JP2014039514A - Seafood anesthetization method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for anesthetizing a seafood safely for a long time and practically simple under an environment containing dissolved carbon dioxide.SOLUTION: By bringing oxygen air bubbles containing gaseous oxygen into contact with the surfaces of the gill-epithelial cell membrane of a seafood, a partial pressure difference of [gaseous oxygen partial pressure]-[oxygen gas partial pressure in capillary vessels of gills] exceeding [partial pressure of oxygen dissolved in water]-[partial pressure of oxygen dissolved in capillary vessels of gills], so that the quantity of oxygen to be taken into the gill sheet capillary vessels is prominently increased. As a result, the respiratory failure, which might occur under a voluntary breathing movement suppressed by an anesthetization, is avoided so that a long-term carbon-dioxide anesthetization can be performed under a water temperature (about 20°C), at which the seafood is usually handled.

Description

The present invention relates to a method and apparatus for performing long-term anesthesia of fish and shellfish in water containing dissolved carbon dioxide.

Conventionally, in fish farming sites, anesthesia is necessary due to the need for sedation of fish during work in order to prevent damage and consumption of fish bodies in situations such as vaccination for disease prevention and gear cutting to prevent biting of trough puffers. Drugs are being used. Currently, an anesthetic mainly composed of eugenol (4-allyl-2-methoxyphenol), which is a kind of food additive, has been approved as a veterinary drug (trade name: FA100), and is an anesthetic for fish. Is used. However, when used at a farm site or the like, the used anesthetic solution is discarded as it is into the ocean or river, which is not preferable from the viewpoint of environmental conservation. In addition, with the increasing consumer interest in food safety, the use of narcotics that may remain in cultured fish has been shunned, and prior to landing due to guidance from the Ministry of Agriculture, Forestry and Fisheries The use of the device has been restricted for seven days, and the usable scenes are narrowing.

As a method of anesthesia for fish without using an anesthetic, a short-term anesthesia technique using carbon dioxide dissolved in water has been known, and recently, sodium bicarbonate, succinic acid and a solidification accelerator are the main raw materials. An anesthetic agent for fish made of a solid carbon dioxide foaming agent made only from a raw material certified as a food additive has been developed (see Patent Document 1). Patent Document 2 discloses a technique for maintaining an active fish in an anesthesia state for a long time in a water tank in which the partial pressure of carbon dioxide gas is adjusted to 55 to 95 mmHg in combination with the cold and hot treatment of fish. Further, Patent Document 3 discloses an ice temperature seawater cooling device for storing and transporting live squid in a low temperature state of an ice temperature state.

With regard to long-term anesthesia methods, fisheries officials are expected to apply to a wide range of uses such as live fish transportation, but conventional long-term anesthesia methods are all based on a method of lowering the temperature of a live fish cart, The live fish transportation method using a live fish tank equipped with a cooling water tank is widely used as a practical anesthesia method because the cost of special vehicle equipment and the risk of drowning during transportation due to the uncertainty of the low temperature physiological characteristics of each fish cannot be avoided. There is a problem that it cannot be used.

Carbon dioxide has long been known to have an anesthetic effect on both terrestrial and aquatic organisms, and is ideal as an anesthesia method for organisms that are food materials in that they do not leave any harmful substances in the body. It can be said that it is an anesthesia method. However, when it is used as an anesthetic gas for aquatic organisms, it causes death due to respiratory failure within a very short time, so there are limited vaccinations for disease prevention and trough puffing to prevent biting. It has been considered that this is a short-term anesthesia method used for applications (see, for example, Non-Patent Document 1). On the other hand, as a general recognition of those involved in the distribution of seafood, it is sufficient for oxygen supply to seafood that the dissolved oxygen (DO) is saturated or kept close to it, even under anesthesia. It is believed that there is no oxygen deficiency under saturated dissolved oxygen. However, this recognition is wrong, and it is due to this erroneous recognition that long-term anesthesia of seafood with carbon dioxide has not been successful to date.

