JPH03983B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a feeding stimulant and feed for fish that increases the amount of food consumed by fish and promotes their growth. "Prior art and its problems" Since the establishment of the global 200 nautical mile fishing rights, Japan, which has benefited greatly from fisheries resources, has been forced to operate within 200 nautical miles of other countries, and naturally The cost of resources is increasing year by year due to regulations on fishing season, catch amount, and payment of fishing fees. In view of this fact, the catch of inshore surface fish and farmed fish is increasing year by year. For this reason, large amounts of raw bait and fishmeal used for nearshore surface fish and farmed fish are administered, and the uneaten bait settles on the ocean floor, which is a source of contamination on the continent and needs countermeasures. Furthermore, the decrease in the effective utilization rate of feed is linked to the decrease in the growth rate of farmed fish, leading to an increase in costs. For this reason, in the current aquaculture industry, which uses fishmeal and live feed from pelagic and inshore fish, improvements in feed composition to increase so-called feed efficiency, in which normal or higher growth can be achieved with less feed, and live feed are needed. It is desired to develop an alternative feed that maintains the same feed efficiency as compound feeds using fishmeal, etc. As part of such research, there have been reports on feeding stimulants that stimulate fish's sense of smell and taste to induce them to eat food. Glutamine is known as a representative example, but at present, no significant effects can be obtained with so-called mixed feeds that are mixed with feed. "Object of the Invention" An object of the present invention is to provide a novel feeding stimulant and a feed using the same. ``Structure of the Invention'' Among living things, animals have the ability to receive all kinds of information in the form of stimuli, process it in the central nervous system, and generate swift and detailed movements in response to changes in the external environment. are doing. Among the many stimuli, the sensations caused by chemical substances are called chemical sensations, and feeding behavior is an especially important sensation both ecologically and behaviorally. In fish, there are few taste buds on the tongue, which are located on the roof of the mouth, and are also distributed in the gills, under the control of the glossopharyngeal nerve.
Fish taste buds are structurally similar to mammals.
The diameter of the taste buds in the gills of adult fish is 50 μm.
Taste cells are supported by supporting cells, and have a protrusion shape with a diameter of about 0.7 μm and a length of about 0.5 to 3 μm, and are covered with mucous membrane. Their lifespan is short, about 11 days, and they are new cells. responds sensitively to stimuli. Multiple cells are grouped together and controlled by a single taste nerve fiber, but there is a phenomenon in which general excitement collides and disappears before the impulse is sent to the nerve fiber, and a single taste cell They also have the ability to respond to different taste sensations, making it extremely difficult to identify tastants and their ingestion behavior. Therefore, the present inventors have discovered that there is always one type of stimulation that is suitable for each receptor, rather than a substance that constantly provides sufficient and strong stimulation for a specific feeding stimulant. efforts were made to identify. This is in accordance with Mueller's law, which states that the type of sensation is determined by the type of receptor, not by the type of stimulus. Regardless of the type, the same sensation is produced, but if the substance is an appropriate stimulus for the receptor, it requires less energy than other stimuli. The feeding stimulant for fish according to the present invention is characterized by comprising β-dimethylpropiotetin and/or a salt thereof represented by the following structural formula (1). Furthermore, the fish feed according to the present invention has the above structural formula:
It is characterized in that β-dimethylpropiotetin and/or its salt shown in (1) is added. β-dimethylpropiotetin (hereinafter abbreviated as Tetin) represented by the above structural formula (1) is produced by mixing and stirring 3-bromopropionic acid and dimethyl sulfide at room temperature for about 2 to 3 hours, and then filtering the mixture. It can be easily synthesized by The feeding stimulant (techin) of the present invention has the effect of increasing the intake of fish and promoting their growth when added to various feeds such as synthetic feeds, semi-natural feeds, and completely natural feeds. . This effect is observed in all kinds of fish, including freshwater fish such as carp, crucian carp, goldfish, eel, rainbow trout, and tilapia, and saltwater fish such as yellowtail, sea bream, spiny lobster, and flounder. The feed of the present invention is characterized by the addition of the above-mentioned feeding stimulant (techin), and the base feed can be any synthetic feed, semi-natural feed, completely natural feed, etc. . The method of adding the feeding stimulant (techin) is not particularly limited, but it is preferable, for example, to mix the base feed with a solution containing 10 ^-9 to 1 M of techin. In this case, the concentration of Tetin in the solution is
