Method for regulating gonadal development of acipenser sinensis broodstock

Abstract

The application provides a Chinese sturgeon parent fish gonad development regulation method, and the regulation process comprises the following steps: 1) according to the daily feeding amount of 0.5-1.0%, the daily feeding frequency of 2 times / d, the Chinese sturgeon parent fish in the gonad development II stage is subjected to gonad starting cultivation, and the parent fish in the gonad development III stage is obtained; 2) according to the daily feeding amount of 0.5-1.0%, the daily feeding frequency of 2 times / d, and the environmental noise limit value of 60 dB, the parent fish in the gonad development III stage is subjected to near-mature cultivation, and the parent fish in the early gonad development IV stage is obtained; 3) the parent fish in the early gonad development IV stage is subjected to reduced feeding type cultivation, and the parent fish with the breeding capacity is obtained. By using the regulation method provided by the application, the Chinese sturgeon parent fish gonad starting rate can be effectively improved, the Chinese sturgeon key parent fish in the gonad development III stage is subjected to fine cultivation, and the gonad normal development into the IV stage and maturity are regulated.

Description

Technical Field

[0001] This invention relates to a method for regulating gonadal development in Chinese sturgeon parent fish, belonging to the field of biotechnology. Background Technology

[0002] The Chinese sturgeon (Acipenser sinensis) is a fish belonging to the class Osteichthyes, superorder Chondrostei, order Acipenseriformes, family Acipenseridae, and genus Acipenser. It is a Class I protected animal in China, listed as Endangered (EN) by the International Union for Conservation of Nature (IUCN), and listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). The Chinese sturgeon exhibits migratory habits between rivers and the sea.

[0003] To protect the Chinese sturgeon species and replenish its wild population, the Chinese Sturgeon Research Institute (CASRI) achieved a breakthrough in artificial breeding technology for the Chinese sturgeon in 1984. Since then, it has conducted artificial spawning, fry rearing, and release programs for wild Chinese sturgeon annually. From the mid-1990s, CASRI began releasing large-scale Chinese sturgeon fry. In 2009, CASRI became the first in China to achieve a breakthrough in fully artificial breeding of Chinese sturgeon, with second-generation offspring entering the Chinese sturgeon release program. To date, over 7 million Chinese sturgeon fry of various sizes have been released, with CASRI releasing over 6 million of them.

[0004] However, the age of sexual maturity for Chinese sturgeon broodstock is long, and it requires a lot of financial, material, and human resources to cultivate them to sexual maturity in an artificial environment. Given the extremely low gonadal conversion rate of Chinese sturgeon broodstock, key broodstock that have entered stage III of gonadal development are even more precious. However, the degeneration of mature broodstock has become a difficult problem that plagues the breeding of Chinese sturgeon. Once the gonads of key broodstock that have entered stage III degenerate, the opportunity for breeding will be missed, and it will take another 3 years or even many years for the degenerated broodstock to mature again.

[0005] Therefore, improving the gonad activation rate of Chinese sturgeon and carrying out refined breeding of key broodstock Chinese sturgeon that have entered stage III of gonad development, and regulating the normal development of gonads to enter stage IV and mature, are important aspects of establishing and practicing a fully artificial breeding system for Chinese sturgeon. Summary of the Invention

[0006] This invention provides a method for regulating gonadal development in Chinese sturgeon parent fish. This method can significantly increase the gonadal activation rate and reduce gonadal degeneration in Chinese sturgeon, which helps to establish and implement a fully artificial breeding system for Chinese sturgeon.

[0007] This invention provides a method for regulating gonadal development in Chinese sturgeon broodstock, the regulation process comprising the following steps:

[0008] 1) By feeding 0.5-1.0% of the feed per day and twice a day, gonadal initiation culture was carried out on Chinese sturgeon broodstock in gonadal development stage II to obtain broodstock in gonadal development stage III;

[0009] 2) With a daily feeding amount of 0.5-1.0%, a daily feeding frequency of 2 times / day, and a breeding environment noise limit of 60dB, the broodstock in the gonadal development stage III were subjected to near-mature breeding to obtain broodstock in the early stage of gonadal development IV.

[0010] 3) The female broodstock in the early stage of gonadal development stage IV were subjected to a first reduced feeding method, reducing the daily feed amount of the female broodstock to 0 and maintaining it within 3 months; the male broodstock in the late stage of gonadal development stage IV were subjected to a second reduced feeding method, reducing the daily feed amount of the male broodstock to 0 and maintaining it within 30 days, with the noise limit of the breeding environment at 40dB, to obtain broodstock with reproductive capacity;

[0011] During steps 2) and 3), the water temperature for aquaculture is 10-27℃, and the stocking density is no higher than 5 kg / m³. 3 ;

[0012] The feeding interval during the regulation process is 8-12 hours, the daytime light intensity is 3000-5000 Lx, and the nighttime light intensity is <20 Lx.

[0013] As described above, in step 1), the stocking density is 5-8 kg / m². 3 .

[0014] In the control method described above, in steps 2) and 3), the stocking density is 2-3 kg / m². 3 .

[0015] As described above, in steps 2) and 3), the feeding amount at 8:00 AM is 60%-70% of the daily feeding amount, and the feeding amount at 4:00 PM is 30%-40% of the daily feeding amount.

[0016] As described above, step 3) of the first reduced-feeding cultivation method includes the following steps:

[0017] The daily feeding amount for the female parent fish was reduced by 0.0017%-0.0067% / day in the first month; and / or, the daily feeding amount was reduced by 0.0067%-0.0150% / day in the second and third months.

[0018] And / or, the second reduced-feeding culture includes the following steps:

[0019] The daily feeding amount for the male parent fish was reduced by 0.017%-0.033% / day, and after 30 days it was reduced to 0 and maintained.

[0020] As described above, step 3) of the first reduced-feeding cultivation method includes the following steps:

[0021] The daily feeding amount of the female parent fish was reduced by 0.0083-0.0333% per feeding during the first month. After the reduction, the daily feeding amount was kept unchanged for 5 days. Then, the daily feeding amount was reduced again by the first reduction amount, and the cycle was repeated until the daily feeding amount was 0.

[0022] And / or, in the second and third months, the daily feeding amount is reduced by 0.0333-0.075% per reduction, and the daily feeding amount is kept unchanged for 5 days after the reduction. Then, the daily feeding amount is reduced again by the second reduction amount, and the cycle is repeated until the daily feeding amount is 0.

