JP2001238561A - Method for preventing generation of saprolegnia and removing generated saprolegnia - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely perform the prevention of the generation of saprolegnia and the removal of the fungi in a fish farm. SOLUTION: Water containing chlorine ion is electrolyzed in an electrolyzed water production apparatus 17 and the electrolyzed water containing residual chlorine is applied to the planospore or mycelia of saprolegnia to exterminate the fungi. Since an agent having teratogenicity or carcinogenicity is not used in the operation, the work is safely and easily performed without causing influence on the environmental.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to breeding and management of fish and fish eggs such as farmed fish and ornamental fish, and more particularly to the prevention and removal of water mold associated therewith.

[0002]

2. Description of the Related Art In hatching and cultivation farms such as rainbow trout and char, water mold occurs in fish bodies and fish eggs due to bacteria classified in the water mold family. Conventionally, malachite green (Malachite gree) has been mainly used for the prevention and treatment of water mold disease in these fish.
n) is used, and it is said that there is no superior product at present.

[0003]

However, the malachite green has been pointed out for its teratogenicity and carcinogenicity to animals, and its use is currently regulated. Therefore, an object of the present invention is to provide means for preventing and removing water mold which is safe and inexpensive and has no effect on the environment.

[0004]

Means for Solving the Problems The inventors of the present invention sought variously for the above means, and as a result, found that the residual chlorine component contained in the electrolyzed water was extremely effective in preventing the generation of water mold. Reached. That is, when tap water or water obtained by adding an electrolytic aid such as salt (NaCl) or potassium chloride (KCl) thereto is electrolyzed, strongly acidic water is generated on the positive electrode side and strong alkaline water is generated on the negative electrode side. but generates strongly acidic water hypochlorite (HOCl) and hypochlorite ion (OCl ^-) include or residual chlorine (dissolved chlorine) such as chlorine gas (Cl _2), the residual chlorine, in particular hypochlorite Chloric acid has been found to be effective against water mold. Therefore, the present invention kills zoospores or hyphae of water mold by causing electrolyzed water containing residual chlorine to act on zoospores or hyphae of water mold (claim 1).

In this case, since acidic water is not suitable for breeding fish, it is preferable to use strongly acidic water and strongly alkaline water in an electrolytic bath or a mixture outside the electrolytic bath. . This mixed water shows weak alkalinity (about pH 7.5) and does not affect the growth of fish. For the generation of electrolyzed water, see, for example, JP-A-11-239791.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An experiment in which electrolyzed water (weakly alkaline water) is applied to zoospores and hyphae of water mold (Saprolegnia parasticta) will be described below. First, FIG. 1 is an explanatory diagram of an experiment in which the ability of electrolyzed water to inhibit the growth of mycelium was examined. In FIG. 1, mycelium 2 was inoculated on a GY (glucose yeast) agar medium 1 in a petri dish,
For 4 days.
Cut a 5 mm circular small piece 3 into a cylindrical cutter, and
Is dipped in electrolyzed water (weakly alkaline water) 4 in a beaker,
The treatment was performed while stirring with an electromagnetic stirrer 5. The residual chlorine concentration (in terms of Cl ₂ ) of the weak alkaline water 4 was 10, 20, 30 ppm, and the treatment time was 5, 15, 30, 60 minutes. The small pieces 3 taken out of the weak alkaline water 4 were washed twice with distilled water 6, and then the small pieces 3 were allowed to stand on the GY agar medium 1 at 15 ° C. for 36 hours to observe the state of hyphae.

Table 1 shows the experimental results together with the results of the tap water treatment of the comparative example. Table 2 shows the results of comparative experiments using malachite green as another drug. Table numbers in the 1 and 2, when the average value of the diameter of mycelial colony on the agar medium of tap water was 100%, which represents the relative value of the same average value of the samples treated with electrolytic water It is.
From Table 1, it was confirmed that the mycelium treated with weak alkaline water having a residual chlorine concentration of 30 ppm for 60 minutes showed no growth and was completely killed. On the other hand, in Table 2, it can be seen that malachite green has a remarkable effect and is completely killed by treatment at 1.0 ppm for 30 minutes.

