Test fish treatment equipment and test fish treatment method using the test fish treatment equipment

Abstract

Provided are: equipment for handling a specimen fish which suppresses damage to the specimen fish, thereby being capable of reliably hold the specimen fish; and a method for handling a specimen fish using said equipment for handling a specimen fish. The equipment comprises a holding tool 1 for holding a specimen fish, and a guiding means 2 which guides the specimen fish together with water up to the holding tool 1, wherein: the holding tool 1 comprises an orientation maintaining groove 3 which maintains the specimen fish in a predetermined orientation; at least an inner surface of the orientation maintaining groove 3 is composed of a flexible material; and the guiding means 2 is configured to comprise an inflow port 2a on one end thereof and an outflow port 2b on the other end thereof.

Description

[Technical Field]

[0001] The present invention relates to a test fish treatment facility (fish holding device) for holding test fish and using them for various biological observations and experiments, and further to a test fish treatment method (administration method for fish) for administering a predetermined treatment to test fish using the test fish treatment facility. [Background technology]

[0002] Known methods of administering test substances to test fish include mixing the test substance with food and putting it into an aquarium for the test fish to eat, or dissolving the test substance in the breeding water and allowing it to be absorbed through the gills (for example, acute toxicity tests for fish in accordance with OECD Test Guideline 203). However, the administration method of introducing test substance-containing feed into an aquarium has the problem that it is difficult to handle the liquid test substance, and furthermore, some of the test substance is left uneaten, making it difficult to accurately determine the amount of intake by the test fish.Furthermore, these administration methods differ from animal experiments using mice and other animals, which use an oral administration method in which the test substance is administered directly to the digestive tract, making it difficult to make appropriate comparisons with those animal experiments. For these reasons, it is desirable to adopt an oral administration method in which the test substance is administered directly to the digestive organs of test fish.

[0003] In recent years, zebrafish have attracted considerable attention as experimental subjects. In animal experiments using test fish such as zebrafish, for example, when holding the test fish for oral administration, it is important to minimize damage to the test fish, i.e., to hold the test fish as gently as possible without damaging the body surface or causing burns. Therefore, a fish holder has been proposed in the past, in which a synthetic resin plate is bent into a U-shape and a flexible material such as sponge or nonwoven fabric is attached to the inner surface that holds the test fish (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Registered Utility Model No. 3051118 Summary of the Invention [Problem to be solved by the invention]

[0005] When holding a test fish during oral administration, the fish holder described in Patent Document 1 makes it possible to gently hold the test fish using a flexible material. However, if the test fish struggles while being held, for example, the fish holder will inevitably be held with a strong force, which is likely to cause some damage to the test fish. In addition, in order to prevent the test fish from thrashing around, it is possible to anesthetize the test fish and hold them, but in that case it becomes unclear whether the experimental results are due to the effect of the test substance on the test fish or the effect of the anesthesia.Furthermore, in experiments involving repeated administration of the test substance, if anesthesia is administered each time, the effect will be repeated, making it impossible to conduct experiments involving repeated administration. Furthermore, even though fish holders exist for holding test fish, there have traditionally been no special devices or solutions for the process of holding the test fish. Therefore, in the past, test fish were scooped up with a net or the like and then held in a fish holder, which likely caused considerable damage to the test fish in the process of holding them in the fish holder.

[0006] The present invention focuses on these conventional problems, and its purpose is to provide test fish treatment equipment that can minimize damage to the test fish and securely hold the test fish in a predetermined posture, and further to provide a test fish treatment method using this test fish treatment equipment. [Means for solving the problem]

[0007] The first characteristic configuration of the test fish processing equipment according to the present invention is: The test substance is administered as a predetermined treatment. Equipped with a holder for holding test fish, The holder is added with water The test fish is provided with a posture-maintaining groove for maintaining a predetermined posture, and at least the inner surface of the posture-maintaining groove is made of a flexible material.

[0008] According to this configuration, the holder for holding the test fish is equipped with a posture-maintaining groove that maintains the test fish in a predetermined posture, so the test fish is held while positioned within the posture-maintaining groove. Furthermore, because at least the inner surface of the posture-maintaining groove is made of a flexible material, the test fish can be gently held by the flexible inner surface of the posture-maintaining groove. Furthermore, even if the test fish tries to struggle, it is less likely to struggle because it is positioned within the posture-maintaining groove, resulting in reduced damage to the test fish. In addition, the test fish can be kept moist and at rest in the holding device, so damage to the test fish can be significantly reduced and predetermined treatments such as oral and parenteral administration can be repeatedly performed on the test fish without anesthesia.

[0009] A second characteristic feature of the test fish processing equipment according to the present invention is that the holder is made of a material that is flexible, permeable, and has water retention properties.

[0010] According to this configuration, the material that makes up the holder is not only flexible but also water-permeable, so when the test fish flows into the posture-maintaining groove along with water, only the test fish remains in the posture-maintaining groove in a relatively short time, which contributes to reducing damage to the test fish. Furthermore, in addition to being water-permeable, the material also has water-retention properties, so while the test fish is maintained in the posture-maintaining groove, the posture-maintaining groove maintains an appropriate water-retention state, which also reduces damage during that time. Furthermore, since the entire holder is made of a material with such properties, such as sponge, it is easier and less expensive to manufacture than when the holder is made by sticking sponge to the inner surface of a posture-maintaining groove.

[0011] A third characteristic feature of the test fish treatment equipment according to the present invention is that the posture-maintaining groove is tapered toward the tip and slopes downward toward the tip.

[0012] According to this configuration, the posture-maintaining groove tapers toward the tip, so that the test fish that flows into the posture-maintaining groove along with the water is guided to gradually approach the predetermined posture as it moves toward the tip. As a result, the test fish will move towards the tip of the water due to its habit, and will gradually be clamped by the inner surface of the posture-maintaining groove and maintained in the specified posture, effectively suppressing damage during this process.

[0013] A fourth characteristic configuration of the test fish treatment equipment according to the present invention is that the posture maintaining groove ,above The difference is that it consists of an upper groove portion that opens toward the upper side and an lower groove portion that continues below the upper groove portion and is wider than the upper groove portion. A fifth characteristic feature of the test fish treatment equipment according to the present invention is that the posture-maintaining groove is formed with the same width from the front end to the rear end.

[0014] With this configuration, the test fish that flows out together with water into the upper groove section that opens upward in the posture-maintaining groove is smoothly received into the upper groove section while maintaining its posture, and is then smoothly guided into the lower groove section formed below it and wider than the upper groove section, allowing the test fish to be held in the lower groove section with little strain.

[0015] The first test fish treatment equipment according to the present invention 6 A characteristic feature of this configuration is that the depth of the posture-maintaining groove is set to be greater than the height of the test fish held in the posture-maintaining groove.

