KR20240068798A - Method for eliminating fish-external parasites using low-concentration hydrogen peroxide solution - Google Patents

Abstract

Provides a safer and more effective method of exterminating external parasites living on the body surface of fish. This is a method of exterminating external parasites in marine fish using low-concentration hydrogen peroxide water, which is characterized by immersing in 30 ppm to 150 ppm hydrogen peroxide water for more than 15 minutes. The sides of the net of the cage are covered with a sheet to maintain the seawater inside. Hydrogen peroxide solution is added to the seawater inside the cage in such a way that the calculated average concentration is 30 ppm to 150 ppm. After 15 minutes or more, the sheet is removed. This is a method of exterminating external parasites in marine fish using low-concentration hydrogen peroxide, which is characterized in that it removes .

Description

Method for exterminating fish external parasites using low concentration hydrogen peroxide {METHOD FOR ELIMINATING FISH-EXTERNAL PARASITES USING LOW-CONCENTRATION HYDROGEN PEROXIDE SOLUTION}

The present invention relates to an exterminator and a method for exterminating external parasites of marine fish (particularly farmed fish). In detail, it relates to a drug and a method for eliminating parasitic parasites such as skin parasites and gill parasites that live on the body surface of fish.

In fish farming, parasitic diseases are a very big problem because they interfere with stable production. Among parasitic diseases, in particular, flatworms belonging to the class Platyhelminth and calligus from the crustacean class Arthropoda are infections that occur in many farmed fish and are considered one of the biggest problems. Among solitary parasites, there are those commonly called skin parasites and those called gill parasites. Parasites called skin parasites include the short-suckered capsara family Neobenedenia girellae and Benedenia seriolae , as well as yellowtails such as amberjack, yellowtail, yellowtail, and sickle yellowtail, as well as horse mackerel, perch, red sea bream, and yellow yellowtail. It is known to be parasitic on many fish species, including tang, redfish, javelin, flounder, pufferfish, and swift. As an on-site diagnostic method, in addition to death accompanied by symptoms such as redness of the epidermis of the abdomen, friction of the fins, and clouding of the eyes, in fish that have received a large amount of parasites, the body surface appears cloudy due to the secretion of a large amount of mucus. can be mentioned. In addition, abnormal swimming is frequently observed, with the body rubbing against the cage net. Symptoms may worsen when the body is rubbed against cages, etc., and the damage may be expanded because the chances of being infected with pathogens from the parasite site increase. When parasitic worms are confirmed, they are exterminated by bathing in fresh water or high-concentration hydrogen peroxide for about 3 minutes, paying attention to the water temperature.

Monoparasites called gill parasites include the flatworm phylum polysaccharidae Heteraxine heterocerca and Zeuxapta japonica , which parasitize on yellowtails, and the same Microcoti, which parasitize on red sea bream. Bivagina tai , Microcotyle sebastis , a parasite on rockfish, Microcotyle sebastisci , a heterobot of the family Dicridophora, a parasite on rockfish. These include Heterobothrium okamotoi and Neoheterobothrium hirame , which are parasitic on flounder. On-site diagnostic methods include fading of gills, anemia of fish, and decrease in obesity. In addition, there are cases where swimming is frequently seen as a result of rubbing against the cage net. In some cases, damage may be expanded by rubbing against cages, etc., as the chance of infection with pathogens increases from friction areas on the body surface. When parasitic worms are confirmed, they are exterminated by bathing in high-concentration hydrogen peroxide for about 3 minutes, paying attention to the water temperature.

In any case, since the labor required for treatment, such as changes in the fish's habitat, and the stress on the fish are large, a simpler treatment method is strongly desired.

In addition, it has recently been recognized that a large number of Lamellodiscus ( Lamellodiscus spp.) is parasitic on the gills of farmed red sea bream, raising concerns about the impact on the host. This worm is also called a gill parasite, and is classified into the genus Lamelodiscus of the family Diplectanidae. There is no established deworming method for this insect.

Parasites called Caligus of the crustacean class of the arthropod phylum include Caligus longipedis, which lives on horse mackerel, Pseudocaligus fugu, which lives on salmonid fish, mullet, and tilapia. These include the parasitic Caligus orientalis. Diagnosis in the field, effects on fish receiving parasites, and deworming methods are the same as for skin parasites. However, the treatment time for deworming in a freshwater bath or hydrogen peroxide bath is about 20 minutes, which is longer than for skin parasites.

The skin parasites that occur in yellowtails are Benedenia seriolae and Neobenedenia zirellae. In addition, Neobenedenia and Girellae have been reported to be parasitic in many marine fish other than yellowtail. The main method of deworming in the field is a medicinal bath using hydrogen peroxide solution (Katayama Chemical Industry Research Institute Co., Ltd., brand name Marine Sour and Hodogaya Chemical Industry Co., Ltd., brand name Sakana Guard) or fresh water bathing. In Japan, hydrogen peroxide is approved as a veterinary drug against Benedenia seriole of perch fish and Vibagina sea bream (gill parasites) of sea bream. The usage/dose for these parasites is 3 minutes at a hydrogen peroxide concentration of 300 ppm. In amberjack farming, the damage caused by Neobenedenia and Zirella is more serious than that of Benedenia and Cerriolae, and hydrogen peroxide is also used to deworm Neobenedenia and Zirella of amberjack. However, this dosage and usage method has a low anthelmintic effect against Neobenedenia and Zirella, and a medicated bath of 300 ppm for 5 to 6 minutes is used in the field. In addition, this agent is highly toxic to amberjack at high temperatures, and death accidents thought to be caused by oxygen deficiency may occur.

In addition, recently, hydrogen peroxide has been approved as a veterinary drug for the pufferfish species Neobenedenia, Girella, Pseudocalis, and Pufferfish, and the dosage and administration is 300 ppm for 20 minutes.

Patent Document 1 describes a method for exterminating external parasites in seawater farmed fish, which involves bathing the fish in a hydrogen peroxide solution with a concentration of 200 to 3000 ppm for 1 to 20 minutes. Patent Document 2 describes a method of bathing with hydrogen peroxide at a concentration of 10 to 100 ppm for 30 to 120 minutes in order to exterminate gyrodactylus in freshwater fish. Patent Document 3 describes a method of bathing with hydrogen peroxide at a concentration of 400 to 2000 ppm for 20 to 120 minutes to prevent heterobotrium disease in self-driving clothes.

Japanese Patent Publication No. 7-51028 Japanese Patent No. 2575240 Japanese Patent No. 2817753

The object of the present invention is to provide a safer and more effective method for exterminating external parasites living on the body surface or gills of fish.

