Method for regulating light environment to promote the development of female gonad of Russian sturgeon

Abstract

This invention discloses a method for regulating the light environment to promote gonadal development in female Russian sturgeon, belonging to the field of aquaculture technology. By regulating light intensity and photoperiod during stages II and III of ovarian development in female Russian sturgeon, the gonadal development rate is accelerated; the daytime light intensity is 7.99±4.44 W / m². 2 / s, nighttime light intensity 4.42±0.95W / m 2 The light cycle is 18-24 hours of light followed by 0-6 hours of darkness, with artificial lighting for 4-6.3 hours, and a 24-hour cycle. By adjusting the intensity of natural daytime light and supplemental LED lighting at night, the light intensity and photocycle are modified to meet the light environment requirements of flow-through cultured female Russian sturgeon during gonadal development. This promotes the speed of gonadal development, increases the average egg diameter, reduces individual differences in gonadal development among female Russian sturgeon, and ultimately improves the productivity and economic benefits of aquaculture enterprises.

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 light environment regulation method for promoting the gonadal development of female Russian sturgeon. BACKGROUND

[0002] As one of the important environmental factors for regulating the growth and development, energy metabolism and reproduction of aquatic animals, light contains three elements of light intensity, spectrum and photoperiod, and its changes directly or indirectly affect the feeding, growth, development, survival and reproduction of aquatic animals. At present, the effects of photoperiod changes on aquaculture objects have been widely used in the fields of improving the growth rate of aquaculture objects and promoting the gonadal development and maturation.

[0003] The regulation of environmental factors on the gonadal development of fish is mainly achieved through the hypothalamic-pituitary-gonadal axis by various sex steroid hormones, including estradiol E2, testosterone T and 11-ketotestosterone 11-KT. The photoperiod is related to the development and maturation of fish gonads, and light stimulates the photoreceptor organs and tissues of fish, and through the central nervous system, causes the secretion of the pituitary gland, thereby affecting the development of the gonads.

[0004] As the main product form of global sturgeon trade, caviar is an expensive aquaculture product, which is made of fish eggs taken from the ovary tissue of sturgeon and salted. Russian sturgeon (Acipenser gueldenstaedti) belongs to Acipenseriformes and occupies an important position among the sturgeon species used for caviar production. However, the long growth cycle, late sexual maturity and large individual differences in gonadal development greatly limit the yield of caviar. It is reported that the sexual maturity of farmed sturgeon requires 6-8 years, and each ovary maturation cycle also requires at least one year, which affects the yield of caviar and inhibits the willingness of practitioners to breed. In current sturgeon farming, light environment regulation lacks sufficient attention and technical support. It is of great significance to establish a simple light environment regulation technology to promote and improve the gonadal development of female Russian sturgeon and the yield of caviar. SUMMARY

[0005] The present application aims to provide a light environment regulation method for promoting the gonadal development of female Russian sturgeon.

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

[0007] A light environment regulation method for promoting the gonadal development of female Russian sturgeon, which promotes the gonadal development speed of female Russian sturgeon by regulating light intensity and photoperiod when the ovary development stage of female Russian sturgeon is in phase II and phase III; the daytime light intensity is 7.99±4.44 W / m 2 / s, and the nighttime light intensity is 4.42±0.95 W / m 2 / s, photoperiod 18-24h light, 0-6h darkness, wherein artificial light 4-6.3h, 24h as a cycle.

[0008] The method further comprises the following steps in the technical scheme:

[0009] (1) Selecting Russian sturgeon female fish at the ovarian development stage of phase II and phase III and having consistent average body length and weight, feeding the fish in a conventional flow aquaculture mode in a cement aquaculture pond until the fish adapt to the environment;

[0010] (2) Irradiating the fish with natural light above the water surface of the aquaculture pond during the day, and the light intensity on the water surface during the day being 7.99±4.44 W / m 2 / s;

[0011] (3) Setting up LED lighting lamps above the water surface of the aquaculture pond for night light supplement of the aquaculture pond, and the light intensity on the water surface during the night being 4.42±0.95 W / m 2 / s;

[0012] (4) Feeding the fish with sturgeon sinking compound feed during the feeding process.

[0013] In the technical scheme, the specific strategy of the light environment regulation is that the LED lighting lamps are turned off during the day, turned on 10 minutes before the beginning of sunset, reach the maximum light intensity near the beginning of the night, and are kept for 30 minutes before the end of the night light supplement, and then are turned off slowly, and the light supplement time during the day is 18-24h.

