A method for determining metabolic body weight index and residual feed intake of prawns

Abstract

The application discloses a kind of determination methods of shrimp metabolic weight index and residual feed intake, belong to aquatic animal genetic breeding technical field.The application determines shrimp specific metabolic weight index by determining the power law relationship between the oxygen consumption rate of shrimp and weight, establishes the precise matching strategy of temperature fixed finger;Meanwhile, metabolic weight gain is replaced by weight gain to construct RFI prediction model, and it is first verified that the individual feed utilization efficiency difference should be the weight gain ability ADG of unit metabolic weight b , so that RFI can truly reflect the energy utilization efficiency of shrimp rather than mass utilization efficiency.The application creatively incorporates the pre-determined specific index as a known constant into the linear regression model, which significantly improves the determination coefficient of the regression model and the estimation accuracy of RFI, laying a methodological foundation for high-precision genetic evaluation of shrimp feed efficiency traits.

Description

Technical Field

[0001] This invention belongs to the field of aquatic animal genetics and breeding technology, specifically relating to a method for determining the metabolic body mass index and remaining feed intake of shrimp. Background Technology

[0002] Early evaluations of animal feed utilization efficiency primarily used two indicators: feed efficiency ratio (FER) and feed conversion ratio (FCR). However, both FER and FCR are ratio traits, which have inherent limitations: individuals with the same FER or FCR may have drastically different feed intake and weight gain. Furthermore, these indicators are highly correlated with growth traits and are easily affected by factors such as individual size and growth rate. Genetic modification of these individuals may lead to decreased population homogeneity or even adverse selection responses.

[0003] To overcome these limitations, Koch proposed the concept of Residual Feed Intake (RFI) in 1963. RFI is the difference between an individual's actual feed intake and the feed intake predicted based on its production performance (e.g., weight gain) and the requirements for maintaining normal bodily functions. RFI is generally not correlated with growth traits and reflects metabolic differences determined by the animal's genetic background. Animals with low RFI consume less feed and have higher feed utilization efficiency. Currently, RFI has become the preferred indicator for improving feed utilization efficiency in livestock and poultry, and standardized measurement and calculation methods have been established.

[0004] However, accurate measurement of the metabolic rate index (RFI) in shrimp still faces key technical bottlenecks. The calculation of RFI relies on accurate estimation of expected feed intake, which is typically obtained through a regression model that includes metabolic body weight and weight gain. In livestock and poultry such as cattle, pigs, and chickens, the metabolic body weight index is uniformly set at 0.75, and for fish at 0.8. However, shrimp are poikilothermic, exoskeletal animals, and their energy metabolism differs fundamentally from that of homeothermic vertebrates. Currently, there is very little systematic research on the metabolic body weight index of shrimp, making it impossible to determine an appropriate index value.

[0005] The lack of this fundamental parameter means that shrimp RFI calculations can only employ multivariate nonlinear regression methods, where the metabolic body mass index is set as an unknown coefficient for model fitting estimation. This results in a low coefficient of determination, making it difficult to guarantee the accuracy of the estimated feed intake, thus limiting the accurate application of the RFI index in shrimp genetic assessment and breeding. Therefore, it is urgent to establish a technical method that can accurately obtain the remaining feed intake of shrimp to overcome the computational bottleneck caused by the lack of metabolic body mass index. Summary of the Invention

[0006] Based on the needs of existing technologies, the purpose of this invention is to provide a method for determining the metabolic body mass index (RFI) and residual feed intake (RFI) of shrimp. This invention addresses the technical bottleneck of insufficient accuracy in RFI calculation due to the lack of a dedicated metabolic body mass index for shrimp. It determines a shrimp-specific metabolic body mass index by measuring the power-law relationship between shrimp oxygen consumption rate and body weight, and reveals the temperature dependence of this index, establishing a precise matching strategy based on temperature. Simultaneously, it constructs an RFI prediction model by replacing body weight gain with metabolic weight gain, enabling the RFI to truly reflect the shrimp's energy utilization efficiency rather than its mass utilization efficiency. This invention solves the long-standing problem hindering the accurate evaluation of shrimp feed efficiency.