While the inventors were researching a medicinal bath using hydrogen peroxide water, they found that by using low-concentration hydrogen peroxide water of 150 ppm or less, greater damage could be inflicted on parasites than when using conventional high-concentration hydrogen peroxide of 300 ppm or more, and more complete extermination was achieved. By finding out that it could be done, the present invention was completed. In addition, by combining low-concentration hydrogen peroxide water with a spraying method (a method of spraying the chemical directly on the cage, etc.), it is possible to prevent oxygen deficiency accidents caused by bathing with a small amount of seawater, which is the existing method, and to save fish. We have discovered an excellent deworming method that is said to be simple and safe compared to existing methods, which is said to greatly reduce the extensive work of gathering and lifting.

The present invention has as its gist the methods (1) to (5) for controlling external parasites in marine fish.

(1) A method for exterminating ectoparasites in marine fish using low-concentration hydrogen peroxide water, characterized by immersing in hydrogen peroxide water with a concentration of 30 ppm to 150 ppm for more than 15 minutes.

(2) Cover at least the side of the cage net with a sheet to maintain the seawater inside, add hydrogen peroxide to the seawater inside the cage in an amount that gives a calculated average concentration of 30 ppm to 150 ppm, and leave for 15 minutes or more. The method of (1), characterized in that the sheet is removed after passage of time.

(3) The method of (1) or (2), wherein the ectoparasites are parasites belonging to the class Flatworm or Crustacea.

(4) The method of (1) or (2), wherein the external parasite is a parasite of the class Calligus of the class Calligus of the Crustaceae of the Arthropod phylum.

(5) External parasites belong to the Capsalidae or Diplectanidae families of short ginger suckers, and the Heteraxine family and Microcotyloidea of multi-suckers. The method of (1) or (2), which is a parasite belonging to the family Diclidophoridae or Neoheterobothrium, or the crustacean Calligus family of the arthropod phylum.

(6) External parasites include Benedenia seriolae, Benedenia epinepheli, Benedenia hoshinai, Benedenia sekii, and Neo-Benedenia. Neobenedenia girellae, Neobenedenia congeri, Lamellodiscus, Zeuxapta japonica, Bivagina tai, Heteracicine. Heteraxine heterocerca, Microcotyle sebastis, Microcotyle sebastisci, Heterobothrium okamotoi, or Neoheterobothrium hirame), Caligus longipedis, Pseudocaligus fugu, and Caligus orientalis. The method of (1) or (2).

(7) The method of any one of (1) to (6), where the fish is a fish belonging to the percussion order.

(8) The method of (7) where the fish is a yellowtail or sea bream fish.

(9) The method of (1) or (2), wherein the immersion time is 15 minutes to 6 hours.

(10) The method of (1) or (2), wherein the immersion time is 15 minutes to 2 hours.

By using the extermination method of the present invention, external parasites can be exterminated more reliably and without adversely affecting the fish. In particular, it can effectively exterminate external parasites such as Benedenia, Seriole, Neobenedenia, Zirella, Zeucsapta, Yaponica, Vibagina, Dom, and Lamelodiscus, which have a significant impact on the aquaculture business.

Figure 1 is a diagram showing the anti-Neobenedenia girellae effect of hydrogen peroxide in Example 1.
Figure 2 is a photograph showing the anti-Neobenedenia girellae effect of hydrogen peroxide solution (300 ppm·3 minutes treatment) in Example 1. A: Control, B: Immediately after treatment and return to seawater, C: 3 minutes after treatment and return to seawater, D: 15 minutes after treatment and return to seawater.
Figure 3 is a photograph showing the anti-Neobenedenia girellae effect of hydrogen peroxide solution (300 ppm·6 minutes treatment) in Example 1. A: Immediately after treatment and return to seawater, B: 30 minutes after treatment and return to seawater, C: 60 minutes after treatment and return to seawater.
Figure 4 is a photograph showing the anti-Neobenedenia girellae effect of hydrogen peroxide solution (75 ppm treatment for 30 minutes and 60 minutes) in Example 1. A: Immediately after returning to seawater after 30 minutes of treatment, B: Immediately after returning to seawater after 60 minutes of treatment, C: 60 minutes after returning to seawater after 60 minutes of treatment, D: Immediately after returning to seawater after 60 minutes of treatment. Returned 10 hours later (D-1: peeled object, D-2: fixed object).
Figure 5 is a diagram showing the anti-Neobenedenia girellae action of 300 ppm and 75 ppm hydrogen peroxide solutions in Example 2.
Figure 6 is a photograph showing Neobenedenia girellae affected by each sphere in Example 2. A: Treated with 300 ppm hydrogen peroxide for 60 minutes and returned to seawater 30 minutes later, B: Treated with 300 ppm hydrogen peroxide for 60 minutes and returned to seawater 30 minutes later, C: Treated with 75 ppm hydrogen peroxide for 60 minutes and returned to seawater 30 minutes later.
Figure 7 is a diagram showing the effect of treatment with 300 ppm and 75 ppm hydrogen peroxide on reinfection of fish with Neobenedenia girellae in Example 6.
Figure 8 is a diagram showing the anti-Benedenia seriolae effect of hydrogen peroxide in Example 7.
Figure 9 is a photograph showing Benedenia seriolae affected by hydrogen peroxide treatment in Example 7. In the figure, arrows indicate atrophy and detachment of the sessile plaques. A: Immediately after treatment with 300 ppm hydrogen peroxide for 3 minutes, B: Immediately after treatment with 300 ppm hydrogen peroxide for 3 minutes and returned to seawater, 2 hours later, C: Immediately after treatment with 75 ppm hydrogen peroxide for 30 minutes, D: Treatment with 75 ppm hydrogen peroxide for 30 minutes Then return to seawater after 2 hours.
Figure 10 is a photograph showing the anti-Zeuxapta japonica action of 300 ppm and 75 ppm hydrogen peroxide in Example 9. In the drawing, the mark indicates atrophy of the fixation plate. A: Immediately after 6 minutes of treatment with 300 ppm hydrogen peroxide, B: After 10 minutes of treatment with 75 ppm hydrogen peroxide.
Figure 11 is a diagram showing the anti-Zeuxapta japonica action of 300 ppm, 75 ppm, and 50 ppm hydrogen peroxide solutions in Example 9.

