JP2007074977A - Method for cultivating fish - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cultivating fish, capable of most simply and efficiently cultivating the healthy fish. <P>SOLUTION: This method for cultivating the fish comprises feeding the cultivated fish with fodder containing Bacillus natto in an amount of 1×10<SP>5</SP>to 1×10<SP>8</SP>counts per g, periodically measuring a number of the Bacillus natto in an enteral residual substance of the fish, and controlling a feeding amount of the fodder containing the Bacillus natto and feeding timing, so that the number of the Bacillus natto in the enteral residual substance of the fish is regulated in a range of 5×10<SP>4</SP>to 5×10<SP>6</SP>counts per g of the enteral residual substance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for culturing fish, and more particularly to a method for culturing fish that feeds food containing natto bacteria. More specifically, by feeding the cultured fish with a natto germ count-specific feed, measuring the natto germ count in the intestinal residue of the fish, and managing the feed amount and timing of the feed containing natto germs, The present invention relates to a fish culture method characterized by controlling the number of natto bacteria in the intestinal residue of fish to a specific range.

  Here, the intestinal residue is digested material remaining in the intestine, or so-called feces that are not excreted from the body as a substance during digestion.

  In addition, Bacillus natto is a type of Bacillus, and a representative type is Bacillus Subcilus Natto. In the present invention, bacteria derived from intestinal residues that survived heat treatment at 60 ° C. for 20 minutes were designated as natto bacteria. In measuring the number of Bacillus natto in the intestinal residue of fish, other miscellaneous bacteria (such as Escherichia coli) can be excluded from the measured value by performing the heat treatment utilizing the heat resistance of Bacillus natto.

  Since Bacillus subtilis containing Bacillus natto is also present in the natural environment, when the fish ingests food in the natural environment, the intestinal residue of the fish contains natto bacillus derived from the feed that is fed. In addition, there are Bacillus subtilis derived from the natural environment.

  Therefore, when measuring the number of Bacillus natto in the intestinal residue of fish, the number of Bacillus natto derived from food and the Bacillus subtilis derived from the natural environment were combined to obtain the number of Bacillus natto.

  Bacillus natto, which is the same as Bacillus subtilis, is known to alleviate various obstacles caused by indigestion, and various feeds and livestock feeds to which Bacillus natto is added have been proposed.

For example, in Patent Document 1, after Bacillus natto is cultured in a medium and sugar is consumed, it is vacuum-dried to obtain a Bacillus natto culture, and this dried Bacillus natto culture is mixed with commercial bait and fed. An invention of construction is disclosed.
JP 51-39295 A

Patent Document 2 discloses that crushed pressed dried soybean cake is fumigated for a predetermined time, allowed to cool, put natto bacteria therein, fermented for a prescribed time, and dried to obtain gravel-like soybean cake, and the obtained gravel Discloses an invention in which a powdery nutrient substance, an adhesive, and water are added to and mixed with a soybean meal.
JP-A-63-301757

Further, as feed for livestock, Patent Document 3 discloses a mixture of chitin and / or chitosan, Bacillus natto, and animal nutrition, and Patent Document 4 discloses a porous inorganic substance, a nutrient substance, and an effective microorganism. An invention is disclosed that mixes with organic substances that have propagated bacterial cells, stimulates the gastrointestinal wall with porous inorganic substances to stimulate peristalsis, and absorbs the gas generated in the gastrointestinal tract to alleviate the malodor of the farm ing.
JP-A-11-32695 Japanese Patent Laid-Open No. 7-10216

Furthermore, Patent Literature 5, Patent Literature 6, and Patent Literature 7 disclose inventions in which natto bacteria are added to a feed and subjected to lactic acid fermentation to increase the absorption of nutrients in the feed.
JP-A-53-98280 JP-A-5-161457 JP-A-6-245711

Patent Document 8 describes an invention that uses mutant Bacillus natto with enhanced extracellular enzyme-producing ability of Bacillus natto as a feed additive to achieve a significant improvement in the body weight gain effect and digestibility. Yes.
JP 58-179439 A

  Further, in Patent Document 9 “Aquaculture fish feed containing Bacillus natto and a method for producing feed for cultured fish containing Bacillus natto”, the present inventors added the number of Bacillus natto added to the feed through an extremely simple production process. By specifying, the mortality rate (%) and the meat growth coefficient are further reduced as compared to the conventional feed, and the feed for cultured fish containing Bacillus natto, which quickly decomposes excreta and prevents aging of the fishing ground, and The manufacturing method is disclosed.

