 as a pH adjuster and passing only air.
, And approximately half of the rotifers were collected every day, the culture water in the culture tank 1 was also changed by about half, and the results of the rotifer density and the daily growth rate during continuous culture are shown. As can be seen from the results of FIG. 2, in this culture method, the rotifer density was 2,
The limit of continuous culture is about 2,000 individuals (N) / ml.

Culturing Example of Influence of Dissolved Oxygen (See FIG. 3) Next, FIG. 3 shows the results of experiments on the influence of dissolved oxygen. FIG. 3 shows a conventional culture period in which only air aeration was performed (0 to 30).
After the culturing period of the day 31), the culturing period of the 31st to 51th days is performed when the oxygen of the small oxygen generator 5 is released from the oxygen disperser 3 into the culture tank 1 to make the dissolved oxygen 2 ppm or more. In an example, the results are shown in FIG. As can be seen from the results in FIG. 3, the rotifer density was 2,000 during the period of the culture method by air aeration (the period of days 0 to 30).
Individual (N) / ml cannot be exceeded, but when combined with oxygen aeration from day 31, rotifer density is 5,000-
Improve to 7,000.

Example of oxygen aeration and pH adjustment of the present invention (see FIG. 4) In the example of FIG. 2, dilute hydrochloric acid solution 14 as a pH adjuster is further charged into culture water tank 1 to adjust the pH to 5 to 7 .5 desirably 6 to
7 so that the non-dissociated ammonia ion N
As a result of suppressing H ₃ -N to 4 ppm or less, the rotifer concentration could be increased to a high density of about 10,000 to 12,000 in continuous culture. The water temperature of the culture water 2 was preferably around 32 ° C. One ton of the culture tank 1 can harvest about 5 billion pieces / day. The feed for the rotifer in this example is freshwater chlorella. Freshwater chlorella can be stably mass-produced industrially at low cost and is therefore a suitable feed for large-scale rotifer cultivation. In addition, the feed of the rotifers of the present invention is not limited to this freshwater chlorella, and may be other feeds.

[0011]

As described above, according to the present invention, good cultivation conditions for rotifers can be obtained by setting the dissolved oxygen to 2 ppm or more and always keeping the pH in the range of 5 to 7.5. The conventional rotifer density can be increased to 2,000 individuals (N) / ml.
From this level, it was possible to dramatically improve the high-density continuous mass culture of 5,000 to 10,000 individuals (N) / ml or more.
When freshwater chlorella is used as a feed for rotifers, it becomes possible to inexpensively and stably cultivate large numbers of rotifers.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a culture apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a culture result by a conventional culture method.

FIG. 3 is an explanatory diagram of a culture result when oxygen is aerated.

FIG. 4 is an explanatory diagram showing a culture result of an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Culture water tank 2 Culture water 3 Oxygen disperser 4 Air discharger 5 Small oxygen generator 6 Air introduction pipe 7 Freshwater chlorella 9 Freshwater chlorella accommodation container 10 Metering pump 11 Titanium heater 12 Control part 13 Special processing mat 14 Dilute hydrochloric acid solution 15 Dilute hydrochloric acid container 16 metering pump

Claims (3)

(57) [Claims] Claims 1. A concentrated rotifer in an open cultivation method of rotifers in which rotifers are fed in an aquarium.
Feed, oxygen is ventilated and the dissolved oxygen in the tank water is constantly 2p
pm or more, and a high-density mass cultivation method for rotifers, characterized in that the pH of the aquarium water is constantly maintained in the range of 5 to 7.5. 2. The method according to claim 1, wherein hydrochloric acid is used as a pH adjuster. 3. The feed is concentrated freshwater chlorella.
Or the high-density mass cultivation method of rotifers according to 2.