Fast, low-loss and effective evaluation system and method for cold stress of tilapia

Abstract

The application discloses a fast, low-loss and effective evaluation system and method for cold stress of red tilapia, and belongs to the technical field of aquaculture.The evaluation system comprises an index layer, a method layer and an application layer.The index layer comprises behavior indexes, body color indexes, blood indexes and caudal fin pigment cell indexes.The method layer is to set a control group and a monitoring group, and to determine the index values respectively, so that the determination value of the control group is taken as a standard value, and the difference degree of the monitoring group and the control group is judged by using an evaluation model.The application layer is to regulate the breeding strategy according to the difference degree of the monitoring group and the control group.The application constructs a four-dimensional quantitative evaluation system, and realizes the grading early warning mechanism for the breeding state of the red tilapia by using a difference degree value algorithm.The application can predict the state of the tilapia, so that the breeder can timely adjust the breeding strategy, and the death problem caused by the cold stress or acute cold stress in the breeding process can be reduced to the maximum.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, and in particular to a rapid, low-loss, and effective evaluation system and method for cold stress in red tilapia. Background Technology

[0002] Red tilapia ( Oreochromis (spp.) is an important economic fish species worldwide, generally believed to be derived from a mutant red Mozambique tilapia ( O. mossambicus ) and other tilapia species such as Nile tilapia ( O. niloticus Red tilapia is a superior breed developed through hybridization and multiple generations of selective breeding. Due to its vibrant coloration, absence of a black membrane in the abdominal cavity, strong adaptability, refreshing taste, and high market price, its aquaculture area in my country has been continuously expanding in recent years, indicating a huge market potential. However, cold stress during winter has been a bottleneck hindering the rapid development of the industry. Winter cold stress mainly manifests as a decrease in the immune and antioxidant capacity of red tilapia due to the drop in water temperature, resulting in a darkening of the fish's appearance, and in severe cases, the entire pond turning black and leading to mass mortality. Therefore, in most parts of my country, red tilapia must be moved to greenhouses for overwintering, increasing the difficulty of aquaculture.

[0003] Determining whether fish are under stress typically requires assessing changes in their behavior and appetite, along with testing for post-mortem oxidative stress and other indicators. This method severely limits the size of research samples and hinders the genetic improvement of fish stress resistance traits. Therefore, there is an urgent need to establish a rapid, non-lethal (low-damage), and effective evaluation system and method for assessing cold stress in fish, which would be a significant innovation in stress identification techniques for species such as red tilapia. Summary of the Invention

[0004] The purpose of this invention is to provide a rapid, low-damage, and effective evaluation system and method for cold stress in red tilapia, in order to solve the problems existing in the prior art. It can timely, effectively, and quickly assess the condition of red tilapia and take corresponding aquaculture measures to reduce cold stress during the wintering period of red tilapia, especially the occurrence of acute cold stress.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a rapid, low-damage, and effective evaluation system for cold stress in red tilapia. The key feature is that the evaluation system comprises an indicator layer, a methodological layer, and an application layer. The indicator layer includes behavioral indicators, body color indicators, blood indicators, and caudal fin pigment cell indicators. The methodological layer involves setting up a control group and a monitoring group, measuring the indicator values ​​in each group, using the control group's measured values ​​as the standard values, and employing an evaluation model to assess the degree of difference between the monitoring group and the control group. The application layer involves adjusting aquaculture strategies based on the degree of difference between the monitoring group and the control group.

[0006] Specifically, the aforementioned behavioral indicators include the fish's feeding behavior, swimming state, and balance; the aforementioned body color indicators include the L* value and b* value of the abdominal skin; the aforementioned blood indicators include total cholesterol, total protein, total bilirubin, urea, norepinephrine, blood glucose, alkaline phosphatase, triglycerides, alanine aminotransferase, and aspartate aminotransferase in the blood; and the aforementioned caudal fin pigment cell indicators include the number, aggregation state, and red body color state of caudal fin pigment cells.

[0007] Specifically, the L* value mentioned above is lightness, representing the brightness or darkness of a color; the b* value mentioned above is the yellow-blue axis, representing the position of the color on the yellow-blue spectral axis.

