Artificial fish nest and phoxinus lagowskii large-scale breeding method

Abstract

The invention belongs to a freshwater fish breeding technology, and particularly relates to a phoxinus lagowskii large-scale breeding method which sequentially comprises the following steps of parent selection, parent breeding, artificial spawning induction, artificial insemination and juvenile fish hatching. Injecting a spawning induction agent, which is composed of 500-1000 IU of chorionic gonadotropin (HCG) per kilogram of fish body weight, 5-10 micrograms of luteinizing hormone releasing hormone analogue (LRH-A2) per kilogram of fish body weight and 1-2 mg / kg of domperidone (DOM) per kilogram of fish body weight, into the bred parent from pelvic fins; the injection dosage of the parent female fish is two times that of the parent male fish. The method solves the problems that phoxinus lagowskii parents are asynchronous in gonad development, do not lay eggs and are not concentrated in egg laying, the induced spawning rate is increased to 98% or above, and meanwhile the production time is shortened. By means of manufacturing and using the artificial fish nest, the natural hatching state of phoxinus lagowskii roes is simulated, damage to the roes in the debonding process is reduced, and the fertilization rate and hatching rate of the roes are increased to 96.8% and 92.1% respectively.

Description

Technical Field

[0001] The invention belongs to freshwater fish breeding technology, and in particular relates to an artificial fish nest and a large-scale breeding method for Gnaphalium ragworm. Background Art

[0002] Phoxinus lagowskii is popular among consumers for its delicious meat, high protein and unsaturated fatty acid content, and lack of intramuscular spines. It is also a small economic fish with broad breeding prospects due to its omnivorous diet, strong disease resistance, and wide adaptability. Under natural conditions, due to the poor synchronization of the gonadal development of the parents of Phoxinus lagowskii, the mating and spawning of the parents are seriously asynchronous, which is not conducive to large-scale breeding. In addition, Phoxinus lagowskii lays sticky eggs, and the sticky substances on the surface of the egg membrane can make the eggs adhere to the substrate or stick to each other in the water, which puts higher requirements on artificial insemination and hatching technology. In traditional technology, the fertilized eggs of Phoxinus lagowskii are mostly hatched by physical debonding and then placed in hatching buckets for hatching, which is a cumbersome process.

[0003] Patent CN1202708C discloses a method for artificial breeding of yellow catfish on a large scale, in which fertilized eggs are placed in flowing water for incubation in a fish nest made of a 60-80 mesh cage. This method may cause the fertilized eggs to fall off and be washed away due to the different viscosity of the egg shells of different fish. Summary of the invention

[0004] In view of the above technical problems, the technical solutions of the present invention include the following aspects: First, an artificial fish nest is proposed, comprising a rigid frame and a 40-mesh screen mesh, wherein the edge of the screen mesh is fixedly connected to the inner wall of the rigid frame and stretched into a sheet.

[0005] Secondly, a method for inducing spawning of shearwater fish is proposed, in which the selected parents are injected through the pelvic fin with an oxytocin consisting of 500-1000 IU / kg fish body weight of human chorionic gonadotropin (HCG), 5-10 μg / kg fish body weight of luteinizing hormone releasing hormone analog (LRH-A2) and 1-2 mg / kg fish body weight of diometron (DOM); the injection dose for female parents is twice that for male parents.

[0006] On the third aspect, a method for large-scale breeding of G. lamarckii is proposed, comprising the following sequence: a parent selection step, a parent cultivation step, an artificial induction step, an artificial insemination step, and a fry hatching step, wherein the artificial insemination step and the fry hatching step are completed using the above-mentioned artificial fish nest; and the artificial induction step is carried out using the above-mentioned G. lamarckii induction method.

