JP2000279055A - Red sea bream with anti-iridovirus character and method for breeding/culturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a red sea bream belonging to a variety which has genetically acquired anti-iridovirus character, thereby having highly growable characteristics, highly resistant to diseases, and suitable for culture. SOLUTION: This red sea bream belongs to a variety which has genetically acquired anti-iridovirus character, or a variety which has been genetically created by concentrating anti-iridovirus character. This red sea bream is pref. bred/ cultured as a seed; furthermore, it is preferable that the spleen of red sea bream infected with iridovirus and attacked with the disease is homogenized, diluted with a HEM medium, filtered through a 450 μm-filter to afford a filtrate, which, in turn, injected into the peritoneal cavity of red sea breams to subject them to iridovirus attack test or the like, the individuals survived are then selected as breeding materials, which are then grown for a certain period, and excellent individuals are selected, thereby more excellent characters are selected to create the aimed red sea breams resistant to iridovirus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a red sea bream having an anti-iridovirus trait and a method of breeding the red sea bream using it as a seed. Red sea bream referred to in the present invention indicates red sea bream in general.

[0002]

2. Description of the Related Art Development of artificial seedling production technology has enabled artificial selection and breeding of red sea bream, and high-growth seedlings have been developed in some areas. However, in recent years, stable production has become difficult due to the occurrence of iridosis, etc., and aquaculture companies have hoped to develop more stable and excellent seeds and seedlings. However, since selection by crossing usually requires a long period of time for crossing over generations to establish a new variety, a new variety with fixed disease-resistant traits in red sea bream has not yet been established.

[0003]

In recent years, in the aquaculture industry, the damage caused by the irid virus has been enormous in various fish species including red sea bream, particularly in seeds and seedlings. Therefore, we aimed to create a strain resistant to the Iridovirus by passing the individuals survived by the Iridovirus attack in red sea bream. The variety of the disease-resistant trait of the present invention is a variety that can provide excellent seeds and seedlings at the farming site.

[0004]

SUMMARY OF THE INVENTION The gist of the present invention is a red sea bream belonging to a variety that has genetically acquired an anti-iridovirus trait. The red sea bream has high growth characteristics. Therefore, the present invention provides a red sea bream belonging to a variety that has genetically acquired an anti-iridovirus trait and has high growth characteristics. The present invention relates to varieties that are genetically produced by enriching anti-iridovirus traits, and thus the present invention belongs to varieties that have acquired genetically anti-iridovirus traits that were created by genetically enriching anti-iridovirus traits The main point is red sea bream. The present invention also provides a red sea bream that belongs to a variety that is genetically produced by concentrating an anti-iridovirus trait and that has a genetically acquired anti-iridovirus trait and that has high growth characteristics. Furthermore, the present invention provides a method for increasing and cultivating red sea bream using the above red sea bream as a seed and seedling.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION << Red sea bream iridovirus disease >> Thai breeding is the main fish species in the marine aquaculture industry after yellowtail. Bacterial diseases, parasitic diseases and the like are known as red sea bream diseases, but in recent years, the damage caused by iridovirus disease has become a serious problem. The disease first occurred on a farm in Shikoku during the summer and autumn of 1990, and caused the mass mortality of red sea bream. The disease ended spontaneously in November when the water temperature dropped to about 20 ° C. However, since 1991, the disease has been repeated at farms in western Japan mainly in the high water temperature season in summer. Histopathological examination of the diseased fish and observation by electron microscopy confirmed virus particles, and inoculation experiments with the grinded filtrate of the diseased fish showed the same lesions as spontaneous disease. It has been categorized into Iridoviridae mainly based on its morphological characteristics.

<< Iridvirus Strain >> The iridvirus strain used in the examples of the present invention is Nippon Fisheries Co., Ltd. Oita Marine Research Center (508-8 Ariakeura, Tsurumi-cho, Nankai-gun, Oita Prefecture).
The virus titer is 10 ^5.8 TCID ₅₀ /
diluted iridvirus stock solution (hereinafter, 1)
Speaking 0 ^4-fold dilutions or ^10-4 times the meaning the virus stock solution of 10 ⁴ fold dilution. ). The titer is 10 ^5.8 T
CID ₅₀ / ml means that the target virus solution is 10 ^5.8
The term "concentration at which cell degeneration can occur at a rate of 1/2 when diluted twice" is used. The iridovirus strain used in the present invention was obtained from cultured red sea bream, in which the iridovirus developed in the Kamae district of Oita Prefecture. The present inventors have confirmed by genetic diagnosis whether or not the diseased fish has been infected with the iridovirus. For the method of genetic diagnosis, see "Disease
ofAquatic Organisms 32: 87-90, 1998 "and" Analytical Biochemsitry 242, 15-19,
1996 "by the present inventors. The diseased red sea bream spleen was homogenized, diluted with MEM medium, and filtered through a 450 μm filter. This filtrate was used as a virus solution in the test.

<< Infectivity of Iridovirus to Red Sea Bream >> When the above-mentioned filtrate or virus culture solution is injected into the abdominal cavity of red sea bream, the feeding gradually becomes poor after 4 or 5 days.
Blackening, fading, threading, etc. of the body color are recognized, and the operation gradually becomes slower and dies. Even small fry tend to be more sensitive as they become smaller. In the dead fish, anemia of the gills and liver and swelling of the spleen are observed 3 to 4 days after the injection, as in the case of naturally occurring fish. The peak of evil death is 7 to 10 days after injection. The higher the water temperature, the shorter the number of lethal days, the higher the evil mortality rate, and no onset at 18 ° C. It almost coincides with the onset in nature.

