JPS6043331B2 - Fish virus disease prevention and treatment agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a novel prophylactic and therapeutic agent for viral diseases of fish.

Viral diseases of fish are becoming more common today as fish farming has become popular.
It is an epidemic disease that has been increasing in number, and is known to rapidly kill large numbers of farmed fish, especially young fish, causing serious damage. No satisfactory preventive or therapeutic agent has been found.

As a result of research into fish virus disease prevention and treatment agents, the inventors discovered the new finding that erythorbic acid and its salts can inactivate viruses that infect fish, such as trout, and can effectively prevent and treat viral diseases. Gain,
As a result of further research, this invention was completed.

Examples of the salts of erythorbic acid, which is an active ingredient of the prophylactic and therapeutic agent of the present invention, include inorganic or organic salts such as sodium salt, potassium salt, ethanolamine salt, and hexylamine salt.

The preventive and therapeutic agent of the present invention is applied to the preventive treatment of fish diseases caused by viruses.

Here, representative viral diseases of fish that are applicable include:
For example, infectious hematopoietic necrosis (infectious hematopoietic necrosis)
usHaematopoietic Necrosis,
IHN) or viral hemorrhagic sepsis (Viral
HaemcrThagicSeptice-mia)V
Typical examples of fish that cause such viral diseases include rainbow trout, kawamasu, red salmon, silver salmon,
Examples include Amago, Yamame, Masunosuke, Brown trout, Himemasu, Salmon, and Shirozake. The method of using the prophylactic and therapeutic agent of this invention is appropriately selected depending on the type of fish, growth period, etc., but in principle, the general method of using known prophylactic and therapeutic agents for fish diseases is applicable.

For example, the preventive treatment agent of the present invention may be filled into capsules or mixed into feed and orally administered to fish, immersing the fish body as a medicinal solution (medicinal bath), injecting it into the reciprocal cavity or back muscle of the fish, or There are methods to disinfect by directly administering it to the rearing water. Generally, the oral administration and injection methods are applied to fish of all ages, and the immersion method (medicinal bath) in a medicinal solution is often applied to fish eggs, fry, etc.

The dosage varies depending on the type of fish, growth period, administration method, etc., but in general, the final concentration of erythorbic acid is 0.01-10% of the feed when added to feed, and 20-10% when added to the feed.
Preferably, the concentration of erythorbic acid is 1000 ppm, and in the case of injection method, the concentration of erythorbic acid is 1000 ppm by weight of the fish.
Good results are often obtained by administering approximately 50 to 500 Mg per 9, and approximately 200 to 2000 M9 per oral administration, but the dosage is not necessarily limited to these dosages and may be administered as necessary. Just increase or decrease the amount. The prophylactic and therapeutic agent of the present invention may be used in combination with various carriers for convenience of use, and may be used in the form of powders, granules, tablets, capsules, liquids, etc., for example.

The carrier referred to herein may be either solid or liquid, or a combination thereof.

Typical specific examples of the carrier include water, white sugar, feed oil, sodium carbonate, sodium hydrogen carbonate, etc., but are not limited to these. Furthermore, the preventive and therapeutic agent of the present invention can be used not only alone, but also in combination with nutrients, feed, other antibacterial agents, anthelmintic agents, insecticides, metabolism improving agents, and the like. Next, this invention will be explained using test examples.

Test Example 1 (In vitro non-activation test of drugs against viruses) 0.02M Tris buffer (PH 7.2) 9.8
mt and copper sulfate aqueous solution (10-5M concentration as copper) 0
．． Pour 1 ml of the mixture into each of 6 test tubes.

An aqueous solution of the test drug (sodium erythorbate or sodium ascorbate as a comparative example) with a concentration of 1110-1 and 10-2M (mol/e) was added to these five test tubes.
．． Dispense 1 ml each to prepare a 1-fold dilution series of the test drug. Separately, as a control, add 0 water to one of the above test tubes.
．． Inject 1 mL. Next, transfer 45 ml from each test tube to another test tube, and transfer the IHN virus-containing aqueous solution (
Virus infection titer 1σ. 1TCID50/ml) 0.5m
Add t, stir thoroughly with a magnetic stirrer, and leave at room temperature.

After 1 gin, 3 oz, and 6 oz, remove the required amount of liquid from each test tube and prepare a 1 oz dilution series for each.

Add this to each well on the Arakarime microplate.
0.05 to cultured RTG-2 cells (Rainbow trout ovary cells) until 80% proliferation (confluence).
Inoculate ml each. The cells are cultured at 15°C and observed under a microscope every day for the presence or absence of CPE (cytopathic effect). After culturing for 14 days, the cells were fixed with formalin and stained with crystal violet in the usual manner, and the presence or absence of CPE expression was confirmed under a microscope for final judgment.

The virus infection titer calculated from the results is shown in Table 1 below. Test example 2 (infection prevention test) Rainbow trout fry (weight 0.9-3.2y1 body length 5.2-
6.2 beds, test area: 14 fish in 1 group, control area: 13 fish in 1 group)
Place them in a glass angle aquarium and raise them under running water.

Sweat trapped virus solution (
Virus concentration: 1Cf). 1TCID50/ml)0.
01ml was injected respectively. After 3 feedings, an aqueous solution of sodium erythorbate was injected into the cavity of the fry in the test section at an amount of 200 m9 per K9 fish weight.

After 2 hours, the same amount of sodium erythorbate aqueous solution was injected again to the fry in the test area.

Thereafter, the fry were observed over a period of time, and the infection prevention effect of sodium erythorbate was determined based on the presence or absence of death of the fry. The cumulative number of deaths over time in the test and control plots is shown in Table 2 below.

Example 1 Sodium erythorbate 5α■ white sugar
5 Prostitution Example 2

Claims (1)

[Claims] 1. Preventive treatment for viral diseases of fish characterized by containing one or more types of erythorbic acid or its salts as an active ingredient.