[0007] The invention solves the problems of asynchronous gonad development, non-spawning and non-centralized spawning of the parents of the Lagosaurus, increases the induced spawning rate to more than 98%, and shortens the production time. The production and use of the artificial fish nest simulates the natural hatching state of the Lagosaurus eggs, reduces the damage to the eggs during the debonding process, and increases the fertilization rate and hatching rate of the eggs to 96.8% and 92.1% respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 : A schematic diagram of the structure of an artificial fish nest according to an embodiment;

[0009] Figure 2 : A flow chart of a method for large-scale breeding of Pseudochelys lamarckianus according to an embodiment of the present invention. DETAILED DESCRIPTION

[0010] Phoxinus lagowskii is classified as belonging to the Cypriniformes, Cyprinidae, Leucophaga subfamily, and Phoxinus genus. Its common names include Liugenchi, Liugenchui, Liugenzi, Liugen, and Liuyu. Its natural waters are mainly distributed in the Heilongjiang River, Tumen River, Liaohe River, Yellow River, and tributaries of the middle and upper reaches of the Yangtze River in my country. Phoxinus lagowskii has delicious meat, high protein and unsaturated fatty acid content, and no intramuscular spines. It is popular among consumers. It has a variety of diets, strong disease resistance, and a wide range of adaptability. It is suitable for large-scale breeding and is a small economic fish with broad breeding prospects. The principle of the physical debonding method of fertilized eggs of Phoxinus lagowskii in the prior art is to use mechanical vibration and friction to remove sticky substances on the surface of the eggs. Improper operation will damage the fertilized eggs, and pathogens will breed in large numbers, resulting in a reduced hatching rate.

[0011] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and substance of the present invention, modifications or substitutions made to the methods, steps or conditions of the present invention all fall within the scope of the present invention.

[0012] The artificial fish nest of some embodiments is as follows Figure 1 , a rigid frame and a 40-mesh screen mesh, the edge of the screen mesh and the inner wall of the rigid frame are fixedly connected to form a sheet.

[0013] Some embodiments involve a method for inducing spawning of sea bream, which specifically includes: injecting a proctocolytic agent consisting of 500-1000 IU / kg fish body weight of human chorionic gonadotropin (HCG), 5-10 μg / kg fish body weight of luteinizing hormone releasing hormone analog (LRH-A2) and 1-2 mg / kg fish body weight of diometron (DOM) into the pelvic fins of selected parents; the injection dose of female parent fish is twice that of male parent fish.

[0014] An implementation method for large-scale breeding of G. lamarckii based on the above implementation method includes the following sequence: a parent selection step, a parent cultivation step, an artificial induction of labor step, an artificial insemination step, and a fry hatching step, wherein the artificial insemination step and the fry hatching step are completed using the artificial fish nest of the above embodiment; and the artificial induction of labor step is carried out using the G. lamarckii induction method of the above implementation method.

[0015] Example 1 Ovulation Induction of Porphyra serrata

[0016] 500 broodstock (females are selected from commercial fish individuals that have been cultured for more than 3 winters and weigh more than 100g; males are selected from commercial fish individuals that have been cultured for more than 2 winters and weigh more than 30g; other embodiments can be selected from sexually mature parents according to the general experience of those skilled in the art) after induced spawning by the following method, with a female-to-male ratio of 300:200, after the following induced spawning steps, continue the later breeding steps including artificial insemination and hatching of young fish. After the above steps are completed, the hatching rate is calculated.

[0017] Each female parent was injected with the following oxytocin via the pelvic fin: 1000 IU / kg fish body weight of human chorionic gonadotropin (HCG), 10 μg / kg fish body weight of luteinizing hormone-releasing hormone analog (LRH-A2), and 2 mg / kg fish body weight of dioic acid (DOM);

[0018] Each male parent was injected with the following oxytocin via the pelvic fin: 500 IU / kg fish body weight of human chorionic gonadotropin (HCG), 5 μg / kg fish body weight of luteinizing hormone releasing hormone analog (LRH-A2) and 1 mg / kg fish body weight of diometron (DOM).

