A method for improving the quantity of eggs obtained in artificial breeding of horseface fish

Abstract

The application discloses an artificial breeding and ovum collecting method of horseface fish, which can improve the quantity of obtained eggs, and the difference from the prior art is that the female fish without squeezed eggs is placed in a pool with water temperature of 18-20 DEG C for temporary breeding for 5-7 hours, taken out and placed in water with water temperature of 0-0.5 DEG C for 3-5 minutes, and then the female fish without squeezed eggs is subjected to second artificial egg squeezing and the egg grains are collected, the success rate of the second artificial egg squeezing can reach more than 95%, compared with the prior art of one-time egg squeezing, the quantity of obtained eggs can be improved by more than 20%, that is, the rate of inducing spawning is improved, and thus the quantity of fertilized eggs, the fertilization rate, the hatching rate and the total number of water flowers are improved.

Description

Technical Field

[0001] This invention belongs to the field of artificial breeding of chub, and particularly relates to a method for obtaining eggs from chub through artificial breeding that can increase the egg yield. Background Technology

[0002] Mackerel Opsariichthys bidens Commonly known as horse chub, horse mackerel, peach blossom fish, or bigmouth mackerel, it belongs to the order Cypriniformes, family Cyprinidae, and genus Cypriniformes. Opsariichthys This is a small, carnivorous fish found in lakes, reservoirs, and rivers. Its flesh is tender and delicious, and it exhibits breeding coloration during the breeding season and is easily hooked, making it economically valuable. However, overfishing in recent years has led to a sharp decline in its natural resources. To protect its species and develop the distinctive economy of mountainous areas, large-scale artificial breeding programs have been implemented.

[0003] The current artificial breeding method involves selecting mature female and male fish as parent fish in late spring and early summer when the water temperature is stable above 17.0℃. The ratio of female to male parent fish should be 1-3:1. Female fish should be selected with a large and soft abdomen, obvious ovarian outline, and slightly red genital opening. Male fish should be selected with bright breeding colors, obvious tubercles on the snout, upper and lower jaws, lower eye socket, gill cover, lateral and posterior parts of the body, and caudal peduncle. When the abdomen is gently pressed, milky white semen will flow out and disperse quickly in the water. Female fish were placed in a temporary holding tank and given two injections of medication to induce spawning, with a 24-hour interval between the first and second injections. Each injection consisted of 0.5 mL of medication per fish. The dosage for the first injection was 3 μg / kg of luteinizing hormone-releasing hormone analog 2 (LHRH-A2), and the dosage for the second injection was 4-6 μg / kg of luteinizing hormone-releasing hormone analog 2 (LHRH-A2), 4-8 mg / kg of domperidone maleate (DOM), and 1500-2000 IU / kg of human chorionic gonadotropin (HCG). Male fish were given an injection of medication to induce spawning at the time of the second injection, with the dosage being half of the total dosage for the female fish. Within 18 to 20 hours after the second injection of induced spawning medication, the female fish should have her eggs squeezed and collected, along with the sperm. Mature eggs and sperm should be squeezed simultaneously into a container of clean water at an egg-to-water ratio of 1:50-1:100. Stir with a feather for 1-2 minutes, then rinse 3-5 times in clean water to remove impurities. Finally, incubate the fish in hatching tanks (or incubation baskets) with a volume of 0.5-1 cubic meters. 3 300,000-500,000 grains / m 3The water level in the hatching tank (or container) should be controlled 1-2 cm above the bottom of the filter screen. The water flow should be sufficient to stir up the eggs and distribute them relatively evenly. The filter screen should be frequently washed during hatching. Hatching should be carried out for 60-70 hours at a water temperature of 18-20℃. At a water temperature of 19-20℃, after 5-6 days of hatching, the fry's body color gradually changes from transparent to grayish-black. When more than half of the yolk sac has been absorbed and the digestive tract is open, they can be released into the pond.

[0004] The aforementioned artificial breeding method involves first squeezing the eggs from the female fish 18 to 20 hours after the second injection of spawning-inducing drugs. Typically, only about 80% of the parent fish release eggs and have them squeezed out during this period, while the remaining 20% ​​do not release eggs, meaning no eggs are squeezed out. When the effects of the spawning-inducing drugs end, most of the remaining 20% ​​still cannot have their eggs squeezed out; only a very small number are squeezed out. Therefore, the existing artificial breeding method suffers from low spawning rates and low egg yields, directly reducing the number of fertilized eggs and the total number of fry, becoming a bottleneck limiting the artificial breeding of chub. Summary of the Invention

[0005] The present invention aims to solve the aforementioned technical problems existing in the prior art and provides a method for artificial breeding and egg collection of chub that can increase the egg yield.

[0006] The technical solution of this invention is: a method for artificial breeding and egg collection of chub that can improve the egg yield, which is carried out in the following steps:

[0007] Step 1. Select female fish with mature gonads and temporarily raise them in a pond with a water temperature of 18-20℃;

[0008] Step 2. Induce spawning in the female fish twice with a 24-hour interval between the first and second injections. Each injection is 0.5 mL per fish.