[0016] With this configuration, the entire height of the test fish is contained within the posture-maintaining groove, allowing the test fish to be held in a more restful state and further significantly reducing damage to the test fish.

[0017] The first test fish treatment equipment according to the present invention 7A characteristic feature of this configuration is that the holder has a rear end side holding portion and a front end side holding portion that divide the posture maintaining groove into two in the longitudinal direction, and these two holding portions are configured to be separable.

[0018] According to this configuration, the holder has a rear-end holding portion and a front-end holding portion that divide the posture-maintaining groove in half longitudinally, and these two holding portions are configured to be separable, so the width of the posture-maintaining groove can be set appropriately. For example, by setting the width at the front end of the rear-end holding portion so that only the mouth or head of the test fish protrudes from the rear-end holding portion toward the front, the test fish can be held by the posture-maintaining groove of the rear-end holding portion, allowing easy and reliable observation of the mouth and head of the test fish. Furthermore, by setting the width at the rear end of the tip-side holding part to a width that allows only the tail fin of the test fish to protrude from the tip-side holding part to the rear end, the test fish can be held by the posture-maintaining groove in the tip-side holding part, making it easy and reliable to observe the tail fin of the test fish.

[0019] The first test fish treatment equipment according to the present invention 8 The characteristic configuration is that the holding device has a front holding portion, an intermediate holding portion, and a rear holding portion that are aligned along the longitudinal direction of the posture-maintaining groove, with the intermediate holding portion located between the front holding portion and the rear holding portion, and these three holding portions are configured to be separable, and the posture-maintaining groove is provided only in the intermediate holding portion of the front holding portion and the intermediate holding portion so that its tip is located at the boundary between the front holding portion and the intermediate holding portion, and is tapered towards the tip when viewed in a plane.

[0020] According to this configuration, the tip of the posture-maintaining groove is located at the boundary between the front and intermediate holding sections, allowing a test fish that moves forward along the water flow in the posture-maintaining groove to be held by the front holding section. By separating the front and intermediate holding sections while holding the test fish in this manner, if the test fish's head is located at the front end, the fish's mouth or head can be observed from the tip of the posture-maintaining groove. This allows for easy and reliable observation of the fish's mouth or head. Furthermore, by making the length of the intermediate holding section equal to the body length of the test fish and separating the intermediate and rear holding sections, the fish's mouth or head can be observed from the rear end of the posture-maintaining groove even if the fish's head is located at the rear end. Furthermore, the presence of the rear holding section makes it easier to position the guide means relative to the intermediate holding section, for example by placing the guide means on the rear holding section.

[0021] The first test fish treatment equipment according to the present invention 9 The characteristic configuration is: companion A guide means is provided for guiding the test fish together with water to the holder, The guide means is configured to have an inlet at one end through which the test fish is introduced together with water, and an outlet at the other end through which the test fish is discharged together with water into the posture-maintaining groove.

[0022] According to this configuration, a guide means is provided for guiding the test fish to the holder together with the water, and this guide means has an inlet at one end through which the test fish is introduced together with the water, and an outlet at the other end through which the test fish is discharged together with the water into the posture-maintaining groove.Therefore, by simply introducing the test fish together with the water into the inlet of the guide means, the test fish will flow toward the holder together with the water and enter the posture-maintaining groove, and damage to the test fish can be greatly reduced even in the process of reaching the posture-maintaining groove.

[0023] The first test fish treatment equipment according to the present invention 10 In a characteristic configuration, the guiding means is configured by a pipe member having the inlet at one end and the outlet at the other end, A pipe-shaped outflow section located adjacent to and above the posture-maintaining groove is connected to the outlet, and the outflow section has slits facing along the posture-maintaining groove, from which the test fish are discharged into the posture-maintaining groove together with water in a predetermined posture.

[0024] According to this configuration, the pipe-shaped outflow section, which is located adjacent to and above the posture maintenance groove and connected to the outflow outlet, has a slit that faces along the posture maintenance groove, and the test fish flows out of the slit into the posture maintenance groove together with water in a predetermined posture, so that the transition of the water and test fish from the outflow outlet to the posture maintenance groove is smooth and reliable, and damage to the test fish during this process is reduced.

[0025] The first test fish treatment equipment according to the present invention 11 A characteristic feature of this device is that it includes a first tank for containing test fish before they are introduced into the introduction port, and a second tank for containing test fish that have been released from the holding device.

[0026] With this configuration, the test fish housed in the first tank can be removed together with the water and immediately placed into the inlet of the guide means. Also, the test fish released from the holder can be immediately placed in the second tank. This reduces the burden associated with transporting the test fish.

[0027] The first test fish treatment equipment according to the present invention 12 The characteristic configuration is a predetermined procedure Administration of the test substance as a guide means for guiding the test fish to be treated together with water to a predetermined treatment section, The guide means is configured to have an inlet at one end through which the test fish is introduced together with water, and an outlet at the other end through which the test fish is discharged together with water into the treatment section.

[0028] According to this configuration, a guide means is provided for guiding the test fish to the holder together with the water, and this guide means has an inlet at one end through which the test fish is introduced together with the water, and an outlet at the other end through which the test fish together with the water flows out into a treatment section such as the posture-maintaining groove mentioned above.Therefore, by simply introducing the test fish together with the water into the inlet of the guide means, the test fish will flow towards the holder together with the water and enter the treatment section, and damage to the test fish can be significantly reduced even in the process of reaching the treatment section.

[0029] The first test fish treatment equipment according to the present invention 13 A characteristic feature of the present invention is that the guide means is formed of a pipe member having the inlet at one end and the outlet at the other end.

[0030] According to this configuration, the guidance means is composed of a pipe member having an inlet at one end and an outlet at the other end, so compared to, for example, a gutter-shaped member with an open top, there is no risk of the test fish jumping out during guidance, not only ensuring reliable guidance of the test fish but also increasing the freedom to set the route up to the treatment section.

[0031] The first test fish treatment equipment according to the present invention 14 A characteristic feature of the present invention is that it includes a water flow forming means for supplying water to the inlet and forming a water flow within the pipe member.

[0032] According to this configuration, water is supplied to the inlet of the guide means by the water flow forming means, and a water flow is formed within the pipe member connected to the inlet.Therefore, the test fish introduced into the inlet can be guided to the outlet by the water flow formed within the pipe member, while minimizing the burden on the test fish, and can be discharged from the outlet to the treatment section.

[0033] The first test fish treatment equipment according to the present invention 15 A characteristic feature of this device is that a funnel-shaped section that guides the test fish into the inlet together with water is connected to the inlet.

