Parasiticide and parasite control methods for perciformes fish

Abstract

To provide control methods by orally administered drugs for Platyhelminthes, Polyopisthocotylea, Heteraxine heterocerca.SOLUTION: Provided is a pesticide for Platyhelminthes, Monogenea, Polyopisthocotylea, Heteraxine heterocerca that infested fish, containing benzimidazole compounds as active ingredients. Preferably, benzimidazole compounds are one or more compounds selected from albendazole, febantel, fenbendazole, oxfendazole, mebendazole, flubendazole, oxibendazole, triclabendazole, licobendazole, and thiabendazole.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an agent and method for eliminating parasites in fish (particularly farmed fish), and more particularly to an agent and method for eliminating parasitism by oral administration of Heteraxine heterocerca, a monogenean parasitic on yellowtail. [Background technology]

[0002] Parasitic diseases are a major problem in fish farming because they hinder stable production. Among parasitic diseases, monogenean worms belonging to the phylum Platyhelminthes and class Monogenea are particularly common and are considered to be one of the biggest problems in farmed fish. Monogenean worms are generally classified as skin worms and gill worms. One of the monogenean parasites called gillworms that parasitize yellowtail is Heterocerca ( Heteraxine heterocerca ) Symptoms seen in the field include discoloration of the gills, anemia in the fish, and a decrease in fatness. In addition, fish may frequently be seen rubbing their bodies against the netting of the fish pens. Rubbing their bodies against the netting of the fish pens increases the chance of infection with pathogenic bacteria through the abrasions on the body surface, which can lead to greater damage. If an infestation of this worm is confirmed, it can be eradicated by bathing the fish in hydrogen peroxide. However, due to the labor required for handling, such as transferring the fish, and the stress it causes to the fish, there is a strong demand for treatment with oral medication.

[0003] Orally administered anthelmintics for monogenean worms are commercially available under the generic name praziquantel (Patent Document 1) as an extermination agent for Benedenia seriolae, which parasitizes the body surface of yellowtail, and under the generic name febantel (benzimidazole compound) (Patent Document 2) as an extermination agent for Heterobothrium okamotoi, which parasitizes the gills of Tetraodontiformes fish. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-92309 [Patent Document 2] WO02 / 005649 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide a method for exterminating Heterocerca, a gill parasite that parasitizes yellowtails, belonging to the phylum Platyhelminthes, class Polyhedrus, family Heteraxineae, by orally administering a drug. [Means for solving the problem]

[0006] In search of an orally administered drug that is effective against Heteraxine heterocerca worms, a serious problem in yellowtail aquaculture, without reducing the appetite of yellowtail when administered orally, we searched various existing veterinary antiparasitic drugs and substances derived from natural products. As a result, we found that albendazole, a commercially available veterinary antiparasitic drug, can be administered orally without reducing the appetite of yellowtail and has an anthelmintic effect, thereby completing the present invention.

[0007] The gist of the present invention is the following pesticides for Heteraxine heterocerca, a member of the class Monogenea of ​​the phylum Platyhelminthes, which are (1) to (7) below.

[0008] (1) An insecticide containing a benzimidazole compound as an active ingredient for the pest Heteraxine heterocerca, a parasitic parasite of fish in the phylum Platyhelminthes, class Monogenea. (2) Benzimidazole compounds include albendazole, febantel, and fenbendazole. The pesticide (1) is one or more compounds selected from the group consisting of benzophenone, oxfendazole, mebendazole, flubendazole, oxibendazole, triclabendazole, ricobendazole and thiabendazole. (3) A pesticide according to (1) or (2), wherein the fish is a Perciformes fish. (4) A pesticide for (3) in which the Perciformes are Seriformes. (5) A pesticide for (4) in which the fish species of the yellowtail family are yellowtail (Seriola quinqueradiata), amberjack (Seriola dumerili), yellowtail amberjack (Seriola lalandi), long-finned amberjack (Seriola rivoliana), Seriola carpenteri, Seriola fasciata, southern amberjack (Seriola hippos), Seriola peruana, and Seriola zonata. (6) The pesticide according to any one of (1) to (5), wherein the benzimidazole compound is administered at a dose 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. [Effects of the Invention]