[0023] And / or, the second reduced-feeding culture includes the following steps:

[0024] The daily feeding amount of the male parent fish was reduced by 0.1-0.2% per feeding, and the daily feeding amount was kept unchanged for 5 days after the reduction. Then, the daily feeding amount was reduced again by 0.1-0.2% per feeding, and the cycle was repeated until the daily feeding amount was 0 and maintained.

[0025] As described above, in steps 2) and 3), the water flow rate is 0.0-0.3 m / s during the period from the middle of gonadal development stage III to the middle of gonadal development stage IV, and 0.5-1.0 m / s after the middle of gonadal development stage IV.

[0026] As described above, in step 1), the daily variation of the aquaculture water temperature should not exceed 3°C.

[0027] And / or, in steps 2) and 3), the daily variation in aquaculture water temperature does not exceed 1℃.

[0028] As described above, the feed nutrient composition during the regulation process includes crude protein ≥ 42.0 wt%, crude fat ≥ 10.0 wt%, crude fiber ≤ 5.0 wt%, crude ash ≤ 16.0 wt%, total phosphorus ≥ 1.2 wt%, and lysine ≥ 2.5 wt%.

[0029] As described above, during the control process, the DO in the aquaculture water is >7.5 mg / L, and the NH4+ is <7.5 mg / L. + <0.5mg / L, NO2 － <0.05mg / L, pH value is 7.5-8.0.

[0030] The present invention provides a method for regulating the gonadal development of Chinese sturgeon broodstock. This method effectively regulates gonadal development by controlling various parameters, including feeding patterns, light intensity, water temperature, and environmental parameters, through phased adjustments. This significantly increases the gonadal activation rate and reduces the gonadal degeneration rate in Chinese sturgeon broodstock, laying a solid foundation for large-scale breeding and release of Chinese sturgeon. Attached Figure Description

[0031] Figure 1 This is a bar chart showing the change in feeding amount in step 1) of a specific embodiment of the present invention;

[0032] Figure 2 This is a water temperature control curve for step 1) in a specific embodiment of the present invention;

[0033] Figure 3 This is a graph showing the feeding amount-time curve for step 3) of the reduced feeding method for female parent fish in a specific embodiment of the present invention.

[0034] Figure 4 This is the water temperature control curve for steps 2) and 3) in a specific embodiment of the present invention;

[0035] Figure 5 This is a graph showing the relationship between different stocking densities and degeneration rates of female parent fish in this invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] This invention provides a method for regulating gonadal development in Chinese sturgeon broodstock, the regulation process comprising the following steps:

[0038] 1) By feeding 0.5-1.0% of the feed per day and twice a day, gonadal initiation culture was carried out on Chinese sturgeon broodstock in gonadal development stage II to obtain broodstock in gonadal development stage III;

[0039] 2) With a daily feeding amount of 0.5-1.0%, a daily feeding frequency of 2 times / day, and a noise limit of 60dB for the aquaculture environment, broodstock in stage III of gonadal development were cultured to near maturity to obtain broodstock in the early stage IV of gonadal development.

[0040] 3) The first reduced feeding method was used to raise female broodstock in the early stage of gonadal development stage IV, reducing the daily feed amount of female broodstock to 0 and maintaining it within 3 months. The second reduced feeding method was used to raise male broodstock in the late stage of gonadal development stage IV, reducing the daily feed amount of male broodstock to 0 and maintaining it within 1 month. The noise limit of the breeding environment was 40dB, and broodstock with reproductive capacity were obtained.

[0041] During steps 2) and 3), the water temperature for aquaculture is 10-27℃, and the stocking density is no higher than 5 kg / m³. 3 ;

[0042] During the regulation process, the daily feeding interval is 8-12 hours, the daytime light intensity is 3000-5000 Lx, and the nighttime light intensity is <20 Lx.

[0043] This invention uses ultrasound and puncture methods to detect the gonadal development stage of Chinese sturgeon broodstock.

[0044] Specifically, in step 1), Chinese sturgeon broodstock in gonadal development stage II are bred with a daily feeding amount of 0.5-1.0% and a daily feeding frequency of 2 times / day to obtain broodstock in gonadal development stage III.

[0045] In detail, the daily feeding amount of the present invention refers to the ratio of the daily feed weight to the average weight of the Chinese sturgeon broodstock. For example, if the average weight of the Chinese sturgeon broodstock is 100 kg, the daily feeding amount is 0.5-1.0%, which means the daily feeding amount is 0.5-1 kg.

[0046] It is understandable that the amount of food consumed by the parent fish in the breeding equipment varies individually during the feeding process, and the amount of food consumed by each parent fish per day also varies.

[0047] The daily feeding amount is 0.5-1.0%, for example, the daily feeding amount includes but is not limited to 0.50%, 0.55%, 0.60%, 0.65%, 0.70%, 0.75%, 0.80%, 0.85%, 0.90%, 0.95%, 1.0%, or any combination thereof.

[0048] During the feeding process, it is necessary to observe the feeding behavior of the Chinese sturgeon parent fish and adjust the feeding amount within the above-mentioned daily feeding range in a timely manner based on their feeding behavior. Figure 1 The bar chart shows the change in feeding amount in a specific implementation method, where the feeding amount is calculated based on the weight of Chinese sturgeon parent fish of 100 kg / fish.

[0049] A daily feeding frequency of 2 times / day means feeding twice a day.

[0050] In step 1) of this invention, the time interval between each feeding is 8-12 hours. For example, the feeding time interval includes, but is not limited to, a range of 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0 or any two of these.

[0051] For example, in one specific implementation, the first feeding is carried out at 8:00 a.m. and the second feeding is carried out at 4:00 p.m.

[0052] This invention does not limit the amount of feed given in two feedings. The amount of feed can be adjusted in a timely manner according to the feeding situation of the Chinese sturgeon broodstock, as well as the water temperature and growth status. For example, if the daily feed amount is 1.0%, the amount of feed given in the first feeding is 0.5%, and the amount of feed given in the second feeding is 0.5%.

[0053] It is understood that in step 1), the aquaculture water needs to be within a suitable flow rate range. This invention does not limit the specific range of the aquaculture water flow rate in step 1), and a suitable flow rate range can be selected according to the actual situation. For example, the aquaculture water flow rate is 0.2-0.5 m / s.

