A method for synergistically increasing the content of ω-3 polyunsaturated fatty acids in oysters during market period

Abstract

The present invention relates to a production technology for high-end oysters, specifically, to a method for synergistically improving the content of ω-3 polyunsaturated fatty acids in oysters during the marketing period. A subtidal oyster culture area rich in bait is selected, and healthy oyster shellfish that meet the marketing specifications are used as samples. The samples are fixed on a subtidal sea culture platform at a specific intertidal altitude position. After more than 30 days of oyster quality improvement culture, the EPA and DHA content in the sample is detected every 7-15 days to determine the marketing period. The EPA and DHA content of oysters using this technology during the marketing period is increased by more than 30% compared with the traditional subtidal culture mode. This method has the significant advantages of being fast and stable, having a wide range of applications, low cost, and better effect, and does not require special feeding bait, and is environmentally friendly. In short, this method can achieve the effect of quickly and synergistically improving the EPA and DHA content of oysters during the marketing period, and significantly improve the quality of oyster products.

Description

Technical Field

[0001] The present invention relates to a production technology for high-end oysters, and in particular to a method for synergistically increasing the content of ω-3 polyunsaturated fatty acids (EPA and DHA) in oysters during market period. Background Art

[0002] EPA and DHA are two important omega-3 polyunsaturated fatty acids with high nutritional value and health benefits. They help lower triglyceride levels in the blood, reducing the risk of heart disease and stroke. They also lower blood pressure, inhibit platelet aggregation, and reduce inflammation in the blood. Furthermore, they promote fetal and infant nervous system development and may enhance cognitive function and learning ability. These fatty acids are commonly supplemented through seafood.

[0003] Oysters are a globally important marine aquaculture shellfish, boasting high nutritional value and serving as both a medicinal and edible marine organism. Oysters contain a rich variety of fatty acids, with EPA and DHA accounting for approximately 40% of their total fatty acid content, making them one of the shellfish with the highest unsaturated fatty acid content among marine organisms. my country produces approximately 80% of the world's oysters, but its share of the international high-end market is very low. Therefore, increasing the EPA and DHA content of Chinese oysters not only directly enhances their nutritional and health benefits but also provides core technical support for the production of high-quality, premium oysters.

[0004] Oysters in my country are all farmed in open waters, and their EPA and DHA content is affected by genetic and environmental factors. Currently, there are reports of genetic improvement of EPA and DHA content through inter-subspecies hybridization (ZL 201110283181.X, ZL201210401568.5), in which EPA and DHA were increased by 10% and 20%, respectively. However, there are currently no reports on related technologies for increasing the EPA and DHA content of oysters through fine environmental regulation. The present invention proposes an environmental regulation method for quickly and synergistically increasing the EPA and DHA content of oysters during the marketing period, which can significantly improve the quality of oysters during the marketing period in a short period of time. Summary of the Invention

[0005] In response to the current problems of extensive aquaculture and low product quality in my country's oyster industry, the present invention systematically studies the impact of fine environmental regulation on EPA and DHA in oysters during the marketing period, and provides a method for synergistically increasing the content of ω-3 polyunsaturated fatty acids (EPA and DHA) in oysters during the marketing period.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A method for synergistically improving the ω-3 polyunsaturated fatty acid content of oysters during the marketing period, using healthy adult oysters that meet marketing specifications as samples, fixing the sample culture cages on the flat surface of a culture platform at a specific intertidal altitude, and cultivating the oysters for more than 30 days to improve their quality and ensure that they are marketed.

[0008] After 30 days of cultivation, the EPA and DHA content in the sample is tested every 7-15 days to determine the marketing period. That is, if the EPA and DHA content in the sample is more than 10% higher than that in the initial sample, the above-mentioned method can be used; the EPA and DHA content of the oysters cultured according to the above method at the marketing period is more than 30% higher than that of the original sample.

[0009] The method for detecting the EPA and DHA content in the sample is to randomly select 30 soft parts of oysters using the present method and 30 soft parts of oysters using the control group sample from the same sea area, take equal amounts of tissue from each individual, and mix 3-5 individuals into one sample for freeze-drying. Gas chromatography is used to determine the proportion of EPA and DHA in the dry weight, and then the accurate time to market using the present technology is evaluated, which is related to the EPA and DHA improvement effect. After culture, the sample can be marketed if the EPA and DHA content is increased by 10% compared with the original sample. The oysters cultured according to the above method at the marketing period have an EPA and DHA content that is more than 30% higher than the original sample.