The content described in Patent Document 9 is a feed mainly composed of animal material and plant material, and 1 × 10 ^{6 to} 5 × 10 ⁶ natto bacteria are contained per 1 g of the feed. Animal feed and wheat flour and corn are produced by adding water to natto bacteria and activating them so that the water content of natto bacteria is 60 to 100%. Feed for cultured fish, characterized by being added to and mixed with a feed mainly composed of plant materials such as starch so that the number of natto bacteria per 1 g of the feed is 1 × 10 ^{6 to} 5 × 10 ⁶ It is.
JP 2003-52314 A

  However, these disclosures merely disclose the content of the bait, how to disperse the bait at the fish farming site, a specific method for managing the health of the fish, No aquaculture technique is disclosed. Therefore, in an actual aquaculture site, trial and error has been repeated every time.

  Accordingly, an object of the present invention is to provide a method for cultivating the simplest, efficient and healthy fish.

In order to solve the above-mentioned problems, the present invention firstly feeds a feed containing 1 × 10 ⁵ to 2 × 10 ⁸ Bacillus natto per gram, and periodically feeds natto in the intestinal residue of fish. By measuring the number of bacteria and controlling the feeding amount and feeding timing of the feed containing Bacillus natto, the number of Bacillus natto in the intestinal residue of fish is 5 × 10 ^{4 to} 5 × 10 ⁶ per 1 g of intestinal residue. It was set as the structure of the culture method of the fish controlled to a range.

  Second, the Bacillus natto is dried together with a medium containing soybeans grown with Bacillus natto to form a spore mixture, and water is added at a ratio of 0.6 to 10 parts by weight with respect to 1 part by weight of the spore mixture. Thereafter, germination was performed at 10 to 40 ° C. for 5 to 10 hours.

The present invention sets the water content of natto bacteria before adding to the bait to 60 to 100%, activates (germinates) the natto bacillus, and counts 1 × 10 ⁵ to 2 × 10 ⁸ natto bacteria per 1 g of bait. The effect of being able to provide healthy aquaculture fish that does not require drugs such as antibiotics in the diet, increases the digestion and absorption rate of the diet, increases the resistance to disease and decreases the mortality rate (%) is there.

  In addition, because of good digestion and absorption, the coefficient of meat increase (the amount of food (g) required to increase the average body weight of cultured fish by 1 g) is also low, that is, the effect that meat can be improved with a small amount of feeding. is there.

  By identifying the number of Bacillus natto in the intestinal residue of the cultured fish, the mortality rate (%) and the coefficient of meat increase are further reduced, the digestibility of the food is improved, and the excretion of the cultured fish in the water Degradation is fast and has the effect of making it possible to prevent aging of fishing grounds.

  Since the cost related to food can be kept low and the mortality rate can be reduced, a simple, low-cost and efficient aquaculture method is enabled.

In order to carry out the present invention, a feed containing 1 × 10 ⁵ to 2 × 10 ⁸ natto bacteria per gram is fed to the cultured fish, and the number of natto bacteria in the intestinal residue of the fish is measured periodically. By controlling the feeding amount and feeding timing of the feed containing natto bacteria, the number of natto bacteria in the intestinal residue of the fish is controlled in the range of 5 × 10 ^{4 to} 5 × 10 ⁶ per gram of intestinal residue. It was realized by doing.

  Hereinafter, a fish culture method according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing the results of aquaculture according to the fish culture method of the present invention.

  First, a method for preparing a bait containing Bacillus natto used in the aquaculture test will be described using the bait used in Test Example (1) -2 as an example.

The bait of Test Example (1) -2 was adjusted as follows. First, 400 g of Bacillus natto spore in a dry powder state of 2 × 10 ⁹ cells / g was dispersed in 1 to 2 liters of water and allowed to stand at room temperature for about 6 hours to activate the Bacillus natto. Next, the activated natto was added to 400 kg of mixed feed and kneaded in a kneader for about 10 minutes to obtain a bait.

  Activation here is germination of the spore cell which is a dormant state. Bacillus natto spores are inactive in a dry state, but are activated in several hours when the water content becomes 60% or more at a temperature near room temperature.

  In addition, the ratio of 0.6-10 weight part of water was favorable for the water content to add. Good results were obtained when the temperature under activity was in the range of 10 ° C to 40 ° C. The activation time is sufficient if it is about 5 to 10 hours.

