A method for promoting the development of the gonads of female Russian sturgeon by mixed breeding of males and females

Abstract

The application discloses a kind of methods for promoting the gonadal development of female Russian sturgeon, belonging to the technical field of aquaculture.In the ovarian development stage of female Russian sturgeon, when it is in phase II-III, by adding male fish for mixed culture, to promote the ovarian development speed of female Russian sturgeon;The number of added male fish accounts for 10% of the total number of fish products, and the male fish is in phase IV-V of the testis development stage.The application can effectively accelerate the ovarian development speed of female Russian sturgeon, increase the average egg diameter of fish eggs, reduce the inter-individual difference of ovarian development of female Russian sturgeon, and effectively improve the productivity level and economic benefit of the breeding enterprise.Meanwhile, the breeding method is simple to operate, and does not need to strictly control the breeding conditions, which can be widely applied to the breeding of sturgeon and other aquatic animals.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of the flow aquaculture of female Russian sturgeon, and particularly relates to a method for promoting the gonadal development of female Russian sturgeon through mixed breeding of male and female Russian sturgeons. BACKGROUND

[0002] In the aquatic ecological environment, the perception of the aquatic organisms to the environment and other organisms is more dependent on pheromones due to the limited vision. The pheromones secreted by fish are mainly divided into three types according to the functions: anti-predation, social relationship and reproduction. Although several types of compounds have been detected, most of the pheromones are mixtures of multiple compounds.

[0003] The pheromones related to reproduction are called sex pheromones, which can induce the gonadal development of aquaculture species, stimulate the reproductive behavior and achieve the synchronization of reproduction. For example, in the artificial reproduction process of Haliotis discus hannai, the use of female abalones treated with male abalones in water can effectively promote the maturation of the gonads and the reproductive behavior of the female abalones. In the cultivation of Nile tilapia (Oreochromis niloticus) and Macrobrachium rosenbergii, different sex ratios can also have a significant impact on the growth and development.

[0004] The Russian sturgeon has a fast growth rate and relatively strong disease resistance, but it has problems such as a long gonadal development cycle, large individual differences and premature follicle closure in the natural and cultivated environments, which undoubtedly affects the further improvement of caviar production and inhibits the desire of practitioners to participate. In the current sturgeon cultivation, the role of mixed breeding of male and female sturgeons and pheromones in production lacks attention and technical support. Establishing a mixed breeding mode of male and female Russian sturgeons is of great significance to promote the ovarian development of sturgeons and the production of caviar, and also has certain reference significance for other aquaculture species. SUMMARY

[0005] The present application aims to provide a method for promoting the gonadal development of female Russian sturgeons through mixed breeding of male and female sturgeons.

[0006] To achieve this object, the technical scheme adopted by the present application is as follows:

[0007] The method for promoting the gonadal development of female Russian sturgeons through mixed breeding of male and female sturgeons comprises the following steps: when the ovarian development of the female Russian sturgeon is in the II-III period, adding male sturgeons for mixed breeding to promote the ovarian development speed of the female Russian sturgeon; the number of the added male sturgeons accounts for 10% of the total number of fish, and the male sturgeons are in the IV-V period of the testis development stage.

[0008] Further, the method specifically comprises the following steps in the technical scheme:

[0009] (1) selecting female Russian sturgeon with ovary development stage at phase II-III and consistent average weight and length, and feeding them in a culture pond in a flow water mode;

[0010] (2) selecting adult male Russian sturgeon with testis development stage at phase IV-V, sperm flowing out through abdominal puncture, and consistent average length and weight, and synchronously feeding the female Russian sturgeon in step (1) in the same culture pond, and the number of male Russian sturgeon accounts for 10% of the total number of fish;

[0011] (3) feeding the Russian sturgeon with sinking compound feed during the whole culture process.

[0012] Further, in the technical scheme, the female Russian sturgeon in step (1) has a weight of 18.92±6.44 kg and a length of 108.38±6.74 cm.

[0013] Further, in the technical scheme, the feeding density in step (1) is about 27 kg / m 3 .

[0014] Further, in the technical scheme, the culture pond in step (1) is a circular cement pond with a diameter of 10 m and a depth of about 1.6 m, and the flow water is circulated 7-9 times per 24 hours; 166 Russian sturgeons are bred in each culture pond, including 150 female Russian sturgeons and 16 male Russian sturgeons.