[0010] The samples are selected from healthy oyster shellfish that have reached market specifications and are cultured in the subtidal zone with abundant bait.

[0011] The standard for selecting a subtidal oyster aquaculture area with abundant bait is that the annual average content of diatoms in the unicellular algae in the area is above 100 cells / mL.

[0012] The selection criteria for the test sample oysters are that the shell is intact, the meat yield of the soft part is greater than 15%, the shell height is greater than 10 cm, and the gonads are in the undeveloped stage.

[0013] The sample is placed in an oyster culture cage with a mesh aperture of 2-3 cm, and the cage is fixed horizontally on the horizontal platform of the culture platform device with a cable tie.

[0014] The method for determining the altitude position of the specific intertidal zone is to query the altitude position A of the average low tide line of the aquaculture sea area where the aquaculture platform device is established, and fix the altitude position of the device platform plane carrying the oyster sample aquaculture cage between 0.35A and 0.86A.

[0015] Beneficial effects of the present invention

[0016] Due to the adoption of the above-mentioned technical solution, the present invention has the following advantages and positive effects compared with the existing technology: the existing technology of genetically improving the EPA and DHA content through hybrid breeding between oyster subspecies has the problems of long breeding cycle and limited adaptability of hybrids to the environment compared with the present technology, which leads to a limited scope of use and is prone to genetic contamination. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with specific examples. It should be understood that the following examples are provided to further illustrate the present invention, rather than to limit the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalents fall within the scope limited by the appended claims of the application.

[0018] Example 1:

[0019] In October 2022, oyster samples to be put on the market were selected from the Jiaonan Sea area of Qingdao. The average annual content of diatoms in unicellular algae in this area is greater than 100 cells / mL, and the water quality meets the NY5052-2001 pollution-free food seawater aquaculture water standard. The selected oysters have complete shells, shell height of 10-12 cm, individual weight of 50-100 g, the weight of the soft part accounts for about 15% of the individual body weight, and the soft body gonads are not developed.

[0020] The sea area of Huangdao District, Qingdao City was selected as the environmental control sea area for increasing the content of EPA and DHA. The water depth of this sea area is about 3m at low tide, the average low tide line A is 100cm, and there is no ice disaster in winter.

[0021] The marine aquaculture platform was constructed of stainless steel. The platform surface (i.e., the cross-section supporting the aquaculture cages) was 4 meters long and 1 meter wide, with support columns anchored to the seabed. The experimental group was set up at an altitude of 0.4° above sea level. A control group was set up at a location -50 cm below the tidal zone (the typical location for conventional subtidal aquaculture methods). Cages containing the selected oysters were then placed on the platform, with the specifications and stocking density consistent with conventional methods.

[0022] In late October 2022, oyster sample cages that have reached market specifications will be placed on the horizontal surface of the platform of the aquaculture platform device at the locations of the experimental and control groups. Among them, the oyster sample cages are oyster aquaculture cages with a mesh aperture of 2-3 cm, which are fixed to the horizontal surface of the aquaculture platform device with cable ties. After more than 30 days of oyster quality improvement aquaculture, the EPA and DHA content in the samples will be tested every 7-15 days to determine the market release period. For each test, 30 soft parts of oysters using this method and 30 oysters from the control group samples in the same sea area will be randomly selected. Equal amounts of tissue will be taken from each individual, and 3-5 individuals will be mixed into one sample for freeze-drying. The proportion of EPA and DHA in the dry weight will be determined by gas chromatography to monitor the improvement effect of EPA and DHA.

[0023] When oysters were released to the market in February 2023, the experimental group contained 1.653% EPA and 1.042% DHA per dry weight, respectively, while the control group (subtidal zone) contained 1.235% EPA and 0.746 DHA per dry weight. The average EPA and DHA content in the experimental group increased by 33.81% and 39.68%, respectively, compared to the control group, with both differences reaching statistical significance.

[0024] Comparative Example:

[0025] In October 2022, oyster samples to be put on the market were selected from the Jiaonan sea area of Qingdao. The annual average content of diatoms in unicellular algae in this sea area is greater than 100 cells / mL, and the water quality meets the NY5052-2001 pollution-free food seawater aquaculture water standard. The selected oysters have complete shells, shell height of 10-12 cm, individual weight of 50-100 g, the proportion of soft body weight to individual body weight is about 15%, and the soft body gonads are not developed.

