JP3002709B1 - Preventive / therapeutic agent for cold water disease and method for its prevention / treatment - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To prevent and treat cold water disease by killing Flexibacter cyclophila which is a causative agent of cold water disease of fish, especially sweetfish or salmon.
The task is to develop therapeutic agents. SOLUTION: The problem can be solved by using a sulfa drug, particularly one obtained by adding sodium chloride to sulfisosol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to Flexibac , a bacterium that causes cold water disease in fish, especially sweetfish.
ter psychrophilus ) to prevent or treat cold water disease.

[0002]

2. Description of the Related Art In recent years, flexibactor cyclophila has been used as a causative agent in ayu culture and ayu release business.
Cold water disease is rampant. Ayu from Lake Biwa, which occupies a large share in the shipment of seeds and seedlings, is likely to be Flexibacter cyclophila-carried fish. But,
The currently approved marine medicines have an inhibitory effect on the growth of Flexibacter cyclophila at normal doses, but none have a bactericidal effect. Therefore, there was no method for chemically disinfecting and removing Flexibacter cyclophila from breeding water while keeping the sweetfish together in the sweetfish ponds. In order to eliminate cold water disease, it is necessary to make the breeding water pathogen-free, but for that purpose, it is necessary to develop a drug having a bactericidal effect. In addition, prevention has been carried out by raising the water temperature to 20 ° C. or higher, disinfecting the eye-opening eggs with an iodine agent, and thoroughly disinfecting the hatching tanks and equipment before storing the eye-opening eggs. However, none of them had a sufficient bactericidal effect, and it was impossible to completely prevent or treat cold water disease.

[0003]

SUMMARY OF THE INVENTION The present invention provides a method and a prophylactic / therapeutic agent for preventing or treating cold water disease by killing Flexibacter cyclophila, a causative agent of cold water disease in fish, especially sweetfish or salmon. The task is to develop

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive efforts to solve the above-mentioned problems, and as a result, have found that they can be solved by adding sodium chloride to sulfa drugs, particularly sulfisosol. That is, the present invention provides (1) prevention of cold water disease in fish comprising a sulfa drug and sodium chloride.
The therapeutic agent, (2) The preventive / therapeutic agent for cold water disease in fish according to (1), wherein the sulfa drug is sulfisosol or a salt thereof.

(3) The prophylactic / therapeutic agent according to (1) or (2), wherein the fish is ayu or salmon, (4)
A method for preventing and treating cold water disease in fish, which comprises adding a therapeutic agent for cold water disease in fish comprising a sulfa drug and sodium chloride to water in which fish live, (5) a method in which the sulfa drug is sulfisosol (4). (6) The method for preventing / treating fish cold water disease according to (6), wherein the fish is ayu or salmon.

[0006] The cold water disease refers to a symptom in which the seedling ayu has white turbidity on the body surface, erosion, ulceration, and bleeding from the vicinity of the sebaceous fin to the caudal peduncle. Coho salmon, rainbow trout, sockeye salmon, etc. show symptoms such as rupture of the yolk sac in larvae, and discoloration of the skin behind the dorsal and sebaceous fins, scaling and erosion of the caudal peduncle, and loss of the caudal fin in juveniles.

In the present invention, salmon is coho salmon,
Includes rainbow trout, sockeye salmon, trout salmon and the like. Further, it can be said that the sulfa drug as a whole is effective in view of the mechanism of action of the sulfa drug, but sulfisosol, which has a low appearance of resistant bacteria, is particularly preferred. What is Sulfisozole?
3-Sulfanilamide isoxazole
amidoisoxazole), which has the following structural formula.

[0008]

Embedded image

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

[0010]

Example 1 A drug, florfenicol, sodium niflustyrenate, and sulfisosol, which were conventionally used in aquatic products such as sweetfish, were added to a liquid medium, and the growth of the bacteria was observed under the following experimental conditions.

Experimental conditions Growth medium: 10-fold diluted BHI medium Bacteria to be tested : Wild species of Flexibacter psychrophilus derived from Lake Biwa Ayu, Shiga Prefecture Cultivation method: Still at 15 ° C. (stir once a day) Proliferation confirmation method: Judgment based on increase in the absorbance of the culture solution using an absorptiometer (measurement wavelength 660 nm)

Experimental procedure: (1) After adding the test bacterium to the growth medium and allowing it to grow sufficiently (absorbance of 0.2 or more, about 1 × 10 ⁸ cells / ml), this bacterial solution is added to a new growth medium at 0.1%. The mixture was added to the culture and cultured (number of test tubes: 3). (2) Two days after the culture, an appropriate amount of a 10-fold diluted BHI medium in which an antibacterial agent or NaCl was dissolved was added, followed by culturing for 5 days, during which the change in the absorbance of the medium was measured daily (additional culture). The absorbance was the average of three culture test tubes.