Parasites that are the subject of the present invention include flatworms belonging to the flatworm class of fish (commonly called skin parasites or gill parasites) and calligus belonging to the crustacean class of arthropods. Parasites called skin parasites include those that live on saltwater fish, such as the monocarpic Benedenia subfamily. In the Benedenia subfamily, for example, Benedenia seriolae , Benedenia epinepheli , Benedenia hoshinai , Benedenia sekii , etc. Neobenedenia such as Benedenia , Neobenedenia girellae , and Neobenedenia congeri can be mentioned. The solitary parasites called gill parasites belong to the multi-sucker family Heteraxine heterocerca , Zeuxapta japonica , and Microcotyre family Vibagina and Dom ( Bivagina tai ), Microcotyle sebastis ( Microcotyle sebastisci ), Dicridophora family Heterobothrium Okamotoi ( Heterobothrium okamotoi ), Neoheterobothrium flatfish ( Neoheterobothrium hirame ) etc. In addition, some parasites called gill parasites are classified as short suckers, and examples include Lamellodiscus spp. Caligus includes Caligus longipedis , Pseudocaligus fugu , and Caligus orientalis , which belong to the Caligus family. It is especially effective for Neobenedenia, Benedenia, Zeucsaptha, Yaponica, Vivagina, Dom and Lamelodiscus.

In the present invention, marine fish refers to marine fish species that are treated as farmed fish or ornamental fish that require the removal of parasites. Among them, those of particular industrial importance are farmed fish, such as puffer fish of the order Pufferfish, bari of the order Pufferidae, tilapia of the cichlid family of the order Percussion, etc., fish species known to be parasitized by fish parasites such as skin parasites and gill parasites, or The drug of the present invention can be used prophylactically or therapeutically in fish species that are likely to be infected with fish parasites.

Fish species that are the subject of the present invention include cultured fish of all ages surviving in seawater, aquarium and commercial viewing fish. In particular, farmed fish include fish from the orders of perch, flatfish, blowfish, herring, and eel, as well as yellowtail, barley, sea bream, flounder, puffer, salmon, and eel. Specifically, amberjack, sick amberjack, yellowtail (seaweed), yellowtail, horse mackerel, striped horse mackerel, yellow mackerel, sea bass, red sea bream, parrot sea bream, river bream, tilapia, snapper, red sea bream, gray sea bream, grouper, brown round sea bream, swordfish. Black-spotted flounder, humpback grouper, spotted flounder, giant flounder, flatfish, flounder, yellow flounder, turbot, turbot, halibut, purple flounder, filefish, yellow tang, filefish, rainbow. Examples include trout, Atlantic salmon, silver salmon, sockeye salmon, etc. In particular, damage from skin parasites has been widely reported in amberjack, yellowtail, barley, snapper, sea bream, barramundi, tilapia, and sea bass.

The hydrogen peroxide used in the present invention is not special and can be any commercially available solution. Since a 35% solution or the like is sold, it is diluted to a specified concentration and used as a medicinal bath. For marine fish, it is conventionally thought that medicinal bathing should be done at a concentration of 300 ppm or more, and this has been practiced as such. However, in the present invention, the bath is performed at a low concentration of 30 ppm to 150 ppm, preferably 30 to 100 ppm, more preferably 30 to 90 ppm, 30 to 80 ppm, and 37.5 to 75 ppm. It is preferable that the medicinal bath time is 15 minutes or more. Although it may vary depending on the fish species, if the concentration is low, no adverse effects are seen on the fish body even if bathed for a long time, so there is no particular upper limit. As shown in Example 5, there were symptoms such as poor feeding at 150 ppm for 6 hours, but there was no death as at 300 ppm, and no abnormalities were observed at 75 ppm. However, there is no need to place unnecessary burden on the fish body, and in terms of work efficiency, the duration is 15 to 120 minutes, preferably 15 to 90 minutes, and more preferably 30 to 60 minutes. Therefore, 15 minutes to 6 hours is preferable at 30 to 150 ppm, and 15 minutes to 2 hours is more preferable. Alternatively, at 30 to 100 ppm, 15 minutes to 6 hours is preferable, and 15 minutes to 2 hours is more preferable.

For example, for parasites of multi-sucker species excluding short-suckers and Vibagina, the most desirable concentration is 37.5 to 75 ppm, and for Vibagina, 75 to 100 ppm is preferable.

This medicinal bath should be administered promptly if parasitic infection is suspected. The medicinal bath can be performed once. Afterwards, if parasite infection is suspected during breeding, this can be done quickly once. In this specification, ppm represents the amount of hydrogen peroxide in water by weight/volume.

The reason why the parasite extermination effect of the medicated bath performed at a low concentration of the present invention is higher compared to the conventional medicated bath performed at a high concentration can be explained as follows from the results of the examples.

When Neobenedenia and Zirella are treated with a hydrogen peroxide concentration of 300 ppm for 6 minutes at a water temperature of 25°C, the worms clearly atrophy, but the suckers (adhesion spots) used to settle in the host do not atrophy or deform. Therefore, the main insect remains adsorbed to the petri dish wall, and the insect gradually recovers after treatment (Example 1). The same thing is thought to be happening on the host body surface, causing the anthelmintic effect to be unstable. In fact, when amberjack infected with Neobenedenia and Girella were bathed under the conditions of a hydrogen peroxide concentration of 300 ppm·6 minutes, the anthelminth rate was 59.1%, which limited the anthelmintic effect (Example 3).

On the other hand, it was found that when Neobenedenia zirella was treated at a low concentration of 75 ppm or 50 ppm for 30 to 60 minutes, the degree of atrophy of the worm was slight, but the suckers were also atrophied and deformed and peeled off from the petri dish wall. Additionally, the shrinkage of Neobenedenia and Zirellae after treatment continued (Example 1).

Even when Neobenedenia and Zirella were treated with a high concentration of hydrogen peroxide (300 ppm) for 60 minutes, the atrophy and deformation of suckers (adhesive spots) was only 30%. Therefore, it became clear that a low concentration of 75 ppm or 50 ppm had a higher effect of shrinking and deforming the suckers of Neobenedenia and Zirella than at a high concentration (Example 2).

Amberjack infected with Neobenedenia and Girella were bathed medicinally under the conditions of a water temperature of 25°C and a hydrogen peroxide concentration of 75 ppm for 30 minutes. The deworming rate was 94.3%. Additionally, the deworming rate at the time of treatment at 50 ppm for 30 minutes was 86.6%. Therefore, it became clear that in the anthelmintic treatment of Neobenedenia and Zirella, it is important to atrophy and deform the sessile plaques, and thereby a high anthelmintic effect can be stably obtained (Example 3). In addition, in Example 4, it was confirmed that a high anthelmintic effect was obtained even under the conditions of 30 or 60 minutes at a hydrogen peroxide concentration of 37.5 ppm. At low concentrations, the sessile patches of Neobenedenia and Zirellae are atrophied and deformed and detached from the host, so there is no factor for the main worms to recover after treatment, and a stable anthelmintic effect can be expected.