[0054] This invention does not limit the specific range of water temperature in step 1). A suitable water temperature range, such as 10-27℃, can be selected according to the actual situation. Figure 2 This is a water temperature control curve for aquaculture in one specific implementation method.

[0055] In step 2), the broodstock in stage III of gonadal development were cultured to near maturity at a daily feeding rate of 0.5-1.0%, a daily feeding frequency of 2 times / day, and a noise limit of 60dB in the aquaculture environment, so as to obtain broodstock in the early stage of stage IV of gonadal development.

[0056] Specifically, in step 2), the same feeding rules as in step 1) are maintained, and the Chinese sturgeon broodstock in gonadal development stage III are cultured to near maturity to obtain broodstock in the early stage of gonadal development stage IV.

[0057] Meanwhile, in step 2), it is necessary to strictly control the breeding environment to maintain a relatively quiet atmosphere. The environmental noise limit in this invention refers to the maximum decibel level of noise generated by a sound source within a 20m straight-line distance from the breeding device. Noise can be detected using a noise detector.

[0058] In step 3), the female broodstock in the early stage of gonadal development stage IV undergo a first reduced feeding method, reducing the daily feeding amount of the female broodstock to 0 and maintaining it within 3 months. The male broodstock in the late stage of gonadal development stage IV undergo a second reduced feeding method, reducing the daily feeding amount of the male broodstock to 0 and maintaining it within 1 month. The noise limit of the breeding environment is 40dB, resulting in broodstock with reproductive capacity.

[0059] The reproductive broodstock of this invention refers to the Chinese sturgeon broodstock that can be artificially induced to spawn or produce sperm, and reproduce offspring through artificial insemination.

[0060] Specifically, the first and second reduced feeding methods in this invention refer to gradually reducing the daily feeding amount during the cultivation process, reducing the daily feeding amount of female broodstock to 0 within 3 months and the daily feeding amount of male broodstock to 0 within 1 month, and then maintaining the daily feeding amount at 0 to conduct fasting cultivation of Chinese sturgeon broodstock until reproductive broodstock are obtained.

[0061] This invention does not limit the specific method of reducing the daily feeding amount. It is understood that the reduction in the daily feeding amount should not be too large. It is necessary to reduce the daily feeding amount by a relatively appropriate and lower amount so that the Chinese sturgeon parent fish can gradually adapt to the lower daily feeding amount.

[0062] In one specific embodiment, the daily feed amount for female parent fish is reduced over three months until it reaches zero; in another specific embodiment, the daily feed amount is reduced in a stepwise manner, that is, reduced once, maintained for a period of time, reduced again and maintained for a period of time, until it reaches zero. The daily feed amount for male parent fish is reduced over one month until it reaches zero; in another specific embodiment, the daily feed amount is reduced in a stepwise manner, that is, reduced once, maintained for a period of time, reduced again and maintained for a period of time, until it reaches zero.

[0063] During step 3), the noise limit for the aquaculture environment is 40 dB.

[0064] For example, the noise level in aquaculture environments includes, but is not limited to, a range of 40 dB, 35 dB, 30 dB, 25 dB, 20 dB, 15 dB, 10 dB, 0 dB, or any combination thereof.

[0065] In addition, during steps 2) and 3), the water temperature for aquaculture should be 10-27℃, and the stocking density should not exceed 5 kg / m³. 3 .

[0066] In detail, the aquaculture water temperature is 10-27℃. For example, the aquaculture water temperature includes, but is not limited to, 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, or any combination thereof.

[0067] It is understandable that the water temperature in aquaculture follows natural rhythms, meaning that the water temperature adjusts with the seasons, with lower temperatures in winter and higher temperatures in summer.

[0068] In one specific embodiment, the temperature in steps 2) and 3) is 10-15°C from December to early April of the following year, 15-20°C from early April to early May and from mid-October to December, and 20-27°C from early May to mid-October.

[0069] Stocking density refers to the ratio of the total mass of Chinese sturgeon broodstock in a culture facility to the volume of the culture water. The stocking density should not exceed 5 kg / m³. 3 For example, stocking density includes, but is not limited to, 5.0 kg / m². 3 4.5kg / m 3 4.0kg / m 3 3.5kg / m 3 3.0kg / m 3 2.5kg / m 3 2.0kg / m 3 1.5kg / m 3 1.0kg / m 3 Or any other not exceeding 5kg / m 3 The range.

[0070] The light intensity also needs to be controlled during the regulation process. The light intensity during the day should be 3000-5000 Lx, and the light intensity at night should be <20 Lx.

[0071] In detail, daytime light intensity includes, but is not limited to, a range of 3000 Lx, 3500 Lx, 4000 Lx, 4500 Lx, 5000 Lx, or any combination thereof.

[0072] Nighttime light intensity includes, but is not limited to, 19Lx, 18Lx, 16Lx, 14Lx, 12Lx, 10Lx, 8Lx, 6Lx, 4Lx or any other range less than 20Lx.

[0073] The light intensity in this invention conforms to the laws of natural light intensity, which varies at different times of the day and is also adjusted with seasonal changes.

[0074] This invention achieves good results by cultivating Chinese sturgeon broodstock at different stages of gonadal development in stages and controlling feeding rules, water temperature, environmental noise limits, and light intensity at different stages of cultivation.

[0075] Furthermore, in one specific embodiment of the present invention, in step 1), the stocking density is 5-8 kg / m². 3 .

[0076] In detail, the stocking density for raising Chinese sturgeon broodstock in gonadal development stage II to obtain Chinese sturgeon broodstock in gonadal development stage III is 5-8 kg / m³. 3 For example, stocking density includes, but is not limited to, 5 kg / m³. 3 5.5kg / m 3 6kg / m 3 6.5kg / m 3 7kg / m 3 7.5kg / m 3 8kg / m 3 Or a range consisting of any two of them.

[0077] Through a series of creative experiments, the inventors discovered that when breeding Chinese sturgeon broodstock in stage II of gonadal development to obtain Chinese sturgeon broodstock in stage III of gonadal development, a stocking density within the aforementioned range is more conducive to the initiation of gonadal development in the Chinese sturgeon broodstock. This is because the aforementioned stocking density range allows for effective utilization of the breeding facilities while exhibiting a significant group feeding effect, marked feeding desire and behavior, and vigorous feeding, which is conducive to the accumulation and storage of nutrients, laying the nutritional foundation and conditions for the initiation of gonadal development. At the same time, this density range will not cause environmental, space, or food stress to the Chinese sturgeon broodstock in stage II of gonadal development, thus meeting their growth and development needs.