[0014] In the technical scheme, the Russian sturgeon female fish in step (1) has a body length of 108.48±6.93 cm and a weight of 18.86±3.57 kg.

[0015] In the technical scheme, the aquaculture pond has a feeding density of 27 kg / m 3 .

[0016] In the technical scheme, the aquaculture pond is a circular cement pond with a diameter of 10 m and a depth of 1.5-1.6 m, the flow water is circulated 7-9 times per day, and 166 Russian sturgeons are bred in each aquaculture pond.

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

[0018] In the technical scheme, the light supplement time refers to the time from when the LED lighting lamps reach the maximum brightness to when the light supplement is completely turned off, a remote wireless controller of the lamps is used to control the light period, and the LED lamps are turned on and off to complete the light supplement for the target time.

[0019] Further, the sinking feed is fed 2-3 times per day, the crude protein content of the feed is greater than 47%, and the crude fat content is greater than 14%.

[0020] The beneficial effects of the present application are:

[0021] The present application meets the demand of female Russian sturgeon for light environment during the development of gonad by artificially controlling light intensity and photoperiod through daytime regulation of natural light intensity and nighttime light supplement according to the demand of Russian sturgeon for specific light environment during the breeding season, promotes the speed of gonad development of Russian sturgeon, significantly improves the average egg diameter of female Russian sturgeon and the number of female fish at stage IV of ovary development, and significantly reduces the number of female fish at early stages II and III of ovary development, thereby improving the productivity level and economic benefits of the breeding enterprise. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The figure is a mode diagram of the light environment regulation system for breeding Russian sturgeon;

[0023] In the figure, 1 is a breeding pond, 2 is a metal frame, 3 is a sunshade net, 4 is an LED lighting lamp, and 5 is a wireless controller. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. The following non-limiting examples can make those skilled in the art more fully understand the present application, but do not limit the present application in any way.

[0025] Example 1

[0026] The project is implemented by selecting a circular breeding pond with a diameter of 10 m in a flow water breeding mode, the depth is 1.5-1.6 m, and a metal frame structure is installed around the breeding pond. A black sunshade net is laid on the metal frame at a height of 180-200 cm above the water pond to reduce the daytime light intensity and prevent the water temperature from being too high. The sunshade net can not be set when the air temperature and water temperature are low in autumn and winter, and the average light intensity on the water surface is 7.99±4.44 W / m 2 / s after shading in summer. Six LED lighting lamps are set below the sunshade net at a height of 180-190 cm above the water surface of the breeding pond for nighttime light supplement of the breeding pond, and the nighttime light intensity on the water surface is 4.42±0.95 W / m 2 / s.

[0027] The Russian sturgeon females with uniform body size and uniform gonad development stage (body length 108.48±6.93 cm, body weight 18.86±3.57 kg, and ovary development stage at phase II and III) were selected, and 166 Russian sturgeon were bred in each breeding pond with a density of 27 kg / m 3 The water was circulated 7-9 times per day, and the water quality parameters were detected regularly. 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. The sinking compound feed was fed 2-3 times per day. During the period, the common diseases of sturgeon such as red beak disease and gonadal infection were prevented and controlled. The breeding period was 150 days.

[0028] The specific strategy of light environment regulation was as follows: the LED lighting lamp was in the off state during the day, and was turned on 10 minutes before the beginning of sunset, and reached the maximum illumination intensity near the night, and was maintained until 30 minutes before the end of night light supplement, and then was slowly extinguished. The light supplement time during the day was 18 hours; for example, on May 18, the light supplement was started at 18:30 and was turned off at 23:30; on June 19, the light supplement was started at 19:00 and was turned off at 23:10; on July 19, the light supplement was started at 19:00 and was turned off at 23:30; on August 18, the light supplement was started at 18:30 and was turned off at 23:40; on September 18, the light supplement was started at 18:00 and was turned off at 0:00; and on October 17, the light supplement was started at 17:20 and was turned off at 0:20. The light supplement time refers to the time from the maximum brightness of the LED lamp to the complete extinguishing of the light supplement.

[0029] Example 2

[0030] The Russian sturgeon (body length, body weight, and gonad development stage were the same as in Example 1) was bred for 150 days using the light regulation method for improving the gonad development of the Russian sturgeon in flow water breeding. The difference from Example 1 was that the light cycle was 24 h light and 0 h darkness during the breeding, and the cycle was 24 h. The breeding environment conditions and feeding mode were the same as in Example 1.