When anesthesia with carbon dioxide is given to seafood (aquatic organisms that respire) under the water temperature (around 20 ° C) at which the seafood is handled, [partial dissolved oxygen partial pressure] -[Oxygen partial pressure of dissolved oxygen in the salmon capillaries] The oxygen diffusion and movement speed is reduced, and the amount of oxygen ingested by the coral lamina is reduced. Depending on the degree, even if fish and shellfish individuals are placed in saturated dissolved oxygen water, the amount of oxygen absorbed from the salmon may not be able to meet the individual oxygen demand. Inferred. Even in the case of carbon dioxide anesthesia for actual seafood, all individuals stop breathing in a very short time, even when anesthesia is performed with carbon dioxide on fish and shellfish in saturated dissolved oxygen water while performing aeration. The fact that they die without exception proves the correctness of this reasoning. Then, in order to prevent the respiratory failure of fish and shellfish under carbon dioxide anesthesia, there is only one method of lowering the individual oxygen demand itself or realizing an oxygen environment exceeding the saturated dissolved oxygen water. Become.

Artificial hibernation induction method (Patent Document 4) or cold carbon dioxide anesthesia method at low temperature (Non-Patent Document 2), and more precise low-temperature anesthesia method using anesthesia apparatus (Patent Document 4) 2). However, these low-temperature anesthesia methods require a whole day of time to acclimate fish and shellfish to a low temperature (5 ° C or lower) without dying, and a large-scale device to lower the temperature together with environmental water. Since much power consumption is unavoidable, practical use as an anesthesia method is very limited.

On the other hand, when anesthesia with carbon dioxide is given to seafood under water temperature (around 20 ° C.) for handling normal fish and shellfish, a certain concentration of carbonated water for anesthesia containing a sufficient concentration of dissolved oxygen is produced in advance. Even if a device (Patent Document 2) that constantly supplies fresh anesthetic carbonated water containing dissolved carbon dioxide gas and dissolved oxygen to an anesthesia water tank is used, only a short period of anesthesia of up to about 20 minutes is possible. is there. Under anesthesia, even in saturated dissolved oxygen water, the amount of oxygen absorbed from the sea bream cannot meet the oxygen demand of fish and shellfish individuals, so fish and shellfish can develop respiratory failure in a matter of minutes. Wake up and die without exception.

Japanese Patent No. 4831409 Japanese Patent No. 4951736 Korean Patent No. 10-0531728 Patent No. 4332206 Takeda Tatsuo et al., “Examination of applicability of carbon dioxide anesthesia to live fish transport”, Journal of the Japanese Fisheries Society, 49 (5), 1983, p. 725-731 Hisadatsu Mitsuda et al., “Application of cold carbon dioxide anesthesia to live fish transport”, Journal of Freezing and Drying Research Society, 37, 1991, p. 54-60

The present invention has been made to solve the above-described problems in conventional anesthesia methods, and a method and apparatus for performing long-term anesthesia on fish and shellfish with a safe and practical convenience in an environment containing dissolved carbon dioxide. Is to provide.

The principle of anesthesia in the present invention is as follows. In order to realize long-term anesthesia with carbon dioxide for fish and shellfish under normal water temperature (around 20 ° C.), the fish and shellfish must be provided with a high oxygen environment exceeding saturated dissolved oxygen water. Respiratory motion reduced by carbon dioxide anesthesia reduces oxygen diffusion due to the partial pressure difference between [partial dissolved oxygen partial pressure in water]-[partial dissolved oxygen partial pressure in the vagina] and is ingested by the thin plate capillaries Lowering the amount of oxygen causes hypoxemia and leads to death. In order to prevent this, a method of remarkably increasing the oxygen diffusion in the buttocks is necessary, and as a new method for that purpose, a method of supplying oxygen by oxygen bubbles containing gaseous oxygen has been devised. That is, by bringing oxygen bubbles into contact with the buttocks, [gaseous oxygen partial pressure] exceeding the partial pressure difference of [water partial dissolved oxygen partial pressure] − [split capillary partial dissolved oxygen partial pressure] − [spider capillaries This is a method of generating a partial pressure difference of [internal dissolved oxygen partial pressure] and remarkably increasing the amount of oxygen ingested into the thin plate capillary.

The first aspect of the present invention includes an anesthesia for fish and seafood, including a step of generating in water a carbon dioxide concentration that exerts an anesthetic effect on the target fish and shellfish, and a step of supplying oxygen bubbles containing oxygen in the water. Is the method.

The oxygen bubbles are preferably supplied so as to be in contact with the sea bream salmon, and more preferably are supplied so as to be in contact with the surface of the sea bream epithelial cell membrane.

It is preferable that the mode value of the particle diameter of oxygen bubbles is 300 nm or less, and it is further desirable to supply oxygen bubbles at a density of 40 million / ml or more.