[0034] According to this configuration, a funnel-shaped inlet section that guides the test fish together with water is connected to the inlet, so by using this funnel-shaped inlet section, it becomes easier for water and test fish to flow into the inlet.

[0035] The first test fish treatment equipment according to the present invention 16 A characteristic feature of the present invention is that the treatment unit is provided with a water receiving portion for receiving water discharged from the outlet.

[0036] According to this configuration, since the water receiving section is provided, even if the test fish discharged from the outlet falls out of the treatment section, the fallen test fish can be accommodated in the water stored in the water receiving section without any burden. Furthermore, if a water level maintaining means is provided that maintains the water level in the water receiving section at a predetermined set water level while draining the water stored in the water receiving section, the wetness of the treatment section immersed in the water stored in the water receiving section can be maintained at a constant level, and the test fish held in the treatment section can be kept appropriately moist.

[0037] The first characteristic configuration of the test fish treatment method according to the present invention is the first or second The feature of the present invention is that a test fish treatment equipment having the above characteristic configuration is used to perform a predetermined treatment on the test fish held in the holder.

[0038] According to this configuration, the first or second The fish are then held in a fixed position, with minimal damage to the fish. This allows the fish to be easily and reliably treated. In addition, the test fish can be kept moist and at rest in the holding device, so damage to the test fish can be significantly reduced and predetermined treatments such as oral and parenteral administration can be repeatedly performed on the test fish without anesthesia.

[0039] A second characteristic feature of the method for treating test fish according to the present invention is that the specified treatment involves oral administration of the test substance directly to the test fish through an oral tube inserted into the oral cavity of the test fish, which is maintained in a specified posture by the posture-maintaining groove of the holding device.

[0040] With this configuration, the test fish is securely held in a predetermined posture in the holder, and the test substance sealed in a syringe or the like is administered orally directly to the test fish through an oral tube inserted into the test fish's mouth, making oral administration easy and reliable. Direct oral administration refers to oral administration in which the test substance is administered directly to the oral cavity of the test fish, as opposed to the conventional method of mixing the test substance with food and putting it into an aquarium for the test fish to eat, or the method of dissolving the test substance in breeding water and allowing it to be absorbed through the gills.

[0041] In addition, direct oral administration of a test substance to test fish can be performed by administering the substance to the test fish using a syringe equipped with an oral tube such as an oral probe while the fish is under general anesthesia. However, with this method, even if an attempt is made to evaluate the effects of the test substance on the test fish, it is difficult to determine whether the effects are due to stress on the test fish caused by the anesthesia or to the test substance itself. Furthermore, when administering a small amount of the test substance to the test fish every day to evaluate its effects, conventional anesthesia methods require the test fish to be anesthetized every day, which places a great deal of stress on the test fish, making such evaluation tests difficult. Therefore, the test fish treatment method of the present invention allows direct oral administration of a test substance to the test fish without anesthesia, minimizing damage to the fish, making it easier to evaluate the effects of the test substance on the test fish and also enabling experiments in which the test substance is administered to the test fish in small amounts every day to evaluate its effects.

[0042] A third characteristic feature of the method for treating test fish according to the present invention is that the specified treatment involves parenteral administration of the test substance to the test fish by injection into the test fish, which is maintained in a specified posture in the posture-maintaining groove of the holding device.

[0043] According to this configuration, the test fish is securely held in a predetermined position in the holder, and the test substance is administered to the test fish by injection, thereby making parenteral administration easy and reliable. Parenteral administration includes, for example, intraperitoneal administration or intravenous administration using an injection. For such parenteral administration, the test fish can be rotated around its anterior-posterior axis using a holder to expose its abdomen to the upper opening of the posture-maintaining groove, making it easy to inject the abdominal part of the test fish. [Brief explanation of the drawings]

[0044] [Figure 1] Overall longitudinal side view of the test fish treatment facility [Figure 2] Plan view of the test fish treatment equipment holder [Figure 3] Cross-sectional plan view of the outflow section of the test fish treatment facility [Figure 4] Rear view showing the relationship between the holder and the outflow section of the test fish treatment equipment [Figure 5] Plan view showing oral administration to test fish [Figure 6] Graph showing the results of Experiment 1 [Figure 7] Graph showing the results of Experiment 2 [Figure 8] 1 is a plan view of a fish holder according to another embodiment; [Figure 9] FIG. 10 is a front view of a holder (intermediate holding portion) in another embodiment; [Figure 10] FIG. 10 is a vertical cross-sectional side view showing the relationship between the holder and the outlet portion in another embodiment. [Figure 11] FIG. 10 is a front view showing the relationship between the holder (intermediate holding portion) and the outflow portion in another embodiment. [Figure 12] FIG. 10 is a perspective view of a holder according to another embodiment; [Figure 13] FIG. 10 is a plan view of an inlet portion of a guide means equipped with a water flow forming means; [Figure 14] A perspective view showing the state of parenteral administration to test fish [Figure 15] Schematic diagram of the entire test fish processing facility [Figure 16] 1 is a plan view of a fish holder according to another embodiment; [Figure 17] FIG. 10 is a front view of a holder (intermediate holding portion) in another embodiment; [Figure 18] FIG. 10 is a front view of a holder (intermediate holding portion) in another embodiment; [Figure 19] FIG. 10 is a front view of a holder (intermediate holding portion) in another embodiment; [Figure 20] FIG. 10 is a front view of a holder (intermediate holding portion) in another embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0045] An embodiment of the test fish treatment equipment and the test fish treatment method using the test fish treatment equipment according to the present invention will be described with reference to the drawings. As shown in Figure 1, the test fish treatment equipment of the present invention is configured with a holder 1 for holding relatively small test fish F (see Figure 2) for use in live experiments, such as zebrafish, and a guide means 2 consisting of a pipe member 2c for guiding the test fish F together with water to the holder 1.As an example, the pipe member 2c is a transparent and flexible pipe made of synthetic resin so that the inside can be seen. As shown in Figure 2, the holder 1 is rectangular in shape when viewed from above, and is made of a flexible, permeable, and water-retaining material, such as a sponge, and has a bottomed, upwardly opening posture-maintaining groove 3 that maintains the test fish F in a predetermined posture in a natural, relaxed state.