[0031] Comparative Example 1

[0032] The Russian sturgeon (body length, body weight, and gonad development stage were the same as in Example 1) was bred for 150 days using the traditional breeding method. The difference from Example 1 was that the light cycle was the natural light cycle, and no night artificial light supplement was performed. The breeding environment conditions and feeding mode were the same as in Example 1.

[0033] According to the process in Example 1, 78.1% of the female Russian sturgeon developed to ovary stage IV under the light treatment mode, with an average fish egg diameter of 2.33±1.03 mm, which was significantly higher than 67.9% and 2.03±1.23 mm of the same size female fish raised without light supplement in the comparative example; 21.9% of the female fish under the light treatment mode were still at ovary development stages II and III, which was significantly lower than 32.1% of the comparative example 1 without light environment regulation.

[0034] According to the process in Example 2, 77% of the female Russian sturgeon developed to ovary stage IV under the light treatment mode, with an average fish egg diameter of 2.31±1.07 mm, which was significantly higher than 67.9% and 2.03±1.23 mm of the same size female fish raised without light supplement in the comparative example 1, and had no significant difference with the results in Example 1; 22% of the female fish under the light treatment mode were still at ovary development stages II and III, which was significantly lower than 32.1% of the comparative example without light environment regulation.

[0035] This shows that the 18-24h light scheme described in the present patent has a better promoting effect on the gonadal development of female Russian sturgeon than the natural light cycle without light time extension.

[0036] The above data were obtained by the following method: after the sturgeon was anesthetized in 400ppm MS-222, it was placed on a fixing frame with the abdomen facing up, a small opening was first made on the abdomen of the sturgeon with a sterilized surgical knife, and then the fish eggs were collected with a puncture egg collector, and then the fish egg diameter and ovary development stage were measured.

[0037] Average fish egg diameter = total length of fish eggs taken out / number of fish eggs

[0038] For oval fish eggs, the length arranged and measured was the long axis of the egg.

[0039] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for regulating the light environment to promote gonadal development in female Russian sturgeon, characterized in that: During stages II and III of ovarian development in female Russian sturgeon, the rate of gonadal development was accelerated by regulating light intensity and photoperiod; the daytime light intensity was 7.99±4.44 W / m². 2 / s, nighttime light intensity 4.42±0.95W / m 2 / s, with a light cycle of 18-24 hours of light and 0-6 hours of darkness, including 4-6.3 hours of artificial supplemental lighting, and a 24-hour cycle. The specific strategy for light environment control is as follows: LED lights are turned off during the day and turned on 10 minutes before sunset. The lights reach their maximum illumination intensity before nightfall and are maintained until 30 minutes before the end of nighttime supplementary lighting, after which they are slowly turned off. The total duration of daytime supplementary lighting is 18-24 hours.

2. The light environment control method according to claim 1, characterized in that: The method specifically includes the following steps: (1) Select female Russian sturgeon in the ovarian development stage II or III and with consistent average body length and weight, and raise them in cement culture ponds using conventional flow-through culture mode; (2) Natural sunlight irradiation above the water surface of the aquaculture pond during the day; the daytime light intensity on the water surface is 7.99±4.44 W / m. 2 / s; (3) LED lights were installed above the water surface of the aquaculture pond at night to supplement the nighttime lighting. The nighttime light intensity of the supplemental lighting on the water surface was 4.42±0.95 W / m. 2 / s; (4) Feed sturgeon sinking compound feed during the rearing process.

3. The light environment control method according to claim 2, characterized in that: The Russian sturgeon female mentioned in step (1) has a body length of 108.48±6.93 cm and a body weight of 18.86±3.57 kg.

4. The light environment control method according to claim 2, characterized in that: The stocking density in the aquaculture ponds is 27 kg / m². 3 .

5. The light environment control method according to claim 2, characterized in that: The aquaculture water temperature is 16-24 ℃, dissolved oxygen is greater than 6 mg / L, pH is 6.5-7.5, ammonia nitrogen content is less than 0.3 mg / L, and nitrite nitrogen content is less than 0.02 mg / L.

6. The light environment control method according to claim 3, characterized in that: Supplemental lighting duration refers to the period from when the LED lighting reaches its maximum brightness until it completely turns off.

7. The light environment control method according to claim 2, characterized in that: Feed sinking feed 2-3 times a day, with crude protein content greater than 47% and crude fat content greater than 14%.

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