[0015] Further, in the technical scheme, the culture pond in step (1) needs to be covered with a sunshade net in summer to prevent high temperature, and the sunshade net is located at a position 1.8-2.0 m above the water surface of the culture pond.

[0016] Further, in the technical scheme, the sinking compound feed in step (3) has a crude protein content of greater than 47%, a crude fat content of greater than 14%, a crude fiber content of 3%, a crude ash content of 8%, a water content of 8.5%, an amino acid content of greater than 3%, a total phosphorus content of less than 2%, a calcium content of greater than 0.8%, and is fed 2-3 times per day with a daily bait rate of 0.1-0.5%.

[0017] Further, in the technical scheme, the water temperature is 16-24℃, the pH is 6.5-7.5, the dissolved oxygen is greater than 6 mg / L, the ammonia nitrogen content is less than 0.3 mg / L, and the nitrite nitrogen content is less than 0.02 mg / L.

[0018] The present application has the following beneficial effects:

[0019] The application can effectively accelerate the development speed of the ovary of Russian sturgeon female fish, improve the average egg diameter of fish eggs, reduce the individual difference of the ovary development of Russian sturgeon female fish, and effectively improve the productivity level and economic benefits of a breeding enterprise. Meanwhile, the breeding method is simple to operate, does not need to strictly control the breeding conditions, and can be applied to the breeding of sturgeon and other aquatic animals on a large scale.

[0020] According to the action of the sex pheromone between male and female fish, the application realizes the stimulation of the gonadal development of female Russian sturgeon by mixing a certain proportion of adult male fish in the female fish, and further significantly improves the average egg diameter of female fish and the number of sturgeon with phase IV ovary which can be immediately used for processing caviar, and significantly reduces the number of female fish with phase II-III ovary which develops earlier. DETAILED DESCRIPTION

[0021] In order to further embody and clarify the purpose and specific technical scheme advantages of the application, the technical scheme in the application will be clearly and completely described below through a specific embodiment. The following non-limiting examples can make those skilled in the art more fully understand the application, but do not limit the application in any way.

[0022] Example 1

[0023] In this embodiment, a circular cement breeding pond with a diameter of 10 m and a depth of 1.5-1.6 m is selected in a flow water breeding mode. A metal frame is installed around the breeding pond, and a sunshade net is covered on the water surface of the breeding pond at a position of 1.8-2 m above the breeding pond relying on the metal frame structure to avoid high water temperature when the air temperature is high.

[0024] 150 female Russian sturgeons with basically consistent body length and weight and ovary development at phase II-III (18.92±6.44 kg, body length 108.38±6.74 cm, average fish egg diameter 1.85±0.37 mm) are selected, and the number of mixed Russian sturgeon males accounts for 10% of the total number of fish in each pond, that is, 16 male fish with consistent body size and testis development at phase IV-V are selected; the above 166 Russian sturgeons are placed in the same breeding pond for breeding, and the breeding density is about 27 kg / m 3 , and the breeding cycle is 160 days.

[0025] The sinking compound feed is fed 2-3 times per day, and the daily bait rate is 0.1%-0.5%. The crude protein content in the compound feed should be greater than 47%, the crude fat content should be greater than 14%, the crude fiber content should be 3%, the crude ash content should be 8%, the water content should be 8.5%, the amino acid content should be greater than 3%, the total phosphorus content should be less than 2%, and the calcium content should be greater than 0.8%.

[0026] Each cement culture pond was circulated 7-9 times per day, and water quality parameters were regularly detected. During the period, the water temperature was 16-24℃, the dissolved oxygen was greater than 6 mg / L, the pH was 6.5-7.5, the ammonia nitrogen content was less than 0.3 mg / L, and the nitrite nitrogen content was less than 0.02 mg / L. During the cultivation period, attention was paid to the prevention and control of common diseases of sturgeon, such as sturgeon red beak disease and bacterial infection of the gonad.

[0027] Comparative Example 1

[0028] Comparative Example 1 is different from Example 1 in that no male Russian sturgeon is mixed in Comparative Example 1, and all the sturgeons cultivated are adult female Russian sturgeons.

