Method for improving body color and growth of young lutjanus erythropterus

Abstract

The invention relates to a method for improving body color and growth of young lutjanus erythropterus, which comprises the following steps of: breeding the young lutjanus erythropterus in an indoor breeding barrel, feeding the young lutjanus erythropterus with feed in the period, feeding the young lutjanus erythropterus once in the morning and afternoon every day, changing water and cleaning the bottom every day, and carrying out breeding under the following conditions: i) continuously aerating in the breeding barrel by using a nano air stone, the concentration of dissolved oxygen is 6.5-7.4 mg / L, ii) the pH value of water in the culture barrel is 7.5-8.4, iii) the water temperature and salinity in the culture barrel are kept relatively unchanged and are 27.3-33.2 DEG C and 25-31 per mill, and iv) the culture barrel is covered with black-out cloth, the illumination condition of culture is set as a blue light source, and the light intensity from the edge to the center of the culture barrel is 250-1500lux; and v) the breeding period is more than 45 days. According to the method, the proper light environment is created for the lutjanus erythropterus according to the preference of lutjanus erythropterus to the light environment, the growth and survival rate of the lutjanus erythropterus can be improved, the brightness and redness value of the lutjanus erythropterus body color can be improved, lutjanus erythropterus seedlings which grow fast, are good in condition and are high in survival are obtained, and the economic benefits of breeding enterprises are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aquaculture, and in particular relates to an artificial breeding method for redfin snapper. Background Art

[0002] Light is one of the important environmental factors that affect the growth and development of aquatic organisms. Fish feeding, growth, development and survival are directly or indirectly affected by light. The current traditional method of directly using natural light is difficult to meet the needs of future intensive factory farming models, and research on efficient light conditions to increase production and improve quality is urgently needed.

[0003] The red-finned snapper (Lutjanus erythopterus) belongs to the class of Osteichthyes, the subclass of Actinopterygii, the order of Perciformes, the family of Lutjanidae, and the genus of Lutjanus. It has a wide range of habitats, and its traces can be seen in reef-sand mixed areas, gravel areas, rocky areas, muddy areas, or independent reefs in the open sea. It is distributed in the Indian Ocean, the Western Pacific Ocean, etc., and in the East China Sea and the South China Sea in China. The red-finned snapper is an important marine economic fish, rich in protein and fat, and belongs to a high-quality fish variety with great economic value. It has become an important breeding object in the southern coastal areas of China and Southeast Asia. However, in the actual breeding and seedling raising process, the survival rate of the red-finned snapper is low. There are few reports on the study of the light quality preference color of the red-finned snapper during its growth process. CN117941644A discloses a transport device and a transport method for improving the survival rate of red-finned snapper seedlings, and discloses that the survival rate can be improved by using white light at a light intensity of 100 lux. Summary of the invention

[0004] The inventors have extensively screened and studied various light quality conditions, and finally obtained a method specifically suitable for improving the body color and growth of redfin snapper juveniles, the method comprising:

[0005] The redfin snapper fry were placed in indoor breeding barrels for breeding. During the breeding period, they were fed with feed, and fed once in the morning and afternoon. The water was changed and the bottom was cleaned every day. The breeding conditions were:

[0006] i) The aquaculture tank uses nano-air stones for continuous aeration, and the dissolved oxygen concentration is 6.5-7.4 mg / L.

[0007] ii) The pH of the water in the culture tank is 7.5-8.4,

[0008] iii) The water temperature and salinity in the culture tank remain relatively unchanged at 25-31°C and 27.3-33.2‰ respectively.

[0009] iv) The culture tank is covered with a shade cloth, the lighting condition for culture is set to a blue light source, and the light intensity from the edge to the center of the culture tank is 250-1500 lux;

[0010] v) The breeding cycle is more than 45 days.