[0019] The effect of Example 1 can be achieved: the induced spawning of the parents can be completed in 4-6 days, and the induced spawning rate is increased to more than 98%. In addition, those skilled in the art unexpectedly found that the female fish after induced spawning in Example 1 has an increased food intake and better adaptability to fish bait; and the parent is slightly injured and can heal quickly, and the probability of parasitic diseases such as wheelworms and Ichthyophthirius and bacterial infection is greatly reduced, and the postpartum survival rate of the parent is as high as more than 97%.

[0020] This embodiment solves the problem of asynchronous gonad development and unconcentrated spawning of the parents of the mullet under natural conditions, and meets the needs of large-scale seed production.

[0021] Example 2

[0022] Based on the above embodiments, some embodiments involve a large-scale artificial propagation method of Pseudochelys lamarckii, the steps are as follows: Figure 2 , including 6 steps of artificial fish nest making, parent selection, parent cultivation, artificial induction of labor, artificial insemination, and hatching of young fish.

[0023] (1) Making artificial fish nests

[0024] Steel bars with a diameter of 0.5 cm are welded into a "day" - shaped frame, with the frame being 1.2 m long and 0.6 m wide; on one side of the frame, a screen silk net with a mesh size of 40 meshes is fixed.

[0025] (2) Select parents

[0026] For females, select commercial fish individuals that have been cultured for more than 3 winter - ages and weigh more than 100 g; for males, select commercial fish individuals that have been cultured for more than 2 winter - ages and weigh more than 30 g.

[0027] (3) Parent cultivation

[0028] Separate male and female parents and cultivate them in an outdoor cement pond. The cultivation density is 20 - 30 tails / m²; the water temperature is 18 - 22 °C; cultivate with flowing water, and the daily water exchange rate is 500% - 1000%; oxygenate for 24 hours, and the dissolved oxygen content is not less than 5 mg / L; feed a formulated feed for carp fingerlings with a crude protein content of 35 - 40%, and the daily feeding amount is 2 - 3%. The cultivation lasts for 5 - 10 days.

[0029] (4) Artificial induced spawning

[0030] The induced - spawning drugs are human chorionic gonadotropin (HCG), luteinizing hormone - releasing hormone analogue (LRH - A2), and domperidone (DOM). Inject into the ventral fin, with a liquid volume of 0.2 mL. The drug dosage for female parents is HCG 1000 IU / kg fish body weight, LRH - A2 10 μg / kg fish body weight, and DOM 2 mg / kg fish body weight; the drug dosage for male parents is half of that for females.

[0031] (5) Artificial insemination

[0032] Two days later, select mature male and female parents for dry - method insemination. Wipe the body surface of the female parent dry with a dry towel, gently press both sides of the abdomen to squeeze the eggs into the egg - holding basin; then take the male parent, wipe the body surface dry, gently press both sides of the abdomen, and drip the semen onto the eggs. The male - female ratio is about 6 - 7:3 - 5; pour in a small amount of physiological saline and shake well to make the sperm and eggs fully mixed, and let it stand in a dark environment for 3 - 5 minutes.

[0033] Immerse the artificial fish nest 10 - 20 cm underwater. Add clear water to the fertilized eggs, shake well, and evenly sprinkle them onto the artificial fish nest. Each fish nest adheres to about 50,000 - 100,000 fish eggs.

[0034] (6) Incubate fry

[0035] Place the artificial fish nests with attached fish eggs in the hatching pond for hatching, with 2-4 fish nests / m2. Micro-aeration is carried out continuously for 24 hours, and the dissolved oxygen content is greater than 5mg / L. Micro-flow water is used for hatching, and the daily water change volume is about 200-300%. The hatching water temperature is 18-20℃, and the fry will hatch after 4-5 days. During the hatching period, formalin (formaldehyde 36%-40%) is sprayed once in the morning and afternoon every day to prevent water mold, with a concentration of 50ppm.