[0008] It should be noted that the control group mentioned above consisted of red tilapia whose living water temperature was maintained at or above 20℃.

[0009] Furthermore, the steps for establishing the above evaluation model include: S1. The significance levels of body color indicators and blood indicators were determined by comparing them with the corresponding indicators of the control group. P A score <0.05 is considered statistically significant and is awarded 1 point; otherwise, no statistically significant difference is considered and is awarded 0 points. S2. Quantify the behavioral indicators and caudal fin pigment cell indicators respectively, and record the scores; S3. Weighting: The weighting coefficient for behavioral indicators is 0.3, the weighting coefficient for body color indicators is 0.25, the weighting coefficient for blood indicators is 0.3, and the weighting coefficient for tail fin pigment cell indicators is 0.15. S4. Equation 1 for obtaining the degree of differentiation. Differentiation score = (behavioral index score × 0.3 + body color index score × 0.25 + blood index score × 0.3 + tail fin pigment cell index score × 0.15) × 20.62 Equation 1.

[0010] Furthermore, the quantitative method for behavioral indicators is: Scenario 1: No abnormal behavior, judged as normal, score 0 points; Scenario 2: Decreased food intake and slower swimming speed are considered mild abnormalities and are scored as 1 point. Scenario 3: Significantly reduced food intake, staying at the bottom and moving little, is judged as moderate abnormality, scoring 2 points; Scenario 4: If the patient stops eating and becomes unbalanced, it is considered a severe abnormality and is scored as 3 points.

[0011] Furthermore, the quantification method for caudal fin pigment cell indicators is as follows: Situation 1: Red blood cells do not aggregate and are characteristically red, which is considered normal and scores 0 points; Situation 2: The presence of reduced and aggregated red pigment cells and decreased red body color, without the presence of melanocytes, is judged as a mild abnormality, scoring 1 point; Situation 3: The presence of reduced and aggregated red pigment cells, decreased red body color, and the appearance of melanocytes indicates a moderate abnormality, scoring 2 points. Situation 4: The presence of reduced and aggregated red pigment cells, decreased red body color, and the presence of melanocytes with a deepening of the melanin system indicates a severe abnormality, scoring 3 points.

[0012] Finally, the breeding strategy is adjusted based on the degree of differentiation, specifically including: 0 < Differentiation value ≤ 20, normal condition, normal breeding should be carried out; If the difference value is 20 < 50, it indicates that a cold stress compensation period has occurred. The water temperature should be raised to 18℃ and vitamin C should be added to the feed. If the difference value is 50 < 70, it indicates a cold stress problem. Isolate the patient, raise the temperature, and administer dexamethasone. If the difference value is 70 < 100, it indicates an acute cold stress problem. The red tilapia should be transferred to a 25°C recovery tank and injected with dexamethasone.

[0013] The key to a rapid, low-damage, and effective method for assessing cold stress in red tilapia lies in using the aforementioned assessment system to evaluate the cold stress in red tilapia. The specific steps are as follows: A control group and a monitoring group were set up, and behavioral indicators, body color indicators, blood indicators and caudal fin pigment cell indicators of red tilapia in the control group and the monitoring group were measured respectively. Using the measured value of the control group as the standard value, the evaluation model was used to assess the degree of difference between the monitoring group and the control group, and the degree of difference value was calculated. Based on the range of the degree of difference, the condition of the red tilapia in the monitoring group was determined and the breeding strategy was adjusted accordingly.

[0014] Specifically, the states of the red tilapia in the monitoring group included normal state, cold stress compensation period state, cold stress state, and acute cold stress state.

[0015] The present invention discloses the following technical effects: This invention constructs a four-dimensional quantitative evaluation system and implements a graded early warning mechanism for the farming status of red tilapia through a differentiation degree value algorithm. This invention can predict the status of tilapia within 6 hours and provide early warning for cold stress or acute cold stress in red tilapia, allowing farmers to adjust their farming strategies in a timely manner and minimize mortality caused by cold stress or acute cold stress during the farming process.

