JP2024040470A - Parasite extermination agent and extermination method for perciformes fish - Google Patents

Abstract

The present invention provides a method for exterminating Heterocerca, a family of the family Heteraxinae, a family of the phylum Platyhelminthes, using an orally administered drug. [Solution] This is a repellent for Heteraxine heterocerca, a polysucker of the phylum Monogenea, which is parasitic on fish, and contains a benzimidazole compound as an active ingredient. The benzimidazole compound includes one or more compounds selected from albendazole, febantel, fenbendazole, oxfendazole, mebendazole, flubendazole, oxibendazole, triclabendazole, ricobendazole, and thiabendazole. preferable. [Selection diagram] None

Description

TECHNICAL FIELD The present invention relates to an agent for exterminating parasites of fish (especially cultured fish) and a method for exterminating parasites. In particular, the present invention relates to a drug and a method for exterminating the parasitism of Heteraxine heterocerca, which is a monogeneous species that parasitizes yellowtails, by oral administration.

Parasitic diseases are a very big problem in fish farming because they interfere with stable production. Among parasitic diseases, monogenean parasites belonging to the class Platyhelminthes are an infectious disease that occurs in many farmed fish and is considered to be one of the most serious problems. Among the monogenetic insects, there are two types that are commonly called spider worms and others called elamids.
One of the monogeneous insects called elamids that parasitizes yellowtails is Heteraxine heterocerca , a polymorphous sucker of the phylum Platyhelminthes. Symptoms in the field include gill discoloration, fish anemia, and decreased obesity. In addition, abnormal swimming, such as rubbing their bodies against the cage net, may be frequently observed. As they rub their bodies against fish pen nets, there is an increased chance of infection by pathogens from the scratches on their body surfaces, which can lead to more damage. If infestation with this worm is confirmed, it can be dewormed by bathing in hydrogen peroxide. However, treatment with drugs that can be administered orally is strongly desired because of the labor involved in transferring and other treatments of the fish and the stress placed on the fish.

An orally administered anthelmintic for monogeneous insects is known as a generic name praziquantel (Patent Document 1), which is used as an exterminator for Benedenia seriolae that parasitizes the body surface of yellowtails, and a generic name febantel (benzimidazole compound) (patent document 1). Reference 2) is sold as an exterminator for Heterobotulium okamotoi, which parasitizes the gills of puffer fish.

Japanese Patent Publication No. 11-92309 WO02/005649

An object of the present invention is to provide a method for exterminating Heterocerca, which is a parasitic eelworm that parasitizes yellowtails, using an orally administered drug.

In search of an orally administered drug that is effective for deworming Heteraxine heterocerca, which is an important problem in aquaculture, without reducing the appetite of yellowtail fish when administered orally, various existing antiparasitic drugs for animals and those derived from natural products were used. We explored substances, etc. As a result, they discovered that albendazole, which is sold as an antiparasitic drug for animals, can be orally administered to yellowtail without reducing their appetite, and that it has an anthelmintic effect, thereby completing the present invention.

The gist of the present invention is a repellent for Heteraxine heterocerca, a polysucker of the phylum Monogenea, of the phylum Platyhelminthes (1) to (7) below.

(1) An exterminator for Heteraxine heterocerca, a polysucker of the phylum Monogenea, which parasitizes fish, and contains a benzimidazole compound as an active ingredient.
(2) The benzimidazole compound is one or more selected from albendazole, febantel, fenbendazole, oxfendazole, mebendazole, flubendazole, oxibendazole, triclabendazole, ricobendazole, and thiabendazole. The pesticide (1) is a compound.
(3) The pesticide according to (1) or (2), wherein the fish are perciformes.
(4) The pesticide according to (3), wherein the perciformes are yellowtail fishes.
(5) Yellowtail fish include yellowtail (Seriola quinqueradiata), amberjack (Seriola dumerili), amberjack (Seriola lalandi), amberjack (Seriola rivoliana), Seriola carpenteri, Seriola fasciata, southern amberjack (Seriola hippos), Seriola peruana, The pesticide (4) is Seriola zonata.
(6) The pesticidal agent according to any one of (1) to (5), wherein the benzimidazole compound is administered at a dosage of 10 to 600 mg/kg/day.
(7) The pesticide according to any one of (1) to (6), wherein the administration period is 3 days or more.