[0011] Preferably, the above-mentioned lighting conditions in the culture are screened by the following method:

[0012] A preference behavior experimental device is used to screen the light intensity range and light quality conditions suitable for the growth of the redfin snapper fry, the preference behavior experimental device includes a breeding bucket, a light source, a video monitor, a nano air circle and a timer switch, and the entire experimental device is covered with a blackout cloth; an equilateral (e.g., 10 cm side length) hexagonal transparent column is placed in the central area of ​​the breeding bucket (e.g., a diameter of about 0.8 meters), and six kinds of LED lights, red light, blue light, yellow light, green light, purple light and white light, are set respectively, and a wavelength tester (e.g., HPCS320 wavelength tester (Hongpu, China)) is used to measure the LED light source, and the height of the LED light from the water surface is adjusted at the same time, so that the light intensity from the edge of the experimental bucket to the center is set at 250 to 2500 lux;

[0013] Before the screening experiment, the red-fin snapper was placed in the experimental device to adapt for a period of time, and then the light source was turned on. The distribution of the fish school was recorded with an infrared camera and continuously monitored. After the experiment, the water was changed and the experimental fish were replaced to repeat the experiment. The number of fish schools appearing in each area was counted by video playback. The distribution percentage of red-fin snapper in different areas was calculated according to the formula: the distribution rate of experimental fish in a certain light quality area = the number of experimental fish in each area / 60×100%;

[0014] The distribution rate of redfin snapper in each area was calculated and used to represent the preference of redfin snapper for different light qualities. The data were expressed as mean ± standard error. The experimental data were analyzed and the significance of differences among groups was tested.

[0015] More preferably, the test time of the above screening experiment is 8:00-18:00. Before the experiment begins, the redfin snapper (e.g., about 60 fish) is placed in the experimental device to adapt for about 30 minutes, then the light source is turned on, and the distribution of the fish is recorded using an infrared camera. The monitoring is continuous for about 10 hours. After the experiment, the water is changed, the experimental fish are replaced, and the experiment is repeated 3 times. The number of fish appearing in each area is counted by video playback. The first 30 minutes is the stress period, and the number of redfin snappers in each interval is counted every 5 minutes. After adaptation, the number of redfin snappers distributed in each area is counted once every 1.5 hours, and each is counted 6 times.

[0016] More preferably, the distribution rate data of redfin snapper in each region are expressed as mean±standard deviation (Mean±SE), and the experimental data are subjected to one-way ANOVA using SPSS27.0 software, and the Duncan method is used to test the significance of differences between groups, with a significance level of α=0.05.

[0017] More preferably, before the redfin snapper fry are placed in the indoor breeding barrel for the breeding, they are first acclimated for 1-3 weeks to adapt them to the new breeding environment, and are fed with feed during the acclimation period, with a full feed once in the morning and afternoon each day, and the water is changed and the bottom is cleaned every day.

[0018] More preferably, the redfin snapper fry are fed once at 08:00 in the morning and 16:00 in the afternoon every day.

[0019] More preferably, the culture is carried out under a light intensity of 750-1500 lux.

[0020] More preferably, the culture is carried out under blue light with a dominant wavelength of 400-500 nm, more preferably 477 nm.

[0021] More preferably, the culture period is 45 to 60 days.

[0022] More preferably, the transparent column is made of acrylic plate.

[0023] The method of the invention is particularly suitable for screening the lighting conditions of redfin snapper fry, and then breeding the redfin snapper fry to improve the body color and promote the growth of the redfin snapper fry.

[0024] Therefore, the present invention analyzes the distribution characteristics of redfin snapper fry under different light qualities and explores the preference of redfin snapper fry for light quality, so as to create a suitable light environment, which can not only improve the growth and survival rate of redfin snapper, but also improve the brightness and redness value of the body color of redfin snapper, obtain redfin snapper seedlings with fast growth, good appearance and high survival rate, and improve the economic benefits of breeding enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of a device for detecting the light quality and intensity preferences of redfin snapper juveniles.

[0026] Figure 2 Statistical chart of light quality preference of redfin snapper juveniles.

[0027] Figure 3 Statistics of light intensity preference of redfin snapper juveniles.

[0028] Figure 4 Cumulative survival rate of redfin snapper juveniles under different light qualities.

[0029] Figure 5 Changes in body weight of redfin snapper juveniles under different light qualities.

[0030] Figure 6 Changes in body length of redfin snapper juveniles under different light qualities. Implementation

[0032] The specific implementation mode of the present invention firstly screens out the most suitable lighting environment for the growth and body color formation of redfin snapper fry through the device of light quality and light intensity preference of redfin snapper fry, and then arranges the most suitable light intensity range and the most preferred light quality above the redfin snapper fry breeding barrel according to the screening results for breeding. Under the breeding conditions of the most suitable light environment, the effect of promoting growth and body color formation can be achieved in 45 days.

[0033] Unless otherwise specified, the percentages described in this application are all percentages by weight.

