CN114304021A - Method for promoting growth and molting of scylla paramamosain by regulating and controlling environmental factors - Google Patents

Abstract

The invention provides a method for promoting the growth and molting of juvenile Scylla simulacrum by regulating environmental factors, which is to cultivate in a blue background aquaculture water, and use a full-spectrum LED lamp as a light source for cultivation; The light intensity of the light source is 11.36‑18.27W m ^‑2 , and the light time is 12‑18 hours; the k value of the culture container space is 29.23‑59.19. The method of the invention improves the growth and molting of juvenile Scylla simulans by setting the illumination parameters, and it is clarified that under the full-spectrum LED lamp, the illumination intensity is set to be 11.36-18.27W m ^-2 , and the photoperiod is L:D=12-18 The maximum growth performance and molting can be achieved in a culture container with a low-light environment, a background color of blue and a culture container space k value of 29.23‑59.19.

Description

A method for promoting the growth and molting of Scylla simulans juveniles by regulating environmental factors

technical field

The invention belongs to the technical field of intermediate cultivation of juvenile Scylla simulans, in particular to a method for promoting the growth and molting of juvenile Scylla simulans by regulating environmental factors.

Background technique

Scylla. paramamosain belongs to the phylum Arthropoda, the class of soft armor, the order Decapoda, the family of the family Scylla, and the genus Scylla. It has the characteristics of delicious meat, high nutritional value, and large market demand. In 2020, the artificial aquaculture output of Scylla simulans is 159,433 tons, which is the seawater crab with the highest aquaculture production in China.

The artificial seedling technology of Scylla simulans has made a breakthrough in my country, but due to the unstable output of artificial seedlings, wild seedlings in fishing sea areas are still mainly used in breeding. In recent years, researchers at home and abroad have done a lot of research on the culture technology and biology of Scylla simulans. At present, the seedlings of Scylla simulatum are mainly obtained in two ways, one is to capture wild Scylla simulans seedlings in natural sea areas, and the other is to cultivate seedlings artificially in indoor cement pools. The artificially cultivated seedlings are not stable enough to achieve large-scale stable emergence. At the same time, the difference of water environment between nursery water and marine pond culture has a certain influence on the survival rate of early juvenile crab culture. Therefore, the intermediate cultivation of Scylla simulans is expected to be an effective means to improve the survival rate of Scylla simulans.

Moulting is an important physiological phenomenon in the growth, development and reproduction of crustaceans, and there is a significant positive correlation between molting and growth of crustaceans. The decline in growth performance caused by slow molting has seriously affected the economic benefits of juvenile Scylla simulacrum.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for promoting the growth and molting of juvenile Scylla simulacrum by regulating environmental factors, namely a method for promoting the growth and molting of juvenile Scylla simulans through illumination, background color and culture container space .

The method for promoting the growth and molting of juvenile Scylla sinensis provided by the present invention is to cultivate in aquaculture water body with a blue background, and use a full-spectrum LED lamp as a light source for cultivation;

Further, the illumination intensity of the light source is 11.36-18.27W m ^-2 , and the illumination time is 12-18 hours;

Further, in the cultivation method, the space k value of the cultivation container is 29.23-59.19.

In the culturing method, the salinity of seawater is 23-25ppt, and the water temperature is 25-27°C.

The method of the invention improves the growth and molting of juvenile Scylla sinensis by setting the illumination parameters, and it is clarified that under the full-spectrum LED lamp, the illumination intensity is set to be 11.36-18.27W m ^-2 , and the photoperiod is L:D=12-18 The maximum growth performance and molting can be achieved in a culture container with a low-light environment, a background color of blue and a culture container space k value of 29.23-59.19.

Description of drawings

Fig. 1: the experimental result figure of the survival, growth and molting of the juvenile Scylla simulans in Example 1;

Figure 2: Fitting curve of specific growth rate and light wavelength of Scylla simulans juveniles;

Fig. 3: The fitting regression curve diagram of the optimum light intensity of Scylla simulans based on a specific growth rate in Example 2;

Fig. 4: the experimental result graph of the survival and growth of the juvenile Scylla simulans in Example 3;

FIG. 5 : Graph of experimental results of the survival, growth and molting of Scylla simulans juveniles in Example 4. FIG.