[0009] According to the present invention, Heteraxine heterocerca, which parasitizes yellowtail, can be eradicated by oral administration. DETAILED DESCRIPTION OF THE INVENTION

[0010] The control of this invention is Heterocerca ( Heteraxine heterocerca ) is also called gillworm because it parasitizes the gills of fish such as yellowtail. The marine fish targeted by the present invention are those parasitized by Heterocerca of the family Heteraxineae, including fish belonging to the order Perciformes, such as fish belonging to the family Carangidae of the order Perciformes, genus Seriola. Examples of fish species belonging to the genus Seriola include yellowtail (Seriola quinqueradiata), amberjack (Seriola dumerili), Japanese amberjack (Seriola lalandi), long-finned amberjack (Seriola rivoliana), Seriola carpenteri, Seriola fasciata, southern amberjack (Seriola hippos), Seriola peruana, and Seriola zonata. In a preferred embodiment, the therapeutic agent or parasiticide of the present invention is used for yellowtail, amberjack, Japanese amberjack, long-finned amberjack, etc., which are particularly commonly farmed.

[0011] The active ingredient of the parasiticide of the present invention is a compound classified as a benzimidazole compound. Benzimidazole compounds are compounds that have a benzimidazole skeleton and are known to function as parasiticides and fungicides. Examples of such compounds include albendazole (methyl N-(5-propylsulfanyl-1H-benzimidazol-2-yl)carbamate), Febantel (methyl (NE)-N-[[2-[(2-methoxyacetyl)amino]-4-phenylsulfanylanilino]-(methoxycarbonylamino)methylidene]carbamate), and fenbendazole. (Fenbendazole;methyl N-(5-phenylsulfanyl-1H-benzimidazol-2-yl)carbamate), Oxfendazole (methyl N-[5-(benzenesulfinyl)-1H-benzimidazol-2-yl]carbamate), Mebendazole (methyl [5-(Benzoyl)benzimidazol-2-yl]carbamate), Flubendazole (methyl N-[5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamate), Oxibendazole, Triclabendazole, Recobe Examples of compounds that can be used include fenbendazole, thiabendazole, and the like, and one or more of these compounds can be used in combination as appropriate. Febantel is known to be a prodrug, and its active ingredients are fenbendazole and oxfendazole. In a preferred embodiment, the parasiticide of the present invention contains albendazole as an active ingredient.

[0012] The antiparasitic agent of the present invention can be effective when administered orally. It can also be administered by immersing fish in a solution containing the agent in a medicated bath, or by injection. The dosage of the parasiticide of the present invention is, for example, 1 / 100 of the fish's body weight per day for any fish. The benzimidazole compound is orally administered at a dose of 10 mg to 600 mg per kg of body weight (hereinafter referred to as "10 to 600 mg / kg / day"), preferably in the range of 10 to 120 mg / kg / day, or 20 to 100 mg / kg / day. The administration period is 1 to 20 days, preferably 3 to 10 days.

[0013] The antiparasitic agent of the present invention can be used alone as the active ingredient, or in combination with other substances, such as auxiliary ingredients such as carriers, stabilizers, solvents, excipients, and diluents, as needed. The form may also be any of the forms typically used for these compounds, such as powder, granules, tablets, and capsules. For fish sensitive to the taste or odor of the compound, a coating method or the like can be used to prevent a decrease in feed palatability and to make the compound less likely to leak.

[0014] In the case of fish, orally administered drugs are typically added to feed. When adding the therapeutic agent or parasiticide of the present invention to feed, it is preferable to use feed that takes into account the nutritional components and physical properties required by each fish species. Typically, pellets are prepared by mixing fish meal, bran, starch, minerals, vitamins, fish oil, etc., or pellets are prepared by mixing frozen fish such as sardines with powdered feed (mash) containing added vitamins and other ingredients. Since the daily feed intake is largely determined by the type and size of the fish, the therapeutic agent or parasiticide of the present invention is added to the feed in an amount calculated to achieve the above-mentioned dosage regimen. The therapeutic agent or parasiticide of the present invention may be administered in a single dose or in divided doses. Since the therapeutic agent of the present invention is used by adding it to fish feed, it is preferable to prepare a formulation suitable for adding an appropriate concentration to the feed consumed by the fish daily. Specifically, it is preferable to formulate the active ingredient so that it is contained in the formulation in an amount of 1 to 50% by weight, preferably 5 to 30% by weight, and more preferably 10 to 20% by weight.