[0007] To achieve the above objectives, the present invention is implemented through the following solution: This invention provides a method for determining the metabolic body mass index of shrimp, the method specifically comprising the following steps: (1) Prepare m 8~10 L well-sealed plastic boxes with lids, make a round hole in the lid, and equip it with a tight rubber plug to completely seal the hole; (2) Prepare fully aerated natural seawater, add more than two-thirds of the volume of seawater with the same salinity to the plastic box, and keep the water volume V in each plastic box the same. (3) Measure the total oxygen consumption rate R of each shrimp at three temperatures: T1, T2 and T3, where T1 < T2 < T3; (4) Based on the power law relationship between the total oxygen consumption rate R per shrimp and the body weight W per shrimp, R = a × W b Taking the natural logarithm of both sides of the equation, we get the linear equation: ln(R) = ln(a) + b × ln(W); Substitute the body weight W and total oxygen consumption rate R of shrimp individuals in good condition and with normal oxygen consumption at each temperature into the linear equation for regression analysis to obtain the slope b value at that temperature. (5) Based on the three different temperatures T1, T2, T3, b1, b2, b3 obtained above, establish the correspondence between metabolic body mass index and temperature b=f(T) to obtain the shrimp metabolic body mass index b corresponding to any given actual farming temperature T0.

[0008] Furthermore, in step (1), m ≥ 60.

[0009] Furthermore, in step (3), T1, T2 and T3 are respectively taken from temperatures in the range of 22~32℃.

[0010] Furthermore, the method for determining the total oxygen consumption rate R per shrimp in step (3) includes the following steps: S1: Prepare 3×m healthy 2~20g shrimp, temporarily raise them for 3~5 days to ensure they have molted once and their physiological state is stable, weigh and record the weight W of each shrimp, accurate to 0.01g. Under each temperature condition, put one shrimp in each plastic box, cover the box and seal it, remove the rubber stopper, insert the dissolved oxygen meter probe into the seawater through the hole in the cover, read the initial dissolved oxygen concentration C1, and measure the initial water temperature T at the same time, then immediately replace the rubber stopper with the hole in the box to keep it sealed. S2: After standing for 3-4 hours, remove the rubber stopper again, insert the dissolved oxygen meter probe into the seawater, read the final dissolved oxygen concentration C2, and measure the final water temperature at the same time. During the measurement, the ambient temperature should be kept constant within the target temperature ±0.5℃ range, and direct sunlight should be avoided. S3: When the temperature difference does not exceed 1℃ within 3-4 hours, calculate the total oxygen consumption rate R of each shrimp. The formula for the total oxygen consumption rate R is as follows: R=(C1- C2)×V / ΔT; Where R is in mgO2 / h; V is the water volume in L; and ΔT is the measurement time interval in h.

[0011] Furthermore, in step S1, the shrimp weighs 2-20 g.

[0012] Furthermore, the method for determining the shrimp metabolic weight index b(T0) corresponding to the actual culture temperature T0 in step 5 specifically includes: Divide the temperature axis into two continuous intervals: Interval 1: T1 ≤ T0 < T2, which is the low temperature to medium temperature range; Interval 2: T2 ≤ T0 ≤ T3, which is the medium to high temperature range; For a given actual aquaculture temperature T0, first determine the temperature range in which T0 falls, and then calculate the value of b(T0) according to the aforementioned correspondence b=f(T), as follows: (1) When T1 ≤ T0 ≤ T2, then b(T0) = b1 + (b2 - b1) / (T2 - T1) × (T0 - T1); (2) When T2 ≤ T0 ≤ T3, then b(T0) = b2 + (b3 - b2) / (T3 - T2) × (T0 - T2); (3) Boundary extrapolation processing: When T0 < T1 (below the lowest temperature measured), take b(T0) = b1; When T0 > T3 (higher than the highest temperature measured), take b(T0) = b3.