Detailed ways

The establishment steps of the method of the present invention are as follows:

1) LED lights with different light colors (wavelengths) are erected on the top of each breeding unit of Scylla simulans, which are full spectrum, purple light (405nm), blue light (470nm), cyan light (510nm), green light (525nm), yellow light Light (570nm) and red light (625nm), the light intensity of each light color is set to 1W m-2, and the photoperiod is 12L:12D.

2) based on the screening result of step 1), determine that the full-spectrum LED lamp is the best light source, and set the equal-difference light intensity gradient, and set the light intensity to be 0, 5, 10, 15, 20, 25 and 30W m ^-2 ; Filter the light intensity;

3) Based on the screening results of steps 1) and 2), set different light periods under the appropriate light intensity range, and set the experimental light periods as a.L:D=0:24; b.L:D=6:18; c.L:D=12 : 12; d.L:D=18:6 and e.L:D=24:0; screen for photoperiod;

4) Based on the screening results of step 1), step 2) and step 3), under suitable lighting environment conditions, six culture container colors of red, yellow, green, blue, black and white are set respectively.

5) Based on the screening results of step 1), step 2), step 3) and step 4), in a suitable lighting environment and a blue culture container, set the ratio of the bottom area of the container to the square ratio of the carapace width of Scylla simulans. Culture containers with k values of 4.42, 17.67, 39.76 and 70.68.

In step 1) to step 5), artificial compound feed is fed during the cultivating process of juvenile Scylla simulacrum.

The present invention will be described in detail below with reference to the embodiments and accompanying drawings.

Example 1: Screening of different wavelengths

1) After sand filtration and reverse osmosis, the seawater with the specified experimental salinity (23-25ppt) enters the independent breeding unit. Set up brackets to install LED lights on the top of the breeding unit.

2) Using artificially cultivated C1 stage Scylla simulans juveniles (12.05±2.15mg) as the experimental material, start the LED lights on the top of the breeding unit, which are full spectrum, violet light (405nm), blue light (470nm), cyan light ( 510nm), green light (525nm), yellow light (570nm) and red light (625nm) LED lights, the light intensity of each light color is set to 1W m-2, and the photoperiod is 12L:12D.

Irradiate for 12 hours a day, and use a shading cloth to shade the breeding rack where the breeding unit is located. The molting situation of Scylla simulatum was observed every day, and after 8 weeks of culture experiments, the optimum light color (wavelength) for the growth of Scylla simulans juveniles was comprehensively evaluated with the specific growth rate and molting frequency during the breeding period as indicators;

(3) During the breeding experiment, artificial compound feed was fed, and the feeding amount was 5% of the body weight. The breeding unit was sucked and replaced with water every day. The nitrite content is lower than 0.5 mg L ^-1 ;

(4) Record the molting of each experimental crab at 8:00 every morning;

(5) After culturing for 8 weeks, count the number of surviving experimental crabs in each experimental group, weigh the weight of each experimental crab and measure the body length, body width and body height;

(6) The optimal growth wavelength was obtained based on the quadratic regression curve with a specific growth rate as an index. Under this wavelength, the juveniles of Scylla simulatus had the best growth performance and could promote their molting.

After 8 weeks of culture experiment, the survival, growth, molting frequency and three-time fitting regression curve of each experimental group are shown in Figure 1 and Figure 2. The results showed that the full spectrum, blue light and cyan light groups had higher viability, significantly higher than those of the violet and yellow light groups, the blue light group had higher weight gain rate and specific growth rate, and the molting frequency was the highest in the full spectrum and cyan light groups, based on three Regression curve fitting found that the optimum light wavelength for growth of Scylla simulans juveniles was 466.67 nm. Therefore, in this example, it is determined that the full spectrum, blue light and cyan light should be used as the light colors of the production light during the cultivation of Scylla simulans juveniles.