[0016] This invention significantly reduces the misjudgment rate and improves prediction accuracy through multi-indicator cross-verification. Applying this invention not only avoids the lag and excessive intervention in traditional aquaculture methods for condition assessment, but also enables precise regulation of feeding strategies. For example, timely drug treatment or heat preservation strategies can reduce winter losses while also minimizing heating costs, saving resources such as drugs and manpower, and improving the economic benefits of red tilapia farming. This invention transforms complex physiological responses into an operable digital decision-making system, constructing a rapid, low-loss, and efficient evaluation system and method for fish cold stress, providing an industrial application paradigm for fish health management. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A photo of the red tilapia "Zhongheng No. 1"; Figure 2 A photograph showing the quantification of pigment cell indicators in the tail fin of a red tilapia. Figure 3 Photograph 2 showing the quantification of pigment cell indicators in the tail fin of red tilapia; Figure 4 Photograph 3 shows the quantitative analysis of pigment cell indicators in the tail fin of red tilapia. Detailed Implementation

[0019] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0020] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0021] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0022] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0023] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0024] In both Examples 1 and 2, the new aquatic cultivar red tilapia "Zhongheng No. 1" was selected as the experimental subject. "Zhongheng No. 1" was developed using a Malaysian red tilapia strain as the breeding base population, with body color and growth rate as the main indicators, through population selection technology and five consecutive generations of breeding. The body color of "Zhongheng No. 1" red tilapia is a stable and consistent pink. (See [link to relevant documentation]). Figure 1 At the start of the experiment, all animals were kept in indoor cylindrical fiberglass water tanks with a diameter of 150 cm and a depth of 120 cm.

[0025] Example 1 At the start of the experiment, 80 healthy and vigorous fish were randomly selected. The initial weight of the selected red tilapia was 72.71 g ± 1.32 g. They were randomly divided into two groups of 40 fish each, resulting in monitoring group 1 and control group 1.

[0026] The experiment was conducted during the overwintering period, with the room temperature below 6℃. The water temperature in control group 1 was maintained at around 20℃, while the water temperature in monitoring group 1 decreased by 2℃ per day, from 20℃ to 8℃.

[0027] Every morning at 8:00 AM during the experiment, the temperature controller of monitoring group 1 was adjusted to be lowered by 2°C. During the experiment, monitoring group 1 and control group 1 used the same commercial fish feed, which was fed twice a day until the day before sampling.

[0028] Each glass tank was aerated for 24 hours per day, with a light intensity of 12 days to 12 liters per day. During the experiment, behavioral indicators of the red tilapia, including feeding, swimming, and balance, were observed and recorded daily.

[0029] At the end of the experiment, fish samples were taken from monitoring group 1 and control group 1.

[0030] Six red tilapia were randomly selected from monitoring group 1 as test samples, and six were randomly selected from control group 1 as control samples. The results are as follows: 1. Observation and quantification results of behavioral indicators: During the experiment, it was found that some of the red tilapia in monitoring group 1 stopped feeding when the water temperature was below 10℃, and sank to the bottom and gradually lost their balance when the water temperature was below 9℃. No fish died during the experiment.

[0031] The specific methods for quantifying behavioral indicators are as follows: Scenario 1: No abnormal behavior, judged as normal, score 0 points; Scenario 2: Decreased food intake and slower swimming speed are considered mild abnormalities and are scored as 1 point. Scenario 3: Significantly reduced food intake, staying at the bottom and moving little, is judged as moderate abnormality, scoring 2 points; Scenario 4: If the patient stops eating and becomes unbalanced, it is considered a severe abnormality and is scored as 3 points.

[0032] At the end of the experiment, among the 6 red tilapia in monitoring group 1, 4 exhibited situation 3, for which the behavioral index was scored 2 points; 2 exhibited situation 2, for which the behavioral index was scored 1 point; the average score was 1.67 for monitoring group 1. All 6 red tilapia in control group 1 were in situation 1.