[0013] This invention also provides a method for determining the remaining feed intake of shrimp. The method is based on the aforementioned metabolic body mass index b(T0) of shrimp, and specifically includes the following steps: (1) Acquisition of individual food intake data In a recirculating aquaculture system, n independent culture units are set up. Each culture unit is covered with a mesh at the bottom to separate uneaten feed from feces. n shrimp weighing 2-5 g are selected and each shrimp is placed in a separate culture unit. They are fed in sufficient quantities multiple times a day. The uneaten feed of each shrimp is collected daily, dried, and weighed. The culture test period is 6-10 weeks, and the temperature is controlled within the target temperature range of T0±0.5℃. During the test period, the total feeding amount W for each shrimp was recorded. total_fed The total residual amount W is obtained by summing the residual dry weight of the feed measured each time. total_res Calculate the total amount of food consumed by each shrimp: W intake = W total_fed -W total_res ; Then calculate the average daily food intake: DFI = W intake / D, where D is the number of days for the aquaculture test; At the beginning and end of the test period, the weight of each shrimp was measured as BW1 and BW2, respectively, with the weight of each shrimp accurate to 0.01 g. The weight gain was calculated as: ΔBW = BW2-BW1. Calculate the average daily weight gain: ADG = ΔBW / D; Calculate median body weight: MW = (BW1 + BW2) / 2; (2) Accurate calculation of remaining feed intake Based on the shrimp metabolic body mass index b(T0) corresponding to the actual culture temperature T0, b(T0) is substituted into the following regression model for predicting feed intake: DFI = a1×MW b(T0) + a2×ADG b(T0) + ε; Among them, ADG b(T0) This refers to the metabolic weight gain of shrimp, which represents the daily weight gain rate per unit metabolic body weight. Multiple linear regression analysis was performed using DFI, ADG, and MW data of n shrimp to fit and obtain the values ​​of a1 and a2. The predicted average daily feed intake (pDFI) per shrimp was calculated based on the predicted feed intake regression model. pDFI = a1×MW b(T0) + a2×ADG b(T0) ; The difference between the actual average daily feed intake (DFI) and the predicted average daily feed intake (pDFI) is ultimately used as the remaining feed intake (RFI) of the shrimp: RFI = DFI - pDFI.

[0014] Furthermore, in step (1), n ​​is not less than 300.

[0015] Furthermore, the shrimp mentioned includes Litopenaeus vannamei.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention establishes for the first time a practical measurement technique for the metabolic body mass index (QMI) specific to shrimp. By combining a closed-loop respiration measurement method with the oxygen consumption rate-body weight power law relationship, the QMI of shrimp under different temperature conditions was accurately obtained, and the dynamic law of this index changing with temperature was further revealed, establishing a bT correspondence. This result breaks the long-standing path dependence of shrimp feed efficiency research, which could only draw on fixed parameters from terrestrial animals (b=0.75) or fish (b=0.80), fundamentally solving the basic scientific problem of the lack of metabolic body mass index in shrimp RFI calculations.

[0017] 2. Based on the scientific discovery that "metabolic body mass index is temperature-dependent", this invention proposes a "temperature-based index determination" strategy to simultaneously determine the specific metabolic body mass index under the RFI measurement temperature conditions. This achieves a precise match between the index and the test conditions. This technical solution avoids the systematic bias of RFI introduced by applying a fixed index at different breeding temperatures, and significantly improves the accuracy and comparability of RFI measurement results.

[0018] 3. This invention breaks through the traditional technical paradigm of simultaneously involving metabolic body mass index and regression coefficients in nonlinear fitting during RFI calculations. It creatively incorporates pre-determined specific indices as known constants into the linear regression model. This technical strategy increases the coefficient of determination of the regression model from 0.5 in traditional methods to over 0.97, resulting in a qualitative leap in RFI estimation accuracy and laying a methodological foundation for high-precision genetic assessment of shrimp feed efficiency traits.

