Alkali-resistant grass carp strain breeding method

Abstract

The application provides a grass carp strain breeding method of alkali resistance, and belongs to the technical field of aquaculture. The application comprises the following steps: capturing wild parent fish in the breeding season of Xiaohaizi grass carp, self-crossing in a water body containing low-concentration NaHCO3, collecting fertilized eggs and transferring into a hatching pool, obtaining F1 generation after hatching; when the F1 generation grows to 1-2 cm, transferring the F1 generation into a water body containing high-concentration NaHCO3 for culture, and screening F1 generation with alkali resistance; transferring the F1 generation with alkali resistance into a water body containing low-concentration NaHCO3 for culture, and using for alkali-resistant breeding of the next generation; continuously breeding for 3-4 generations, and the alkali-resistant grass carp is obtained. The application takes wild parent fish of Xiaohaizi grass carp as the breeding basis, adopts NaHCO3 solution stress, and can obtain alkali-resistant grass carp through multi-generation breeding, and provides a basis for promoting the development of the breeding industry in saline-alkali water area.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, and in particular relates to a method for breeding alkali-tolerant grass carp strains. Background Technology

[0002] The water quality of saline-alkali water is complex, with high alkalinity and high pH, ​​resulting in low survival rate and low yield of freshwater fish fry. As a result, most saline-alkali water areas are left idle and cannot be effectively utilized, which restricts the large-scale development of the aquaculture industry.

[0003] Grass carp, belonging to the Cypriniformes order, Cyprinidae family, Leuciscinae subfamily, and *Ctenopharyngodon* genus, is one of the four major freshwater aquaculture species in China. Grass carp is rich in unsaturated fatty acids, which are beneficial to blood circulation, making it a good food for cardiovascular patients. It also contains abundant selenium, which, when consumed regularly, has anti-aging and beautifying effects, and may also have a certain preventive effect against tumors. For those who are weak or have poor appetite, grass carp meat is tender and not greasy, and can stimulate the appetite and provide nourishment. Addressing the problems of low utilization rates and a lack of suitable aquaculture species in highly alkaline water areas, this study provides a breeding method for alkali-tolerant grass carp, which is beneficial to promoting the development of the aquaculture industry in saline-alkali waters. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for breeding alkali-tolerant grass carp, which can breed alkali-tolerant grass carp and provide a foundation for promoting the development of aquaculture industry in saline-alkali waters.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A method for breeding alkali-tolerant grass carp includes the following steps: Wild parent fish are captured during the grass carp breeding season in Xiaohaizi, and self-pollination is carried out in water containing low concentrations of NaHCO3. Fertilized eggs are collected and transferred to a hatching pond to obtain the F1 generation. When the F1 generation grows to 1-2 cm, it is transferred to water containing high concentrations of NaHCO3 for cultivation, and alkali-tolerant F1 generation is selected. The alkali-tolerant F1 generation is then transferred to water containing low concentrations of NaHCO3 for cultivation for the next generation of alkali-tolerant breeding. After 3-4 generations of continuous breeding, the resulting grass carp are alkali-tolerant.

[0007] Preferably, the concentration of NaHCO3 in the water containing low concentrations of NaHCO3 is 10–15 mmol / L.

[0008] Preferably, the concentration of NaHCO3 in the water containing high concentrations of NaHCO3 is 30–48 mmol / L.

[0009] Preferably, the incubation conditions for the fertilized eggs are: water temperature 20-28℃, NaHCO3 concentration in the water 5-10 mmol / L, pH value 7.5-8.2, and dissolved oxygen 5-8 mg / L.

[0010] Preferably, the sex ratio of the wild parent fish is 2 to 3:1.

[0011] Preferably, wild parent fish are caught in Xiaohaizi Reservoir.

[0012] Preferably, the gonads of wild grass carp parent fish in Xiaohaizi have developed to stage V.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] This invention provides a method for breeding alkali-tolerant grass carp. Based on wild grass carp broodstock from Xiaohaizi, different concentrations of NaHCO3 solution are used to stress grass carp at different stages. After multiple generations of selection, alkali-tolerant grass carp can be obtained, providing a foundation for promoting the development of aquaculture in saline-alkali waters. Detailed Implementation

[0015] This invention provides a method for breeding alkali-tolerant grass carp, comprising the following steps: capturing wild parent fish during the grass carp breeding season in Xiaohaizi, performing self-pollination in water containing low concentrations of NaHCO3, collecting fertilized eggs and transferring them to a hatching pond, and obtaining F1 generation after hatching; when the F1 generation grows to 1-2 cm, transferring the F1 generation to water containing high concentrations of NaHCO3 for culture, and screening for alkali-tolerant F1 generation; transferring the alkali-tolerant F1 generation to water containing low concentrations of NaHCO3 for culture for the next generation of alkali-tolerant breeding; continuously breeding for 3-4 generations to obtain alkali-tolerant grass carp.