<< Method of producing anti-iridovirus red sea bream >> (1) Acquisition of iridvirus strain, determination of injection timing, optimum concentration, etc. (2) Production of parent fish Selection and breeding of anti-iridovirus high-growth parent fish (3) Production of surviving red sea bream F1 The surviving individual is selected as a breeding material by subjecting it to an iridvirus attack test or the like. At this time, it is preferable to add more excellent traits by using a selection for selecting an individual having excellent growth for a certain period. (4) Evaluation of anti-iridoviral properties of the produced F1

<< High growth characteristics >> In aquaculture, the seeds and seedlings that grow fast grow in size in a short period of time.
It is an excellent property that enables direct improvement of aquaculture efficiency and large fish production. In the present invention, “high growth characteristics” is used in a broad sense in which high growth is promised by genetic factors and environmental factors. When a parent fish having high growth characteristics is selected as a parent fish for the production of disease-resistant F1, genetically greatly contributes to the enrichment of anti-iridovirus traits, it takes many years to establish new varieties by normal selection and crossing. It is considered that new varieties with fixed disease resistance traits were established without requiring crossing.

[0010] Seedling production is obtained by fertilized eggs by natural spawning in the aquarium of the parent fish or by artificial fertilization. The fertilized eggs are housed in a breeding aquarium, and given a biological feed such as rotifer, artemia, and an artificial compound feed according to the growth stage of the hatched fish, and reared and raised. For aquaculture production, breeding starts from fry (seed and seedlings). Red sea bream can be cultivated in onshore aquaculture facilities and marine cages. As a feed, fresh fish and mixed feed can be used. The breeding exploits the productivity of the environment, such as by the release of fry, to improve fishery production.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments. The present invention is not limited by these examples.

Example Production of anti-iridovirus red sea bream (1) Parent fish used for production of anti-iridovirus red sea bream Parent fish A group: A group of individuals that survived a plurality of iridvirus attack tests and were reared with parent fish. Parent fish B group: 5500 red sea bream juveniles (average weight 27.5
g) was attacked by the Iridovirus and survived 124
A group that has been trained with the tail as the parent fish. (2) Production of Irido-surviving red sea bream F1 A × A group: fry obtained by artificial insemination from females in parent fish group A and males in parent fish group A. A × B group: fry obtained by artificial insemination from females in parent fish group A and males in parent fish group B.

(3) Evaluation method In the same aquarium, a group of 25 test fish of 11 g to 15 g injected intraperitoneally with 10 ^-4 or 10 ^-6 times of iridovirus mixed with 25 fish not hit with virus The animals are reared and their survival rates are evaluated for resistance to iridvirus. That is, 50 μl of 10 ^5.8 TCID 50 / ml virus stock solution (10 ⁴ times dilution or 10 ⁶ times dilution) was weighed 11 to 1
5 g of the above-mentioned two test plots F1 were injected into the abdominal cavity, and non-poured fishes of the same test plot were further mixed and bred, and the survival rate of each control group obtained from a normal parent fish (11- 15g). In the present embodiment, infection of a virus-cast fish is called primary infection, and infection of a non-cast fish is called secondary infection. Such infection test systems do not generally exist,
The terms primary infection and secondary infection are defined in this example. (4) Results The final survival rate values are shown in Table 1, and the changes in the survival rates are shown in FIG. 1 for the 10 ^-4 dilution of the virus solution and in FIG. 2 for the 10 ^-6 dilution. The survival rates of the A × A group and the A × B group, which were produced using the surviving fish of the iridvirus as a parent, were higher in the primary infection and the secondary infection at 10 ⁻⁴ dilution than in the control group. In addition, the peak of death tended to be later than the control group in both the A × A group and the A × B group.

[0014]

[Table 1] Survival rate (%) in each test area ─────────────────────────────── Attack Conditions Control group A × A group A × B group １０10 ⁴ times dilution (pour Fish) 9.1 48 31.8 (Unpoured fish) 32 64 45 10 ^6- fold diluted solution (Poured fish) 10.5 36 22.7 (Non-poured fish) 48 6861.9 ───────────────────────────

[0015]

Industrial Applicability According to the present invention, a line that has resistance to the iridvirus has been created by continuing the individuals that survived the attack by the iridvirus in red sea bream.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a drawing showing a change in a survival rate of a virus liquid 10 ^-4 dilution group.

FIG. 2 is a drawing showing the transition of the survival rate of a virus solution 10 ⁻⁶ dilution.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tokutaka Hirasawa 508-8 Ariakeura, Tsurumi-cho, Nankai-be-gun, Oita Japan Inside the Oita Marine Research Center, Japan Fisheries Co., Ltd. (72) Shun-ichiro Oshima, Ariake-ura, Tsurumi-cho, Oita 508-8 Nippon Fisheries Co., Ltd. Oita Ocean Research Center (72) Inventor Toru Samsung 508-8 Nippon Fisheries Co., Ltd. Oita Ocean Research Center (72) Inventor Kazuhiko Hata Oita Prefecture 508-8 Ariakeura, Tsurumi-cho, Nankai-bu Nippon Fisheries Co., Ltd. Oita Marine Research Center F-term (reference) 2B104 AA01 BA08

Claims (4)

[Claims] 1. A red sea bream belonging to a variety that has genetically acquired an anti-iridovirus trait. 2. The red sea bream of claim 1 having high growth characteristics. 3. The red sea bream according to claim 1, which is a cultivar produced by genetically concentrating an anti-iridovirus trait. 4. A method for breeding red sea bream using the red sea bream of claim 1, 2 or 3 as a seedling.