[0019] 4. This invention breaks through the traditional RFI model paradigm that uses body weight gain as a predictor variable, and for the first time proposes to construct an RFI prediction model by replacing body weight gain with metabolic weight gain. The theoretical basis is that after the nutrients in feed are digested and absorbed, part is used for basal maintenance metabolism, and part is deposited into body tissues. The energy deposition efficiency has a power-law relationship with body weight (W... b This is directly related to [the individual's] feed utilization efficiency. Therefore, what truly reflects the differences in individual feed utilization efficiency is the weight gain per unit of metabolic body weight, rather than absolute body weight gain. Among these, ADG [is related to...]. b This refers to metabolic weight gain as defined in this invention. It represents the daily weight gain rate per unit of metabolic body weight and more accurately reflects the efficiency of feed energy conversion into body tissues than the traditional absolute daily weight gain.

[0020] 5. By fixing the b value as a known constant rather than participating in regression fitting, this invention significantly improves the stability and accuracy of the model, with the coefficient of determination R² of the regression model exceeding 0.97. Furthermore, combined with the residual feed intake (RFI) measurement method provided by this invention, it can be seen that the lower the RFI value, the lower the actual feed intake of the shrimp is compared to the expected feed intake based on its metabolic weight gain and maintenance metabolic needs, i.e., the higher the feed utilization efficiency. This provides a more accurate and intuitive understanding of feed utilization, offering technical support for aquaculture. Attached Figure Description

[0021] Figure 1 Box plots showing the distribution of individual body weight and oxygen consumption at three temperature levels.

[0022] Figure 2 The graph shows the body mass index (b=0.608) of shrimp at 24.5~25.5℃. The scatter points represent the measured data, the solid line is the linear regression fitted line, and the gray shaded area represents the 95% confidence interval of the fitted line.

[0023] Figure 3 The graph shows the body mass index (b=0.631) of shrimp at 26.5~27.5℃. The scatter points represent the measured data, the solid line is the linear regression fitted line, and the gray shaded area represents the 95% confidence interval of the fitted line.

[0024] Figure 4 The graph shows the body mass index (b=0.694) of shrimp at 28.5~29.5℃. The scatter points represent the measured data, the solid line is the linear regression fitted line, and the gray shaded area represents the 95% confidence interval of the fitted line.

[0025] Figure 5 Box plots are shown for ADG and DFI of 787 shrimp. The horizontal line above the box for each trait represents the 75th percentile of the data, the horizontal line in the middle of the box represents the median of the data, and the horizontal line below the box represents the 25th percentile of the data.

[0026] Figure 6 The pDFI and DFI histograms are for 787 shrimp. The curves on the contours of each trait histogram are the kernel density estimation curves, and the vertical dashed line in the middle represents the median.

[0027] Figure 7 The figures show the box plot and histogram of the radiometric index (RFI) for 787 shrimp. Figure a is the box plot of the RFI, where the horizontal line at the top of the box represents the 75th percentile of the data, the horizontal line in the middle of the box represents the median of the data, and the horizontal line at the bottom of the box represents the 25th percentile of the data. Figure b is the histogram, where the curve on the outline is the kernel density estimation curve, and the vertical dashed line in the middle also represents the median. Detailed Implementation

[0028] The technical solution of the present invention will be further described in detail with reference to the following specific examples, but the scope of protection of the present invention is not limited to the scope described in the examples.

[0029] Example 1 This embodiment provides a method for measuring the metabolic body mass index of shrimp and a method for determining the remaining feed intake of shrimp, the details of which are as follows: 1. A method for measuring the metabolic body mass index of shrimp, specifically including the following steps: (1) Prepare m 8~10 L well-sealed plastic boxes with lids. Use a drill to make a circular hole in the lid and equip it with a tight rubber plug to completely seal the hole; m≥60.

[0030] (2) Prepare fully aerated natural seawater, add more than two-thirds of the volume of seawater with the same salinity to the plastic box, and keep the water volume V in the plastic box the same.

[0031] (3) Measure the total oxygen consumption rate R of each shrimp at three temperatures: T1, T2 and T3, where T1 < T2 < T3; the temperatures of T1, T2 and T3 are respectively taken from the range of 22~32℃.