[0034] The following examples further describe and verify exemplary embodiments within the scope of the present invention. These examples are intended to be illustrative only and should not be considered as limitations of the present invention, as many changes can be made without departing from its spirit and scope. Except for those shown and described herein, various modifications of the present invention will be apparent to those skilled in the art and are intended to fall within the scope of the appended claims.

[0035] Embodiment 1:

[0036] The preference of redfin snapper juveniles for different light qualities (red, blue, yellow, green, purple and white) and different light intensities (250-2500 lux) was determined as follows:

[0037] 1) Installation of the detection device: Use hot melt adhesive to splice 6 acrylic plates with a length of 80 cm and a width of 10 cm into an equilateral hexagonal acrylic column, and paste different colors of cellophane on each side, namely red, blue, yellow, green and purple. Place the acrylic column with different colors of cellophane in the center of the experimental barrel, and place a nano-gas stone circle outside the acrylic column. Use a 25W LED lamp as the experimental light source, and adjust the height of the lamp from the water surface so that the light intensity from the edge to the center of the experimental barrel is set at 250-2500lux.

[0038] 2) The camera records the distribution of experimental fish.

[0039] 3) Use a water pump to add 30cm of water from the reservoir into the experimental bucket.

[0040] 4) Selection of redfin snapper fry: 60 healthy, vigorous and uniformly sized redfin snapper fry were selected and placed in the detection device to adapt for 30 minutes.

[0041] 5) Lighting experiment: After 30 minutes, turn on the LED light for a 10-hour lighting experiment. The experimental test time is 8:00-18:00. After the experiment, change the water and the experimental fish, and repeat the experiment 3 times.

[0042] 6) Data statistics: The number of fish in each area was counted by video playback. The first 30 minutes was the stress period, and the number of redfin snappers in each area was counted every 5 minutes. After adaptation, the number of redfin snappers in each area was counted once every 1.5 hours, and each time was counted 6 times. The distribution percentage (distribution rate) of redfin snappers in different areas was calculated according to the formula: distribution rate of experimental fish in a certain light quality area = number of experimental fish in each area / 60×100%

[0043] 7) Experimental results: After turning on the light, the juvenile redfin snapper showed a continuous movement response, swimming randomly to each light source area. Statistical results showed that whether in the stress period or the adaptation period, the distribution rate of the juvenile redfin snapper in the blue light area was the highest, 36.34% and 28.51% respectively, and the distribution rate in the yellow light area was the lowest, 3.41% and 11.05% respectively. There was a significant difference in preference for different light qualities (P<0.05), and the preferred light intensity was 250-1500 lux.

[0044] Embodiment 2:

[0045] In order to optimize the light environment for the breeding of redfin snapper fry and improve their growth efficiency, according to the results of the preference color experiment, blue light with the highest distribution rate of redfin snapper fry and yellow light with the lowest distribution rate were selected as the experimental group, white light was used as the control group, and the light intensity was set to 750 lux. A 60-day breeding experiment was carried out to determine the light quality conditions that are conducive to the growth of redfin snapper fry, providing a theoretical basis for the healthy, rapid growth and welfare breeding of redfin snapper fry.

[0046] (1) The experiment was conducted in a light-shielded compartment. Shade cloth was used to cover different treatment groups to avoid cross-contamination of light sources between treatment groups and ensure the stability of lighting conditions in each group. Three groups were set up in the experiment, namely blue light, yellow light, and white light control groups. The light intensity was set to 750 lux. Three replicates were set up in each treatment group. At the beginning of the experiment, 60 redfin snapper juveniles were placed in each experimental bucket with an initial body weight of 4.39±0.76g. The experimental period was 60 days. The light intensity was measured and calibrated with a spectrophotometer after feeding every morning. The light cycle was controlled by an electronic timer and set to 10L:14D. The fish were fed once a day at 08:00 am and 16:00 pm. To maintain water quality, water was changed and the bottom was cleaned twice a day. The amount of food fed and the number of deaths in each experimental bucket were recorded every day. Every 15 days, 3 redfin snappers (9 in each group) were randomly picked from each bucket and their body weight (g), body length (cm) and color difference were measured.

[0047] (2) Data analysis: The data results were expressed as mean ± standard deviation (Mean ± SD). The experimental data were statistically analyzed using SPSS27.0 software. One-way ANOVA was used to compare the significance of differences between data using the new multiple range method (Duncan). A significant difference was considered when P < 0.05.