[0078] Furthermore, in one specific embodiment of the present invention, in steps 2) and 3), the stocking density is 2-3 kg / m². 3 .

[0079] In detail, the stocking density of Chinese sturgeon broodstock in stage III of gonadal development to reproductive capacity is 2-3 kg / m³. 3 For example, stocking density includes, but is not limited to, 2.0 kg / m³. 3 2.1kg / m 3 2.2kg / m 3 2.3kg / m 3 2.4kg / m 3 2.5kg / m 3 2.6kg / m 3 2.7kg / m 3 2.8kg / m 3 2.9kg / m 3 3.0kg / m 3 Or a range consisting of any two of them.

[0080] Through extensive and creative experiments, the inventors controlled different stocking densities of female Chinese sturgeon broodstock to explore the rate of gonadal degeneration under different stocking densities, specifically as follows: Figure 5As can be seen, when the stocking density meets the above-mentioned range, the gonadal degeneration rate of the obtained Chinese sturgeon broodstock is low, and the reproductive effect is excellent. This is because Chinese sturgeon broodstock in gonadal development stage III are more sensitive to stress from environmental and spatial factors. The above-mentioned stocking density can reduce competition and pressure among the Chinese sturgeon broodstock for nutrients, environment, and space, reducing stress factors and making their living environment more stable and comfortable. This promotes the growth and development of the Chinese sturgeon broodstock, maintains the normal function of their reproductive system, and improves reproductive efficiency.

[0081] Furthermore, in a specific embodiment of the present invention, in steps 2) and 3), the feeding amount at 8:00 am is 60%-70% of the daily feeding amount, and the feeding amount at 4:00 pm is 30%-40% of the daily feeding amount.

[0082] Specifically, during the process of raising and developing Chinese sturgeon broodstock in stage III of gonadal development into broodstock capable of reproduction, the daily feeding amount should be 60%-70% at 8:00 AM and 30%-40% at 4:00 PM.

[0083] In one specific implementation, the daily feeding amount is 1.0%, with 0.6-0.7% fed at 8:00 AM and 0.3-0.4% fed at 4:00 PM.

[0084] When the above feeding rules are adopted, the feeding needs of Chinese sturgeon broodstock at different times can be better met, and it can help maintain the nutritional balance of Chinese sturgeon broodstock, promote their metabolism, thereby reducing the risk of gonadal degeneration, improving their reproductive effect, and better controlling the gonadal development of Chinese sturgeon broodstock.

[0085] Furthermore, in a specific embodiment of the present invention, step 3) the first reduced feeding-type cultivation includes the following steps:

[0086] For female broodstock, the daily feeding amount was reduced by 0.0017%-0.0067% / day during the first month; and / or, the daily feeding amount was reduced by 0.0067%-0.0150% / day during the second and third months.

[0087] And / or, the second reduced-feeding rearing includes the following steps: reducing the daily feed amount of male broodstock by 0.017%-0.033% / day, reducing it to 0 daily feed amount after 30 days and maintaining it thereafter.

[0088] In this invention, the reduction in daily feeding amount refers to the decrease in daily feeding amount per unit of days. Taking a daily feeding amount of 0.0017% / day and an initial daily feeding amount of 0.5% as an example, it means that the daily feeding amount on the first day decreases by 0.0017% to 0.4983%, and the daily feeding amount on the fifth day decreases by 0.0017% (5 times) of the initial daily feeding amount, i.e., a decrease of 0.0085% to 0.4915%.

[0089] In detail, the daily feed amount for female broodstock in the early stage of gonadal development (stage IV) was reduced by 0.0017%-0.0067% per day during the first month of rearing. For example, the reduction range includes, but is not limited to, 0.0017% / day, 0.0020% / day, 0.0025% / day, 0.0030% / day, 0.0035% / day, 0.0040% / day, 0.0045% / day, 0.0050% / day, 0.0055% / day, 0.0060% / day, 0.0067% / day, or any combination thereof.

[0090] In the second and third months, the daily feeding amount should be reduced by 0.0067%-0.0150% / day. For example, the reduction range includes, but is not limited to, 0.0067% / day, 0.0070% / day, 0.0075% / day, 0.0080% / day, 0.0085% / day, 0.0090% / day, 0.0095% / day, 0.0010% / day, 0.0015% / day, or any combination thereof.

[0091] For male broodstock that have reached the late stage IV of gonadal development, the daily feeding amount was reduced by 0.017%-0.033% / day, and after 30 days, the daily feeding amount was reduced to 0 and maintained.

[0092] For example, the daily feed reduction rate is 0.017% / day, 0.020% / day, 0.025% / day, 0.030% / day, 0.033% / day, or any combination thereof.

[0093] It is understandable that the original feeding rules for male parent fish during the early to late stages of gonadal development stage IV remain unchanged.

[0094] In one specific implementation, the reduction in daily feeding amount is as follows: Figure 3 As shown, March is the early stage of stage IV gonadal development, March-April is the first month, and April-June are the second and third months.

[0095] When the reduction is within the above range, on the one hand, it can allow female Chinese sturgeon broodstock to gradually adapt to less food intake, effectively avoiding the adverse effects of a sudden reduction in daily feeding on their growth and health. On the other hand, it can also better manage the nutritional status of female Chinese sturgeon broodstock, reduce the risk of gonadal degeneration, and improve their reproductive performance and quality of life.

[0096] Furthermore, in a specific embodiment of the present invention, step 3) reduced feeding breeding includes the following steps: the daily feeding amount of female parent fish in the first month is reduced by 0.0083-0.0333% / time according to the first reduction amount, and the daily feeding amount is kept unchanged for 5 days after reduction. Then, the reduction is carried out again according to the first reduction amount, and the cycle is repeated until the daily feeding amount is 0.

[0097] And / or, in the second and third months, the daily feeding amount is reduced by 0.0333-0.075% per reduction, and the daily feeding amount is kept unchanged for 5 days after the reduction. Then, the daily feeding amount is reduced again by the second reduction amount, and the cycle is repeated until the daily feeding amount is 0.