[0029] At the same time, at the same location, in the same breeding place and environment, 166 female Russian sturgeons with basically the same body length and weight as in Example 1 and with the ovary development at the II-III stage were selected, and the above-mentioned total of 166 Russian sturgeons were bred in the same breeding pond, with a breeding density of about 27 kg / m 3 , and a breeding cycle of 160 days. The water quality conditions, the sinking compound feed, the feeding frequency and the daily bait rate during the breeding process were the same as in Example 1.

[0030] Comparative Example 2

[0031] Comparative Example 2 is different from Example 1 in that the number of male Russian sturgeons mixed in Comparative Example 2 accounts for 20% of the total number of fish in each pond, 32 male sturgeons and 134 female sturgeons. The rest of the conditions are the same as in Example 1 and Comparative Example 1.

[0032] In Example 1, after 160 days of mixed breeding of females and males, 78% of the female Russian sturgeons developed to the ovary IV stage, with an average egg diameter of 2.46±0.99 mm, which was significantly higher than 68% and 2.09±1.23 mm in Comparative Example 1 without mixed breeding of females and males (with the same initial state); at the same time, 21% of the female sturgeons were still at the ovary II-III stage under the mixed breeding of females and males, which was significantly lower than 32% in Comparative Example 1 without mixed breeding of females and males. This shows that the use of 10% male Russian sturgeons for mixed breeding significantly outperforms the all-female breeding without mixed breeding of males in promoting the development of the gonad of female Russian sturgeons.

[0033] In Comparative Example 2, after 160 days of mixed breeding of females and males, 72% of the female Russian sturgeons developed to the ovary IV stage, with an average egg diameter of 2.29±1.04 mm, which was lower than 78% and 2.46±0.99 mm in Example 1; at the same time, 30% of the female sturgeons were still at the ovary II-III stage under the mixed breeding of 20% males, which was higher than 21% in Example 1. This shows that the use of 10% male Russian sturgeons for mixed breeding outperforms the method of using 20% male Russian sturgeons in promoting the development of the gonad of female Russian sturgeons.

[0034] The above data is obtained by the following method: 400 ppm MS-222 anesthetic is prepared in a basket, and the sturgeon is placed in the basket for anesthesia, and then the sturgeon is placed on a metal fixing frame with the abdomen facing up, a small opening is made on the abdomen of the fish with a sterilized surgical knife, and then the fish eggs are taken out using a puncture egg taking device, and the diameter of the fish eggs is measured and the development stage of the ovary is determined.

[0035] Average fish egg diameter = total length of fish eggs taken out / number of fish eggs

[0036] Total length of fish eggs taken out is the length measured after arranging the long axis of all fish eggs taken out along the scale.

[0037] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions described in the foregoing examples can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for polyculture of males and females to promote gonadal development in female Russian sturgeon, characterized in that: Select female Russian sturgeon with consistent average weight and body length, and whose ovarian development is in stage II-III. Add male sturgeon for mixed culture to promote the ovarian development speed of female Russian sturgeon, increase the average egg diameter of female sturgeon and the number of sturgeon with stage IV ovaries. Adult male Russian sturgeon with testes in stages IV-V, who had semen flowing out via abdominal puncture and had the same average body length and weight were selected and raised in the same flowing water culture pond as females. The number of males accounted for 10% of the total number of fish and they were fed sturgeon sinking formulated feed throughout the entire culture process.

2. The method for mixed-sex rearing according to claim 1, characterized in that: The female Russian sturgeon weighs 18.92 ± 6.44 kg and measures 108.38 ± 6.74 cm in length.

3. The method for mixed-sex rearing according to claim 1, characterized in that: The stocking density is 27 kg / m² 3 .

4. The method for mixed-sex rearing according to claim 1, characterized in that: The aquaculture ponds need to be covered with shade nets in summer, with the shade nets positioned 1.8-2.0 m above the aquaculture water surface.

5. The method for mixed-sex rearing according to claim 1, characterized in that: The sinking compound feed contains more than 47% crude protein, more than 14% crude fat, 3% crude fiber, 8% crude ash, 8.5% moisture, more than 3% amino acids, less than 2% total phosphorus, and more than 0.8% calcium. It is fed 2-3 times a day with a daily feed conversion ratio of 0.1-0.5%.

6. The method for mixed-sex rearing according to claim 1, characterized in that: The water temperature is 16-24 ℃, pH is 6.5-7.5, dissolved oxygen is greater than 6 mg / L, ammonia nitrogen content is less than 0.3 mg / L, and nitrite nitrogen content is less than 0.02 mg / L.