[0033] 2. Results of body color index testing: The L*, a*, and b* values ​​of the skin on the back and belly of the fish were measured using a ColorQuest XE (Hunterlab, USA) colorimeter. The L* value represents the lightness or brightness of the color; the a* value represents the position of the color on the red-green spectral axis; and the b* value represents the position of the color on the yellow-blue spectral axis.

[0034] The results are shown in Table 1.

[0035] Table 1: Detection results of body color indicators in red tilapia of monitoring group 1 and control group 1 Note: * indicates the significance level ( P <0.05) As shown in Table 1, based on the quantification of body color indicators, a score of 1 is awarded when the L* value of the abdominal skin of the red tilapia in monitoring group 1 is significantly lower than that in control group 1; a score of 1 is also awarded when the b* value of the abdominal skin of the red tilapia in monitoring group 1 is significantly lower than that in control group 1. In this embodiment, the body color indicator score of the red tilapia in monitoring group 1 is 1 point.

[0036] 3. Blood test results Blood was collected from red tilapia via tail vein sampling. Serum samples were obtained after centrifugation at 4°C (3000 rpm, 15 min). Complete blood count (CBC) parameters were measured using a Mindray BS-400 Q2080 biochemical analyzer (Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China). The results are shown in Table 2.

[0037] Table 2: Blood routine test results of red tilapia in monitoring group 1 and control group 1 Note: * indicates the significance level ( P <0.05), ** indicates a highly significant difference ( P <0.01).

[0038] As shown in Table 2, the levels of urea (UREA), norepinephrine (NE), and blood glucose (GLU) in the serum of red tilapia in monitoring group 1 were significantly higher than those in control group 1. P <0.05); Alkaline phosphatase (ALP), total bilirubin (TBIL), and total cholesterol (TC) levels were significantly lower than those in control group 1 ( P <0.05). There were no significant differences between the two groups in other indicators.

[0039] According to the evaluation system of the present invention, six indicators in the blood, namely total cholesterol (TC), total bilirubin (TBIL), urea (UREA), norepinephrine (NE), blood glucose (GLU) and alkaline phosphatase (ALP), showed significant differences compared with control group 1. The blood indicators of the red tilapia in monitoring group 1 were 6 points.

[0040] 4. Observation and quantification results of caudal fin pigment cell indicators A small piece of caudal fin was collected from the upper right side, and the number and characteristics of caudal fin pigment cells were observed under a microscope to determine the caudal fin pigment cell index.

[0041] According to the evaluation system of the present invention, the quantification method of the caudal fin pigment cell index is as follows: Situation 1: Red blood cells do not aggregate and are characteristically red, which is considered normal and scores 0 points; Situation 2: The presence of reduced and aggregated red pigment cells and decreased red body color, without the presence of melanocytes, is judged as a mild abnormality, scoring 1 point; Situation 3: The presence of reduced and aggregated red pigment cells, decreased red body color, and the appearance of melanocytes indicates a moderate abnormality, scoring 2 points. Situation 4: The presence of reduced and aggregated red pigment cells, decreased red body color, and the presence of melanocytes with a deepening of the melanin system indicates a severe abnormality, scoring 3 points.

[0042] At the end of the experiment, among the 6 red tilapia in monitoring group 1, 3 exhibited situation two, for which the behavioral index was scored 1 point; 3 exhibited situation three, for which the behavioral index was scored 2 points. Taking the average, the score for the caudal fin pigment cell index in monitoring group 1 was 1.5. All 6 red tilapia in control group 1 were in situation one.

[0043] The test and quantification results of each indicator in this embodiment are shown in Table 3.

[0044] Table 3: Test and quantification results of various indicators for monitoring group 1 Calculate the degree of difference based on Equation 1.