If it is less than 10 ^-9 M, the effect of stimulating feeding on fish will not be sufficiently obtained, and if it exceeds 1 M, odor will be generated, the effect will be reduced, and a large amount of acrylic acid, a decomposition product, will be generated, which may be toxic. There is sex. In addition, in the present invention, in addition to Tetin represented by the structural formula (1), salts thereof such as sodium and potassium may be used, and similar effects can be obtained even with these salts. "Embodiments of the Invention" (1) Experimental Apparatus and Method FIG. 1 shows an apparatus used for experiments on the feeding stimulation effects of various substances. In the figure, 1 is a water tank, which is supported on a stand 2. A fish 3 is placed in an aquarium 1. A support 4 is erected on the side of the water tank 1, and an arm 6 is connected to the recording needle 5.
is rotatably supported by the support column 4 via a support shaft 7. A thread 8 is connected to the rear end of the recording needle 5.
A magnet 9 is fixed to the lower end of the magnet 9.
The thread is stretched by bringing it into close contact with the bottom of the aquarium 1. Experimental bait 10 is attached to the part of the string 8 that is immersed in the water of the aquarium 1. On the other hand, a recorder body 11 is installed on the side of the water tank 1, and the recorder body 11 has an inverted L-shaped support 12.
has been erected. A rotary drum 13 is rotatably supported between the column 12 and the recorder main body 11, and the tip of the recording needle 5 mentioned above is in sliding contact with the rotary drum 13. The rotating drum 13 is configured to rotate once every 2 minutes and 50 seconds by a drive mechanism (not shown) provided inside the recording apparatus main body 11. To explain the experimental method using the above-mentioned device, first, experimental bait 1 containing various feeding stimulants was prepared.
0, the bait 10 is attached to the thread 8, and the bait 10 is submerged at an intermediate height in the water of the aquarium 1. Then, the rotary drum 13 is rotated to record the pecked state of the bait 10 by the fish 3. That is, when the fish 3 pecks the bait 10, the string 8 held by the magnet 9 is pulled, the recording needle 5 swings, and a record is made on the rotating drum 13. In this way, the number of times the fish 3 pecked the bait 10 was measured while the rotating drum 13 rotated once. In addition, at the same time as replacing the test water for each test, the thread 8, the fish 3, and the aquarium 1 were thoroughly washed with breeding water. (2) Preparation of feed The test feed was prepared as follows. That is, as a base feed, cellulose powder was used as a simple synthetic feed, a mixed feed of equal amounts of cellulose powder and powder of a commercially available natural solid feed for carp was used as a semi-natural feed, and the above-mentioned natural solid feed for carp was used as a completely natural feed. Using. On the other hand, an aqueous solution containing 10 ^-3 M of the substance to be tested for feeding stimulation effect was prepared. Then, 0.5 g of the above base feed was taken, 0.8 ml of the above test liquid was added thereto, and the mixture was kneaded in a mortar to prepare a feed. Preliminary Test Example (Experiment on Amino Acids) First, several amino acids that have been reported as substances that strongly stimulate the sense of smell and taste of fish were measured for their feeding stimulating effects on goldfish using the method described above. That is, each amino acid is dissolved in water to prepare a test solution of 10 ^-3 M, and this test solution is
0.8 ml was added to 0.5 g of cellulose powder and kneaded to prepare a test bait. This bait was attached to the string of the above-mentioned device, and the number of times the goldfish pecked it was measured. The results are shown in Table 1. Table 1 shows the number of glutamine pecks.
It is evaluated as a relative value with 100. Also,
In Table 1, Gln: glutamine, Val: valine, Leu: leucine, Ser: serine, Thr: threonine, Glu: glutamic acid, Arg: arginine,
Lys: Meaning of lysine. Table 1 shows that, as reported so far, glutamine has the best feeding effect, followed by glutamic acid, arginine, leucine, etc. in that order.