According to a second aspect of the present invention, there is provided a fish tank comprising a water tank containing the target fish and shellfish, a means for supplying carbon dioxide into the water tank, and a means for supplying oxygen bubbles containing oxygen into the water tank. A kind of anesthesia device.

In the present invention, the seafood is a concept including aquatic organisms having a swimming property that ingests oxygen by respiration such as cephalopods and crustaceans in addition to fishes.

According to the present invention, carbon dioxide is dissolved in water to supply dissolved carbon dioxide having an anesthetic effect to the target fish and shellfish, and under anesthesia, an individual's oxygen demand can be satisfied even in a saturated dissolved oxygen environment. As a method for solving this problem, by supplying oxygen bubbles containing oxygen, it is possible to safely give anesthesia without killing fish and shellfish under normal water temperature (around 20 ° C.).

The outline | summary of the anesthesia method based on implementation of this invention is demonstrated. To induce and maintain the appropriate depth of anesthesia existing for each species of seafood (anesthesia depth corresponding to the first to second phases of anesthesia in human general anesthesia = thalamus, subcortical nucleus, spinal cord paralysis) In order to supply a suitable concentration of carbon dioxide continuously and accurately to the heel part of the individual, arbitrary carbon dioxide is dissolved in the entire water tank by aeration to adjust it to a concentration suitable for the induction and maintenance of anesthesia. At the same time, in order to supply oxygen exceeding the oxygen demand of the individual fish and shellfish, gaseous oxygen is continuously supplied as water bubbles so as to come into direct contact with the coral part of the individual. In the heel part in contact with oxygen bubbles, oxygen is diffused and transferred by the partial pressure difference between [Gaseous oxygen partial pressure]-[Partial dissolved oxygen partial pressure in the cocoon capillary]. The amount of oxygen produced increases dramatically.酸 素 The amount of oxygen ingested into thin-walled capillaries depends on the diffusion coefficient depending on the diameter, pressure, and number of bubbles in contact with the epithelial cell membrane surface. The amount of oxygen ingested by the thin plate capillaries by contact increases, and it is theoretically possible to realize a high oxygen concentration environment exceeding the oxygen demand of the individual under carbon dioxide anesthesia by this method.

Next, the environmental oxygen concentration that makes it possible to satisfy the oxygen demand of seafood under anesthesia will be described. The oxygen concentration of air is approximately 21% (atmospheric composition = volume percentage is 78% nitrogen, 21% oxygen, 0.93% argon, and about 0.03% carbon dioxide). Under this oxygen concentration, oxygen is replenished to meet the individual oxygen demand. When anesthetizing terrestrial animals such as humans and domestic animals, oxygen inhalation is given to avoid respiratory failure as a complication of anesthesia, but the oxygen concentration at this time is adjusted in the range of approximately 40% to 80%. The That is, respiratory failure as a complication that occurs under spontaneous breathing movement suppressed by anesthesia is avoided by supplying oxygen about 2 to 4 times that breathes in a normal state. Anesthesia-suppressed respiratory center reduces spontaneous respiratory movement and causes hypoxemia, and oxygen concentration decreases in the periphery of the whole body, causing respiratory failure as a complication. Increase the partial pressure difference of [alveolar oxygen partial pressure]-[alveolar capillary partial pressure] by increasing the inhaled oxygen concentration by 2 to 4 times, and the amount of oxygen taken into the alveolar capillaries Compensates for pulmonary respiratory movements that have declined in function. Naturally, it is presumed that this phenomenon is also applicable to fish and shellfish, which is a phenomenon observed in land animals performing pulmonary breathing, that is, under anesthesia, oxygen supply is required several times that of the normal living environment. However, if so, it is difficult to provide long-term anesthesia for fish and cephalopods that inhabit seawater. This is because the ocean surface oxygen concentration is in the range of 6 to 7.5 mg / L at most survey points (85 to 100% of the saturated oxygen concentration), and the fish and shellfish live in water that is almost saturated with dissolved oxygen. Because. It is impossible to raise the concentration of dissolved oxygen several times with respect to water in a state of 100% dissolved oxygen by any method. Therefore, when anesthesia with carbon dioxide is performed under the water temperature (around 20 ° C) that normally handles seafood, hypoxemia is caused by respiratory movement suppressed by anesthesia within a very short period of minutes, resulting in respiratory failure. They die suddenly. In order to prevent this, it is necessary to provide an anesthesia fish and shellfish with an oxygen concentration environment that is at least several times higher than the normal living environment.