[0045] Equation 1 is as follows: The degree of differentiation is calculated as follows: (behavioral index score × 0.3 + body color index score × 0.25 + blood index score × 0.3 + tail fin pigment cell index score × 0.15) × 20.62. In Equation 1, 20.62 is used as a constant coefficient to standardize the score to a percentage system. That is, the maximum score after weighting is 4.85 points. 100 ÷ 4.85 ≈ 20.62. The degree of differentiation for monitoring group 1 was 57.24. Adjustments to aquaculture strategies were determined based on this degree of differentiation, specifically including: 0 < Differentiation value ≤ 20, normal condition, normal breeding should be carried out; If the difference value is 20 < 50, it indicates that a cold stress compensation period has occurred. The water temperature should be raised to 18℃ and vitamin C should be added to the feed. If the difference value is 50 < 70, it indicates a cold stress problem. Isolate the patient, raise the temperature, and administer dexamethasone. If the difference value is 70 < 100, it indicates an acute cold stress problem. The red tilapia should be transferred to a 25°C recovery tank and injected with dexamethasone.

[0046] Based on the above criteria, it can be concluded that monitoring group 1 has experienced cold stress. Monitoring group 1 should be isolated, warmed up, and injected with dexamethasone.

[0047] Example 2 At the start of the experiment, 80 healthy and vigorous fish were randomly selected. The initial weight of the selected red tilapia was 45.07 g ± 0.27 g. They were randomly divided into two groups of 40 fish each, resulting in monitoring group 2 and control group 2.

[0048] The experiment was conducted during the overwintering period, with room temperature below 6℃. The water temperature in control group 2 was maintained at around 21℃, while the water temperature in monitoring group 2 decreased by 1℃ every half hour until it reached 10℃. No feeding was provided during the experiment until sampling.

[0049] Each glass tank was aerated for 24 hours per day, with a light intensity of 12 days to 12 liters per day. During the experiment, behavioral indicators of the red tilapia, including feeding, swimming, and balance, were observed and recorded.

[0050] At the end of the experiment, fish samples were taken from monitoring group 2 and control group 2.

[0051] Six red tilapia were randomly selected from monitoring group 2 as test samples, and six were randomly selected from control group 2 as control samples. The results are as follows: 1. Observation and quantification results of behavioral indicators: During the experiment, it was found that as the temperature decreased, some of the red tilapia in monitoring group 2 gradually slowed down, until at 9°C, the fish sank to the bottom and basically stopped swimming. No fish died during the experiment.

[0052] The specific methods for quantifying behavioral indicators are as follows: Scenario 1: No abnormal behavior, judged as normal, score 0 points; Scenario 2: Decreased food intake and slower swimming speed are considered mild abnormalities and are scored as 1 point. Scenario 3: Significantly reduced food intake, staying at the bottom and moving little, is judged as moderate abnormality, scoring 2 points; Scenario 4: If the patient stops eating and becomes unbalanced, it is considered a severe abnormality and is scored as 3 points.

[0053] At the end of the experiment, among the 6 red tilapia in monitoring group 2, 5 exhibited situation four, for which the behavioral index was scored 3 points; 1 exhibited situation three, for which the behavioral index was scored 2 points; the average score was 2.83 for monitoring group 2. All 6 red tilapia in control group 2 were in situation one.

[0054] 2. Results of body color index testing: The L*, a*, and b* values ​​of the skin on the back and abdomen of the fish were measured using a ColorQuest XE (Hunterlab, USA) colorimeter. The results are shown in Table 4.

[0055] Table 4: Detection results of body color indicators of red tilapia in monitoring group 2 and control group 2 Note: * indicates the significance level ( P <0.05) As shown in Table 4, based on the quantification of body color indicators, when the L* value of the abdominal skin of the red tilapia in monitoring group 2 was significantly lower than that in control group 2, 1 point was awarded; when the b* value of the abdominal skin of the red tilapia in monitoring group 2 was significantly lower than that in control group 2, 1 point was awarded.

[0056] In this embodiment, the body color index of the red tilapia in monitoring group 2 was 2 points.

[0057] 3. Blood test results Blood was collected from red tilapia via tail vein sampling. Serum samples were obtained after centrifugation at 4°C (3000 rpm, 15 min). Complete blood count (CBC) parameters were measured using a Mindray BS-400 Q2080 biochemical analyzer (Mindray Bio-Medical Electronics Co., Ltd., Shenzhen, China). The results are shown in Table 5.

[0058] Table 5: Blood routine test results of red tilapia in monitoring group 2 and control group 2 Note: * indicates the significance level ( P <0.05), ** indicates a highly significant difference ( P <0.01).