[0016] This invention utilizes wild broodstock grass carp caught in the Xiaohaizi Reservoir during the breeding season. Xiaohaizi grass carp are plump and healthy, with delicate, smooth flesh, no unpleasant odor, and a delicious, pure, and chewy taste, making them an excellent aquaculture species. The Xiaohaizi Reservoir is located in the Xiaohaizi depression, an alluvial plain on the northwestern edge of the Tarim Basin and the lower reaches of the Yarkand River. The water is clear, clean, and slightly alkaline, with abundant natural food, making it highly suitable for aquatic animal growth. This invention, using wild broodstock grass carp caught in the Xiaohaizi Reservoir as a breeding basis, helps to obtain alkaline-tolerant grass carp strains.

[0017] In this invention, the gonads of wild grass carp broodstock captured in Xiaohaizi develop to stage V. The captured wild broodstock are then transferred to a breeding pond for further cultivation. The water in the breeding pond contains a low concentration of NaHCO3, with the NaHCO3 concentration being 10-15 mmol / L, preferably 12-13 mmol / L.

[0018] In this invention, the female-to-male ratio of wild grass carp broodstock in the breeding pond is 2-3:1, and the wild broodstock undergo self-fertilization to obtain fertilized eggs. As an feasible method, the self-fertilization in this invention adopts a natural spawning and fertilization process.

[0019] This invention involves collecting fertilized eggs and transferring them to an incubation tank for incubation. The incubation conditions are as follows: water temperature 20–28°C, NaHCO3 concentration in the water 5–10 mmol / L, pH value 7.5–8.2, and dissolved oxygen 5–8 mg / L. Preferably, the water temperature is 22–25°C, the NaHCO3 concentration is 7–8 mmol / L, the pH value is 7.8–8, and the dissolved oxygen is 7–8 mg / L.

[0020] In this invention, the fertilized eggs hatch into the F1 generation. After further cultivation, when the F1 generation reaches a body length of 1-2 cm, they are transferred to a selection tank. The water in the selection tank contains a high concentration of NaHCO3, specifically 30-48 mmol / L, preferably 38-45 mmol / L. The F1 generation is screened in this high-NaHCO3-containing water to select those with alkali tolerance. Preferably, the F1 generation that survives 20-38 hours of cultivation is considered alkali-tolerant. These alkali-tolerant F1 generation cells are then transferred to a rearing tank for the next generation of alkali-tolerant breeding. The water in the rearing tank contains a low concentration of NaHCO3, specifically 10-15 mmol / L, preferably 12-13 mmol / L.

[0021] In the specific embodiments of the present invention, the daily breeding and management of grass carp in Xiaohaizi can be carried out using conventional management methods in the field.

[0022] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0023] Example 1

[0024] A breeding method for alkali-tolerant grass carp, the steps of which are as follows:

[0025] During the breeding season of grass carp in Xiaohaizi Reservoir, wild parent fish whose gonads have developed to stage V are captured.

[0026] The captured wild parent fish were transferred to a breeding pond with a NaHCO3 concentration of 10 mmol / L. The male-to-female ratio of the wild grass carp parent fish in the breeding pond was 2:1. The wild parent fish self-fertilized by spawning naturally.

[0027] Fertilized eggs were collected and transferred to an incubation tank for hatching. The incubation conditions were: water temperature 25℃, NaHCO3 concentration 6 mmol / L, pH 7.8, and dissolved oxygen 6 mg / L. F1 generation was obtained after hatching.

[0028] When the F1 generation grows to 1-2 cm, the F1 generation is transferred to the screening tank. The NaHCO3 concentration in the water of the screening tank is 32 mmol / L. After culturing for 30 hours, the surviving F1 generation is the alkali-tolerant F1 generation.

[0029] Alkali-tolerant F1 generation was transferred to a culture pond with a NaHCO3 concentration of 10 mmol / L for the next generation of alkali-tolerant grass carp breeding.

[0030] Alkali-tolerant grass carp can be obtained by continuous breeding for four generations.

[0031] Example 2

[0032] A breeding method for alkali-tolerant grass carp, the steps of which are as follows:

[0033] During the breeding season of grass carp in Xiaohaizi Reservoir, wild parent fish whose gonads have developed to stage V are captured.