Example 2: Screening of light intensity

Screening the effects of different light intensities on the survival, growth and molting of Scylla simulans juveniles includes the following steps:

1) A bracket is installed on the top of the breeding unit to install a full-spectrum LED lamp, an iso-difference light intensity gradient is set, and the experimental light intensity is set to be 0, 5, 10, 15, 20, 25 and 30W m ^-2 ;

2) Using the juvenile mud crab (20.09±3.17mg) of C2 stage as the experimental material, start the LED light on the top of the breeding unit, irradiate for 12 hours a day, and use a shading cloth to shade the breeding rack where the breeding unit is located. The molting situation of Scylla simulatum was observed every day, and after 8 weeks of culture experiment, the optimum light for the growth of Scylla simulans juveniles was comprehensively evaluated based on the fitting regression model with the specific growth rate and molting frequency during the breeding period as indicators. strength range;

3) During the breeding experiment, artificial compound feed was fed, and the feeding amount was 5% of the body weight. The breeding unit was sucked and replaced with water every day. Nitrate content is less than 0.5 mg L ^-1 ;

4) Record the molting of each experimental crab at 8:00 every morning;

5) After 8 weeks of culturing, count the number of surviving experimental crabs in each experimental group, weigh the body weight of each experimental crab and measure body length, body width and body height;

6) Using a specific growth rate as an index, the optimal growth light intensity range was obtained based on the regression curve. Within this light intensity range, the growth performance of Scylla simulatum juveniles was the best, and it could promote its molting.

Results: After 8 weeks of culture experiment, the optimal light intensity range for the growth of Scylla simulans juveniles based on the regression curve was 11.36-18.27W m ^-2 . Therefore, in the process of cultivating Scylla simulans juveniles, full-spectrum illumination with a light intensity of 11.36-18.27Wm ^-2 should be used to promote the growth and molting of juvenile Scylla simulans.

The survival, growth, molting and regression curves of each experimental group are shown in Table 1 below.

Table 1: Effect of light intensity on the growth performance and survival of Scylla simulans

The results of regression curve analysis showed that the optimum light intensity range for the growth of Scylla simulans juveniles was 11.36-18.27Wm ^-2 .

Example 3: Screening of photoperiods

Screening the effects of different light cycles on the survival, growth and molting of Scylla simulans juveniles, including the following steps:

1) Take the full-spectrum LED lamp as the only light source, and the illumination intensity is 12-15W m ^-2 ; different illumination periods are set, respectively 1) L:D=0:24; 2) L:D=6:18; 3) L:D=12:12; 4) L:D=18:6 and 5) L:D=24:0,

2) The juvenile Scylla sinensis (13.20±2.48mg) in C1 stage was used as the experimental material;

3) During the breeding experiment, artificial compound feed was fed, and the feeding amount was 5% of the body weight. The breeding unit was sucked and replaced with water every day. Nitrate content is less than 0.5 mg L ^-1 ;

4) Record the molting of each experimental crab at 8:00 every morning;

5) After 8 weeks of culturing, count the number of surviving experimental crabs in each experimental group, weigh the body weight of each experimental crab and measure body length, body width and body height;

6) Using the specific growth rate as an index, the optimal growth light cycle range was obtained, and the growth performance of Scylla simulans juveniles was the best within this light intensity cycle range.

As shown in Figure 4, after 8 weeks of culture experiment, the light cycle of L:D=12:12, L:D=18:6 is more conducive to the growth of juvenile Scylla sinensis. Therefore, in order to improve the growth performance of juvenile Scylla simulans during the cultivation process of juvenile Scylla simulans, a light cycle with a light time of 12 to 18 hours should be adopted.

Example 4: Screening the background color of culture

A method for screening the background color of aquaculture water for the survival, growth and molting of Scylla simulans juveniles, comprising the following steps:

1) The juvenile crabs were temporarily cultured in plastic buckets for 3 days, and the juvenile crabs (0.02±0.01g) which were healthy, vigorous and complete with complete appendages were selected and placed in a polyethylene culture container (inner size) with 0.5L seawater. : 130mm×83mm×48mm). The colors of the breeding containers are red, yellow, green, blue, black and white;

2) Put a juvenile crab in each breeding container, the seawater used for breeding is filtered and UV-sterilized, the salinity is 22-25ppt, the temperature is 25-27℃, the dissolved oxygen is >6mg/L, the pH value is 8-8.5, and the total ammonia nitrogen (TAN)＜0.5mg/L;

3) During the breeding experiment, artificial compound feed was fed, and the feeding amount was 5% of the body weight, and the breeding unit was sucked and changed water every day;

4) The molting of each experimental crab was recorded daily.