According to the present invention, Heteraxine heterocerca that parasitizes yellowtails can be exterminated by oral administration.

As a control for the present invention, Heteraxine
heterocerca ) is also called Elamushi because it parasitizes the gills of yellowtails and other species.
The marine fish that are the targets of the present invention are those that are parasitized by Heterocerca of the family Heteraxinae. Examples of such marine fish include fish belonging to the order Perciformes, for example, fish belonging to the genus Amberinae of the order Perciformes.
Fish species belonging to the genus Amberjack include Seriola quinqueradiata, Seriola dumerili, Seriola lalandi, Seriola rivoliana, Seriola carpenteri, Seriola fasciata, Seriola hippos, Seriola peruana, Seriola An example is zonata. In a preferred embodiment, the therapeutic agent or antiparasitic agent of the present invention is used for amberjack, amberjack, amberjack, amberjack, and amberjack, which are particularly widely cultivated.

The active ingredient of the antiparasitic agent of the present invention is a compound classified as a benzimidazole compound. A benzimidazole compound is a compound having benzimidazole as a basic skeleton, and is known to function as a parasitic agent and a fungicide. Albendazole; methyl N-(5-propylsulfanyl-1H-benzimidazol-2-yl)carbamate), Febantel; methyl (NE)-N-[[2-[(2-methoxyacetyl)amino]-4- phenylsulfanylanilino]-(methoxycarbonylamino)methylidene]carbamate), Fenbendazole; methyl N-(5-phenylsulfanyl-1H-benzimidazol-2-yl)carbamate); )-1H-benzimidazol-2-yl]carbamate), Mebendazole; methyl [5-(Benzoyl)benzimidazol-2-yl]carbamate), Flubendazole; methylN-[5-(4-fluorobenzoyl)-1H -benzimidazol-2-yl]carbamate), oxibendazole, triclabendazole, ricobendazole, or thiabendazole, and one or more of these compounds can be used in appropriate combination. . Febantel is known to be a prodrug, the active ingredients of which are fenbendazole and oxfendazole.
In a preferred embodiment, the antiparasitic agent of the present invention contains albendazole as an active ingredient.

The antiparasitic agent of the present invention can exert its effect by oral administration. It is also possible to administer by immersing the fish in a solution containing the drug, or by injection.
The dosage of the parasiticide of the present invention is, for example, 1 fish body weight per day for any fish.
The dosage of the benzimidazole compound is 10 mg to 600 mg per kg (hereinafter referred to as "10 to 600 mg/kg/day"), preferably 10 to 120 mg/kg/day, 20 to 100 mg/kg/day. Administer orally for a range of days. The administration period is 1 to 20 days, preferably 3 to 10 days.

The antiparasitic agent of the present invention uses the above-mentioned compound as an active ingredient alone, or in combination with other substances, for example, auxiliary ingredients such as carriers, stabilizers, solvents, excipients, and diluents, if necessary. It can be used as Moreover, the form may be any form commonly used for these compounds, such as powder, granules, tablets, and capsules. For fish that are sensitive to the taste and smell of compounds, methods such as coating can prevent a decrease in feed palatability and make it difficult for the compounds to leak out.

In the case of fish, orally administered drugs are usually added to feed. When adding the therapeutic agent or antiparasitic agent of the present invention to feed, it is preferable to use a feed that takes into account the nutritional components and physical properties required for each species of fish. Usually, it is made into pellets by mixing fishmeal, bran, starch, minerals, vitamins, fish oil, etc., or it is made by mixing frozen fish such as sardines with powdered feed (mash) made by adding vitamins, etc. to fishmeal. It is used in pellet form. Since the daily feed intake is approximately determined depending on the type and size of the fish, the therapeutic agent or parasitic agent of the present invention is added to the feed in an amount converted to the above-mentioned dosage. The therapeutic agent or antiparasitic agent of the present invention may be administered in a single daily dose or may be administered in several doses. Since the therapeutic agent of the present invention is used by being added to fish feed, it is preferably formulated into a formulation suitable for adding at an appropriate concentration to the feed that fish ingest per day. Specifically, it is preferable to formulate and use the active ingredient so that it contains 1 to 50% by weight, preferably 5 to 30% by weight, and more preferably 10 to 20% by weight.