[0059] As shown in Table 5, the levels of blood glucose (GLU), total protein (TP), and triglycerides (TG) in the serum of red tilapia in monitoring group 2 were significantly higher than those in control group 2. P <0.05); the levels of alkaline phosphatase (ALP), total bilirubin (TBIL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were significantly lower than those in the control group 2 ( P <0.05). There were no significant differences between the two groups in other indicators.

[0060] According to the evaluation system of the present invention, seven blood indicators, including blood glucose (GLU), total protein (TP), triglycerides (TG), alkaline phosphatase (ALP), total bilirubin (TBIL), alanine aminotransferase (ALT), and aspartate aminotransferase (AST), showed significant differences from those of control group 2. The blood indicators of the red tilapia in monitoring group 2 were 7 points.

[0061] 4. Observation and quantification results of caudal fin pigment cell indicators A small piece of caudal fin was collected from the upper right side, and the number and characteristics of caudal fin pigment cells were observed under a microscope to determine the caudal fin pigment cell index.

[0062] According to the evaluation system of the present invention, the quantification method of the caudal fin pigment cell index is as follows: Situation 1: Red blood cells do not aggregate and are characteristically red, which is considered normal and scores 0 points; Situation 2: The presence of reduced and aggregated red pigment cells and decreased red body color, without the presence of melanocytes, is judged as a mild abnormality, scoring 1 point; Situation 3: The presence of reduced and aggregated red pigment cells, decreased red body color, and the appearance of melanocytes indicates a moderate abnormality, scoring 2 points. Situation 4: The presence of reduced and aggregated red pigment cells, decreased red body color, and the presence of melanocytes with a deepening of the melanin system indicates a severe abnormality, scoring 3 points.

[0063] At the end of the experiment, among the 6 red tilapia in monitoring group 2, 5 exhibited situation three, for which the behavioral index was scored 2 points; 1 exhibited situation two, for which the behavioral index was scored 1 point. Taking the average, the score for the caudal fin pigment cell index in monitoring group 2 was 1.83. All 6 red tilapia in control group 2 were in situation one.

[0064] The test and quantification results of each indicator in this embodiment are shown in Table 6.

[0065] Table 6: Test and Quantification Results of Various Indicators in Monitoring Group 2 The degree of differentiation is calculated according to Equation 1, which is shown in Example 1.

[0066] The differentiation value for monitoring group 2 was 76.8. Adjustments to aquaculture strategies were based on this differentiation value, specifically including: 0 < Differentiation value ≤ 20, normal condition, normal breeding should be carried out; If the difference value is 20 < 50, it indicates that a cold stress compensation period has occurred. The water temperature should be raised to 18℃ and vitamin C should be added to the feed. If the difference value is 50 < 70, it indicates a cold stress problem. Isolate the patient, raise the temperature, and administer dexamethasone. If the difference value is 70 < 100, it indicates an acute cold stress problem. The red tilapia should be transferred to a 25°C recovery tank and injected with dexamethasone.

[0067] Based on the above criteria, it can be concluded that monitoring group 2 has developed acute cold stress. The red tilapia in monitoring group 2 should be immediately transferred to a 25°C recovery tank and injected with dexamethasone.