[0046] As shown in Figure 2, the posture-maintaining groove 3 of the holder 1 is provided over the entire length from the rear end to the tip of the holder 1 so that its longitudinal length, i.e., its front-to-rear length L, is longer than the body length of the test fish F. For example, if the test fish F is a zebrafish with a body length of approximately 40 mm, it is desirable to set the length L of the posture-maintaining groove 3 to approximately 50 mm. The width of the posture-maintaining groove 3 gradually tapers toward the tip in plan view, so that the rear end has a maximum width W1 that is wider than the width of the test fish F and the tip has a minimum width W2 that is narrower than the width of the test fish F. The bottom 3a of the posture-maintaining groove 3 is configured to slope downward toward the tip in side view, as shown in Figure 1. The holder 1 has a rear-end holding portion 1a and a front-end holding portion 1b that longitudinally bisect the posture-maintaining groove 3, and these holding portions 1a, 1b are configured to be separable. The width of the posture-maintaining groove 3 at the front end of the rear-end holding portion 1a is set to an intermediate width W3 that allows only the mouth or head of the test fish F to protrude from the rear-end holding portion 1a toward the front end when the test fish F is maintained in a predetermined posture by the posture-maintaining groove 3 of the rear-end holding portion 1a, as shown in Figures 2 and 5.

[0047] As shown in Figure 1, the guidance means 2 for guiding the test fish F is composed of a pipe member 2c, with an inlet 2a at one end of the pipe member 2c through which the test fish F is introduced together with water, and an outlet 2b at the other end of the pipe member 2c through which the test fish F is discharged together with water into the posture-maintaining groove 3. A funnel-shaped inlet section 4 is connected to the inlet 2a, which guides the test fish F together with water into the inside of the pipe member 2c, and a pipe-shaped outlet section 5 is connected to the outlet 2b, and the outlet section 5 is positioned adjacent to and above the posture-maintaining groove 3. As shown in Figure 3, the outflow section 5 has a tapered slit 5a that discharges the test fish F together with water into the posture-maintaining groove 3 in a predetermined posture, and the slit 5a of the outflow section 5 is arranged so that it faces the posture-maintaining groove 3 of the holder 1 from above, as shown in Figure 4, and the guiding means 2 and holder 1 equipped with the funnel section 4 and outflow section 5 are installed by an installation device 6 not shown in Figure 1, only a portion of which is shown, so that the funnel section 4 of the guiding means 2 is located above and the outflow section 5 is located below. In the illustrated embodiment, the funnel portion 4 and the outflow portion 5 are configured as separate parts from the pipe member 2c, but either one or both of them may be configured integrally with the pipe member 2c.

[0048] The pipe member 2c serving as the guide means 2 is arranged in a downward inclined state from the inlet 2a to the outlet 2b. The inclination of the pipe member 2c is appropriately set so that the test fish F introduced into the inlet 2a can be appropriately guided to the outlet 2b while reducing the burden on the test fish F. For example, the vertical height of the pipe member 2c between the inlet 2a and the outlet 2b is preferably within the range of 100 to 300 mm. If the height of the pipe member 2c is less than 100 mm, the test fish F introduced into the inlet 2a may stop midway through the pipe member 2c and not reach the outlet 2b. On the other hand, if the height of the pipe member 2c exceeds 300 mm, the test fish F introduced into the inlet 2a may move too quickly toward the outlet 2b, placing too much strain on the test fish F. Alternatively, the test fish F may forcefully exit the outlet 2b and enter the posture-maintaining groove 3 in a vertical position. Alternatively, the test fish F may forcefully exit the outlet 2b and fall out of the posture-maintaining groove 3. The horizontal front-to-rear distance between the inlet 2a and the outlet 2b in the pipe member 2c is preferably within the range of 150 to 300 mm. If the distance between the pipe member 2c and the outlet 2b is less than 150 mm, the distance traveled by the test fish F introduced into the inlet 2a toward the outlet 2b may be too short, resulting in the test fish F being unable to determine its orientation. On the other hand, if the distance between the pipe member 2c and the outlet 2b exceeds 300 mm, the distance traveled by the test fish F introduced into the inlet 2a toward the outlet 2b may be too long, placing too much strain on the test fish F.

[0049] As shown in Figure 13, a water supply pipe 15 is connected to the funnel section 4, supplying water SW into the funnel section 4. This water supply pipe 15 functions as a water flow forming means that supplies water to the inlet 2a of the guiding means 2 and forms a water flow WF in the pipe member 2c. Because the water flow WF is formed in the pipe member 2c connected to the inlet 2a, the test fish F introduced into the inlet 2a can be guided by the water flow WF formed in the pipe member 2c to the outlet 2b, and then discharged from the outlet 2b into the posture-maintaining groove 3 of the holder 1, while minimizing the burden on the test fish F moving in the pipe member 2c. 13, the water supply direction through the water supply pipe 15 in the funnel section 4 is set to the circumferential direction with the inlet 2a as the central axis. This causes the water flow WF to swirl inside the funnel section 4 before flowing into the inlet 2a, keeping the entire inner wall surface of the funnel section 4 wet and reducing the burden on the test fish F that are introduced.

[0050] Next, we will explain the method of treating test fish using this test fish treatment equipment. First, the test fish treatment equipment is set up as shown in Figure 1, and a test fish F is placed into the funnel-shaped inlet portion 4 together with water. As the water flows downward inside the pipe member 2c, the test fish F swims with its head facing downward, as is its natural tendency, and enters the posture-maintaining groove 3 together with the water through the slit 5a of the outlet portion 5, assuming a predetermined posture, that is, with its head facing toward the tip-side holding portion 1b. In the posture-maintaining groove 3, the water flows further toward the tip of the holder 1, so the test fish F is swept away with it, and finally stops in a position where it is clamped in the posture-maintaining groove 3. When the rear end holding portion 1a of the holder 1 is separated from the front end holding portion 1b in this clamped state, as shown in Figure 5, only the mouth or head of the test fish F is set to protrude from the rear end holding portion 1a toward the front end, so that the test fish F can be maintained in a predetermined posture in the posture maintaining groove 3 of the rear end holding portion 1a, and the test substance can be directly orally administered to the test fish F using a syringe 7 equipped with an oral probe 8 (oral tube).

[0051] Specifically, the test substance is sealed in a syringe 7, and the tip 8a of an oral probe 8 attached to the syringe 7 is inserted into the oral cavity of the test fish F, and the test substance is administered orally directly to the test fish F through the oral probe 8. At this time, the test fish F is held so that only its mouth or head protrudes from the rear-end holding portion 1a toward the tip, so that the gill covers of the test fish F are clamped and closed by the posture-maintaining grooves 3. Therefore, the test substance administered orally directly is prevented from leaking out of the body of the test fish F through the gills, and almost the entire amount of the test substance is ingested by the test fish F. Furthermore, the test substance is not limited to liquid form, but may be in jelly, paste, or solid form. Furthermore, the test substance may be mixed into feed, encapsulated in tiny capsules, or coated with the test substance, and then dispersed in a dispersion liquid such as water and administered orally directly to the test fish F.