Next, the diameter and density of oxygen bubbles for giving a high oxygen concentration environment to fish and shellfish will be described. The size of buoyancy is determined by the diameter of the bubbles present in the water, and is reflected in the speed of rising in the water. The rising speed of bubbles in water depends on the liquid properties, but in water, the Reynolds number Re is almost 1 at a diameter of about 100 μm. Furthermore, since Re <1 behaves as a solid sphere depending on the flow state of the spherical bubble interface, the Stokes formula is well adapted. Moreover, it is known that the measurement result of the experiment using distilled water and tap water also substantially corresponds with the calculated value by the Stokes formula. Therefore, the rising speed of bubbles in water is calculated as shown in the table below. In other words, bubbles (nanobubbles) having a diameter of 1 μm or less are maintained in position without floating when considered in time units. Therefore, in order to continuously supply oxygen bubbles at a stable concentration to fish and shellfish individuals that cannot move under anesthesia, bubbles having a particle size of 1 μm or less without buoyancy are suitable.

In the heel portion in contact with the oxygen bubbles, oxygen is diffused and transferred by a partial pressure difference between [gaseous oxygen partial pressure] − [dissolved oxygen partial pressure in the vascular capillary]. The amount of oxygen ingested into the thin plate capillaries changes according to the diffusion coefficient depending on the diameter (pressure inside the bubble) and the number of oxygen bubbles in contact with the membrane surface of the epithelial cells. The amount of oxygen ingested by the thin-walled capillaries increases by contacting the membrane surface. The relationship between the bubble diameter in water and the pressure in the bubble can be expressed by the Young-Laplace equation, and the relationship is given by “ΔP = 4σ / d”. At this time, assuming that the surface tension of water σ = 72.8 mN / m (20 ° C.) and the pressure around the bubble is 1 atm, the following is obtained.

That is, in order to increase the oxygen diffusion rate and increase the amount of oxygen ingested by the thin plate capillaries, the partial pressure difference between [gaseous oxygen partial pressure] − [dissolved oxygen partial pressure in salmon capillaries] is increased. For this purpose, the smaller the oxygen bubble diameter, the more efficient the geometric series. Actually, there is a certain limit to the number of oxygen bubbles that can contact the membrane surface of the epithelial cells, so the fraction between [gaseous oxygen partial pressure] and [partial oxygen dissolved oxygen partial pressure] It is considered that oxygen bubbles having a particle size of 300 nm or less with a pressure difference of 10 times or more exert a remarkable effect in order to increase the total amount of oxygen taken into the thin plate capillaries.

Next, examples carried out for confirming the effects of the present invention will be described.
<< Example 1: Confirmation of anesthesia limit time when carbon dioxide anesthesia was performed on fish and shellfish at a water temperature of 20 ° C >>
It is known that when seafood is anesthetized with carbon dioxide under the water temperature (around 20 ° C.) for handling normal seafood, it will die in a very short time even with saturated dissolved oxygen. The limit time for anesthesia is confirmed by experiment. Table 3 shows the types and number of fish and shellfish used in the experiment. The water temperature in the experimental 700 L water tank was adjusted to 20 ° C., and the dissolved oxygen (DO) of the seawater in the water tank was kept saturated using a normal air pump and air stone. Under saturated dissolved oxygen, carbon dioxide was bubbled into water to increase the concentration of dissolved carbon dioxide at a rate of 0.5% increase per minute, and the concentration was increased until fish and shellfish were anesthetized. The time point when the body movement except the respiration movement of the buttocks and the body movement stopped was confirmed with a monitor camera was evaluated as the start of anesthesia. Thereafter, the anesthesia was continued while maintaining a slightly higher concentration than the carbon dioxide concentration under anesthesia. Every 5 minutes, the individuals whose phlegm activity stopped were pulled up and confirmed to die. As a result, all individuals died within 30 minutes after anesthesia, and the progress is as shown in Table 4. In addition, the carbon dioxide concentration in water was measured with a CGP-31 type carbon dioxide concentration meter manufactured by Toa DKK Corporation and expressed in v / v%.

