JP2006288234A - Disease-resistant rearing method for fry of marine fish - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop and provide a disease-resistant method for fry of marine fish affording consumers with sense of security by stabilizing fry production and reducing chemical agents used. <P>SOLUTION: The disease-resistant method for fry of marine fish comprises the following practice: in rearing the fry by an artificial fry-raising method, rearing water is subjected to low-saline treatment by adding fresh water, the resultant low-saline condition is maintained for a given period, and the fry thus raised is returned to the whole seawater; that is, in rearing the fry by an artificial fry-raising method, rearing water is subjected to diluted seawater treatment(low-saline treatment), and after the lapse of a given period, the fry thus raised is returned to the whole seawater. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an anti-pathological rearing method for larvae and juvenile fish in marine fish.

  Conventionally, oral administration of drugs has been generally used as a means of controlling diseases caused in the breeding of marine fish larvae by artificial seedling production methods. However, it has been difficult to control disease by this method for larvae before feeding artificial feed.

In addition, mortality in the larval stage is often caused by damage to epidermal cells, which is thought to be due to an increase in the number of unspecified bacteria, in addition to those caused by specific pathogenic organisms (parasites and bacteria). Therefore, in order to suppress the number of bacteria in the breeding aquarium, a chemical bath treatment with a drug is performed. For example, as in Patent Document 1.
JP-A-8-9821

  However, due to the revision of the Pharmaceutical Affairs Law, the use of marine drugs has been restricted, and this method can no longer be used. For this reason, it is necessary to improve the anti-disease properties of larvae and fish as disease control instead of drugs.

  Accordingly, the present invention is to develop and provide an anti-disease method for larvae and juvenile fish in marine fish that gives a sense of security to consumers by reducing fish seedling production and chemicals.

  By adjusting the salinity of the breeding water, it compensates for the decrease in the osmotic pressure control function caused by epidermal cell damage, suppresses energy consumption by controlling the osmotic pressure, and maintains the physiological function to prevent the disease. It is an anti-pathological rearing method for larvae and juvenile fish in marine fish that can be improved.

  Moreover, the present invention develops and provides an anti-pathological rearing method for larvae and juvenile fish in marine fish, which is a disease control alternative to drugs and is safe and can also protect the surrounding environment.

  According to the present invention, by adjusting the salinity concentration of the breeding water, it is possible to compensate for the decrease in the osmotic pressure adjustment function caused by the damage of the epidermis cells, and to suppress the energy consumption due to the osmotic pressure adjustment and to maintain the physiological function. It has extremely beneficial effects such as being able to improve anti-disease properties.

  Moreover, by implementing this invention, as shown in FIG. 1, the number of dead fishes becomes extremely small, and it becomes possible to reduce a chemical | medical agent. As a result, fish seedling production is stabilized, and there are effects such as giving the producers a sense of security and giving consumers a sense of security.

  Therefore, the present invention is characterized in that when breeding marine fish larvae and juveniles by the artificial seed production method, the breeding water is subjected to diluted seawater treatment (low salinity treatment), and after a certain period of time, it is returned to total seawater. It consists of an anti-pathological rearing method of larvae and juvenile fish in marine fish.

An embodiment of the present invention will be described in detail, but the present invention is not limited to this.
If it demonstrates based on Table 1, the experiment which dilute seawater treatment was performed about the fry of the onyokoze larva in the test area.
The observation time after the start of the test is 28 hours later.
When seawater was used for all breeding water, 38 of 40 fish died and the mortality rate was 95%.
When 2/3 seawater was used as breeding water, 5 out of 40 fish died and the mortality rate was 12.5%.
When 1/3 seawater was used as breeding water, 1 of 40 fish died and the mortality rate was 2.5%.

Next, as a control group, an experiment was conducted to dilute seawater treatment of healthy fish under the influence of salt treatment.
As shown in Table 2, the observation time after the start of the test is 24 hours later.
When seawater was used for all breeding water, 5 of 40 fish died and the mortality rate was 5%.
When 2/3 seawater was used as breeding water, 3 out of 40 fish died and the mortality rate was 7.5%. When 1/3 seawater was used as breeding water, 0 of 40 fish died and the mortality rate was 0%.

  In this way, the mortal death of Oniokose fry was reduced when the salinity concentration was adjusted to 1/3 seawater.

Next, as shown in Table 3, an experiment was performed when the seawater was replaced with seawater having a predetermined salinity at a time. The observation time after the start of the test is 14 hours later. And the following result was obtained.
When seawater was used for all breeding water, 30 of 40 fish died and the mortality rate was 75%.
When 1/3 seawater was used as breeding water, 5 out of 40 fish died and the mortality rate was 12.5%.

Furthermore, as shown in Table 4, an experiment was performed when adjusting to seawater with a predetermined salinity concentration over 2 hours. The observation time after the start of the test is 24 hours later. And the following result was obtained.
When seawater was replaced with 1/3 to 3/3 for breeding water, it was 0 out of 40 and the mortality rate was 0%.
When 1/3 seawater was used as breeding water, it was 0 out of 40 and the mortality rate was 0%.

  After the low salinity treatment (1/3 seawater) of the fried fish, it returned to the whole seawater.

  The present invention has industrial applicability in that it establishes and contributes to these disease control techniques, and establishes and contributes to fish culture methods based on these techniques.

It is a graph which shows one Example of this invention.

Claims (1)

  When breeding marine fish larvae by artificial seedling production method, low salinity treatment is performed by adding fresh water to the breeding water, and after maintaining the low salinity for a certain period, it is returned to the whole seawater How to breed.

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