[0008]

[Table 1]

[0009]

[Table 2]

Next, FIG. 2 is an explanatory view of an experiment for examining the growth inhibiting ability of electrolyzed water on zoospores. In FIG.
A GY culture solution 7 consisting of 500 ml of distilled water, 5 g of glucose and 1.25 g of yeast extract was placed in a jar, and the agar medium 1 described above was added.
An 8 × 8 mm square piece 8 cut out from the edge of the colony with a knife was put into a liquid medium 7 and cultured at 15 ° C. for 6 days. When the mycelium grew into a white floc in the solution, the mycelium was washed three times with distilled water 6 to remove zoospores released into the water.
At room temperature for 3 days, and then immersed the zoospores in electrolyzed water (weakly alkaline water) in a beaker.
With stirring. The residual chlorine concentration of weak alkaline water is 2.5, 5.0, 7.5, 10, 15, 20, 30 ppm, and the treatment time is 10
Seconds, 1, 5, and 15 minutes.

Then, 1 ml of test water (zoospore concentration: 2 × 1
0 ⁷ pcs / l, 2 × 10 ⁵ pcs / l) with 3 hemp seeds 9 and sterile tap water 30
The mixture was transferred to a petri dish containing ml with a dropper, and allowed to stand at 15 ° C. for 5 days. The experiment was performed three times while changing the residual chlorine concentration and the zoospore concentration. Tables 3 to 5 show the results. In addition, a comparative experiment was performed using a malachite green aqueous solution and a sodium hypochlorite aqueous solution as other agents, and the results are shown in Table 6. In the table, + and-symbols indicate one sample (one hemp seed 9), + indicates zoospore activity, and-indicates death. From these experimental results, the residual chlorine concentration
It can be seen that the zoospores can be completely killed by weak alkaline water of about 2.5 ppm. Although malachite green has a remarkable effect, it has a problem in use as described above.

[0012]

[Table 3]

[0013]

[Table 4]

[0014]

[Table 5]

[0015]

[Table 6]

Based on the above experimental results, an experiment for preventing water mold from electrolyzed water using an actual fish egg hatching apparatus will be described. FIG. 1 is a longitudinal sectional view showing a schematic configuration of the hatching device 10. In FIG. 3, the hatching apparatus 10 has a water tank 11 partitioned into two front and rear hatching chambers 12 by a partition plate and a water passage 13 in front of the tank, and a rainbow trout fish egg 14 is placed in each hatching chamber 12. Several levels of net shelves 15 are provided. Water (spring) from the water channel 13 on the near side to the water tank 11
Is continuously flowed, and this water flows upward and downward through each hatching chamber 12 to wash out the fish eggs 14 as indicated by the arrows, overflows and is discharged out of the tank. The capacity of the water tank 11 is 25 l
The flow rate of spring water is 24 l / min. Normally, only the spring water flows in the hatching device 10, but in the experiment, a device in which only the spring water flows and a device in which the flow is switched to the electrolytic water were juxtaposed and compared.

FIG. 4 is a plan view showing a pipe connection for the above experiment. In FIG. 4, the first hatching device 10-1 and the second hatching device 10-1
The hatching device 10-2 is installed side by side, and the spring water once stored in the spring tank 16 is always supplied in parallel to the hatching devices 10-1 and 10-2. Further, an electrolyzed water generator 17 is provided adjacent to the spring tank 16, and the electrolyzed water is supplied to the first hatching device 10-1 by switching the three-way cock 18. In the experiment, only the spring water was constantly supplied to the second hatching device 10-2, and the first hatching device 10-1 was twice a day, one hour, and twice a week, that is, two hours a week. 3 weak alkaline water with a residual chlorine concentration of 30 ppm obtained in the electrolyzed water generator 15
The flow was switched to spring water at a flow rate of 1 / min. In this case, the water in the water tank 11 (FIG. 3) was almost completely replaced with electrolyzed water in about 30 minutes, and showed a residual chlorine concentration of 30 ppm.