[0036] The use of the artificial fish nest in Example 2 effectively simulates the natural hatching state of the eggs of the herring, reduces the damage to the eggs during the debonding process, and increases the fertilization rate and hatching rate of the eggs to 96.8% and 92.1% respectively, making the production operation simple and convenient.

[0037] In some other preferred embodiments, immature female parents are screened and injected with oxytocin drugs, with the dosage being the same as in step (4).

[0038] The preparation and use of the artificial fish nest in Example 2 simulates the natural hatching state of the eggs of the herring, improves the fertilization rate and hatching rate of the eggs, and at the same time reduces the debonding process of the fertilized eggs, thereby facilitating production operations.

[0039] Control trial 1

[0040] 500 broodstock were selected, with a male-female ratio of 300:200. Each selected female parent was injected with an oxytocin containing the following ingredients through the pelvic fin: 500 IU / kg of fish weight of chorionic gonadotropin (HCG), 5 μg / kg of fish weight of luteinizing hormone releasing hormone analog (LRH-A2) and 1.5 mg / kg of fish weight of dioconazole (DOM); each selected male parent was injected with an oxytocin containing the following ingredients through the pelvic fin: 300 IU / kg of fish weight of chorionic gonadotropin (HCG), 2 μg / kg of fish weight of luteinizing hormone releasing hormone analog (LRH-A2) and 0.5 mg / kg of fish weight of dioconazole (DOM). After the above induced spawning steps, artificial breeding was continued in the later stage according to the steps of artificial insemination and hatching of young fish in the later stage of Example 2. After the above steps were completed, the hatching rate was counted.

[0041] After the above-mentioned induction steps, it was found during the artificial insemination step that less than 50% of the female fish were mature parents, the fertilization rate and hatching rate of the eggs were only 85.4% and 79.6.1%, and 4-5 rounds of injections of oxytocin were required for the induction rate of the female parents to reach 80%.

[0042] Control trial 2

[0043] The artificial fish nest was a 1.2m long, 0.6m wide frame made of 0.5cm diameter steel bars welded together in a Japanese shape. It was fixed with a 30-mesh silk screen. The artificial fish nest was used for artificial insemination and hatching of young fish. The results showed that the fish eggs did not form a clumping mass and were easily dispersed by running water, affecting the fertilization and hatching rates.

[0044] Control trial 3

[0045] According to the artificial induction method of artificial breeding of largemouth black bass disclosed in the technical document with application number 202010919868.7, the induced labor of the Labrella gizzard mullet was carried out. According to the disclosed method, a mixture of 1500IU / mL of chorionic gonadotropin + 200μg / mL of luteinizing hormone releasing hormone analogue No. 2 + 10mg / mL of dioxin maleate was prepared respectively. 0.8ml of the above-mentioned induced labor mixture was injected for every 500g of female fish. The injection site was the inner side of the pelvic fin of the fish body, and the needle was inserted obliquely with a depth of 1cm. The male fish was injected with the above-mentioned induced labor mixture on the next day. The injection method was the same as that of the female fish, and the injection dosage was halved. After 2 rounds of induced labor, the induced labor rate of the Labrella gizzard mullet parents was 85%, and the fertilization rate of the fertilized eggs of the Labrella gizzard mullet was 75%.

[0046] Control experiment 4

[0047] The invention of the authorized patent CN1202708C discloses a method for artificial breeding of yellow catfish on a large scale. According to the composition and dosage of the oxytocin agent, 7% of the parents were found to have overmature gonads.

[0048] Although the present invention has been described in detail above by general description, specific implementation methods and experiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. An artificial fish nest, characterized in that: It includes a rigid frame and a 40-mesh silk screen. The edge of the silk screen is fixedly connected to the inner wall of the rigid frame, forming a sheet.