[0052] At least the tip 8a of this oral probe 8, which is inserted through the mouth of the test fish F, is made of a flexible material, which reduces the strain on the test fish F during insertion. Furthermore, the base end of this tip 8a is provided with a mark 8b that allows the user to visually identify the area that should be inserted through the mouth of the test fish F, so even an inexperienced experimenter can perform stable and safe direct oral administration. The oral probe 8 and syringe 7, which are flexible, can be manufactured by integral molding. If the oral probe 8 and the syringe 7 are manufactured as a single unit, it is possible to prevent test substances such as administration agents from remaining at the connection between the oral probe 8 and the syringe 7, and it is also possible to prevent the connection from coming loose during direct oral administration.

[0053] [Experimental Example] Experiments 1 to 4 were conducted to confirm the effectiveness of the method for treating test fish using the test fish treatment equipment according to the present invention. The direct oral administration method used in each experiment was as follows: (Direct oral administration method) Example: In the state shown in Figure 5 (a state in which the test fish F is held in a holder 1 using the test fish treatment equipment of the present invention), the test substance is administered orally directly to the test fish F using a syringe without anesthetizing it. Comparative Example: While holding a test fish in a hand wearing laboratory rubber gloves, test substance is directly orally administered to test fish F using a syringe without anesthetizing it.

[0054] [Experiment 1] For each of the direct oral administration methods of the Examples and Comparative Examples, an effect evaluation experiment was conducted to determine the relationship between the concentration of the test substance and the mortality rate by administering the test substance to test fish under the following experimental conditions. (Experimental conditions) Test fish, number of individuals: zebrafish, 4 to 5 individuals / 1 aquarium x 6 Test substance: 3 concentrations (10mg / kg, 100mg / kg, 1000mg / kg) potassium dichromate solution Dose per individual: 20 μL (Experimental results) The relationship between the concentration of the test substance and the mortality rate obtained in this experiment is shown in Figure 6. The results of this experiment showed a greater correlation between the concentration of the test substance administered to the test fish and the mortality rate when the direct oral administration method of the Example was used than when the direct oral administration method of the Comparative Example was used. Therefore, it can be said that by using the test fish treatment equipment of the present invention, direct oral administration can be performed with greater precision than when the test fish are held with hands wearing laboratory rubber gloves.

[0055] [Experiment 2] For the direct oral administration method of the example, an effect evaluation experiment was carried out to determine the relationship between the concentration of the test substance and the mortality rate by administering the test substance to test fish under the following experimental conditions. (Experimental conditions) Test fish, number of individuals: zebrafish, 5 individuals / 1 aquarium x 4 Test substance: Potassium dichromate solution in four concentrations (10 mg / kg, 100 mg / kg, 500 mg / kg, 1000 mg / kg) Dose per individual: 20 μL (Experimental results) The relationship between the concentration of the test substance and the mortality rate obtained in this experiment is shown in Figure 7. In this experiment, as in Experiment 1 above, a correlation was observed between the concentration of the test substance administered to the test fish and the mortality rate when the direct oral administration method of the embodiment was used. Therefore, it can be said that direct oral administration can be performed with high accuracy by using the test fish treatment equipment of the present invention.

[0056] [Experiment 3] In each of the direct oral administration methods of the Examples and Comparative Examples, an experiment was conducted to visually confirm leakage of the test substance administered to the test fish from the gills under the following experimental conditions. (Experimental conditions) Test fish, number of individuals: zebrafish, 4 individuals / 1 tank x 1 Test substance: methylene blue (Experimental results) In the direct oral administration method used in the comparative example, ethylene blue was released from the gills of all four test fish in the aquarium. Leakage of ethylene blue (test substance) was visible. On the other hand, in the direct oral administration method of the example, leakage of ethylene blue (test substance) was not visible in all four test fish in the aquarium. Therefore, it can be said that by using the test fish treatment equipment of the present invention, direct oral administration can be performed with higher precision and without causing damage to the test fish than when the test fish are held with hands wearing laboratory rubber gloves.

[0057] [Experiment 4] In the direct oral administration method of the example, an experiment was conducted to evaluate damage to test fish by continuously administering the substance orally at a predetermined frequency under the following experimental conditions. (Experimental conditions) Test fish, number of individuals: zebrafish, 10 individuals x 2 Test substance: methylene blue (Experimental results) In the direct oral administration method of the present embodiment, when direct oral administration was performed once a week on 10 test fish, no fish died even after about two months. Furthermore, when direct oral administration was performed three times a week on another 10 test fish, no fish died even after about two months. Therefore, it can be said that by using the test fish treatment equipment of the present invention, direct oral administration can be performed with high precision without damaging the test fish.

[0058] [Another embodiment of the holder] Next, other embodiments 1 and 2 of the holder 1 will be described with reference to the drawings. In describing the other embodiments of the holder 1, the description will mainly focus on configurations that differ from the previous embodiment, and descriptions of parts that are configured in the same way as the previous embodiment will be omitted.

[0059] (Another embodiment 1 of the holder 1) 8, the holder 1 has a front holding portion 1c, an intermediate holding portion 1d, and a rear holding portion 1e that are aligned along the longitudinal direction of the posture-maintaining groove 3, with the intermediate holding portion 1d located between the front holding portion 1c and the rear holding portion 1e. The holder 1 is configured so that the three holding portions, the front holding portion 1c, the intermediate holding portion 1d, and the rear holding portion 1e, can be separated freely.

[0060] The posture-maintaining groove 3 is provided only in the intermediate holding portion 1d among the front holding portion 1c, the intermediate holding portion 1d, and the rear holding portion 1e. The posture-maintaining groove 3 is provided over the entire length of the intermediate holding portion 1d, from the rear end to the front end. In other words, the front end of the posture-maintaining groove 3 is located at the boundary between the front holding portion 1c and the intermediate holding portion 1d, and the rear end is located at the boundary between the intermediate holding portion 1d and the rear holding portion 1e. The posture-maintaining groove 3 is formed so that its length L in the front-to-rear direction is equal to or slightly longer than the body length of the test fish F. For example, if the test fish F is a zebrafish with a body length of approximately 40 mm, it is desirable to set the length L of the posture-maintaining groove 3 to approximately 50 mm.