[0048] (3) Experimental results: The cumulative survival rate of redfin snapper fry in different light color groups decreased with the increase of experimental time, and the blue light group had the highest survival rate. During the experiment, the weight of the blue light group on the 45th day was significantly higher than that of the white light group and the yellow light group. The weight of the 60th day redfin snapper fry had significant differences among the three groups, from high to low, namely the blue light group, the white light group and the yellow light group (P<0.05). The body length of the blue light group at 45 and 60 days was significantly higher than that of the other two groups, and there was no significant difference between the white light group and the yellow light group. The statistical results of the body color of each part of the redfin snapper fry at each experimental stage are shown in Tables 1-4. The blue light group had higher brightness and redness values, and there was a significant difference compared with the control group at 30 days. The above results show that the use of blue light with a light intensity of 750 lux can achieve a good effect on promoting body color of redfin snapper fry for 30 days, and can also promote the formation of growth body color at 45 days.

[0049] Table 1 Effects of 15-day light exposure on the skin color of juvenile redfin snapper

[0050]

[0051] Table 2 Effects of 30-day light exposure on the skin color of juvenile redfin snapper

[0052]

[0053] Table 3 Effects of 45-day light exposure on the skin color of juvenile redfin snapper

[0054]

[0055] Table 4 Effects of 60-day light exposure on the skin color of juvenile redfin snapper

[0056]

[0057]

Claims

1. A method for improving the body color and growth of redfin snapper fry, characterized in that: The redfin snapper fry were placed in indoor breeding barrels for breeding. During the breeding period, they were fed with feed, and fed once in the morning and afternoon. The water was changed and the bottom was cleaned every day. The breeding conditions were: i) The aquaculture tank uses nano-air stones for continuous aeration, and the dissolved oxygen concentration is 6.5-7.4 mg / L. ii) The pH of the water in the culture tank is 7.5-8.4, iii) the water temperature and salinity in the culture tank remain relatively unchanged at 27.3-33.2°C and 25-31‰, respectively; iv) the culture tank is covered with a shade cloth, the lighting conditions for culture are set to a blue light source, and the light intensity from the edge to the center of the culture tank is 250 to 1500 lux; v) The breeding cycle is more than 45 days.

2. The method for improving the body color and growth of redfin snapper juveniles according to claim 1, characterized in that: The lighting conditions for the culture were screened by the following method: A preference behavior experimental device is used to screen the light intensity range and light quality conditions suitable for the growth of the redfin snapper fry. The preference behavior experimental device includes a breeding bucket, a light source, a video monitor, a nano aeration circle and a timer switch, and the entire experimental device is covered with a blackout cloth; an equilateral hexagonal transparent column is placed in the central area of ​​the breeding bucket, and six kinds of LED lights, namely red light, blue light, yellow light, green light, purple light and white light, are set respectively. The LED light source is measured by a wavelength tester, and the height of the LED light from the water surface is adjusted at the same time, so that the light intensity from the edge of the experimental bucket to the center is set at 250 to 2500 lux; Before the screening experiment, the red-fin snapper was placed in the experimental device to adapt for a period of time, and then the light source was turned on. The distribution of the fish school was recorded with an infrared camera and continuously monitored. After the experiment, the water was changed and the experimental fish were replaced to repeat the experiment. The number of fish schools appearing in each area was counted by video playback. The distribution percentage of red-fin snapper in different areas was calculated according to the formula: the distribution rate of experimental fish in a certain light quality area = the number of experimental fish in each area / 60×100%; The distribution rate of redfin snapper in each area was calculated and used to represent the preference of redfin snapper for different light qualities. The data were expressed as mean ± standard error. The experimental data were analyzed and the significance of differences among groups was tested.

3. The method for improving the body color and growth of redfin snapper fry according to claim 1, characterized in that: Before placing the redfin snapper fry in the indoor breeding barrel for the breeding, they are first acclimated for 1-3 weeks to adapt them to the new breeding environment. During the acclimation period, they are fed with feed once in the morning and afternoon every day, and the water is changed and the bottom is cleaned every day.

4. The method for improving the body color and growth of redfin snapper juveniles according to claim 1, characterized in that: The redfin snapper fry were fed once at 08:00 in the morning and 16:00 in the afternoon every day.

5. The method for improving the body color and growth of redfin snapper juveniles according to claim 1, characterized in that: The light intensity is 750 lux.

6. The method for improving the body color and growth of redfin snapper juveniles according to claim 1, characterized in that: The main wavelength of the blue light is 477nm.

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