Medicinal bathing with hydrogen peroxide at aquaculture sites is carried out by preparing a solution with a hydrogen peroxide concentration of 300 ppm on a pool-shaped sheet of approximately 200 t and storing fish therein. When amberjack is bathed with a hydrogen peroxide concentration of 150 ppm or higher, the fish swims vigorously up and down in the first 1 to 3 minutes, perhaps due to the stimulation (Example 5). There have been cases of fatal accidents thought to be caused by oxygen deficiency during high temperatures in the summer, and the vigorous swimming observed in this test was thought to be one of the causes. On the other hand, when amberjack was immersed in a hydrogen peroxide concentration of 75 ppm for 6 hours, there was no adverse effect on swimming or feeding behavior the next day (Example 5). From these results, it became clear that if the hydrogen peroxide concentration was less than 150 ppm, especially 75 ppm or less, it was possible to bathe the amberjack without any adverse effects. In addition, it became clear that the medicinal bath treatment at a high concentration damaged the body surface of the amberjack, making it susceptible to reinfection with Neobenedenia and Zirella, while the treatment at a low concentration did not damage the body surface (Example 6).

The bathing method used in Norwegian salmon farming uses a skirt method that surrounds the sides of the cage with a sheet. This method can secure dissolved oxygen in the rearing environment because there is no need to move the fish into a narrow medicine bath. Additionally, it is also possible to maintain dissolved oxygen in environmental water by aeration of oxygen or air. By combining this method with the present invention, a relatively long medicament bath of 30 to 60 minutes is possible.

For the injection of chemicals, a dedicated container material is designed in which many holes are formed in a cylindrical tube, so that the medicine can be sprayed from the surface layer to the bottom layer of the cage simultaneously. Additionally, the medication can be spread evenly by the swimming of the fish.

Specifically, the side of the net of the cage is covered with a sheet to maintain the seawater inside, and an amount of hydrogen peroxide solution that has a calculated average concentration of 30 ppm to 150 ppm is added to the seawater inside the cage, and left for 15 minutes. After the above period has elapsed, preferably 15 minutes to 6 hours, or 15 minutes to 2 hours, more preferably 30 to 60 minutes, the medicated bath of the present invention can be performed by removing the sheet. With this method, it is possible to medicate the fish without putting stress on it.

It was confirmed that the same results were obtained not only for Neobenedenia and Zirellae but also for Benedenia and Seriole (Examples 7, 11, and 12). Additionally, in an in vivo test, it became clear that it exerts a clear anthelmintic effect even against Lamelodiscus (Example 8). Benedenia and Seriolae are classified into the genus Benedenia of the short-skinned suckers, Neobenedenia and Zirellae are classified into the genus Neobenedenia, and Lamelodiscus are classified into the genus Lamelodiscus. Low-concentration hydrogen peroxide baths were thought to be effective against parasites of the sweet ginger sucker class because they commonly exhibited a high anthelmintic effect on these parasites.

In addition, the transformation and persistence of parasites during low-concentration treatment were also observed in the sessile spots where the vaginae of Zeucsapta yaponica were arranged (Example 9). As a result of in vivo testing, it became clear that it exerts a clear anti-parasitic effect even against the main insect (Examples 11 and 12). In addition, it showed a clear repellent effect on Vibagina and Dom (Example 10). Zeucsapta and Yaponica are classified into the Zeucsapta genus of the short ginger Dahu suckers, and Vibagina and Dom are classified into the related Vibagina genus. Because low-concentration hydrogen peroxide baths had a high anthelmintic effect on these parasites, it was thought that they were also effective on the parasites of the Dangin Ginger Dahu suckers.

Examples of the present invention are described below, but the present invention is not limited to these in any way.

Example 1

<Anthelmintic effect of low-concentration hydrogen peroxide treatment on Neobenedenia and Zirella in vitro-1>

Test method: Approximately 100 g of 4 yellowtails were placed in one 100 liter tank, and 2,000 Neobenedenia and Zirella hatched larvae were introduced into the tank to attack. The fish were sampled 14 days after the attack, and the adult worms living on the body surface were recovered with tweezers and used for testing. Additionally, the water temperature during the rearing period was 25±0.5°C. UV-sterilized filtered seawater was used, and the supply rate was 1.2 liters/min. Commercially available EP feed was used as feed, feed was supplied once a day, and the feed amount was 2% of the fish body weight.

Ten adult worms each were housed and settled in seven 90 mm tissue culture petri dishes containing 20 ml of seawater. After settling, it was washed three times with seawater. The seawater was removed with a decanter, and the remaining seawater was wiped off with Kimwipes. 20 ml of each test solution was added thereto and cultured at room temperature of 25°C. After treatment, the cells were washed four times with seawater, 20 ml of seawater was added, and cultured for 10 hours. Immediately after treatment and return to seawater, every 30 minutes after return to seawater for 2 hours, and 10 hours after treatment, atrophied individuals and adults detached from the chalet wall were counted and recorded. In addition, in order to determine the size of Neobenedenia and Zirella presented in the test, the body length of 30 individuals of the main insect was measured.

Test group: The test group is shown in Table 1.

Results and Discussion

The length of the main insect provided in the test was 4.17 ± 0.25 mm.

Hydrogen peroxide solution is an insect repellent for Benedenia and Ceriollae, which live on the body surface of yellowtails, and Vibagina and sea bream, which live on the gills of red sea bream. The dosage and dosage is 300 ppm of hydrogen peroxide for 3 minutes.

In test group 1, Neobenedenia and Zirellae showed moderate atrophy immediately after being treated and returned to seawater (Figures 1 and 2B), and the degree of atrophy increased until about 10 minutes after being transferred to seawater. , 3 out of 10 subjects suffered from severe atrophy (Figure 2C). However, the atrophied individuals gradually recovered (Figure 2D), and all individuals recovered from atrophy 30 minutes after being returned to seawater (Figure 1).

All Neobenedenia zirellae in test group 2 were severely atrophied immediately after they were treated and returned to seawater ( Fig. 3A ). Even 30 minutes after treatment and return to seawater, all individuals were atrophied (Figure 1), but the atrophy was recovered to a moderate level (Figure 3B). 60 minutes after being returned to seawater, 90% of the animals had recovered from atrophy (Figure 1, Figure 3C).

In Test Group 1 and Test Group 2, the sessile patches (large suckers) of Neobenedenia girella did not shrink at both the 3 and 6 minute treatment times (Figures 2B & C, Figure 3A). In view of the above, the Benedenia deworming conditions of a hydrogen peroxide concentration of 300 ppm for 3 minutes and a treatment time of 6 minutes doubling the treatment time will allow the fish to come into contact with each other in a relatively short period of time for the atrophied main worms to recover. It was thought that physical action, such as rubbing, removes the main insects from the body surface, thereby exerting an anti-parasitic effect. It is thought that there is a limit to the anthelmintic effect since individuals that do not receive physical action recover.