[0032] (4) Based on the power law relationship between the total oxygen consumption rate R per shrimp and the body weight W per shrimp, R = a × W b Taking the natural logarithm of both sides of the equation, we obtain the linear equation: ln(R) = ln(a) + b × ln(W), where a is the coefficient; Substitute the body weight W and total oxygen consumption rate R of shrimp individuals in good condition and with normal oxygen consumption at each temperature into the linear equation for regression analysis to obtain the slope b value at the corresponding temperature. S1: Prepare 3×m healthy shrimp weighing 2~20g each, temporarily raise them for 3~5 days to ensure they have molted once and are in a stable physiological state. Weigh and record the weight W of each shrimp, accurate to 0.01g. Under each temperature condition, place one shrimp in each plastic box, cover and seal the box, remove the rubber stopper, insert the dissolved oxygen meter probe into the seawater through the hole in the cover, read the initial dissolved oxygen concentration C1, and measure the initial water temperature T at the same time. Then immediately replace the rubber stopper with the hole in the box to keep it sealed. S2: After standing for 3-4 hours, remove the rubber stopper again, insert the dissolved oxygen meter probe into the seawater, read the final dissolved oxygen concentration C2, and measure the final water temperature at the same time. During the measurement, the ambient temperature should be kept constant within the actual aquaculture temperature T0±0.5℃ range, and direct sunlight should be avoided. S3: When the temperature difference does not exceed 1℃ within 3-4 hours, calculate the total oxygen consumption rate R of each shrimp. The formula for the total oxygen consumption rate R is as follows: R=(C1- C2)×V / ΔT; Where R is in mgO2 / h; V is the water volume in L; and ΔT is the measurement time interval in h.

[0033] (5) Based on the three different temperatures T1, T2, T3, b1, b2, b3 obtained above, establish the correspondence between metabolic body mass index and temperature b=f(T).

[0034] Based on the correspondence b=f(T), the method for determining the metabolic body mass index b(T0) of shrimp corresponding to the actual culture temperature T0 is as follows: Divide the temperature axis into two continuous intervals: Interval 1: T1 ≤ T < T2, which is the low temperature to medium temperature range; Interval 2: T2 ≤ T ≤ T3, which is the medium to high temperature range; For any given actual aquaculture temperature T0, first determine if T0 falls within the following temperature range, and then calculate the value of b(T0) according to the corresponding relationship b=f(T), as follows: (1) When T1 ≤ T0 ≤ T2, then b(T0) = b1 + (b2 - b1) / (T2 - T1) × (T0 - T1); (2) When T2 ≤ T0 ≤ T3, then b(T0) = b2 + (b3 - b2) / (T3 - T2) × (T0 - T2); (3) Boundary extrapolation processing: When T0 < T1 (below the lowest temperature measured), take b(T0) = b1; When T0 > T3 (higher than the highest temperature measured), take b(T0) = b3.