  The Bacillus natto added to the bait is an R-9 bacterial species prepared by Nitto Kasei Kogyo Co., Ltd. (Shiga Prefecture), cultured in a medium containing soybean raw material and dried together with soybeans. The mixed feed used here is a mixture of 70-80% by weight of frozen sardines, mackerel, etc. and 20-30% by weight of Hamachi fry EP Special 1 (manufactured by Nisshin Marubeni Feed Co., Ltd.). .

  Moreover, as feed used for the feed, plant materials and animal materials were mainly used. Plant materials include wheat flour, corn starch, and yellow flour.

Thus, about 2 × 10 ⁶ Bacillus natto bacteria are included in the feed of Test Example (1) -2 adjusted in this way. Actual measured results natto number of bacteria, food 1g per 2.4 × 10 ⁶ pieces of Bacillus natto was detected. In addition, the measurement of the natto microbe number in a bait was performed by the method mentioned later by the agar plate culture method after performing the above-mentioned heat treatment.

  Since the number of Bacillus natto measured here is in good agreement with the calculated value, there are few Bacillus natto brought in from the mixed feed, and it seems that it is derived from Bacillus natto added almost entirely.

  In addition, the obtained bait has increased viscoelasticity due to flour gluten, corn gluten, etc. contained in EP Special No. 1 for Hamachi fry (manufactured by Nisshin Marubeni Feed Co., Ltd.), and is more viscous due to secretions of Bacillus natto. Join and have a good unity. Therefore, the bait formed in a spherical shape at the time of feeding by an air feeding machine is difficult to disperse even in seawater, can be efficiently fed to farmed fish, and the fishing ground is not easily polluted with the bait.

  Similarly, the number of Bacillus natto contained in 1 g of each test example shown in FIG. 1 <Table 1> and <Table 2> was adjusted.

  Here, <Table 1> in FIG. 1 shows the mortality rate (%) of the cultured fish when fed with a diet containing Bacillus natto at a predetermined concentration for 6 months, the meat growth coefficient, and natto per gram of intestinal residue. It is the table | surface which showed the number of bacteria.

  On the other hand, <Table 2> in FIG. 1 shows the mortality rate (%), growth coefficient, and intestinal residue of cultured fish when a diet containing a predetermined concentration of Bacillus natto for one month is fed in a stress environment. It is the table | surface which showed the natto microbe number per 1g.

The meat increase coefficient is the amount of feed (g) required to increase 1 g of fish meat per animal over a certain period, and can be easily obtained by the following equation (1). The thickness increase coefficient calculated | required according to Formula (1) means that digestion and absorption of the food were so favorable that the value was small. Therefore, the meat increase coefficient is an index of an effective aquaculture method.
Thickening factor = (total amount of feed (g) / average number of live cultured fish)
/ (Average fish weight (g) after aquaculture / measurement-average fish weight (g) at the start of aquaculture)
... Formula (1)

  In addition, the average number of surviving cultured fish was a simple average of the number of animals at the start of the cultivation and at the time of measurement. This approximation is valid only when the survival rate is 95% or higher (less than 5% mortality).

Further, the mortality rate (%) is the ratio (%) of the cultured fish that died in the cage and was calculated by the following equation (2). The smaller the value of the mortality rate (%) obtained according to the formula (2), the more healthy the growth is due to the effect of Bacillus natto. Therefore, the mortality rate (%) is an index of an effective aquaculture method.
Mortality rate (%) =
(Deaded cultured fish / total number of cultured fish that was sacrificed at the start of cultivation) x 100 (2)

  Next, an aquaculture test method using the fish culture method according to the present invention will be described. The farmed ginger used in this test is categorized by experiment.

  The separated cultured fish used in this test are separated from each other by about 200m or more so that the food used in each experimental example does not affect other fish farmed even if there is a tide flow. , Installed in a similar environment.

  The number of Bacillus natto bacteria in the intestinal residue of fish was determined by random sampling for each sacrifice (experimental example) on the 15th, 30th, 60th, 120th, and 180th days from the start of cultivation. The intestinal residue of cultured fish was used.

  Next, 10 intestinal residues were taken out in a sterile room, ground for 10 animals, and subjected to the above-mentioned measurement of the number of Bacillus natto in the intestinal residues.

  In addition, the number of Bacillus natto in 1 g of average intestinal residues in <Table 1> and <Table 2> is an average value on each measurement day.