[Table] Example 1 (Experiment using simple synthetic feed) An experiment similar to the above was conducted using glutamine and several sulfur-containing compounds. That is, a test solution was prepared by dissolving each substance in water to a concentration of 10 ^-3 M, and 0.8 ml of this test solution was added to 0.5 g of cellulose powder and kneaded to prepare a test bait. As a blank, bait prepared by adding 0.8 ml of water to 0.5 g of cellulose powder and kneading the mixture was also used. These baits were attached to the device described above, and the number of pecks by goldfish was measured. The measurements were carried out five times for each test, and the evaluation was based on the total number of pecks. The result is
As shown in Table 2. In Table 2, there are two values for water addition because measurements were taken at the beginning and end of the experiment, respectively. From Table 2, it was confirmed that the effect of Tetin far exceeds that of glutamine, which has been reported as the strongest olfactory and taste stimulant for freshwater fish and saltwater fish in general. Also,
A good effect was also found on dimethyl sulfide (left side of structural formula (1)), which is a decomposition product of Tetin.

[Table] Example 2 (Experiment using semi-natural bait) Next, using a semi-natural bait, tests were conducted for tettin and glutamine. That is, 0.8 ml of water or each test solution (tetin or glutamine concentration 10 ^-3 M) was added to 0.5 g of a mixed feed prepared by mixing equal amounts of cellulose powder and powder of natural solid feed for carp, and the mixture was mixed to prepare the test solution. A diet was prepared. As a blank, bait prepared by adding 0.8 ml of water to 0.5 g of cellulose powder and kneading the mixture was also used. Using these baits, the number of pecks by goldfish was measured in the same manner as in Example 1. The results are shown in Table 3. From Table 3, it can be seen that the effect of Tetin is good even when semi-natural baits are used, while the effect of glutamine is not found when semi-natural baits are used. In addition, the feeding stimulation effect of Tetin was measured in the same manner as above except that crucian carp was used as the fish. The results are shown in Table 4. Table 4 shows that the feeding stimulating effect of Tetin is also observed in crucian carp.

【table】

[Table] Example 3 (Experiment using natural bait) Next, an experiment similar to Example 2 was conducted using natural bait. In other words, 0.5 g of powdered natural solid feed for carp is mixed with water or a test solution (techin concentration).
10 ^-3 M) was added and mixed to prepare a test bait. As a blank, 0.5 g of cellulose powder was added with water or a test solution (tetin concentration).
10 ^-3 M) was added and mixed to prepare a test bait. As a blank, bait prepared by adding 0.8 ml of water to 0.5 g of cellulose powder and kneading the mixture was also used. Table 5 shows the results of measuring the number of pecks of goldfish using these baits, and Table 6 shows the results of measuring the number of pecks of crucian carp. From Tables 5 and 6, it can be seen that even when natural feed is used, the effect of Tetin is observed on both goldfish and crucian carp.

【table】

[Table] Example (Experiment on the decomposition product of Tetin) In order to investigate the effect of Tetin, dimethyl sulfide and acrylic acid, which are both its constituent components and a decomposition product, were added to increase the feeding stimulation effect on goldfish. It was measured. The bait used was prepared by adding 0.8 ml of each test solution (10 ^-3 M concentration) to 0.5 g of cellulose powder and kneading the mixture. The results are shown in Table 7. From Table 7, the effect of Tetin clearly surpassed the effects of both dimethyl sulfide and acrylic acid compounds, either alone or in combination, so this effect of Tetin is not due to the decomposition products of this compound. That is clear.