<< Example 2: Confirmation of carbon dioxide concentration at which anesthetic effect appears in seafood >>
Table 6 shows the types and number of fish and shellfish used in the experiment. The water temperature in the experimental 700 L water tank is adjusted to 20 ° C., and oxygen bubbles having the particle size distribution shown in Table 5 are continuously supplied to the water tank by an oxygen bubble generator (Formac CT manufactured by NAC), and carbon dioxide is The concentration of dissolved carbon dioxide was increased at a rate of 0.5% increase per minute and increased until the seafood was anesthetized. The time point when the body movement except the respiration movement of the buttocks and the body movement stopped was confirmed with a monitor camera was evaluated as the start of anesthesia. Thereafter, the supply of carbon dioxide was stopped when the concentration reached a level slightly higher than the concentration of carbon dioxide subjected to anesthesia, and immediately after that, the carbon dioxide was expelled from the water tank by aeration, and gradually the carbon dioxide was gradually reduced at a rate of 1% / 30 min. The concentration was lowered to awaken the seafood from anesthesia. As a result, all fish and shellfish used in the experiment were awakened normally, and no individual was observed to have any abnormality in macroscopic findings at 6 hours after awakening. That is, it becomes clear that long-term carbon dioxide anesthesia can be performed for a wide range of seafood under water temperature (around 20 ° C.) for handling normal seafood, and the course is as shown in Table 7. As for squid, the excitement state at the initial stage of anesthesia triggered one of the three animals, and the experiment was temporarily stopped. ing. When anesthetizing squids, a method of increasing carbon dioxide concentration that reduces excitement during the anesthesia-inducing phase is necessary to completely suppress the reaction of spitting smears that may be triggered by the mild excitement that appears in the early anesthesia. It is considered necessary to search.

<< Example 3: Demonstration experiment of long-term anesthesia with carbon dioxide >>
In the experiment, five Isaki animals weighing approximately 450 g were used. The water temperature in the experimental 700 L water tank is adjusted to 20 ° C., and oxygen bubbles having the particle size distribution shown in Table 5 are continuously supplied to the water tank by an oxygen bubble generator (Formac CT manufactured by NAC), and carbon dioxide is Was ventilated to raise the concentration of dissolved carbon dioxide to 5% and anesthetize Isaki. When the concentration of dissolved carbon dioxide reached 5%, it was confirmed with a monitor camera that all the individuals had no swimming behavior and the body movement except for the respiratory movement of the heel portion was stopped. Thereafter, anesthesia was performed for 20 hours while maintaining the carbon dioxide concentration in the range of 5.0 to 4.5%. After anesthesia, carbon dioxide was expelled from the water tank by aeration, and the seafood was awakened from anesthesia by gradually decreasing the carbon dioxide concentration at a rate of 1% / 30 min. All individuals subjected to the experiment for 2 to 3 hours when the carbon dioxide concentration was sufficiently lowered were awakened normally, and no abnormal individuals were observed even after 24 hours of awakening. That is, it has been demonstrated that the simultaneous supply of dissolved carbon dioxide and nano-sized oxygen bubbles enables safe and long-term anesthesia to fish and shellfish under normal handling water temperature (around 20 ° C.). That's right.

According to the present invention, it is possible to transport fish and shellfish that have been sedated by anesthesia for a long time and over a long distance. Fish and shellfish that have been sedated by anesthesia have reduced physiological and metabolic activities, so that deterioration of water quality can be suppressed and the loading rate in a limited aquarium can be improved. After a safe long-term anesthesia for seafood, the new anesthesia technology that made it possible to return to the original awake state and swim around as a live fish can be used on land, air, sea, or any other means of transportation. This makes it possible to carry fish and shellfish while keeping them alive for long distances that were previously impossible. Also, in fish farming sites, etc., it can be used for sedation of fish to prevent damage and consumption of fish in various situations such as vaccination for disease prevention and gear cutting to prevent biting of trough fish. .

Claims (6)

Producing a carbon dioxide concentration in the water that exerts an anesthetic effect on the target seafood;
Supplying oxygen bubbles containing oxygen into the water,
Anesthesia method for seafood. Supplying the oxygen bubbles in contact with the seafood salmon,
The method for anesthetizing fish and shellfish according to claim 1. Supplying the oxygen bubbles in contact with the surface of the sea urchin epithelial cell membrane,
The method for anesthetizing fish and shellfish according to claim 2. The mode of the particle size of the oxygen bubbles is 300 nm or less,
The method for anesthetizing fish and shellfish according to any one of claims 1 to 3. Supplying the oxygen bubbles at a density of 40 million / ml or more,
The method for anesthetizing fish and shellfish according to any one of claims 1 to 4. An apparatus for carrying out the method according to any one of claims 1 to 5,
An aquarium containing the target seafood,
Means for supplying carbon dioxide into the aquarium;
Means for supplying oxygen bubbles containing oxygen into the water tank;
Seafood anesthesia device.