[0098] During the late stage IV gonadal development of male broodstock, the daily feeding amount was reduced by 0.1-0.2% per feeding. After the reduction, the daily feeding amount was kept unchanged for 5 days. Then, the amount was reduced again by 0.1-0.2% per feeding, and the cycle was repeated until the daily feeding amount was 0 and maintained.

[0099] In this invention, the first reduction amount and the second reduction amount refer to the difference between the daily feeding amount before each reduction and the daily feeding amount after the reduction.

[0100] Once the female Chinese sturgeon enters the early stage of gonadal development (stage IV), the daily feeding amount is reduced in a step-by-step manner.

[0101] Specifically, for female parent fish, the daily feeding amount in the first month is reduced by 0.0083-0.0333% per feeding. After the reduction, the daily feeding amount is kept unchanged for 5 days. Then, the daily feeding amount is reduced again by the first reduction amount, and the cycle continues until the daily feeding amount is 0.

[0102] The first reduction amount is 0.0083-0.0333% / time. For example, the first reduction amount includes, but is not limited to, 0.0083% / time, 0.0085% / time, 0.0090% / time, 0.0095% / time, 0.0100% / time, 0.0150% / time, 0.0200% / time, 0.0250% / time, 0.0300% / time, 0.0333% / time, or any combination thereof.

[0103] Taking an initial feeding amount of 1% and a first reduction amount of 0.0333% per instance as an example, on the first day of the first month, the daily feeding amount is reduced to 0.9667%, and maintained at 0.9667% for 5 days. Subsequently, the daily feeding amount is reduced to 0.9334%, and maintained at 0.9334% for 5 days. The first reduction with the first reduction amount is considered the first cycle, and a total of 6 cycles are performed. The sixth reduction is to 0.8002%, and maintained at 0.8002% for 5 days.

[0104] In the second and third months, the daily feeding amount was reduced by 0.0333-0.075% per cycle according to the second reduction amount. After the reduction, the daily feeding amount remained unchanged for 5 days. Then, the reduction was carried out again according to the second reduction amount. This cycle was repeated 12 times until the daily feeding amount was 0.

[0105] The second reduction is 0.0333-0.075% per instance. For example, the second reduction includes, but is not limited to, a range of 0.0333% per instance, 0.0350% per instance, 0.040% per instance, 0.045% per instance, 0.050% per instance, 0.055% per instance, 0.060% per instance, 0.065% per instance, 0.070% per instance, 0.075% per instance, or any combination thereof.

[0106] Taking the initial daily feeding amount of the second month as 0.9% and the second reduction amount as 0.075% / time as an example, the daily feeding amount is reduced to 0.825% on the first day of the second month and maintained at 0.825% for 5 days. Then the daily feeding amount is reduced to 0.75% and maintained at 0.75% for 5 days. The first cycle begins with the reduction using the second reduction amount, and the cycle is repeated 12 times. The 12th cycle reduces the daily feeding amount to 0.

[0107] For male parent fish, the daily feeding amount should be reduced by 0.1-0.2% per feeding, and the daily feeding amount should be kept unchanged for 5 days after the reduction. Then, the daily feeding amount should be reduced again by 0.1-0.2% per feeding, and the cycle should be repeated until the daily feeding amount is 0 and maintained.

[0108] Taking an initial daily feeding amount of 1.0% and a reduction amount of 0.2% as an example, on the first day of the second month, the daily feeding amount is reduced to 0.8%, and the daily feeding amount is maintained at 0.8% for 5 days. The first cycle begins with the first reduction amount of 0.2%, and the cycle is repeated 6 times. The 6th cycle reduces the daily feeding amount to 0 and maintains it.

[0109] When the daily feeding amount is reduced in accordance with the above reduction method, on the one hand, the Chinese sturgeon broodstock can gradually adapt to less food intake, effectively avoiding the adverse effects of a sudden reduction in daily feeding amount on their growth and health. On the other hand, it can also better manage the nutritional status of the Chinese sturgeon broodstock, reduce the risk of gonadal degeneration, and improve their reproductive efficiency and quality of life.

[0110] Furthermore, in a specific embodiment of the present invention, in steps 2) and 3), the water flow rate is 0.0-0.3 m / s during the middle of gonadal development stage III to stage IV, and 0.5-1.0 m / s after the middle of gonadal development stage IV.

[0111] Specifically, during the middle of gonadal development stage III to stage IV, the flow rate of the culture water is 0.0-0.3 m / s. For example, the flow rate of the culture water includes, but is not limited to, 0.0 m / s, 0.05 m / s, 0.10 m / s, 0.15 m / s, 0.20 m / s, 0.25 m / s, 0.3 m / s, or any combination thereof.

[0112] After the mid-stage of gonadal development (stage IV), the flow rate of the culture water is 0.5-1.0 m / s. For example, the flow rate of the culture water includes, but is not limited to, 0.50 m / s, 0.55 m / s, 0.60 m / s, 0.65 m / s, 0.70 m / s, 0.75 m / s, 0.80 m / s, 0.85 m / s, 0.90 m / s, 0.95 m / s, 1.0 m / s, or any combination thereof.

[0113] The present invention does not limit the method of controlling the flow rate of aquaculture water. Common flow rate control methods in the field can be selected, such as controlling the flow rate by increasing the inflow volume and direction or by using a flow pump to generate flow.

[0114] When the water flow rate in steps 2) and 3) is within the above-mentioned range, it can better stimulate the gonadal stability of Chinese sturgeon broodstock and reduce the gonadal degeneration rate. This is because water flow is extremely important for the maturation of reproductive gonads and spawning and sperm production in anadromous fish. Generally, anadromous fish can only generate a high level of energy metabolism during their anadromous journey, stimulating the synthesis and release of sex hormones, thus enabling the gonads to fully mature. When the gonads develop to stage IV, water flow stimulation plays an important role in the further development and maturation of the gonads. During the broodstock rearing period, frequent water flow or appropriate water flow stimulation before spawning can promote gonadal development, maturation, spawning or sperm production, and improve the fertilization rate.

[0115] Furthermore, in a specific embodiment of the present invention, in step 1), the daily variation of the aquaculture water temperature is no higher than 3°C; and / or, in steps 2) and 3), the daily variation of the aquaculture water temperature is no higher than 1°C.