2. A method for inducing spawning of P. lamarckii, characterized in that: Inject the selected parents intraperitoneally with an oxytocic agent composed of chorionic gonadotropin (HCG) at 500 - 1000 IU / kg fish body weight, luteinizing hormone-releasing hormone analogue (LRH-A2) at 5 - 10 μg / kg fish body weight, and domperidone (DOM) at 1 - 2 mg / kg fish body weight; the injection dose for female parent fish is twice that of male parent fish.

3. A method for large-scale breeding of Pseudochelys lamarckii, characterized in that: It includes the following steps in sequence: the step of selecting parents, the step of cultivating parents, the step of artificial induced spawning, the step of artificial insemination, and the step of hatching fry. Among them, the artificial fish nest as claimed in claim 1 is used to complete the artificial insemination step and the fry hatching step; the artificial induced spawning method as claimed in claim 2 is used for the artificial induced spawning step.

4. The method for large-scale breeding of Pseudosphagnum larvae according to claim 3, wherein: The specific artificial insemination step includes: Screen mature parents with a male-female ratio of 6 - 7:3 - 5; Take the female parent, dry the body surface, and gently press both sides of its abdomen to squeeze the eggs into a container; Take the male parent, dry the body surface, and gently press both sides of the abdomen to drip the semen onto the eggs; Add normal saline to the container to fully mix the eggs and semen, and let it stand for 3 - 5 minutes in a light-proof environment to obtain fertilized eggs; Immerse the artificial fish nest 10 - 20 cm underwater, add the fertilized eggs to clear water and shake well, then evenly sprinkle them onto the artificial fish nest, and each fish nest adheres to about 50,000 - 100,000 fertilized eggs.

5. The large-scale breeding method of Pseudosphagnum larvae according to claim 4, characterized in that: It also includes the step of artificially inducing spawning of immature female parents again.

6. The large-scale breeding method of Pseudosphagnum larvae according to claim 5, characterized in that: The step of hatching young fish specifically comprises: placing artificial fish nests with fertilized eggs attached at a density of 2-4 pieces / m 2 Place them in a hatching pond for incubation, and maintain the following conditions during the incubation: 24 hours continuous micro-aeration, dissolved oxygen content greater than 5 mg / L, micro-flow water incubation, daily water replacement of about 200-300%, incubation water temperature of 18-20°C, and the incubation step lasts for 4-5 days before the fry are hatched.

7. The large-scale breeding method of Pseudosphagnum larvae according to claim 6, characterized in that: In the fry hatching step, the following disinfection steps are also included: Sprinkle formalin into the hatching pond once in the morning and once in the afternoon every day, each time at a volume fraction of 36% - 40% and a concentration of 50 ppm.

8. The large-scale breeding method of Pseudochelys lamarckii according to claim 3, characterized in that: In the step of selecting parents, female parent individuals of Phoxinus lagowskii Dybowski that have been cultured for more than 3 winter ages and weigh more than 100 g are selected; male parent individuals of Phoxinus lagowskii Dybowski that have been cultured for more than 2 winter ages and weigh more than 30 g are selected.

9. The large-scale breeding method of Pseudochelys lamarckii according to claim 3, characterized in that: The specific step of cultivating parents includes: separating male and female parents, cultivating them in an outdoor cement pond with a cultivation density of 20 - 30 tails / m²; the water temperature is 18 - 22 °C; cultivating with running water, and the daily water exchange rate is 500% - 1000%; aerating for 24 hours, and the dissolved oxygen content is not less than 5 mg / L; feeding a formulated feed for common carp fingerlings with a crude protein content of 35 - 40%, and the daily feeding amount is 2 - 3%. The cultivation lasts for 5 - 10 days.

10. The artificial fish nest according to claim 1, characterized in that: Its frame is a rectangular frame welded by steel bars with a diameter of 0.5 cm, with a frame length of 1.2 m and a width of 0.6 m.

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