[0061] As shown in Figures 8 and 9, the posture-maintaining groove 3 includes an upper groove portion 3b that opens upward from the upper end surface of the intermediate holding portion 1d, and a lower groove portion 3c that is formed below the upper groove portion 3b and continues to the upper groove portion 3b. Both the upper groove portion 3b and the lower groove portion 3c are provided along the entire length of the intermediate holding portion 1d, from the rear end to the front end. The width of the upper groove portion 3b is the same at any position in the longitudinal direction and is narrower than the width of the test fish F. The width of the lower groove portion 3c is wider than the width of the upper groove portion 3b. The groove portion 3c is tapered, with its vertical and horizontal widths gradually narrowing toward the front end. Specifically, the lower groove portion 3c is circular when viewed in the longitudinal direction, while the lower groove portion 3c is conically shaped, tapering toward the front end. The vertical width (depth) of the posture-maintaining groove 3 is set to be larger than the vertical width (height of the test fish F) of the test fish F held in the posture-maintaining groove 3 at any position in the longitudinal direction. Furthermore, in this embodiment, the vertical width (depth) of the lower groove portion 3c is set to be larger than the vertical width (height of the test fish F) of the test fish F at any position in the longitudinal direction. This allows the entire height of the test fish F to fit within the lower groove portion 3c of the posture-maintaining groove 3, allowing the test fish F to be held in a more restful state in this lower groove portion 3c, thereby further significantly reducing damage to the test fish F. For example, the depth of the lower groove portion 3c is preferably within the range of 5 to 25 mm. If the depth of the lower groove portion 3c is less than 5 mm, it may be difficult for the test fish F to enter the lower groove portion 3c. On the other hand, if the depth of the lower groove portion 3c is more than 25 mm, the test fish F that has entered the lower groove portion 3c may be difficult to maintain in a vertical position and to assume a horizontal position. Also, the width of the lower groove portion 3c is wider than the width of the test fish F at any position in the longitudinal direction.

[0062] As shown in Figures 8 and 10, the rear holding portion 1e is sized so that its upper end surface is located lower than the upper end surface of the intermediate holding portion 1d. A recess 11 is formed in the rear holding portion 1e, recessing downward from its upper end surface. The bottom of the recess 11 slopes downward toward the tip, and its width increases toward the tip. The recess 11 is formed in a shape that follows the outer shape of the pipe member 2c, which slopes downward toward the tip. The recess 11 is formed so that its lower end is located higher than the upper end of the lower groove portion 3c. When the rear holding portion 1e is aligned adjacent to the rear end side of the intermediate holding portion 1d, it blocks the lower groove portion 3c from the rear end side and also blocks part of the upper groove portion 3b from the rear end side.

[0063] As shown in FIG. 9, the intermediate holding portion 1d has an upper portion 12 and a lower portion 13 located below the upper portion 12. The upper portion 12 is formed to have a narrower width than the lower portion 13. Therefore, the upper portion 12 is more easily deformed in the width direction than the lower portion 13, and as shown in FIGS. 10 to 12, the upper portion 12 is more easily expanded in the width direction when the outflow portion 5 is installed in the posture-maintaining groove 3. That is, as shown in FIG. 11, the outflow portion 5 is inserted into the upper groove portion 3b of the posture-maintaining groove 3 while expanding the upper portion 12 in the width direction, and the slit 5a of the outflow portion 5 is positioned directly above the lower groove portion 3c. Note that at least the upper side of the upper groove portion 3b can be formed wider to facilitate the positioning and insertion of the outflow portion 5 relative to the upper groove portion 3b. Furthermore, because the upper portion 12 is formed with a narrow width as described above, the lower portion 13 can be easily deformed by bending it upward. Therefore, the intermediate holding portion 1d can be easily deformed by bending the lower portion 13 upward while compressing the upper portion 12 in the width direction, thereby making it easy to round it. This makes it possible to hold the test fish F by compressing the lower groove portion 3c from below and both sides in the width direction, and to compress the upper groove portion 3b in the width direction and close it.

[0064] When the holder 1, with the outflow section 5 removed, pinches the upper portion 12 from both the left and right sides and compresses the lower groove portion 3c from both sides in the width direction to hold the test fish F in the lower groove portion 3c, it is desirable that the thickness T of each of the left and right upper portions 12 be within the range of 5 to 40 mm. If the thickness T of the upper portion 12 is less than 5 mm, the compressive force transmitted to the test fish F held in the lower groove portion 3c when the upper portion 12 is pinched from both the left and right sides may be too great, placing too much strain on the test fish F. On the other hand, if the thickness T of the upper portion 12 is more than 40 mm, the compressive force transmitted to the test fish F held in the lower groove portion 3c when the upper portion 12 is pinched from both the left and right sides may be too small, making it difficult to hold the test fish F properly and preventing the gill operculum of the test fish F from being properly closed.

[0065] 10, the front holding portion 1c is shaped so that its upper end surface is flush with the upper surface of the intermediate holding portion 1d. Therefore, when the front holding portion 1c is in contact with the tip side of the intermediate holding portion 1d, it blocks the upper groove portion 3b and the lower groove portion 3c from the tip side.

[0066] 10 and 12, the pipe member 2c is placed on the recess 11 of the rear holding part 1e with the tip of the outflow part 5 in contact with the front holding part 1c. The outflow part 5 is placed in the posture maintaining groove 3 with its lower part sandwiched between the upper part 12 of the intermediate holding part 1d, and the slit 5a is arranged along the lower groove part 3c of the posture maintaining groove 3 so as to face it from above.

[0067] [Treatment method for test fish] The method for treating test fish F in this embodiment is configured as a method for performing a predetermined treatment on test fish F held in a holder 1 using the test fish treatment equipment described above. In this method of processing the test fish F, the test fish processing equipment described above is used, so when holding the test fish F, the test fish F can be held reliably in a predetermined posture while minimizing damage to the test fish F. Then, in this state, the test fish F held in the holder 1 is subjected to a predetermined treatment, so the treatment can be carried out easily and reliably. Furthermore, because the test fish F can be held in the holder 1 in a moisturized and resting state, predetermined treatments such as oral administration or parenteral administration can be carried out repeatedly on the test fish F without anesthesia, while significantly minimizing damage to the test fish F. Specific examples of the treatment method for the test fish F include an oral administration method in which the test substance is orally administered directly to the test fish F through an oral probe 8 inserted into the oral cavity of the test fish F maintained in a predetermined posture by the posture maintaining groove 3 of the holder 1, as shown in Figure 5, and a parenteral administration method in which the test substance is administered parenterally to the test fish F by injection into the test fish F maintained in a predetermined posture by the posture maintaining groove 3 of the holder 1, as shown in Figure 14. These oral administration method and parenteral administration method will be explained below.