  Here, the general measuring method of Bacillus natto will be described. A sample (here, natto bacteria in food or intestinal residue) dissolved or extracted in pure water and diluted is mixed with 1 ml agar plate medium and cultured. The number of colonies that occur after an appropriate time is counted with the naked eye, and the number of bacteria is identified as one colony originally growing from one fungus, and the original (here, (Natto bacteria in food or intestinal residue) is determined (Japan Food Analysis Association, supervised by the Ministry of Health and Welfare, “Guide for Food Sanitation Inspection.” In this test, bacteria other than Bacillus natto are excluded. The heat treatment was performed before dilution.

  Hereinafter, each test example will be specifically described. Since the present embodiment is an example conducted after a preliminary test which is not described, failure examples which are not worthy of description are omitted. In other words, the specifications of food necessary for controlling the number of intestinal natto bacteria in farmed fish, details of the increase or decrease in the number of natto bacteria contained in the food, etc. were kept to the minimum necessary description.

  The relationship between the number of feeding days per month and the feeding amount follows a normal method, and during the period when the average weight of the fish is 300 g or less, 8% of the body weight is fed every day, and when it exceeds 300 g, the weight increases by about 100 g. Every time, the weight was decreased by 1%, and after reaching 800 g, 2% feeding was continued. Therefore, at the time of the start of the culture in this test, the feed amount is 3% between 700 and 800 g, and if it exceeds 800 g, the feed amount is 2% of the total fish weight. The same applies to the following experimental examples.

Test Example (1) -1 feeds feed containing 1 × 10 ⁵ natto bacteria per gram to 6560 hamachi having an average weight of 780 g at the start of cultivation (May 20, 2004), During the six months from June 2004 to November 2004, the number of natto bacteria in the intestinal residue was measured once a month on the 15th day, and cultured based on the measurement results.

In Test Example (1) -2, feed containing 2 × 10 ⁶ natto bacteria per gram was fed to 7890 hamachi fish with an average weight of 780 g at the start of cultivation (May 20). The average body weight and the number of Bacillus natto in the intestinal residue were measured every 15th day and once a month.

In Test Example (1) -3, feed containing 2 × 10 ⁷ natto bacteria per gram was fed to 6950 hamachi fish with an average weight of 780 g at the start of cultivation (May 20). Over the previous 6 months, the average body weight and the number of natto bacteria in the intestinal residue were measured every 15th day and once a month.

In Test Example (1) -4, 1 × 10 ⁸ Bacillus natto per gram was fed to 6340 hamachi with an average weight of 780 g at the start of cultivation (May 20). The average body weight and the number of Bacillus natto in the intestinal residue were measured every 15th day and once a month.

  Test example (2) is a control group for comparison. Feed the feed under the same conditions as in Test Example (1) except that it does not contain Bacillus natto into 7780 hamachi fish with an average weight of 790 g at the start of cultivation (April 15) until November of the same year The average body weight and the number of Bacillus natto in the intestinal residue were measured every 15th day and once a month.

Test Example (3) -2 (By the way, Test Example (3) -1 is not described here. Test Example (3)-with similar conditions to facilitate comparison with Test Example (1) -2) 2), 2 × 10 ⁶ Bacillus natto per gram was fed to 6450 hamachi fish with an average weight of 880 g at the start of cultivation (May 20). Farmed for one month until the moon.

In Test Example (3) -3, feed containing 5 × 10 ⁶ natto bacteria per gram was fed to 6740 Hamachi with an average weight of 760 g at the start of cultivation (May 27, 2004). It was cultured for one month in June of the same year.

  In addition, in the sacrifices of Test Example (3) -2 and Test Example (3) -3, a water turbine that keeps flashing electric light at intervals of 5 minutes at night and stirs water that generates large noise is sacrificed. A total of 5 units were operated on the outside and center of the four corners. That is, a culture test under an external stress environment.

  Hereinafter, the test results when cultured for 6 months shown in Table 1 in FIG. 1 will be described.

Natto number of bacteria in Test Example (2) were a detection limit of 10 or less ^two / g. Test example (2) is a control group for comparison.

  Even after 6 months from the start of cultivation, natto bacteria are not detected in 1 g of the intestinal residue of Test Example (2). Therefore, in this test, the uptake of natto bacteria from the natural environment can be ignored. It can also be seen that there is no effect of the food fed between the individual sacrifices.

  Therefore, it can be said that the Bacillus natto detected in the other experimental examples is established in the intestines of the cultured fish.