[0116] In this invention, the daily water temperature variation refers to the difference between the highest and lowest water temperature values ​​each day.

[0117] When the daily temperature variation in the culture water is within the above range, the stress caused by temperature changes can be minimized, thereby improving the gonad activation and gonad stability of Chinese sturgeon broodstock.

[0118] Furthermore, in a specific embodiment of the present invention, the feed nutrient composition during the regulation process includes crude protein ≥42.0wt%, crude fat ≥10.0wt%, crude fiber ≤5.0wt%, crude ash ≤16.0wt%, total phosphorus ≥1.2wt%, and lysine ≥2.5wt%.

[0119] In this invention, crude protein refers to the total amount of nitrogen-containing substances in feed, including soluble and insoluble proteins, which can provide the Chinese sturgeon broodstock with the necessary amino acids and nitrogen sources to support their metabolism and tissue growth.

[0120] In this invention, crude fat refers to the fat in the feed, which provides energy and essential fatty acids for Chinese sturgeon broodstock, helping to maintain the health of the fish and promote their growth and development.

[0121] In this invention, crude fiber refers to insoluble fiber in feed, which mainly comes from plant-based raw materials such as rice husks and soybean meal.

[0122] In this invention, crude ash refers to the content of inorganic substances in feed. Crude ash is mainly composed of minerals and other inorganic substances, such as calcium, phosphorus, and magnesium.

[0123] In this invention, total phosphorus refers to the total content of all forms of phosphorus in the feed, such as inorganic phosphorus and organic phosphorus.

[0124] When the nutritional composition of the feed meets the above range, it can synergistically achieve the breeding of Chinese sturgeon broodstock and effectively regulate the gonadal development of Chinese sturgeon broodstock.

[0125] Furthermore, in one specific embodiment of the present invention, during the regulation process, the DO in the aquaculture water is >7.5 mg / L, and the NH4+ is <7.5 mg / L. + <0.5mg / L, NO2 － <0.05mg / L, pH value is 7.5-8.0.

[0126] In this invention, DO refers to the concentration of dissolved oxygen in water. For example, DO of 8 mg / L means that 8 mg of oxygen is dissolved in 1 L of water.

[0127] This invention does not limit the amount of DO and NH4 in aquaculture water. + NO2 － pH testing can be performed using methods commonly used in this field, such as using an automated water quality analyzer, a handheld water quality analyzer, or titration to determine DO and NH4. + NO2 － Water quality indicators such as pH.

[0128] This invention does not limit the amount of DO and NH4 in aquaculture water. + NO2 －pH control methods include increasing DO content in aquaculture water by supplying liquid oxygen to the ponds or through air aeration, and controlling NH4 through water exchanges and wastewater discharge. + NO2 － Water quality indicators such as pH.

[0129] When the water quality parameters of the aquaculture water meet the above range, it can not only improve the survival rate of Chinese sturgeon broodstock, but also further achieve gonadal regulation of Chinese sturgeon broodstock.

[0130] The following detailed description of the method for regulating gonadal development in Chinese sturgeon broodstock provided by the present invention is provided through specific embodiments.

[0131] The Chinese sturgeon parent fish in this invention are derived from the first-generation parent fish bred and raised by the Chinese Sturgeon Research Institute.

[0132] Example 1

[0133] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock includes the following steps:

[0134] 1) By feeding female Chinese sturgeon in stage II of gonadal development with a daily feed amount of 0.5-1.0% and a daily feeding frequency of 2 times / day, gonadal initiation culture was carried out to obtain broodstock in stage III of gonadal development;

[0135] During the cultivation process, the water temperature follows natural rhythm changes, such as... Figure 4 As shown, the daily temperature variation in the aquaculture water should not exceed 3℃; the stocking density should be 5-8 kg / m³. 3 .

[0136] 2) With a daily feeding amount of 0.5-1.0%, a daily feeding frequency of 2 times / day, and a noise limit of 60dB for the aquaculture environment, broodstock in stage III of gonadal development were cultured to near maturity to obtain broodstock in the early stage IV of gonadal development.

[0137] The water flow velocity during aquaculture is 0.0-0.3 m / s; the water temperature during cultivation is 10-27℃ and follows natural rhythm changes, such as... Figure 3 As shown, the daily temperature variation in the aquaculture water should not exceed 1℃, and the stocking density should be 2-3 kg / m³. 3 The noise limit for aquaculture environments is 60 dB.

[0138] 3) Reduced feeding was used to raise broodstock in the early stage of gonadal development (stage IV). The reduced feeding method for female broodstock was as follows: In the first month, the daily feed amount was reduced by 0.0083-0.0333% per feeding, and the daily feed amount was kept constant for 5 days after the reduction. Then, the reduction was repeated 6 times. In the second and third months, the daily feed amount was reduced by 0.0333-0.075% per feeding, and the daily feed amount was kept constant for 5 days after the reduction. Then, the reduction was repeated until the daily feed amount was 0. The noise limit of the breeding environment was 40dB, and female broodstock with reproductive capacity were obtained.

[0139] The reduced feeding method for male broodstock is as follows: the daily feeding amount for male broodstock is maintained at 0.5-1.0%. For male broodstock in the late stage of gonadal development stage IV, the feeding amount is reduced by 0.1-0.2% per cycle. After reduction, the daily feeding amount is kept unchanged for 5 days. Then, the feeding amount is reduced again by 0.1-0.2% per cycle. This cycle is repeated until the daily feeding amount is 0 and maintained. The noise limit of the breeding environment is 40dB. Male broodstock with reproductive capacity are obtained.

[0140] During the cultivation process, the water temperature is maintained between 10-27℃ and follows natural circadian rhythms, with daily temperature variations not exceeding 1℃, and the stocking density is 2-3 kg / m³. 3 .

[0141] During the early to mid-stage of gonadal development stage IV, the water flow rate was 0.0-0.3 m / s. After the mid-stage of gonadal development stage IV, the water flow rate was 0.5-1.0 m / s.

[0142] The feed composition includes crude protein ≥42.0wt%, crude fat ≥10.0wt%, crude fiber ≤5.0wt%, crude ash ≤16.0wt%, total phosphorus ≥1.2wt%, and lysine ≥2.5wt%. The feeding amount is 60%-70% of the daily feed intake at 8:00 AM and 30-40% at 4:00 PM. Daytime light intensity is 3000-5000 Lx, and nighttime light intensity is <20 Lx. The aquaculture water flow rate is 0.2-0.5 m / s. The aquaculture water quality parameters are DO >7.5 mg / L and NH4+ >7.5 mg / L. + <0.5mg / L, NO2 － <0.05mg / L, pH value is 7.5-8.0.