In Test Group 3 and Test Group 5, all individuals were shrunk to a moderate level immediately after being returned to seawater after 30 minutes of treatment ( Figs. 1 and 4A ). Both treatments showed a tendency for significant shrinkage after treatment and transfer to seawater. This trend is the same as the 3-minute treatment at 300 ppm. More than half of the atrophied main worms recovered after 30 minutes, but one atrophied main worm was observed even 1 hour and 30 minutes after being returned to seawater (Figure 1). All of them had atrophied adhesion zones, making it impossible for them to settle down in the chalet.

In Test Group 4 and Test Group 6, there was moderate shrinkage immediately after treatment, and no significant difference from Test Group 3 and Test Group 5 was recognized. In both treatments, atrophy tended to progress after treatment and transfer to seawater. In particular, in test group 4, the number of individuals peeling off from the petri dish gradually increased 60 minutes after being returned to seawater, and the peeling rate after 60 minutes reached 100%. Even 120 minutes after treatment in both test groups, more than half of the individuals were shriveled. As the point of atrophy, sessile plaques were prominent (Figures 4B & C). In addition, in test group 4, 7 main insects were observed that had not recovered even after 10 hours, and 4 of them were not settled in the petri dish. Atrophy of the fixation zone continued, and atrophy was observed not only in individuals that were not anchored to the petri dish, but also in individuals that were anchored (Figure 4D).

These results show that even at low concentrations of 75 ppm and 50 ppm, Neobenedenia and Girella can be dewormed by treatment for 30 to 60 minutes. In particular, in that it shrinks the sessile patches of Neobenedenia and Zirella, it was thought to stably demonstrate a high repellent effect compared to the high-concentration, short-time treatment used in conventional cages.

Additionally, in test group 7, no atrophy or peeling of Neobenedenia and Zirella from the petri dish was observed during the test period.

Example 2

<Anthelmintic effect of low-concentration hydrogen peroxide treatment on Neobenedenia and Zirella in vitro-2>

Test method: The test was conducted in the same manner as Example 1. Neobenedenia zirellae, which had been parasitic on the yellowtail for 12 days after attack, were used for testing, and 10 adult insects each were housed in 3 petri dishes and allowed to settle. After 30 minutes of treatment, immediately after the 60-minute treatment was completed and returned to seawater, and 30 minutes after being returned to seawater, atrophied individuals and adults peeled from the chalet wall were counted and recorded.

Test group: The test group is shown in Table 2.

Results and Discussion

The length of the main insect provided in the test was 3.86 ± 0.29 mm.

Neobenedenia in test group 1 shrank 2 to 3 minutes after starting treatment, and shrunk became noticeable 6 minutes later. However, in observations 30 minutes after treatment, immediately after 60 minutes of treatment, and 30 minutes after treatment was completed and returned to seawater, all Neobenedenia and Zirella individuals were shriveled, but the main worms that had peeled off from the chalet wall were It was recorded as 3 individuals (Figure 5). 30 minutes after the treatment was completed and the fish were returned to the seawater, although the bodies of all the animals were affected to the point where they turned white and could not move, no atrophy or deformation was observed in the fixation patches of the seven animals and they were settled in the dishwasher. (Figure 5, Figure 6A & B). Of those 7 individuals, 2 had barely peeled off from the petri dish wall after 1 hour of incubation after treatment. These two individuals were judged to be dead because their marked atrophy had become mild and their bodies were clearly cloudy.

The number of individuals peeled from the petri dish in test group 2 was 9 immediately after the 60-minute treatment and 30 minutes after the treatment was completed and returned to the seawater ( Fig. 5 ). The exfoliated worm not only had a shrunken body, but also had clearly atrophied and deformed fixation patches ( Fig. 6C ), reproducing the test results of Example 1.

From the above results, it was revealed that low concentrations of 75 ppm or 50 ppm had a clearly higher effect of shrinking and deforming the suckers of Neobenedenia and Girella than the high concentrations that are commonly used. These results show that low-concentration treatment of hydrogen peroxide, such as 75 ppm or 50 ppm, removes atrophied insects from the body surface of atrophied Neobenedenia and girella by contact between fish or rubbing against cage nets or obstacles. In addition to the physical action of the usual dose to cause Neobenedenia and Zirella to detach from the host, it also has the effect of atrophying and deforming the fixation patches used to settle in the host and detaching it from the host's body surface. It was thought that it stably exhibited a high anthelmintic effect compared to treatment.

Additionally, in test group 3, no atrophy or peeling of Neobenedenia zirella from the petri dish was observed during the test period.

Example 3

<Anthelmintic effect of low-concentration hydrogen peroxide treatment on Neobenedenia and Zirella in vivo-1>

Test method: 48 amberjacks with an average fish weight of about 130 g were reared in a 500 liter tank for about 7 days and allowed to acclimatize at a water temperature of 25°C. The feed supplied during that time was commercial feed, and the feed supply rate was set at 2% of the fish body weight. The injection of water was 8.3 liters/min. After acclimatization, approximately 4,500 hatched Neobenedenia and Zirella larvae were placed in a 500 liter tank, and the water was allowed to remain stagnant for 1 hour to attack the main insects. Seven days after attack by hatched larvae, fish were transferred to seven 200 liter tanks and test plots were set up (Table 3). The remaining 4 fish were continued to be reared in a 500 liter water tank to measure the length of Neobenedenia/Jirella when treated with hydrogen peroxide, and when treated with a medicinal bath, the main insects were recovered and the body length of 30 individuals was measured. Water injection during the rearing period was 6.7 liters/min. Nine days after the attack, each fish was treated with a medicinal bath in a 200 liter square tank, and after treatment, the fish were transferred back to the 200 liter rearing tank and reared until the next day. All fish were sampled, fish body weight was measured, and parasitic Neobenedenia girellae were counted. Evaluation of the anthelmintic effect was conducted by comparing the number of Neobenedenia and Zirella parasites in each group.

Test group: The test group is shown in Table 3.

Results and Discussion

The body length of Neobenedenia and Zirella at the time of chemical treatment was 3.01 ± 0.43 mm, and it was an adult.

Table 3 shows the anthelmintic effect on the main worms parasitic on amberjack.