As can be seen from Figure 5, the background color of the blue container can significantly improve the survival rate and growth performance of juvenile Scylla simulans.

Example 5: Screening the k value of the size of the breeding space

Determining the effect of the space size of the culture container on the survival and growth of Scylla simulans juveniles includes the following steps:

1) The juvenile crabs were temporarily cultured in plastic buckets for 3 days, and healthy, vigorous and complete appendages were selected for the juvenile crabs (0.14±0.02g) in polyethylene culture containers with different space sizes. The space size of the breeding container is represented by the value of k, k=A/CW ² , A is the bottom area of the container, CW is the width of the carapace, and the k values are set to 4.42, 17.67, 39.76 and 70.68 respectively;

2) Put a juvenile crab in each breeding container, the seawater used for breeding is filtered and UV-sterilized, the salinity is 16-17ppt, the temperature is 22-25℃, the dissolved oxygen is more than 6mg/L, the pH value is 8-8.5, the total ammonia nitrogen (TAN)＜0.1mg/L;

3) During the breeding experiment, artificial compound feed was fed, and the feeding amount was 5% of the body weight, and the breeding unit was sucked and changed water every day;

4) The molting of each experimental crab was recorded daily.

Therefore, the survival rate and growth performance of Scylla simulans can be improved by setting the k value of the container space size to 29.23-59.19.

The survival and growth results of each experimental group are compared in Table 2 below.

Table 2 Influence of culture container space on growth performance and survival of Scylla simulans

The above results indicate that setting parameters such as artificial light, background color and space size of the culture container during the cultivation of Scylla simulans juveniles will help to improve the survival, growth and molting of juvenile Scylla simulans.

Example 6: Cultivate the juvenile Scylla simulans using the established method

1) The juvenile crabs were temporarily cultured in plastic buckets for 3 days, and the juvenile crabs (28.33mg) that were healthy, vigorous and complete with complete appendages were selected in blue culture containers. Each culture container was separated by a plastic partition. The container is divided into 9 independent breeding units (10*10*10).

2) Put a juvenile crab in each breeding unit, the seawater used for breeding is filtered and UV-sterilized, the salinity is 23-25ppt, the temperature is 22-25℃, the dissolved oxygen is more than 6mg/L, the pH value is 7.5-8.5, the total ammonia nitrogen (TAN)＜0.1mg/L;

3) The juvenile Scylla simulans in the C2 stage was set as the experimental material (initial weight=28.33mg), the full-spectrum LED lamp was used as the only light source, the light intensity was 12W m ^-2 , the photoperiod was 12L:12D, and the background color of the culture container was is blue, and the initial k value is 126.5. The experimental crabs in the control group were cultured under dark conditions, and the differences in growth and molting of Scylla simulatum juveniles between the two groups were compared and observed.

4) During the breeding test period, artificial compound feed was fed once a day, and the feeding amount was 5% of the body weight, and the breeding unit was sucked and changed water every day;

5) The survival and molting of each experimental crab were recorded daily.

The results showed that compared with the control group, there was no significant difference in the survival rate and intermolt period of the experimental group from C2 to C4, but the growth performance (end weight, weight gain rate, specific growth rate) of the experimental group was significantly higher than the mean level. control group (Table 3).

Table 3: Effects of environmental factors on the growth performance, survival and molting of Scylla simulans

The above results show that the method of the present invention can effectively promote the growth of juvenile Scylla simulans.

Claims (6)

1. A method for promoting the growth and the molting of young Scylla paramamosain is characterized in that the young Scylla paramamosain is cultured in a blue background culture water body, and a full-spectrum light source is used as a light source for culture.

2. The method of claim 1, wherein the light source has an illumination intensity of 11.36 to 18.27W m^-2。

3. The method of claim 1, wherein the illumination time of the light source is 12 to 18 hours.

4. The method of claim 1, wherein the culture vessel has a k-value of 29.23 to 59.19.

5. The method of claim 1, wherein the salinity of the seawater in the cultivation method is 23-25 ppt.

6. The method of claim 1, wherein the seawater temperature in the cultivation method is 25-27 ℃.

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