[0026] The sea area of Huangdao District, Qingdao City was selected as the environmental control sea area for increasing the content of EPA and DHA. The water depth of this sea area is about 3m at low tide, the average low tide line A is 100cm, and there is no ice disaster in winter.

[0027] The marine aquaculture platform was constructed of stainless steel. The platform (i.e., the cross-section supporting the cages) was 4 meters long and 1 meter wide, with support columns anchored to the seabed. The platforms were set up at altitudes of 1.40 and 2.40 meters above sea level as experimental groups, while a control group was located at -50 cm below the tidal zone. Cages containing the selected oysters were then placed on the platforms, using the same cage specifications and stocking density as conventional methods.

[0028] In late October 2022, oyster samples that have reached market specifications will be placed in the experimental and control groups. The oysters will be fixed by placing the samples in oyster culture cages with a mesh size of 2-3 cm. The cages are placed horizontally with cable ties and then fixed on the horizontal surface of the culture platform. After more than 30 days of oyster quality improvement culture, the EPA and DHA content in the samples will be tested every 7-15 days to determine the market launch period. For each test, 30 soft parts of oysters using this method and 30 oysters from the control group using the same sea area will be randomly selected. Equal amounts of tissue will be taken from each individual, and 3-5 individuals will be mixed into one sample for freeze-drying. The proportion of EPA and DHA in dry weight will be determined by gas chromatography to monitor the improvement effect of EPA and DHA.

[0029] When oysters were released to the market in February 2023, the dry weight percentages of EPA and DHA in the experimental group (1.40A) were 1.310 and 0.900, respectively; the dry weight percentages of EPA and DHA in the experimental group (2.40A) were 1.210 and 0.974, respectively; and the dry weight percentages of EPA and DHA in the control group (subtidal zone) were 1.235 and 0.746, respectively. The average EPA and DHA contents in the experimental groups increased by -2.02% to 6.07% and 20.64% to 30.60%, respectively, compared to the control group.

[0030] As can be seen from the above examples, the degree of improvement in EPA and DHA in Example 1 is significantly higher than that in the comparative example, and the EPA and DHA in the comparative example do not achieve a synergistic improvement effect. The main technical difference between Example 1 and the comparative example lies in the specific parameters of the oyster culture platform's altitude position in the intertidal zone. This shows that the synergistic and significant improvement in EPA and DHA can only be achieved within the parameter range specified in this patent. This shows that the different platform plane positions of the culture platform directly affect the growth conditions.

[0031] The above are only specific embodiments of the invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using the concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A method for synergistically increasing the content of ω-3 polyunsaturated fatty acids in oysters during market period, characterized by: Healthy oysters that meet market specifications are used as samples. Sample culture cages are fixed on the flat surface of the culture platform at a specific intertidal altitude. The oysters are cultured for more than 30 days to improve their quality and be confirmed for market release. The method for determining the altitude position of the specific intertidal zone is to query the altitude position A of the average low tide line of the aquaculture sea area where the aquaculture platform device is established, and fix the altitude position of the device platform plane carrying the oyster sample aquaculture cage between 0.35A and 0.86A.

2. The method for synergistically increasing the content of ω-3 polyunsaturated fatty acids in oysters during market period according to claim 1, characterized in that: The samples are selected from healthy oyster shellfish that have reached market specifications and are cultured in the subtidal zone with abundant bait.

3. The method for synergistically increasing the content of ω-3 polyunsaturated fatty acids in oysters during market period according to claim 2, characterized in that: The standard for the bait-rich subtidal aquaculture sea area is that the annual average content of diatoms in the unicellular algae in the sea area is above 100 cells / mL.

4. The method for synergistically increasing the content of ω-3 polyunsaturated fatty acids in oysters during market period according to claim 2, characterized in that: The selection criteria for healthy oysters are that the shell is intact, the meat yield of the soft part is greater than 15%, the shell height is greater than 10 cm, and the gonads are in the undeveloped stage.

5. The method for synergistically increasing the content of ω-3 polyunsaturated fatty acids in oysters during market period according to claim 1, characterized in that: The samples were placed in oyster culture cages with a mesh size of 2-3 cm, and the cages were fixed horizontally on the horizontal platform of the culture platform device using cable ties.