The neobenedenia and zirella deworming rate in test group 1 (dose and usage method for deworming Benedenia and seriole using hydrogen peroxide solution) was 33.5%. In addition, the extermination rate of test group 2, where the immersion time was 6 minutes, was 59.1%. From the test results of Example 1, treatment with a hydrogen peroxide concentration of 300 ppm for 6 minutes strongly atrophies the body of Neobenedenia girella, but does not cause atrophy or deformation of the sessile spots (large suckers) of the main insect. It has been proven that atrophied and exfoliated worms recover in about 1 hour. From the results of this test, the anthelmintic effect under these conditions is exerted by physical actions such as contact between fish and rubbing against the cage net in a relatively short period of time until the atrophied main worms recover. It has become clear that there is a limit to the anti-parasitic effect simply by shrinking the body.

The deworming rate of test group 3 was 94.3%, and the deworming rate of test group 4 was 99.2%, showing a high anthelmintic effect. In addition, the anthelminth rate in test group 5 was 86.6%, and the anthelminth rate in test group 6 was 97.5%, showing a similarly high insecticide effect. In Examples 1 and 2, these low-concentration treatments shrank not only the body but also the sessile zone of Neobenedenia zirella. From Examples 1 and 2 and the results of this test, it became clear that it is important to atrophy and deform the fixation plaque in the anthelmintic treatment of Neobenedenia and Zirellae, and that a high anthelmintic effect can be stably obtained thereby.

Example 4

<Anthelmintic effect of low-concentration hydrogen peroxide treatment on Neobenedenia and Zirella in vivo-2>

Test method: The test was conducted at a water temperature of 30°C, and the operation was performed in the same manner as in Example 3. 42 amberjacks with an average fish weight of about 130 g were reared in a 500 liter tank for about 7 days and acclimatized to a water temperature of 30°C. The number of Neobenedenia and Zirella hatched larvae used in the attack was approximately 5,500. Three days after the attack of the hatched larvae, the fish were transferred to six 200 liter tanks and test plots were set up (Table 4). Each group was treated with a medicinal bath 7 days after the attack, and the anthelmintic effect was evaluated 8 days after the attack.

Test group: The test group is shown in Table 4.

Results and Discussion

The body length of Neobenedenia and Zirellae at the time of chemical treatment was 3.01 ± 0.18 mm, and they were adults.

Table 4 shows the anthelmintic effect on the main worms parasitic on amberjack. The results of Example 3 were reproduced. And, it was found that even at a low hydrogen peroxide concentration of 37.5 ppm, a high anthelmintic effect is exhibited by treating for 30 to 60 minutes.

Example 5

<Effect of hydrogen peroxide on amberjack-1>

Test method: Six amberjacks with an average fish weight of approximately 208 g were housed in six 200 liter tanks each. The fish were acclimatized by rearing them at 25°C for 7 days. The feed supplied during this period was commercial feed, and the feed supply rate was set at 2% of the fish body weight. The injection of water was 6.7 liters/min.

A prescribed amount of hydrogen peroxide was diluted with seawater in advance, and the breeding water was kept stagnant without flowing and then added to each tank. After that, observation was conducted for up to 6 hours. After 6 hours of treatment, the water was returned to running water.

Test group: The test group is shown in Table 5.

Results and Discussion

The observation results are shown in Table 6. In the treatment group with a hydrogen peroxide concentration of 300 ppm or more, the fish swam vigorously up and down 1 to 3 minutes after the start of the immersion treatment. After that, swimming abnormalities subsided, but around 15 minutes after the start of immersion, large openings and gill covers were observed repeatedly. Before death, the fish repeated frantic swimming, sideways and slow swimming, and died with patterns on its body surface. The remaining fish that survived in the 300 ppm treatment group, 2 Mido, showed moderate behavior. Although the occurrence of dead fish was not recognized in the 150 ppm treatment group, abnormal swimming and opening during treatment, and abnormalities in feeding behavior the day after treatment were confirmed. Accordingly, it was found that the concentration of 300 ppm, which is the usual dose for deworming Benedenia and Seriole in percussion fish, causes toxicity to fish in a short period of time. On the other hand, in the 75 ppm treatment group, which is 1/4 the usual amount, no abnormalities were observed during immersion, and no abnormalities were recognized even after completion of immersion or when feeding feed the next day. Accordingly, it was found that at a concentration of less than 150 ppm, especially 75 ppm or less, long-term medicament treatment was definitely possible without adverse effects on the fish. And, treatment at low concentrations, such as this concentration or 50 ppm, is a condition for atrophying and deforming the sessile patches of Neobenedenia and Zirella, thereby stably demonstrating a high anthelmintic effect.

In aquaculture fields, deaths thought to be caused by oxygen deficiency may occur in hydrogen peroxide baths during high summer temperatures. It is generally known that this medicinal bath causes damage to the gills of fish the higher the water temperature. In this test, vigorous swimming behavior was observed 1 to 3 minutes after the start of treatment in spheres above 150 ppm. Therefore, it was thought that the cause of the fatal accident was not only the effect of hydrogen peroxide on the gills, but also the vigorous swimming, which was a factor causing oxygen deficiency.

Example 6

<Effect of hydrogen peroxide on amberjack-2>

Test method: 33 amberjacks with an average fish weight of approximately 195 g were identified by labeling them with electronic tags, and were reared in a 500 liter tank for 7 days to acclimatize. Rearing conditions such as water supply, feed amount, and water temperature were in accordance with Example 3. After acclimatization, the fish were transferred to three 200 liter tanks, each tank containing 11 fish, and the fish's tag numbers were recorded. The test groups were a group treated with a hydrogen peroxide concentration of 300 ppm for 3 minutes, a group treated with a hydrogen peroxide concentration of 75 ppm for 30 minutes, and an untreated control group. After the treatment, all the fish were again housed in one 500 liter tank, about 7,200 hatched Neobenedenia and Zirella larvae were introduced, and the water was allowed to remain stagnant for 1 hour. Six days after the attack, all fish were sampled and parasitic Neobenedenia girellae were counted. Safety evaluation after treatment was conducted by comparing the Neobenedenia and Girella parasitic numbers in each plot.

Results and Discussion

The observation results are shown in Figure 7. The number of parasites in the 3-splitting section with a hydrogen peroxide concentration of 300 ppm was significantly higher than that in the untreated control section. On the other hand, the parasitic number of the 75 ppm·30 minute sphere was the same value as that of the control sphere. From the above results, it was thought that high-concentration hydrogen peroxide baths, such as the usual dose, caused some kind of disorder, such as peeling of mucus, on the fish's body surface even after a short treatment of several minutes, making it susceptible to reinfection with parasites. On the other hand, it was found that long-term treatment at a low concentration did not cause enough damage to the fish's body surface to make it susceptible to reinfection with parasites. Therefore, it has become clear that the safety of fish according to the present invention is higher than that of the conventional method not only during processing but also after processing.