After one month, the hatching apparatus 10-
1 and 10-2 fish eggs were observed. What was treated with electrolyzed water, and not treated as a control group, the general method, that is,
Only when the eggs were placed in the hatching apparatus, the eye-opening rates were compared with those obtained by immersing in eggs for 15 minutes and sterilizing. Table 7 shows the results. As is clear from Table 7, the eggs treated with the electrolyzed water had a higher eye-opening rate than the eggs not treated with the electrolyzed water. In the electrolyzed water treatment area, since water mold hardly occurred on the dead eggs, a high eye-opening rate was obtained.

[0019]

[Table 7]

From the above experimental results, it was confirmed that the water mold zoospores floating in the water were killed by the electrolyzed water to prevent the generation of water mold, and that the water mold once generated was similarly sterilized. Therefore, by injecting the electrolyzed water into the running water of the hatching apparatus or the circulating water of the culture pond at a fish farm or the like, it is possible to prevent the generation of water mold and to remove the generated water mold.

[0021]

As described above, according to the present invention, by preventing and eliminating the generation of water mold using electrolyzed water, the danger and troublesome work of handling a teratogenic or carcinogenic agent can be obtained. In addition to being able to easily produce electrolyzed water and eliminating the need for wastewater treatment, the equipment is simplified, and safe and inexpensive measures against water mold can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the procedure of an experiment for confirming the ability of electrolytic water to inhibit the growth of fungal hyphae.

FIG. 2 is an explanatory diagram showing the procedure of an experiment for confirming the growth inhibiting ability of electrolyzed water against water mold zoospores.

FIG. 3 is a longitudinal sectional view showing a schematic configuration of a fish egg hatching apparatus.

FIG. 4 is a pipe connection diagram of an experiment using the fish egg hatching apparatus of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Agar medium 2 Water mold mycelium 3 Mycelium small piece 4 Weak alkaline water 5 Electromagnetic stirrer 6 Distilled water 7 Agar culture liquid 8 Mycelium small piece 10 Hatching device 11 Aquarium 14 Fish egg 15 Net shelf 16 Spring tank 17 Electrolyzed water generator 18 Three-way cock

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/50 531 C02F 1/50 531M 540 540B 560 560F (71) Applicant 500091704 Hiromi Tanaka Hana Suzuka, Mie Prefecture 1541, Kawamachi 31 (71) Applicant 500091508 Enri Maekawa 52-15, Shinyashiki, Noguchi-cho, Toyokawa-shi, Aichi Prefecture (72) Inventor Hiroshi Deno 1-1-1, Tanabe-Shinda, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Fuji Electric Co., Ltd. (72 ) Inventor Masaaki Nakamura 1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-city, Kanagawa Prefecture, Fuji Electric Co., Ltd. (72) Inventor Toshio Takagi 1-1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-ku, Kanagawa Prefecture, Fuji Electric Co., Ltd. (72) Inventor Masaaki Kashiwagi 2844-2, Uchida, Oza, Ano-cho, Aki-gun, Mie Prefecture (72) Inventor Ryuji Ueno 722-21, Shibumicho, Tsu-shi, Mie Prefecture (72) Inventor Hiromi Tanaka 3141-154-1 Hanakawa-cho, Suzuka-shi, Mie (72) Inventor Ryo Maekawa 52-15 Shin-Yashiki, Noguchi-cho, Toyokawa-shi, Aichi F-term (reference) 2B104 BA13 EF11 4D061 DA03 DA06 DB07 DB08 EA02 EB02 EB14

Claims (2)

[Claims] 1. A method for preventing and removing water mold, which comprises causing electrolyzed water containing residual chlorine to act on zoospores or hypha of water mold. 2. The method according to claim 1, wherein the electrolyzed water is weakly alkaline water obtained by mixing strongly acidic water and strongly alkaline water generated by electrolyzing water containing chlorine ions. Prevention and removal of water mold.