[0034] The captured wild parent fish were transferred to a breeding pond with a NaHCO3 concentration of 12 mmol / L. The male-to-female ratio of the wild grass carp parent fish in the breeding pond was 3:1. The wild parent fish self-fertilized by spawning naturally.

[0035] Fertilized eggs were collected and transferred to an incubation tank for hatching. The incubation conditions were: water temperature 23℃, NaHCO3 concentration 8 mmol / L, pH 8.2, and dissolved oxygen 6 mg / L. F1 generation was obtained after hatching.

[0036] When the F1 generation grows to 1-2 cm, the F1 generation is transferred to the screening tank. The NaHCO3 concentration in the water of the screening tank is 42 mmol / L. After culturing for 24 hours, the surviving F1 generation is the alkali-tolerant F1 generation.

[0037] Alkali-tolerant F1 generation was transferred to a culture pond with a NaHCO3 concentration of 12 mmol / L for the next generation of alkali-tolerant grass carp breeding.

[0038] Alkali-tolerant grass carp can be obtained by continuous breeding for three generations.

[0039] Example 3

[0040] A breeding method for alkali-tolerant grass carp, the steps of which are as follows:

[0041] During the breeding season of grass carp in Xiaohaizi Reservoir, wild parent fish whose gonads have developed to stage V are captured.

[0042] The captured wild parent fish were transferred to a breeding pond with a NaHCO3 concentration of 14 mmol / L. The male-to-female ratio of the wild grass carp parent fish in the breeding pond was 3:1. The wild parent fish self-fertilized by spawning naturally.

[0043] Fertilized eggs were collected and transferred to an incubation tank for hatching. The incubation conditions were: water temperature 25℃, NaHCO3 concentration 8 mmol / L, pH 8, and dissolved oxygen 6 mg / L. F1 generation was obtained after hatching.

[0044] When the F1 generation grows to 1-2 cm, the F1 generation is transferred to the screening tank. The NaHCO3 concentration in the water of the screening tank is 48 mmol / L. After culturing for 20 hours, the surviving F1 generation is the alkali-tolerant F1 generation.

[0045] Alkali-tolerant F1 generation was transferred to a culture pond with a NaHCO3 concentration of 14 mmol / L for the next generation of alkali-tolerant grass carp breeding.

[0046] Alkali-tolerant grass carp can be obtained by continuous breeding for three generations.

[0047] Experimental Example 1

[0048] Verify the semi-lethal alkalinity of alkali-tolerant grass carp obtained in Implementation 1–3.

[0049] Methods: Sixty alkali-tolerant grass carp were randomly divided into six groups and placed in water with alkalinity of 2 g / L, 4 g / L, 6 g / L, 8 g / L, 10 g / L and 12 g / L respectively. The mortality of the grass carp was observed and the half-lethal alkalinity (g / L) was calculated.

[0050] Results: The half-lethal alkalinity (LD50) of alkali-tolerant grass carp in Example 1 was 7.6 g / L, in Example 2 it was 8.4 g / L, and in Example 3 it was 7.8 g / L. This demonstrates that the method provided by this invention can effectively breed alkali-tolerant grass carp.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for breeding alkali-tolerant grass carp, characterized in that, Includes the following steps: Wild parent fish were captured during the breeding season of grass carp in Xiaohaizi. They were then self-fertilized in water containing low concentrations of NaHCO3. The fertilized eggs were collected and transferred to a hatching pond. After hatching, the F1 generation was obtained. When the F1 generation grows to 1-2cm, it is transferred to water containing a high concentration of NaHCO3 to screen for alkali-tolerant F1 generation; the alkali-tolerant F1 generation is then transferred to water containing a low concentration of NaHCO3 for cultivation and used for the next generation of alkali-tolerant breeding; after 3-4 generations of continuous breeding, the alkali-tolerant grass carp is obtained. The concentration of NaHCO3 in the water containing low concentrations of NaHCO3 is 10~15 mmol / L; The concentration of NaHCO3 in the water containing high concentrations of NaHCO3 is 30~48 mmol / L; The incubation conditions for the fertilized eggs are: water temperature 20~28℃, NaHCO3 concentration in the water 5~10mmol / L, pH value 7.5~8.2, and dissolved oxygen 5~8mg / L.

2. The breeding method according to claim 1, characterized in that, The sex ratio of the wild parent fish is 2-3:

1.

3. The breeding method according to claim 1, characterized in that, Wild parent fish were caught in Xiaohaizi Reservoir.

4. The breeding method according to claim 1, characterized in that, The gonads of wild grass carp parent fish in Xiaohaizi have developed to stage V.