Example 7

<Anthelmintic effect of low-concentration hydrogen peroxide solution treatment on Benedenia and seriole in vitro>

Test method: Approximately 150 g of 4 yellowtails were housed in one 100 liter tank, and 1,300 hatched Benedenia and Seriola larvae were introduced into the tank to attack. The fish were sampled 19 days after the attack, and the adult worms living on the body surface were recovered with tweezers and used for testing. Additionally, the water temperature during the rearing period was 20.5±0.5°C. Yellowtail breeding and in vitro testing were conducted in the same manner as in Example 1. In addition, the counts of shriveled individuals and adult worms peeled off from the wall of the chalet were counted immediately after treatment and return to seawater, and every 30 minutes for 2 hours after return to seawater.

Test group: The test group is shown in Table 7.

Results and Discussion

The length of the main insect used in the test was 5.30 ± 0.31 mm.

As for the Benedenia seriole in test group 1, all individuals were severely shrunk immediately after treatment (Figure 9A), and 3 out of 10 individuals were peeling off from the petri dish wall (Figure 8). After treatment and return to seawater, 30 minutes later, 4 additional specimens were peeled off from the chalet wall. The adherent plaque of the exfoliated object was atrophied and deformed (Figure 9B). However, 3 individuals recovered from atrophy during the 90 minutes following treatment and return to seawater. In the test of Neobenedenia zirella in Example 1, no exfoliated worms were observed under these conditions, and all individuals recovered from atrophy within 30 minutes after treatment and return to seawater. These results show that Benedenia and Ceriollae are more sensitive to hydrogen peroxide than Neobenedenia and Zirella and are easily affected.

In test group 2, delamination of 5 specimens was observed immediately after treatment, and an additional 4 specimens delaminated within 90 minutes after treatment and return to seawater. In this district, 1 individual recovered from atrophy. Since individuals recovering from atrophy were observed in both test groups, it is possible that the deworming effect has limitations and the deworming results are not stable.

In test group 3, all the individuals shrank and peeled off from the petri dish wall at 13 minutes after the start of treatment. Also in test group 4, 10 out of 10 individuals shrank at 13 minutes from the start of treatment, 9 individuals peeled off, and the remaining 1 individual also peeled off within 30 minutes. In both groups, no atrophy or recovery from detachment was observed in 10 exfoliated specimens when observed 2 hours after treatment and return to seawater. Additionally, the adherent plaque of the detached object was atrophied and deformed (Figures 9C & D).

In test group 4, the body became cloudy and movement stopped about 30 minutes after treatment and return to seawater, so the worm was thought to have died.

In view of the above, treatment at 75 ppm for 30 minutes caused the adhesion patches of Benedenia seriole to shrink and deform, and did not recover even after about 2 hours after treatment, so treatment at 300 ppm for 3 minutes or 300 ppm for 6 minutes It was found that it exhibited a more stable anthelmintic effect than powder treatment.

Additionally, in the untreated control group, no atrophy of Benedenia seriole or peeling from the petri dish was observed during the test period.

Example 8

<Anthelmintic effect of low-concentration hydrogen peroxide treatment on Lamelodiscus in vivo>

Test method: 50 red sea bream cultured in outdoor cages were provided for testing. The average fish weight of this group was approximately 74 g. Red sea bream was transferred from the cage to a 1 t tank on land, and 10 red sea bream each were housed in five 30 L tanks containing 15 L of seawater. To prevent oxygen deficiency, ventilation was performed using a small air pump. Each predetermined amount of hydrogen peroxide solution was dissolved in 50 ml seawater, placed in a container containing fish and stirred, and the fish were immersed for a predetermined period of time. After treatment, the container was tilted to catch the fish through a bag-shaped net, and about 3 liters of seawater was poured from the top for washing. The fish were returned to a container containing 18 liters of seawater and reared for 1 hour while aerating. Afterwards, the fish were sampled and Lamelodiscus parasitic on the gills were counted. The anthelmintic effect was evaluated by comparing the number of Lamelodiscus parasites in each plot. The temperature of the seawater used in the test was 22.0°C.

Test group: The test group is shown in Table 8.

Results and Discussion

The Lamelodiscus extermination rate in the 300 ppm·3 minute treatment group was 0%. The dosage and usage method for deworming Vivagina and Dome did not show an anti-parasitic effect. In addition, even in the 300 ppm·15 minutes treatment group, the number of parasitic worms was the same as that in the control group and did not show an anti-parasitic effect. The red sea bream in the 300 ppm·15 crater was affected by this treatment just before the end of treatment and was in a state of collapse, so further treatment was thought to be impossible. On the other hand, in the 75 ppm·30 minutes treatment group and the 100 ppm·30 minute treatment group, a clear anthelmintic effect was recognized (Table 8), and no abnormalities such as swimming of fish were observed.

These results show that low-concentration, long-time treatment has a greater effect on the grazing stage of Lamelodiscus than high-concentration, short-time treatment. The effectiveness of long-term treatment with low concentration of hydrogen peroxide was also confirmed for this insect.

Benedenia, Seriolae, Neobenedenia, Zirellae, and Lamelodiscus are classified as short ginger suckers. Low-concentration hydrogen peroxide baths were thought to be effective against parasites of the sweet ginger sucker class because they commonly exhibited a high anthelmintic effect on these parasites.

Example 9

<Anthelmintic effect of low-concentration hydrogen peroxide treatment on Zeucsapta and yaponica in vitro>

Test method: The gills of five farmed amberjacks weighing approximately 1.4 kg were obtained, and Zeucsapta yaponica living on the gill plates was collected while still parasitic on the gill plates. The in vitro test was conducted in the same manner as in Example 1, using 5 individuals of each worm. Observations were conducted for 30 minutes in the middle of treatment, immediately after treatment and return to seawater, and every 10 minutes after return to seawater, and atrophied individuals were counted and recorded.

Test group: The test group is shown in Table 9.

Results and Discussion

The worms treated at 300 ppm·3 minutes and 6 minutes showed mild body atrophy even immediately after treatment (Figure 10A), and recovered from the atrophy within about 10 minutes after treatment (Figure 11). On the other hand, the main worms in the 75 ppm·60 minutes treatment group clearly shrank from 6 to 10 minutes of treatment (Figure 10B). In addition, all of the main insects in the 75 ppm, 60-minute treatment group shrank even 30 minutes after treatment, and only one individual in the 50 ppm, 60-minute treatment group recovered even after 30 minutes. Atrophy of the main worms in the low-concentration treatment group was observed not only in the body but also in the fixation zone where the graspers are arranged (Figure 10B).