Examples of the present invention will be described below, but the present invention is not limited thereto.

<Effect of albendazole administration on feeding behavior of yellowtail>
Yellowtail was housed in a 120-liter aquarium. Sand-filtered and ultraviolet sterilized seawater was poured into each tank at 2.4 liters/min. Fish weight was measured the day before albendazole administration. After acclimatization, test feed was fed to each fish species and each group for 5 consecutive days. Albendazole was administered once a day. To prepare albendazole-added feed, put a predetermined amount of commercially available feed and albendazole into a polyethylene bag, add 2-fold diluted spreader SE 30 (manufactured by Bussan Food Science Co., Ltd.) to the feed and stir. I went by doing that. The feed for the control group was prepared by adding only diluted SE 30 in an amount of 4% of the weight of the feed and stirring. The amount of food fed was 2% of the fish body weight. The effect of albendazole on feeding was evaluated by observing feeding status. Table 1 shows the water temperature, the weight of the fish tested at the start of the test, the number of fish tested, the dose of albendazole, and the results.

Results and Discussion Administration of albendazole at 600 mg/kg for 5 days had no effect on feeding behavior. When similar tests were conducted on other fish species, feeding was adversely affected by administration of 80mg/kg of fish body weight for 5 days in tiger puffer fish, and of 10mg/kg of fish body weight for 5 days in marine trout and coho salmon. The effects of albendazole administration on feed intake vary depending on the species of fish, and it was found that in yellowtail, even a dose as high as 600 mg/kg fish body weight did not reduce appetite during the administration period.

<Anthelmintic effect of albendazole against Heteraxine heterocerca>
Forty-five yellowtail juveniles with an average weight of 23 g were housed in a 200-liter aquarium. Thereafter, the hatched larvae of Heteraxine heterocerca were introduced into the aquarium six times to produce fish infected with the main worm. Thirty-one days after the first challenge, the fish were weighed and divided into 5 groups of 9 fish each, and each group was housed in a separate 100-liter aquarium. Starting from the next day, albendazole was orally administered for 5 days. The test plots are shown in Table 2. Water was poured into the water tank under the same conditions as in Example 1. The water temperature during the test period was 25°C.
Three days after completing the oral treatment, all fish were picked and Heteraxine heterocerca were counted. In addition, the main worms were counted by dividing them into those with a body length of 1 mm or more and those with a body length of less than 1 mm. In this test, the main worms that were infected in the early stage became adults, and the next generation that hatched and laid eggs was infected. It was judged. The evaluation was performed by comparing the number of parasites between the control plot and the albendazole oral administration plot.

Results and Discussion The results are shown in Table 3. The number of Heteraxine heterocerca parasites larger than 1 mm in the albendazole 20 mg/kg fish body weight treatment area for 3 and 5 days was significantly lower than that in the control area. Parasitism of this parasite less than 1 mm also tended to be less compared to the control. In the area where 80 mg/kg fish weight was administered for 5 days, almost 100% of the parasitic main worms were dewormed. Therefore, it was revealed that albendazole exerts an anthelmintic effect against Heteraxine heterocerca orally.
Since albendazole does not reduce the appetite of yellowtail and can be administered reliably, it is possible to reliably deworm the main worms. The present invention is believed to be industrially useful.

An effective exterminator can be provided by oral administration of Heteraxine heterocerca, a parasite that parasitizes cultured fish.

Claims (1)

An exterminator for Heteraxine heterocerca, a polysucker of the phylum Monogenea, which parasitizes fish, and contains a benzimidazole compound as an active ingredient.