[0143] Example 2

[0144] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0145] Step 3) During the reduced feeding process, the daily feeding amount of female parent fish was reduced by 0.0017%-0.0067% / day in the first month, and by 0.0067%-0.0150% / day in the second and third months, until the daily feeding amount was reduced to 0.

[0146] Maintain a daily feeding rate of 0.5-1.0% for male broodstock, and reduce the daily feeding rate of broodstock in the late stage of gonadal development stage IV by 0.017%-0.033% / day, reducing the feeding rate to 0 and maintaining it.

[0147] Example 3

[0148] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0149] In step 1), the stocking density is 10 kg / m². 3 .

[0150] Example 4

[0151] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0152] In steps 2 and 3), the stocking density is 4 kg / m². 3 .

[0153] Example 5

[0154] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0155] In steps 2 and 3), the feeding amount at 8:00 AM is 50% of the daily feeding amount, and the feeding amount at 4:00 PM is 50% of the daily feeding amount.

[0156] Example 6

[0157] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0158] In step 3), during the reduced feeding method of rearing, the reduction rate of female parent fish in the first three months is 0.0055%-0.0111%.

[0159] When male parent fish enter the late stage of gonadal development (stage IV), the daily feed amount should be 0.5-1.0%. During the month of reduced feeding, the daily feed amount should be reduced by 0.017% for the first ten days and by 0.017%-0.042% for the next twenty days.

[0160] Example 7

[0161] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0162] In step 3), the water flow rate during the middle of stage IV of gonadal development is 0.4 m / s.

[0163] Example 8

[0164] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0165] In step 1), the daily temperature variation of the aquaculture water is 4°C.

[0166] In steps 2) and 3), the daily temperature variation of the aquaculture water is 2°C.

[0167] Example 9

[0168] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0169] The feed composition includes 40 wt% crude protein, 6-8 wt% crude fat, 6 wt% crude fiber, 17 wt% crude ash, ≥1.2 wt% total phosphorus, and 2 wt% lysine.

[0170] Example 10

[0171] In this embodiment, the regulation process of gonadal development in Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0172] DO is 6 mg / L, pH is 6.5-7.0, NH4+ + <0.5mg / L, NO2 － The concentration is 0.06-0.1 mg / L.

[0173] Comparative Example 1

[0174] The regulatory process of gonadal development in Chinese sturgeon broodstock in this comparative example includes the following steps:

[0175] 1) Chinese sturgeon broodstock in gonadal development stage II were bred using freshwater fish as the main feed source, with a daily feeding rate of 0.5-1.0% and a feeding frequency of once per day. Artificial rearing was carried out using flowing river water, and the water temperature was regulated year-round according to the annual temperature variations of the river. The water DO > 5.5 mg / L and NH4 < 0.5 mg / L were maintained. + <0.5mg / L, NO2 － <0.1 mg / L, pH value 6.5, to obtain broodstock fish in stage III gonadal development;

[0176] 2) During the period from stage III to the beginning of stage IV of gonadal development, the water flow rate should be controlled at 0.2 to 0.5 m / s. After the gonadal development reaches stage IV, the water flow rate should be controlled at 1.0 to 1.5 m / s.

[0177] Comparative Example 2

[0178] The regulatory process of gonadal development in Chinese sturgeon broodstock in this comparative example includes the following steps:

[0179] The following parameters were used to cultivate gonadal development in broodstock of Chinese sturgeon at gonadal development stage II:

[0180] Referring to the annual temperature variation of the Yangtze River downstream of Gezhouba Dam in Yichang, the aquaculture water temperature is controlled at 6-28.5℃; the feed nutritional composition includes: crude protein ≥40.0wt%, crude fat 6-8wt%, crude fiber ≤6.0wt%, crude ash ≤17.0wt%, calcium ≤5wt%, total phosphorus ≥1.2wt%, lysine ≥2wt%, and moisture ≤12wt%.

[0181] During the period of low water temperature when the breeding water temperature is below 12℃, the winterization feed is regulated by using a low daily feed rate of less than 1%. When the gonads of the offspring Chinese sturgeon broodstock develop to the level of stage III or above, the daily feed rate is strictly controlled to less than 1% to ensure that the gonads of the broodstock develop steadily.

[0182] The aquaculture water quality parameters were: DO 6 mg / L, pH 6.5-7.0, and NH4+. + ≤0.5mg / L, NO2 － ≤0.11mg / L.

[0183] For broodstock cultured at stage III or above of gonadal development, the light intensity should be controlled below 10,000 Lx;

[0184] During the process of gonadal development from stage III to the beginning of stage IV, the water flow rate of the culture water should be controlled at 0.2–0.5 m / s. After the gonadal development reaches stage IV, the water flow rate should be controlled at 0.5–1.0 m / s.

[0185] Comparative Example 3

[0186] The regulation process of gonadal development in the comparative Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0187] Step 3) Do not reduce the feeding amount during the rearing process; the daily feeding amount remains at 0.5-1.0%.

[0188] Comparative Example 4

[0189] The regulation process of gonadal development in the comparative Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0190] The daily feeding frequency is once per day.

[0191] Comparative Example 5

[0192] The regulation process of gonadal development in the comparative Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0193] Noise level in the aquaculture environment > 90 dB.

[0194] Comparative Example 6

[0195] The regulation process of gonadal development in the comparative Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0196] The daily feeding interval is 6 hours.

[0197] Comparative Example 7

[0198] The regulation process of gonadal development in the comparative Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0199] In steps 2) and 3), the stocking density is 6 kg / m². 3 .

[0200] Comparative Example 8

[0201] The regulation process of gonadal development in the comparative Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0202] In steps 2) and 3), the water temperature for aquaculture reaches 28℃.

[0203] Comparative Example 9

[0204] The regulation process of gonadal development in the comparative Chinese sturgeon broodstock is basically the same as in Example 1, except that:

[0205] The daytime light intensity is 5500-10000 Lx, and the nighttime light intensity is <20 Lx.