Long-term treatment at a low concentration causes Zeucsapta and yaponica to atrophy for a long period of time, and the atrophy is severe and affects the fixation zone where the valva is arranged, so it has a more repellent effect than treatment at 300 ppm for 3 minutes or 300 ppm for 6 minutes. It has been proven to work stably.

Additionally, in the untreated control group, no atrophy of Zeuxapta japonica was observed during the test period.

Example 10

<Anthelmintic effect of low-concentration hydrogen peroxide treatment on Vibagina and Dom in vivo>

Test method: 50 red sea bream cultured in outdoor cages were provided for testing. The average fish weight of this group was approximately 61 g. Red sea bream was transferred from the cage to a 1 t tank on land, and 10 red sea bream each were housed in five 30 L tanks containing 15 L of seawater. To prevent oxygen deficiency, ventilation was performed using a small air pump. Each predetermined amount of hydrogen peroxide solution was dissolved in 50 ml seawater, placed in a container containing fish and stirred, and the fish were immersed for a predetermined period of time. After treatment, the container was tilted to catch the fish through a bag-shaped net, and about 3 liters of seawater was poured from the top for washing. The fish were returned to a container containing 18 liters of seawater and reared for 1 hour while aerating. Afterwards, the fish were sampled and the Vibagina dome parasitic on the gills were counted. Evaluation of the anthelmintic effect was conducted by comparing the number of parasites in Vibagina and Dome in each district. Meanwhile, the temperature of the seawater used in the test was 23.2°C.

Test group: The test group is shown in Table 10.

Results and Discussion

The Vibagina and Dome deworming rate in the 300 ppm, 3 minute treatment group (capacity and usage method for deworming Vibagina and Dome using hydrogen peroxide water) was 64%. In this section, immediately after the start, the fish swam vigorously as if bouncing on the surface of the water. From this behavior, it was thought that the high concentration treatment was toxic or irritating to the red sea bream. The main insect extermination rate in the group treated with 100 ppm for 30 minutes was 89%, and in the group treated with the same concentration for 60 minutes, it was 100%. In addition, the insecticide rate in the 75 ppm·60 minutes treatment group was 99%. There was no change in the swimming of fish in these low-concentration treatment groups from the start of treatment to the end, and no abnormalities were observed in the fish.

From these results, it was revealed that low-concentration, long-term treatment with hydrogen peroxide exerts a high anthelmintic effect on the gill parasite Vibagina sea bream without causing obvious toxicity or irritation to the red sea bream.

Example 11

<Anthelmintic effects of low-concentration hydrogen peroxide treatment on Benedenia, Seriole, Neobenedenia, Zirella, and Zeuxapta, Yaponica in vivo>

Test method: 400 amberjacks weighing approximately 430 g, which were cultured in outdoor cages, were provided for testing. 15 t of seawater was added to the bath sheet, and a hydrogen peroxide solution was added and stirred so that the hydrogen peroxide concentration was 75 ppm. 390 fish were accommodated and immersed for 30 minutes. After treatment, fish were transferred to cages. Sampling was conducted by lifting 10 rice each before and the day after treatment. Benedenia, Seriole, Neobenedenia, and Zirellae living on the body surface were counted, and Zeucsapta and Yaponica living on the gills were counted. The anthelmintic effect was evaluated by comparing the number of parasites in each group. Additionally, the temperature of the seawater at the time of treatment was 28.5°C.

Results and Discussion

The results are shown in Table 11. In the treated fish, parasitism of Benedenia, Seriolae, Neobenedenia, Zirella, and Zeucsapta, Yaponica was not observed, and the deworming rate for all parasites was 100%.

Accordingly, the effectiveness of the present invention was proven even under such large-scale conditions.

Example 12

<Effectiveness test of low-concentration hydrogen peroxide treatment using amberjack skirt method>

Test method: Wrap a 48 m long and 10 m wide sheet around a 11.5 m So they surrounded the fence. An amount of hydrogen peroxide with an average concentration of 35 ppm was added to the seawater in the sheet for 5 minutes, and after 60 minutes, the sheet around the cage was removed. Sampling was conducted by lifting 10 rice each before and the day after treatment. Benedenia seriolae and Neobenedenia zirella (n = 10) living on the body surface were counted, and Zeucsapta and yaponica (n = 5) living on the gills were counted. The anthelmintic effect was evaluated by comparing the number of parasites in each group. Additionally, the temperature of the seawater at the time of treatment was 26°C.

Results and Discussion

The hydrogen peroxide concentration was 35 ppm at the start, 15 ppm after 30 minutes, and 3 ppm after 60 minutes, and was gradually diluted. The number of skin parasites (Neobenedenia and Benedenia) was 110 ± 48.3 individuals/mi before treatment and 28.9 ± 24.3 individuals/mi after treatment. The number of Zeucsapta parasites was 110.8 ± 49.0 individuals/unit before treatment and 54.0 ± 41.6 individuals/unit after treatment. Therefore, the effectiveness of treatment with low-concentration hydrogen peroxide solution was verified even in the skirt method under conditions in which the agent is gradually diluted.

Industrial applicability

By the method of the present invention, external parasites living on fish can be eradicated more safely and efficiently using hydrogen peroxide water currently used in aquaculture fields.

Claims (4)

A drug for atrophy or deformation of suckers or fixation spots of external parasites of marine fish, containing low concentration hydrogen peroxide,
Characterized in that it is used in a method of atrophying or deforming the suckers or fixation spots of external parasites by immersing the fish in hydrogen peroxide at a concentration of 37.5 ppm to 100 ppm for 30 to 60 minutes,
The marine fish is a marine fish belonging to the perch order,
A drug wherein the external parasite belongs to the family Capsaraidae or Directanididae of the flatworm phylum and the Heteracchycineceae or Microcorthyraidae family of the multi-stage sucker family. According to claim 1,
In the above method, at least the side of the cage net is covered with a sheet, the sea water inside is maintained, and hydrogen peroxide is added to the sea water in the cage in an amount such that the calculated average concentration is 37.5 ppm to 100 ppm, and 30 Agent characterized in that the sheet is removed after ~60 minutes. The method of claim 1 or 2,
External parasites include Benedenia, Seriolae, Benedenia, Epinefeli, Benedenia, Hosinai, Benedenia, Sekii, Neobenedenia, Zirellae, Neobenedenia, Congeri, Lamelodiscus, Zeucsapta, Yapo. Drugs that are Nica, Vivagina·Dom, Heterakicine·Heterocerca, Microchotyre·Sebastis, or Microchotyre·Sebastischin. The method of claim 1 or 2,
A drug where the fish is a yellowtail or sea bream fish.