Experimental example (1) -1 will be described. The sacrificial hamachi that was fed with 1 × 10 ⁵ natto bait per gram was compared to the hamat that was cultivated only in the bait that did not contain natto in experimental example (2). %) And the coefficient of increase in wall thickness were not significantly different, but slightly decreased. In addition, the mortality rate (%) of Experimental Example (1) -1 was 2.5%, and the thickness increase coefficient was 3.28. The number of natto bacteria in 1 g of the average intestinal residue at this time was 5 × 10 ⁴ .

Experimental example (1) -2 will be described. The sacrificial hamachi, which was fed with bait containing 2 × 10 ⁶ natto per gram, drastically reduced the mortality rate (%) and the coefficient of meat increase compared to the hamachi of the experimental example (2). did.

In addition, the mortality rate (%) of Experimental Example (1) -2 was 1.7%, and the coefficient of wall thickness was 3.21, which was the best result among the experimental examples. At this time, the number of natto bacteria in 1 g of the average intestinal residue was 5 × 10 ⁵ .

Experimental example (1) -3 will be described. Ginger hamachi fed with bait containing 2 × 10 ⁷ natto bacteria per gram has lower mortality (%) and meat growth coefficient than the hamachi of experimental example (2). However, although both the number of Bacillus natto in the feed fed from Experimental Example (1) -2 and the number of Bacillus natto colonized in the intestine are high, the effect does not reach Experimental Example (1) -2.

In addition, the mortality rate (%) of Experimental Example (1) -3 was 2.0%, and the thickness increase coefficient was 3.25. At this time, the number of natto bacteria in 1 g of the average intestinal residue was 2 × 10 ⁶ .

Experimental example (1) -4 will be described. The ginger hamachi fed with bait containing 2 × 10 ⁸ natto bacteria per gram had a slight decrease in both mortality (%) and meat growth coefficient compared to the hamachi in experimental example (2). However, it does not reach Experimental Example (1) -2 and further does not reach Experimental Example (1) -3.

In addition, the mortality rate (%) of Experimental Example (1) -4 was 2.4%, and the thickness increase coefficient was 3.38. At this time, the number of natto bacteria in 1 g of the average intestinal residue was 5 × 10 ⁶ .

  From the results of <Table 1> above, the number of Bacillus natto (units / g) in the feed to be fed first and the number of Bacillus natto (individuals / g) in the intestinal residue are slightly higher under certain conditions. However, if <Table 2> is added, the correlation is not necessarily maintained if the conditions change.

  Secondly, in order to improve the mortality rate (%) and the coefficient of meat increase, it is not necessary to give more cultured natto bacteria to cultured fish, and it has been found that there is an appropriate range.

The appropriate range is 1 × 10 ⁵ to 2 × 10 ⁸ per gram of bait as shown in Table 1 in FIG. 1, considering the effect and cost. More desirably, it is 2 × 10 ⁶ per 1 g of bait.

The number of Bacillus natto colonizing in the intestine is 5 × 10 ^{4 to} 5 × 10 ⁶ per 1 g of intestinal residue, and more desirably 5 × 10 ⁵ -2 × 10 ⁶ per 1 g of intestinal residue. is there.

  Hereinafter, the test results when cultured for one month in the stress environment shown in Table 2 in FIG. 1 will be described.

  Here, Experimental Example (1) -2 and Experimental Example (1) -3 are the experimental results of Experimental Example (1) -2 and Experimental Example (1) -3 one month after the start of cultivation in <Table 1>. is there. In other words, it is a culture method that does not give stress, and it is possible to see the effect of feeding bait containing Bacillus natto in a stress environment.

From the results of Experimental Example (1) -2 and Experimental Example (1) -3, the habit of a ginger fed with 2 × 10 ⁶ natto bacteria per gram and 2 × 10 ⁷ is 1 Until the month, the mortality rate (%) was close to zero.

Experimental example (3) -2 will be described. Experimental example (1) -2 in which ginger hamachi fed with bait containing 2 × 10 ⁶ natto bacteria per gram under the above stress environment was given bait having the same concentration of natto bacteria Compared with Hamachi, the mortality rate (%) and the wall-thickening factor are less than those of Experimental Example (1) -2.

In addition, the mortality rate (%) of Experimental Example (3) -2 is 0.9%, and the thickness increase coefficient is 3.55. The number of bacteria in 1 g of the average intestinal residue at this time was 1 × 10 ⁴ cells / g.