[0206] Test case

[0207] The female Chinese sturgeon broodstock obtained from Examples 1-10 and Comparative Examples 1-9 were tested in stages according to the B-ultrasound detection method. The gonadal development initiation rate and gonadal maturity rate were statistically analyzed, as shown in Table 1. The success rate refers to the ratio of the number of broodstock with reproductive capacity to the number of broodstock in gonadal development stage II.

[0208] Table 1

[0209]

[0210]

[0211] The male Chinese sturgeon broodstock obtained from Examples 1-10 and Comparative Examples 1-9 were tested in stages according to the B-ultrasound detection method. The gonadal development initiation rate and gonadal maturity rate were statistically analyzed, as shown in Table 2. The success rate refers to the ratio of the number of broodstock with reproductive capacity to the number of broodstock in gonadal development stage II.

[0212] Table 2

[0213]

[0214]

[0215] After years of research and practice, the rate of gonadal development initiation in female Chinese sturgeon broodstock has significantly increased, with the average initiation rate rising from the initial 3.25% to 20.58%, and the highest initiation rate reaching 27.59%. The average initiation rate of gonadal development in male Chinese sturgeon broodstock has increased from the initial 12.77% to 26.40%, which is far higher than the industry average of 4-6% initiation rate. In particular, the number of Chinese sturgeon broodstock transitioning from stage II to stage III has increased significantly since 2020-2023. Meanwhile, the number and proportion of breeding-capable broodstock have increased significantly. The proportion of female broodstock has steadily increased from an initial average of 37.50% to an average of over 71.41%. In particular, following the control method in Example 1, the gonadal degeneration rate of female Chinese sturgeon broodstock has decreased to 8.33%, and the proportion of breeding-capable broodstock has increased to 91.67%. The proportion of male broodstock has steadily increased from an initial 33.33% to 93.33%. This has laid a solid foundation for the large-scale breeding and release of Chinese sturgeon and has played an important role and significance in the conservation of the Chinese sturgeon species.

[0216] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for regulating gonadal development in Chinese sturgeon broodstock, characterized in that, The regulation process includes the following steps: 1) By feeding 0.5-1.0% of the feed per day and twice a day, gonadal initiation culture was carried out on Chinese sturgeon broodstock in gonadal development stage II to obtain broodstock in gonadal development stage III; 2) With a daily feeding amount of 0.5-1.0%, a daily feeding frequency of 2 times / day, and a breeding environment noise limit of 60dB, the broodstock in the gonadal development stage III were subjected to near-mature breeding to obtain broodstock in the early stage of gonadal development IV. 3) The female broodstock in the early stage of gonadal development stage IV were subjected to a first reduced feeding method, reducing the daily feed amount of the female broodstock to 0 and maintaining it within 3 months; the male broodstock in the late stage of gonadal development stage IV were subjected to a second reduced feeding method, reducing the daily feed amount of the male broodstock to 0 and maintaining it within 30 days, with the noise limit of the breeding environment at 40dB, to obtain broodstock with reproductive capacity; During steps 2) and 3), the water temperature for aquaculture is 10-27℃, and the stocking density is no higher than 5kg / m³. The feeding interval during the regulation process is 8-12 hours, the daytime light intensity is 3000-5000 Lx, and the nighttime light intensity is <20 Lx.

2. The control method according to claim 1, characterized in that, In step 1), the stocking density is 5-8 kg / m³.

3. The control method according to claim 1, characterized in that, In steps 2) and 3), the stocking density is 2-3 kg / m³.

4. The control method according to any one of claims 1-3, characterized in that, In steps 2) and 3), the amount of feed given at 8:00 am is 60%-70% of the daily feed amount, and the amount of feed given at 4:00 pm is 30%-40% of the daily feed amount.

5. The control method according to any one of claims 1-3, characterized in that, Step 3) The first reduced-feeding cultivation includes the following steps: The daily feeding amount for the female parent fish was reduced by 0.0017%-0.0067% / day in the first month; and / or, the daily feeding amount was reduced by 0.0067%-0.0150% / day in the second and third months. And / or, the second reduced-feeding culture includes the following steps: The daily feeding amount for the male parent fish was reduced by 0.017%-0.033% / day, down to 0 and maintained.

6. The control method according to any one of claims 1-3, characterized in that, Step 3) The first reduced-feeding cultivation includes the following steps: The daily feeding amount of the female parent fish was reduced by 0.0083-0.0333% per feeding during the first month. After the reduction, the daily feeding amount was kept unchanged for 5 days. Then, the daily feeding amount was reduced again by the first reduction amount, and the cycle was repeated until the daily feeding amount was 0. And / or, in the second and third months, the daily feeding amount is reduced by 0.0333-0.075% per reduction, and the daily feeding amount is kept unchanged for 5 days after the reduction. Then, the daily feeding amount is reduced again by the second reduction amount, and the cycle continues until the daily feeding amount is 0. And / or, the second reduced-feeding culture includes the following steps: The daily feeding amount of the male parent fish was reduced by 0.1-0.2% per feeding, and the daily feeding amount was kept unchanged for 5 days after the reduction. Then, the daily feeding amount was reduced again by 0.1-0.2% per feeding, and the cycle was repeated until the daily feeding amount was 0 and maintained.

7. The control method according to any one of claims 1-3, characterized in that, In steps 2) and 3), the water flow rate is 0.0-0.3 m / s from the middle of gonadal development stage III to the middle of gonadal development stage IV, and 0.5-1.0 m / s after the middle of gonadal development stage IV.

8. The control method according to any one of claims 1-3, characterized in that, In step 1), the daily temperature variation of the aquaculture water should not exceed 3℃; And / or, in steps 2) and 3), the daily variation in aquaculture water temperature does not exceed 1℃.

9. The control method according to any one of claims 1-3, characterized in that, The feed nutrient composition during the regulation process includes crude protein ≥ 42.0 wt%, crude fat ≥ 10.0 wt%, crude fiber ≤ 5.0 wt%, crude ash ≤ 16.0 wt%, total phosphorus ≥ 1.2 wt%, and lysine ≥ 2.5 wt%.

10. The control method according to any one of claims 1-3, characterized in that, During the regulation process, the DO in the aquaculture water was >7.5 mg / L, and the NH4+ was <7.5 mg / L. ＋ <0.5 mg / L, NO2 － <0.05 mg / L, pH value is 7.5-8.0.

Images