[0015] Examples of the present invention will be described below, but the present invention is not limited to these examples. [Example]

[0016] <Effects of albendazole administration on feeding behavior of yellowtail> Yellowtail were housed in 120-liter tanks. Sand-filtered and ultraviolet-sterilized seawater was poured into each tank at a rate of 2.4 liters per minute. The fish were weighed the day before albendazole administration. After acclimation, each fish species and each group was fed the test feed for five consecutive days. Albendazole was administered once a day. To prepare albendazole-added feed, a specified amount of commercial feed and albendazole was placed in a polyethylene bag, and a 2-fold diluted spreader SE30 (Bussan Food Science Co., Ltd.) was added. The control group's diet was prepared by adding 4% of the diet weight of diluted ethanol (manufactured by the Company) and stirring. The experiment was conducted by adding only SE-30 at 4% of the feed weight and stirring. The amount of feed given was 2% of the fish's body weight. The effect of albendazole on feed intake was evaluated by observing the feeding behavior. The water temperature, test fish weight at the start of the experiment, number of test fish, albendazole dose, and results are shown in Table 1.

[0017] Results and Discussion A 5-day administration of albendazole at 600 mg / kg body weight did not affect feeding. A similar study was conducted on another fish species, the tiger pufferfish, and a 5-day administration of albendazole at 80 mg / kg body weight did not affect feeding. Albendazole adversely affected feeding in trout and coho salmon at 10 mg / kg for 5 days. The effect of administration on feeding varies depending on the fish species, with a high dose of 600 mg / kg body weight in yellowtail. It was found that even this amount did not reduce appetite during the administration period.

[0018] [Table 1] [Example]

[0019] <Anthelmintic effect of albendazole against Heteraxine heterocerca> Forty-five yellowtail fry with an average weight of 23 g were placed in a 200-liter tank. Hatched Heterocerca larvae were placed in the tank to produce infected fish. 31 days after the first challenge, the fish were weighed and divided into five groups of nine fish each, and each group was placed in a separate 100-liter tank. Oral administration of albendazole was carried out for 5 days from the day of administration. The test groups are shown in Table 2. Water was poured into the tank under the same conditions as in Example 1. The water temperature during the test period was kept at 25°C. Three days after the oral administration treatment was completed, all fish were taken and Heteraxine heterocerca was counted. The number of worms was also 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. The parasites that were initially infected in the test grew into adults, laid eggs, and hatched, and the next generation was considered to be infected. The evaluation was carried out by comparing the number of parasites in the control group and the albendazole oral administration group.

[0020] [Table 2]

[0021] Results and Discussion The results are shown in Table 3. The number of Heteraxine heterocerca parasites of 1 mm or larger in the treatment groups of 20 mg albendazole / kg fish body weight for 3 and 5 days was significantly lower than in the control group. The number of parasites of less than 1 mm also tended to be lower than in the control group. The treatment group of 80 mg albendazole / kg fish body weight for 5 days In this study, albendazole was effective in eliminating almost 100% of the parasitic worms. It was found that oral administration of the drug exerts an anthelmintic effect against Heterocerca laxiginae. Albendazole can be administered reliably without reducing the appetite of yellowtail, and therefore, the anthelmintic parasite can be reliably eliminated.The present invention is considered to be industrially beneficial.

[0022] [Table 3] [Industrial Applicability]

[0023] This study provides an effective oral repellent for the parasite Heteraxine heterocerca, which infects farmed fish.

Claims

[Claim 1] An extermination agent for Heteraxine heterocerca, a multi-postsucker of the class Monogenea of ​​the phylum Platyhelminthes that parasitizes fish, containing a benzimidazole compound as an active ingredient.

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