(3) The antibacterial agent or NaCl
An appropriate amount was taken out of the medium to which was added daily, added to a new growth medium, and the growth of the bacteria in the medium was observed (back culture). The number of days until growth in the back culture was defined as the number of days until the growth when the absorbance of the measurement day exceeded 0.006 or more from the absorbance immediately after the return culture, and the average of three culture test tubes was shown. As a result, florfenicol and sulfisosol showed an effect of inhibiting the growth of bacteria, but did not have a bactericidal effect (Table 1).

[0014]

[Table 1]

[0015]

[Example 2] Even if it is ayu, it is said that marine ayu seedlings are hardly susceptible to cold water disease, so from the viewpoint that sodium chloride may have any effect,
Flexibacter psychr
The inhibitory effect of sodium chloride on the growth of S. ophilus was examined.

The results are shown in Tables 2 and 3, and when the liquid medium has a sodium chloride concentration of 1% or more at 15 ° C., Flexobacter cyclophila ( Flex
ibacter psychrophilus ), 2%
Then, 5 days after the addition of sodium chloride, Flexibacter cyclophila ( Flexibacter psychr
ophilus ).

[0017]

[Table 2] (Addition culture)

[0018]

[Table 3] (Return culture: 0.1 ml was taken out from the added culture solution.
diluted to ml)

[0019]

Example 3 Therefore, it was decided to examine the combined effect of sulfisosol, which has the highest growth inhibitory effect on Flexibacter psychrophilus , with sodium chloride. Based on the results of Example 2, experiments were carried out under the same conditions as in Example 1 for the case where the amount of sulfisosol was reduced and sodium chloride was added more, and the case where the amount of sulfisosol was increased and sodium chloride was added less. went. Tables 4 and 5 show the results when the amount of sulfisosol was reduced and the amount of sodium chloride was increased.

[0020]

[Table 4] (Addition culture)

[0021]

[Table 5] (Return culture: 0.1 ml was taken out from the added culture solution.
diluted to ml)

From Table 5, it was found that 5 ppm of sulfisozole contained 1: 1.
When 05% sodium chloride was added, it was found that Flexibacter cyclophila was removed from the test tube 5 days after the addition. It can be seen from Tables 4 and 5 that when sulfisosol is 5 ppm or 10 ppm, the sodium chloride content is 1.05% or 2.05%.
Bacterial growth was significantly suppressed compared to ntrol, but there was no significant difference between the two. That is, when sulfisosol is 5 ppm or 10 ppm, sodium chloride exhibits a remarkable effect from 1.05%.

[0023]

EXAMPLE 4 Next, the results when the amount of sulfisosol was increased and the amount of sodium chloride was decreased were shown in Tables 6 and 7.
Shown in

[0024]

[Table 6] (Addition culture)

[0025]

[Table 7] (Back culture: 0.01 ml was taken out from the added culture solution and diluted to 5 ml)

According to Table 7, 400 ppm of sulfisosol,
When each drug is added to the culture medium so as to have a sodium chloride concentration of 0.55%, the bacteria are not removed even after 5 days of the addition alone. However, when they are added simultaneously, the bacteria are removed from the test tube from the test tube on the 2nd day of the addition. It can be seen that the filler was sterilized.

As can be seen from the results of Tables 6 and 7, when sulfisosol and sodium chloride are used in combination, a remarkable effect is seen as compared with control or sodium chloride alone. However, when 400 ppm of sulfisosol and 0.55% and 1.05% of sodium chloride are used in combination,
It can be seen that there is no significant difference between 0.55% and 1.05% of sodium chloride.

That is, 400 ppm of sulfisosol
When sodium chloride is used, sodium chloride has a remarkable effect from 0.55%. When the results of Tables 4, 5, 6 and 7 are combined, it is preferable to use sulfisozole and sodium chloride in combination in order to effectively sterilize Flexobacter cyclophila, which is the causative bacterium of cold water disease.

[0029]

Industrial Applicability According to the present invention, it is possible to effectively sterilize the flexibacter cyclophila, which is a causative agent of cold water disease of fish, especially ayu or salmon, and to prevent or treat cold water disease. .

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Claims (6)

(57) [Claims] 1. A preventive / therapeutic agent for cold water disease in fish comprising a sulfa drug and sodium chloride. 2. The preventive / therapeutic agent for cold water disease in fish according to claim 1, wherein the sulfa drug is sulfisosol or a salt thereof. 3. The prophylactic / therapeutic agent according to claim 1, wherein the fish is sweetfish or salmon. 4. A method for treating cold water disease in fish, comprising adding a therapeutic agent for cold water disease in fish comprising a sulfa drug and sodium chloride to water in which fish live. 5. The method for preventing and treating cold water disease in fish according to claim 4, wherein the sulfa drug is sulfisosol or a salt thereof. 6. The method according to claim 4, wherein the fish is ayu or salmon.