[0068] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A rapid, low-loss, and effective cold stress assessment system for red tilapia, characterized in that... The evaluation system comprises an indicator layer, a method layer, and an application layer. The indicator layer includes behavioral indicators, body color indicators, blood indicators, and caudal fin pigment cell indicators. The method layer involves setting up a control group and a monitoring group, measuring the indicator values ​​of each group, using the measured values ​​of the control group as the standard values, and using an evaluation model to assess the degree of difference between the monitoring group and the control group. The application layer involves adjusting the breeding strategy based on the degree of difference between the monitoring group and the control group. The behavioral indicators include the fish's feeding behavior, swimming state, and balance state; the body color indicators include the L* value and b* value of the abdominal skin; the blood indicators include total cholesterol, total protein, total bilirubin, urea, norepinephrine, blood glucose, alkaline phosphatase, triglycerides, alanine aminotransferase, and aspartate aminotransferase in the blood; the caudal fin pigment cell indicators include the number, aggregation state, and red body color state of the caudal fin pigment cells; The L* value is lightness, representing the brightness or darkness of a color; the b* value is the yellow-blue axis, representing the position of the color on the yellow-blue spectral axis. The steps for establishing the evaluation model include: S1. The significance levels of body color indicators and blood indicators were determined by comparing them with the corresponding indicators of the control group. P A score <0.05 is considered statistically significant and is awarded 1 point; otherwise, no statistically significant difference is considered and is awarded 0 points. S2. Quantify the behavioral indicators and caudal fin pigment cell indicators respectively, and record the scores; S3. Weighting: The weighting coefficient for behavioral indicators is 0.3, the weighting coefficient for body color indicators is 0.25, the weighting coefficient for blood indicators is 0.3, and the weighting coefficient for tail fin pigment cell indicators is 0.

15. S4. Equation 1 for obtaining the degree of differentiation. Differentiation score = (behavioral index score × 0.3 + body color index score × 0.25 + blood index score × 0.3 + tail fin pigment cell index score × 0.15) × 20.62 (Equation 1); The quantification method for behavioral indicators is as follows: Scenario 1: No abnormal behavior, judged as normal, score 0 points; Scenario 2: Decreased food intake and slower swimming speed are considered mild abnormalities and are scored as 1 point. Scenario 3: Significantly reduced food intake, staying at the bottom and moving little, is judged as moderate abnormality, scoring 2 points; Scenario 4: If the patient stops eating and becomes unbalanced, it is considered a severe abnormality and is scored as 3 points. Adjusting aquaculture strategies based on the degree of differentiation, specifically including: 0 < Differentiation value ≤ 20, normal condition, normal breeding should be carried out; If the difference value is 20 < 50, it indicates that a cold stress compensation period has occurred. The water temperature should be raised to 18℃ and vitamin C should be added to the feed. If the difference value is 50 < 70, it indicates a cold stress problem. Isolate the patient, raise the temperature, and administer dexamethasone. If the difference value is 70 < 100, it indicates an acute cold stress problem. The red tilapia should be transferred to a 25°C recovery tank and injected with dexamethasone.

2. The rapid, low-damage, and effective cold stress assessment system for red tilapia as described in claim 1, characterized in that, The control group consisted of red tilapia whose living water temperature was maintained at or above 20°C.

3. The rapid, low-loss, and effective cold stress assessment system for red tilapia as described in claim 1, characterized in that, The quantification method for caudal fin pigment cell indicators is as follows: Situation 1: Red blood cells do not aggregate and are characteristically red, which is considered normal and scores 0 points; Situation 2: The presence of reduced and aggregated red pigment cells and decreased red body color, without the presence of melanocytes, is judged as a mild abnormality, scoring 1 point; Situation 3: The presence of reduced and aggregated red pigment cells, decreased red body color, and the appearance of melanocytes indicates a moderate abnormality, scoring 2 points. Situation 4: The presence of reduced and aggregated red pigment cells, decreased red body color, and the presence of melanocytes with a deepening of the melanin system indicates a severe abnormality, scoring 3 points.

4. A rapid, low-damage, and effective method for evaluating cold stress in red tilapia, characterized in that... The evaluation of cold stress in red tilapia using the evaluation system described in claim 1 includes the following specific steps: A control group and a monitoring group were set up, and behavioral indicators, body color indicators, blood indicators and caudal fin pigment cell indicators of red tilapia in the control group and the monitoring group were measured respectively. Using the measured value of the control group as the standard value, the evaluation model was used to assess the degree of difference between the monitoring group and the control group, and the degree of difference value was calculated. Based on the range of the degree of difference, the condition of the red tilapia in the monitoring group was determined and the breeding strategy was adjusted accordingly.

5. The rapid, low-damage, and effective method for evaluating cold stress in red tilapia as described in claim 4, characterized in that, The states of the red tilapia in the monitoring group include normal state, cold stress compensation period state, cold stress state, and acute cold stress state.

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