[0068] (Oral administration method) An oral administration method for directly orally administering to a test fish F using a test fish treatment facility that employs the holder 1 of this embodiment will be described. First, the test fish treatment equipment is set up as shown in Figures 10 and 12, and a test fish F is placed into the funnel-shaped inlet portion 4 (see Figure 1) together with water. As water flows downward inside the pipe member 2c, the test fish F swims with its head facing downward, as is its natural tendency, and enters the posture-maintaining groove 3 of the holder 1 through the slit 5a of the outlet portion 5 in a predetermined posture, i.e., with its head facing the tip, and stops with its head in contact with the front holding portion 1c. In this state, if the intermediate holding portion 1d of the holder 1 is separated from the front holding portion 1c and the rear holding portion 1e to hold the test fish F, the mouth or head of the test fish F will be located near the tip of the intermediate holding portion 1d, allowing direct oral administration to the test fish F using a syringe 7 equipped with an oral probe 8. Furthermore, there are cases where the test fish F enters the posture-maintaining groove 3 in a posture opposite to the predetermined posture, i.e., with its tail fin pointing toward the tip, but in this case the tail fin stops with its tail fin in contact with the front holding part 1c. If the test fish F is held in this state by separating the intermediate holding part 1d of the holder 1 from the front holding part 1c and the rear holding part 1e, the mouth or head of the test fish F will be located near the rear end of the intermediate holding part 1d, and the test fish F can be administered orally directly using a syringe 7 equipped with an oral probe 8.

[0069] (Parenteral administration method) A parenteral administration method will be described in which a test substance is administered to the test fish F by injection using a test fish processing facility that employs the holder 1 of this embodiment. First, the test fish treatment equipment is set up as shown in Figures 10 and 12, and the test fish F is held in the posture maintaining groove 3 of the intermediate holding portion 1d of the holder 1 in the same manner as in the oral administration method described above. Next, as shown in Figure 14, when the injection site to be inserted with the injection needle 9a of the syringe 9 is the abdominal Fa of the test fish F, the abdominal Fa of the test fish F can be exposed above the posture-maintaining groove 3 by rotating the test fish F around its axis, for example by alternately moving the upper portions 12 on both the left and right sides of the posture-maintaining groove 3 of the holder 1, without directly touching the test fish F and without placing any strain on the test fish F. Then, the injection needle 9a of the syringe 9 can be inserted into the abdominal Fa of the test fish F maintained in a predetermined posture in the posture-maintaining groove 3, thereby performing so-called intraperitoneal administration, in which the test substance is administered. In addition to intraperitoneal administration, the injection needle 9a of the syringe 9 can also be inserted into a vein of the test fish F for intravenous administration.

[0070] [Other equipment configurations] FIG. 15 shows the overall configuration of a test fish processing facility 100 in which the holding device 1 and guiding means 2 described above are integrated with other facility components. The test fish processing equipment 100 includes a first water tank 21 for storing test fish F before they are introduced into the inlet 2a of the guiding means 2, and a second water tank 30 for storing test fish F that have been released from being held by the holder 1. This allows the test fish F stored in the first water tank 21 to be removed together with water and immediately introduced into the inlet 2a of the guiding means 2. In addition, the test fish F that have been released from being held by the holder 1 can be immediately stored in the second water tank 30.

[0071] Furthermore, a measuring tank 22, such as a transparent beaker, is provided near the first tank 21 and the inlet 2a of the guiding means 2 to temporarily accommodate the test fish F removed from the first tank 21 before being introduced into the inlet 2a. The measuring tank 22 is placed on a weighing scale 23, which measures the weight of the test fish F accommodated in the measuring tank 22. Furthermore, the measuring tank 22 is used for measuring body length, individual identification, and sex determination through external observation and image processing. For example, individual identification and sex determination can be performed by image processing of the captured image of the test fish F based on its face, pattern, etc. Water is stored in the measuring tank 22 to accommodate the test fish F comfortably. This stored water is introduced into the inlet 2a together with the test fish F. Although not shown, a water supply tap can be provided to replenish the measuring tank 22 with water.

[0072] The test fish processing equipment 100 is provided with a holder 1 as a treatment unit and a water receiving section 25 that receives water discharged from the outlet 2b of the guide means 2. As a result, even if a test fish F discharged from the outlet 2b falls out of the holder 1, the fallen test fish F can be accommodated without strain in the water stored in the water receiving section 25. Furthermore, the water receiving section 25 is provided with a drain outlet 26a that leads to a drain pipe 26 for draining the stored water. A net can be provided at this drain outlet 26a to prevent the test fish F that falls out of the holder 1 from flowing out into the drain pipe 26. Furthermore, a water level maintaining means can be constructed to maintain the water level in water receiving section 25 at a predetermined set water level by positioning drain outlet 26a slightly above the bottom surface of water receiving section 25. By providing such a water level maintaining means, the wetness of holder 1 installed in water receiving section 25 is maintained at a constant state, and the moisture content of test fish F held in holder 1 is maintained at an appropriate state.

[0073] In order to accurately maintain the positional relationship between the guiding means 2 and the holder 1, it is desirable to provide a means for positioning the holder 1 in the water receiving portion 25. Although not shown, such positioning means can have the following configurations. For example, the holder 1 can be installed at a predetermined location on the water receiving portion 25 by providing a mark at the water receiving portion 25 and aligning the holder 1 with the mark. Alternatively, the holder 1 can be installed at a predetermined location on the water receiving portion 25 by providing a magnet or magnetic material at a predetermined location on the water receiving portion 25 and on the holder 1, thereby attracting the magnets or magnetic material to the water receiving portion 25. Alternatively, the holder 1 can be installed at a predetermined location on the water receiving portion 25 by providing a hook-and-loop fastener at a predetermined location on the water receiving portion 25 and on the holder 1, thereby attracting the magnets or magnetic material to the water receiving portion 25. Alternatively, the holder 1 can be installed at a predetermined location on the water receiving portion 25 by providing a recess at a predetermined location on the water receiving portion 25 and fitting the holder 1 into the recess. Such a test fish processing facility 100 can be entirely enclosed with a cover to prevent contamination from entering. Furthermore, clean air can be supplied to the space enclosed by this cover.

[0074] [Another embodiment] (1) In the previous embodiment, the entire holder 1 was made of sponge, but it can also be made of other flexible, permeable, and water-retentive materials, such as nonwoven fabric. Furthermore, it can also be made of materials other than sponge and nonwoven fabric, such as soft rubber or synthetic fabric, as long as it is flexible. In this case, the entire holder 1 can be made of a flexible material, or, for example, the holder 1 can be made of inflexible polystyrene foam, with a flexible material affixed to the inner surface of the posture-maintaining groove 3 of the holder 1. The shape of the posture-maintaining groove 3 of the holder 1 can be modified as appropriate depending on the species and habits of the test fish F. It is not necessary to configure the groove 3 so that it tapers toward the tip in a plan view or so that its bottom 3a slopes downward toward the tip in a side view. In particular, it is preferable to modify the width of the posture-maintaining groove 3 to suit in vivo observation and experiments. For example, the width of the posture-maintaining groove 3 of the holder 1 can be configured to widen toward the tip in a plan view, or to have a shape that does not change between the base end and the tip in a plan view. The bottom of the posture-maintaining groove 3 of the holder 1 can be configured to slope upward toward the tip, or to be horizontal between the base end and the tip.