[0009] The dosage of the first injection was 3 μg / kg fish of luteinizing hormone-releasing hormone analog No. 2;

[0010] The dosage of the second injection was 4-6 μg / kg fish of luteinizing hormone-releasing hormone analog 2, 4-8 mg / kg fish of dioxone maleate, and 1500-2000 IU / kg fish of human chorionic gonadotropin.

[0011] Step 3. Within 18-20 hours after the second injection, perform the first artificial egg extraction on the female fish and collect the eggs. After that, place the female fish with extracted eggs in a pond with a water temperature of 18-20℃ for postpartum recovery, and place the female fish without extracted eggs in another pond with a water temperature of 18-20℃ for temporary rearing.

[0012] Step 4. Take out the female fish that have not had their eggs extracted after being temporarily kept for 5-7 hours and place them in water at 0-0.5℃ for 3-5 minutes. Then, perform a second artificial egg extraction on the female fish that have not had their eggs extracted and collect the eggs.

[0013] The difference between this invention and the prior art is that the female fish that have not yet had their eggs squeezed out are temporarily kept in a pond at a water temperature of 18-20℃ for 5-7 hours, and then taken out and placed in water at 0-0.5℃ for 3-5 minutes. Then, the female fish that have not yet had their eggs squeezed out are subjected to a second artificial egg squeezing and the eggs are collected. The success rate of the second artificial egg squeezing can reach more than 95%. Compared with the existing technology, the number of eggs obtained can be increased by more than 20% compared with the single egg squeezing, that is, the spawning rate is increased, thereby increasing the number of fertilized eggs, fertilization rate, hatching rate and total number of fry. Detailed Implementation

[0014] The present invention provides a method for artificial breeding and egg collection of chub that can increase the egg yield, comprising the following steps:

[0015] Step 1. Select female fish with a swollen and soft abdomen, obvious ovarian outline and slightly red genital opening, and temporarily keep them in a pond with a water temperature of 18-20℃.

[0016] Step 2. Induce spawning in the female fish twice with a 24-hour interval between the first and second injections. Each injection is 0.5 mL per fish.

[0017] The dosage of the first injection was 3 μg / kg fish of luteinizing hormone-releasing hormone analog No. 2;

[0018] The second injection consisted of luteinizing hormone-releasing hormone analogue No. 2 at 5 μg / kg fish, dioxone maleate at 6 mg / kg fish, and human chorionic gonadotropin at 1800 IU / kg fish.

[0019] Step 3. Within 18-20 hours after the second injection, perform the first artificial egg extraction on the female fish and collect the eggs. That is, squeeze the eggs directly into a container filled with clean water for artificial insemination. After that, place the female fish with the extracted eggs in a pond with a water temperature of 18-20℃ for postpartum recovery. Place the female fish without extracted eggs in another pond with a water temperature of 18-20℃ for temporary rearing.

[0020] Step 4. Take out the female fish that have not had their eggs extracted after 6 hours of temporary rearing and place them in water at 0-0.5℃ for 4 minutes. Then, perform a second artificial egg extraction on the female fish that have not had their eggs extracted and collect the eggs for artificial insemination.

[0021] This invention conducted three batches of artificial breeding experiments on chub at a fish farm in Liaoyang County. The first and second batches were basically bred using existing techniques, except that after the first artificial egg extraction, the females that did not produce eggs were temporarily kept in a pond at 18-20℃ for 6 hours before the second egg extraction. The third batch, except for the two egg extractions performed according to the method described in this invention, followed the same procedures as existing techniques for egg collection, male spawning induction, artificial insemination, hatching, and stocking. The experimental batches and results are shown in Table 1.

[0022] Table 1

[0023]

[0024] As shown in Table 1, the first batch did not yield any eggs during the second artificial egg-collecting process, and the second batch only yielded a small number of eggs during the second artificial egg-collecting process, with a spawning rate of only 0.5%. In contrast, the third batch, using the method of this invention, yielded an additional 1.8 kg of eggs during two egg-collecting processes, increasing the egg yield by 21.2%. The spawning rate of the additional eggs reached 98%, the fertilization rate reached 45%, the hatching rate reached over 85%, and the total number of fry increased by 170,000.

Claims

1. A method for improving the number of eggs obtained in artificial reproduction of Ophiocephalus punctatus, characterized by Follow these steps in sequence: Step 1. Select female fish with mature gonads and temporarily raise them in a cement pond with a water temperature of 18-20℃; Step 2. Induce spawning in the female fish twice with a 24-hour interval between the first and second injections. Each injection is 0.5 mL per fish. The initial injection dose was 3 μg / kg of luteinizing hormone-releasing hormone analogue No. 2; The second injection consisted of luteinizing hormone-releasing hormone analog 2 at 5 μg / kg, dioxone maleate at 6 mg / kg fish, and human chorionic gonadotropin at 1800 IU / kg. Step 3. Within 18-20 hours after the second injection, perform the first artificial egg extraction on the female fish and collect the eggs. After that, place the female fish with extracted eggs in a pond with a water temperature of 18-20℃ for postpartum recovery. Place the female fish without extracted eggs in another cement pond with a water temperature of 18-20℃ for temporary rearing. Step 4. Take out the female fish that have not had their eggs extracted after 6 hours of temporary rearing and place them in water at 0-0.5℃ for 4 minutes. Then, perform a second artificial egg extraction on the female fish that have not had their eggs extracted and collect the eggs.

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