[Table] Although the above results are for goldfish or crucian carp, the effects of Tetin were also confirmed when using other fish species. Example 5 (Breeding test) Add 160 ml of water or test solution (techin concentration 10 ^-3 M) to 100 g of a mixed feed prepared by mixing equal amounts of cellulose powder and powder of natural solid feed for carp, and knead the mixture for testing. A diet was prepared. 0.05 of this bait every day
As a result of raising crucian carp for 30 days by feeding 1 g/fish,
The weight gain of crucian carp was 20% in the case without the addition of Tetin, and 50% in the case with the addition of Tetin. Thus, by using the feeding stimulant of the present invention, the effect of promoting the growth of fish can also be obtained. Example 6 (method for measuring olfactory chordal electroencephalograms) FIGS. 2, 3, and 4 show an apparatus and method for measuring olfactory chordal electroencephalograms. In the figure, 21 is a shield box, 22 is breeding water for breathing, 23 is breeding water for adding test liquid, 24
is the test solution, 25 is the input box, 27 is the ground, 28 is the olfactory tract, 29 is the olfactory brain, 30 is the optic lobe, 31 is the cerebellum, 3
2 is a test fish, and 33 is an electroencephalograph. As shown in the figure, a test fish 32 is placed inside the shield box 21. Since the test fish 32 is anesthetized with galamin trithiodide (a muscle relaxant), it cannot breathe (its gills do not move), and breeding water 22 is introduced into the oral cavity to supply oxygen. On the other hand, breeding water 2
3 is constantly introduced through the nostril. In this state, when the test liquid 24 is dropped into the flow of the rearing water 23, the test liquid 24 mixes with the flow of the rearing water 23, reaches the olfactory epithelial cells in the nostrils, and stimulates them. This stimulation becomes electrical stimulation and flows through the olfactory tract 28, and the olfactory brain 2
9, it is thought to be transmitted to the optic lobe 30 and cerebellum 31 to induce feeding behavior. In this experiment,
This electrical stimulation is taken out from the electrode 26 in contact with the olfactory tract 28 and transmitted to the input box 25, and then further transmitted to the input box 25.
5 exits the shield box 21 and is led to an electroencephalograph 33, where stimulation waves are recorded. Figure 5a shows the electroencephalogram when 10 ^-3 M of Tetin was instilled using the method described above.
Figure 5b shows the electroencephalogram when 10 ^-3 M was instilled. In the figure, the arrow indicates the time point at which the test liquid was dropped. Thus, it can be seen that at a concentration of 10 ^-3 M, tettin and glutamine have similar stimulating effects. Next, use the method described above to extract Tetin.
Figure 6a shows the brain waves when 10 ^-6 M of glutamine was instilled, and Figure 6b shows the brain waves when 10 ^-6 M of glutamine was instilled. Thus, it can be seen that at 10 ^-6 M, the stimulatory effect of Tetin hardly changes, whereas the stimulatory effect of glutamine sharply decreases.
Therefore, even in extremely small amounts, tetin has the effect of stimulating the olfactory tract of fish, and can be said to be an epoch-making substance as a feeding stimulant. "Effects of the Invention" As explained above, according to the present invention, Tetin is used as a feeding stimulant, and by adding it to various feeds, it stimulates the sense of smell and taste of fish, and improves the feed quality. Feed efficiency can be increased by feeding them. In addition, glutamine, which has been attracting attention for a long time, loses its additive effect as it becomes more nutritious feed.
The effects of adding Tetin to simple synthetic feeds, semi-natural feeds, and completely natural feeds are clear. Furthermore, since the optimum effect can be obtained when the amount of Tetin added to the feed is approximately 10 ^-3 M, it is thought that the cost increase due to addition to the feed is also small. Therefore, the present invention aims at adding Tetin to live baits and fishmeal-containing feeds that have been used up until now to further increase their feed efficiency, and to improve part or all of the feed compositions that have been used up to now. Furthermore, it can be used to replace low-cost synthetic or natural products and improve poor intake by adding Tetin, and new developments in the aquaculture industry can be expected.

[Brief explanation of the drawing]

Figure 1 is a schematic explanatory diagram of the apparatus used in experiments on the feeding stimulation effects of various substances, Figure 2 is a schematic diagram showing the experimental apparatus used to measure the olfactory brain waves of fish, and Figure 3 is a schematic diagram of the apparatus. Fig. 4 is an enlarged view of the main part showing the details of the above experimental method, Fig. 5 a is a chart showing the brain waves when 10 ^-3 M of Tetin was dropped in the above experiment, and Fig. 5 b is the above experiment. Figure 6a is a chart showing the brain waves when 10 ^-3 M of glutamine was added in the above experiment, Figure 6b is a chart showing the brain waves when 10 ^-6 M of glutamine was added in the above experiment, and Figure 6b is a chart showing the brain waves when 10 -3 M of glutamine was added in the above experiment. This is a chart showing the brain waves when ^-6M was instilled.

Claims (1)

[Scope of Claims] 1. A feeding stimulant for fish characterized by comprising β-dimethylpropiotetin and/or a salt thereof represented by the following structural formula. 2. A fish feed characterized by adding β-dimethylpropiotetin and/or a salt thereof represented by the following structural formula. 3. The fish feed according to claim 2, which is obtained by kneading a solution containing 10 ^-9 to 1M of the β-dimethylpropiotetin.