Therefore, even under a stress environment, even if the bait has an optimum concentration of Bacillus natto (2 × 10 ⁶ cells / g) for efficient aquaculture as shown in <Table 1> above, It was found that efficient cultivation is not possible when the number of Bacillus natto colonized within the plant is low.

  In other words, the effect on mortality (%) and the coefficient of increase in wall thickness depends on the number of Bacillus natto colonized in the intestine, and has a higher effect on more effective aquaculture than the number of Bacillus natto contained in the bait. Is shown. This seems to be due to a decrease in the amount of food in the cultured fish.

Experimental example (3) -2 will be described. In the above stress environment, ginger hamachi fed with a feed containing 5 × 10 ⁶ natto bacteria per gram was given a diet having a lower natto bacteria content (1)- Compared with Hamachi of No. 2, neither mortality (%) nor a wall-thickening factor is equivalent to Experimental example (1) -2.

In addition, the mortality rate (%) of Experimental Example (3) -3 is 1.2%, and the thickness increase coefficient is 3.46. At this time, the average number of bacteria in 1 g of intestinal distillate was 2 × 10 ⁴ .

Therefore, even if the number of Bacillus natto in 1 g of the fed food is within the expected value, the number of Bacillus natto in the intestinal residue of fish is 5 × 10 ⁴ to 1 g due to some cause such as stress and environmental factors. When it deviated from the range of 5 × 10 ⁶ (Test Example (3) -2, (3) -3), it was found that the cultured fish could not be efficiently cultivated.

  From this, it is necessary to change the aquaculture conditions under the stress environment, including feeding the feed containing higher concentrations of Bacillus natto, but it is preferable not to increase the amount of feeding, By improving the environment, the number of natto bacteria in the intestinal residue is kept at a favorable level.

  It is possible to determine whether or not there is a stress environment that adversely affects aquaculture (somewhat not noticed) by observing the number of Bacillus natto in the fish intestinal residue. For this reason, the effect of the present invention is great.

Therefore, from the results of <Table 1> and <Table 2> in FIG. 1, while measuring the number of natto bacteria in the intestinal residue of fish regularly, 1 × 10 ^{6 to} 5 × 10 ⁸ natto bacteria By controlling the feeding timing and feeding amount of the contained food, and by improving the stress environment, the number of Bacillus natto in the intestinal residue of the cultured fish is 5 × 10 ^{4 to} 5 × 10 ⁶ cells / g. By cultivating while managing, the simplest, efficient and healthy way to cultivate fish is realized.

In addition, although only aquaculture was explained here, the range of 1 × 10 ⁵ to 2 × 10 ⁸ per 1 g of bait, salmon, flounder, rockfish, amberjack, hiramasa, puffer fish, carp, eel and trout The feed is mainly made of plant material and animal material containing Bacillus natto, and the number of Bacillus natto per gram of fish intestinal residue is controlled to be in the range of 5 × 10 ^{4 to} 5 × 10 ^6. As with Hamachi, it increases the digestion and absorption rate of the feed, lowers the coefficient of increase in meat, increases the resistance to diseases and decreases the mortality rate (%), and requires drugs such as antibiotics in the feed The result is that we can provide healthy farmed fish that are not.

  In addition, the natto bacteria at this time were dried together with a medium in which natto bacteria were grown to form a spore mixture, and water was added at a ratio of 0.6 to 10 parts by weight with respect to 1 part by weight of the spore mixture. What was germinated by placing it at -40 ° C for 5-10 hours was used.

  Therefore, the present invention is not limited to hamachi but can be said to be a fish culture method that can be widely used in other seawater fish and freshwater fish culture methods.

It is a figure showing the culture result by the fish culture method which is this invention.

Claims (4)

A method for culturing fish, characterized by feeding a food containing Bacillus natto and controlling the number of Bacillus natto per gram of fish intestinal residue to be in the range of 5 × 10 ^{4 to} 5 × 10 ⁶ . The method for culturing fish according to claim 1, wherein the amount of Bacillus natto is in the range of 1 x 10 ⁵ to 2 x 10 ⁸ per gram of bait.   The method for cultivating fish according to claim 1 or 2, wherein the feed is mainly made of plant material and animal material. The Bacillus natto is dried together with the medium in which the Bacillus natto is grown to form a spore mixture, and after adding water at a ratio of 0.6 to 10 parts by weight with respect to 1 part by weight of the spore mixture, The method for culturing fish according to any one of claims 1 to 3, wherein the fish is germinated after 5 to 10 hours.

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