[0075] For example, a posture-maintaining groove 3 can be formed in the intermediate holding portion 1d of the holder 1 as shown in Figures 16 and 17. That is, this posture-maintaining groove 3 is formed with the same width from the front end to the rear end and is composed of an upper groove portion 3b that opens upward and a lower groove portion 3c that continues downward and is wider than the upper groove portion 3b. By employing such a posture-maintaining groove 3, a test fish F that flows out together with water into the upper groove portion 3b that opens upward in the posture-maintaining groove 3 can be smoothly received into the upper groove portion 3b while maintaining its posture, and then smoothly guided into the lower groove portion 3c that is formed below it and is wider than the upper groove portion 3b, so that the test fish F can be held in the lower groove portion 3c with little strain. Furthermore, in the previous embodiment, the shape of the lower groove portion 3c in the intermediate holding portion 1d of the holder 1 when viewed in the longitudinal direction was circular, but it can also be triangular as shown in Figure 18, elliptical as shown in Figure 19, or a narrow groove shape in which the wide lower groove portion 3c (see Figures 8, 9, 16, and 17) is omitted as shown in Figure 20.

[0076] (2) In the previous embodiment, the holder 1 is divided into a rear end holding portion 1a and a front end holding portion 1b, and the test fish F is maintained in a predetermined posture by the posture maintaining groove 3 in the rear end holding portion 1a, and only the mouth or head of the test fish F protrudes from the rear end holding portion 1a to the front end. However, it can also be configured so that only the tail fin of the test fish F protrudes. For example, the rear end can be tapered gradually towards the tip when viewed in a plane, with the rear end having the maximum width W1 and the tip end having the minimum width W2, and the test fish F can be maintained in a predetermined posture by the posture maintaining groove 3 in the tip holding portion 1b, so that only the tail fin of the test fish F protrudes from the tip holding portion 1b to the rear end, in which case observation of the tail fin of the test fish F can be easily and reliably carried out. However, the holder 1 does not necessarily have to be divided into two parts, and the holder 1 can be configured as a single unit as a whole, or can be divided into three parts.

[0077] (3) In the previous embodiment, the guide means 2 is configured with a transparent and flexible pipe member 2c made of synthetic resin. However, the guide means 2 may be configured with, for example, an opaque and inflexible pipe member made of metal. Furthermore, the guide means 2 may be configured with something other than a pipe member, for example, a trough-shaped member with an open top. In addition, an example has been shown in which a funnel-shaped funnel portion 4 is connected to the inlet 2a of the pipe member 2c, which is the guide means 2, and a pipe-shaped outlet portion 5 is connected to the outlet 2b, but these funnel portion 4 and outlet portion 5 are not essential, and the implementation can also be carried out without these funnel portion 4 and outlet portion 5. The test fish treatment equipment of the present invention can be used for various purposes, not only for direct oral administration to test fish, but also for various biological observations of test fish and blood sampling. [Industrial Applicability]

[0078] The present invention can be suitably used as a test fish treatment device and a test fish treatment method that can securely hold test fish in a predetermined posture. [Explanation of symbols]

[0079] 1 Holder 1a Retention part on the rear end side 1b Tip side retention part 2 Guidance means 2a Inlet 2b Outlet 2c Pipe member 3 Posture maintenance groove 3a Bottom of the posture maintenance groove 4 Funnel part 5 Outlet 5a Slit 7 syringes 8 Oral tube 9 injection 15 Water supply pipe (water flow forming means) 21 First Tank 25 Water receiving section 30 Second Tank 100 Test fish processing equipment F Test fish SW water supply WF water flow

Claims

1. A holder for holding a test fish to which a test substance is administered as a predetermined treatment is provided, The holder has a posture maintaining groove for maintaining a test fish introduced together with water in a predetermined posture, and at least the inner surface of the posture maintaining groove is made of a flexible material; The posture-maintaining groove of this test fish treatment equipment comprises an upper groove portion that opens upward and a lower groove portion that continues downward from the upper groove portion and is wider than the upper groove portion.

2. 2. A test fish treatment facility as described in claim 1, wherein the posture maintaining groove is formed with the same width from the front end to the rear end.

3. A holder for holding a test fish to which a test substance is administered as a predetermined treatment is provided, The holder has a posture maintaining groove for maintaining a test fish introduced together with water in a predetermined posture, and at least the inner surface of the posture maintaining groove is made of a flexible material; A guide means is provided for guiding the test fish together with water to the holder; The guiding means is configured to have an inlet at one end through which the test fish is introduced together with water, and an outlet at the other end through which the test fish is discharged together with water into the posture maintaining groove, the induction means is constituted by a pipe member having the inlet at one end and the outlet at the other end, A pipe-shaped outflow section located adjacent to and above the posture-maintaining groove is connected to the outlet, and the outflow section has a slit that faces along the posture-maintaining groove, and the test fish is discharged from the slit into the posture-maintaining groove together with water in a predetermined posture.

4. A test fish processing facility as described in claim 3, comprising a first tank for housing test fish before they are introduced into the introduction port, and a second tank for housing test fish that have been released from being held by the holding device.

5. 4. A test fish treatment facility as claimed in claim 3, further comprising a water flow forming means for supplying water to the inlet and forming a water flow within the pipe member.

6. 4. The test fish treatment equipment according to claim 3, further comprising a funnel-shaped portion connected to said inlet for guiding said test fish together with water to said inlet.

7. A test fish processing equipment as described in claim 3, further comprising a water receiving portion in which the holder is installed and which receives water discharged from the outlet.

8. A test fish processing equipment as described in any one of claims 1 to 7, wherein the holder is made of a material that is flexible, permeable, and has water retention properties.

9. A test fish processing equipment as described in any one of claims 1 to 7, wherein the posture maintaining groove is tapered toward the tip.

10. A test fish processing equipment described in any one of claims 1 to 7, wherein the depth of the posture maintaining groove is set to be greater than the height of the test fish held in the posture maintaining groove.

11. A method for treating test fish, characterized in that a test substance is administered as a predetermined treatment to test fish held in the holder using the test fish treatment equipment described in any one of claims 1 to 7.

12. The method for treating test fish described in claim 11, characterized in that the specified treatment involves oral administration of the test substance directly to the test fish through an oral tube inserted into the oral cavity of the test fish maintained in a specified posture by the posture maintaining groove of the holding device.

13. The method for treating test fish described in claim 11, characterized in that the specified treatment involves parenteral administration of a test substance to the test fish by injection into the test fish maintained in a specified posture in the posture maintaining groove of the holding device.

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