[0035] 2. A method for determining the remaining feed intake of shrimp, wherein the method is based on the shrimp metabolic body mass index b(T0), and specifically includes the following steps: (1) Acquisition of individual food intake data In a recirculating aquaculture system, n independent culture units are set up, with n not less than 300. Each culture unit is covered with a mesh screen at the bottom to separate uneaten feed from feces. n shrimp weighing 2-5 g are selected, and each shrimp is placed in a separate culture unit. They are fed in sufficient quantities multiple times a day. The uneaten feed of each shrimp is collected daily, dried, and weighed. The culture test period is 6-10 weeks, and the temperature is controlled within the actual culture temperature T0 ± 0.5℃. During the test period, the total feeding amount W for each shrimp was recorded. total_fed The total residual amount W is obtained by summing the residual dry weight of the feed measured each time. total_res Calculate the total amount of food consumed by each shrimp: Wintake = W total_fed - W total_res ; Based on the total feed intake per shrimp, calculate the average daily feed intake (DFI): DFI = W intake / D, where D is the number of days for the aquaculture test; At the beginning and end of the test period, the weight of each shrimp was measured as BW1 and BW2, respectively, with the weight of each shrimp accurate to 0.01 g. The weight gain was calculated as: ΔBW = BW2-BW1. Calculate the average daily weight gain: ADG = ΔBW / D; Calculate median body weight: MW = (BW1 + BW2) / 2; (2) Accurate calculation of remaining feed intake Based on the shrimp metabolic body mass index b(T0) corresponding to the actual culture temperature T0, b(T0) is substituted into the following regression model for predicting feed intake: DFI = a1×MW b(T0) +a2×ADG b(T0) + ε; Among them, ADG b(T0) This refers to the metabolic weight gain of shrimp, which represents the daily weight gain rate per unit metabolic body weight. Multiple linear regression analysis was performed using DFI, ADG, and MW data of n shrimp to fit and obtain the values ​​of a1 and a2. Based on the predicted feed intake regression model, the predicted average daily feed intake (pDFI) per shrimp was calculated: pDFI = a1×MW b(T0) + a2×ADG b(T0) ; The difference between the actual average daily feed intake (DFI) and the predicted average daily feed intake (pDFI) is ultimately used as the remaining feed intake (RFI) of the shrimp: RFI = DFI - pDFI.

[0036] This embodiment determines the shrimp-specific metabolic weight index by measuring the power law relationship between shrimp oxygen consumption rate and body weight, and reveals the temperature dependence of the index, establishing a precise matching strategy of "temperature-based index determination"; at the same time, it constructs an RFI prediction model by replacing body weight gain with metabolic weight gain, so that RFI can truly reflect the shrimp's energy utilization efficiency rather than mass utilization efficiency.

[0037] Example 2 Based on the method for determining the metabolic body mass index and the method for determining the residual feed intake of shrimp provided in Example 1, this example uses the above methods to determine the residual feed intake (RFI) of Litopenaeus vannamei, specifically including the following: 1. Determination of metabolic body mass index and establishment of its temperature dependence (1) Prepare 76 10 L well-sealed plastic boxes with lids. Use a drill to make a round hole in the lid and equip it with a tight rubber plug to completely seal the hole.

[0038] (2) Prepare fully aerated natural seawater, use a salinity meter to measure the salinity of the seawater, the salinity is about 28, and add 9L of seawater with the same salinity to each plastic box.

[0039] (3) Perform the following operations at three temperature levels: 25℃, 27℃, and 29℃ respectively: Prepare 230 healthy Litopenaeus vannamei shrimp weighing 2-18g each, temporarily raise them for 5 days to ensure they have molted once and are in a stable physiological state, weigh and record the weight W of each shrimp (accurate to 0.01 g). At each temperature level, place one shrimp in each plastic box, cover and seal the box, remove the rubber stopper, insert the dissolved oxygen meter probe into the seawater through the hole in the cover, read the initial dissolved oxygen concentration C1 (mgO2 / L), and simultaneously measure the initial water temperature T (℃). Then immediately replace the rubber stopper with the hole in the box to keep it sealed.

[0040] (4) After standing for 3 hours, remove the rubber stopper again, insert the dissolved oxygen meter probe into the seawater, and read the final dissolved oxygen concentration C2 (mgO2 / L). At the same time, measure the final water temperature. During the measurement, the ambient temperature should be kept constant within ±0.5℃ of the target temperature, and direct sunlight should be avoided.

[0041] (5) When the temperature difference does not exceed 1℃ within 3 hours, the total oxygen consumption rate R (mgO2 / h) per shrimp is calculated using the following formula: R = (C1 - C2) × 9 / 3. The box plots showing the distribution of individual body weight and oxygen consumption at the three temperature levels are shown below. Figure 1 As shown.

[0042] (6) Based on the power law relationship between oxygen consumption rate R and body weight W, R = a × W b Transform both sides of the equation by taking the natural logarithm: ln(R) = ln(a) + b×ln(W); At the three temperature levels, 76, 67, and 60 shrimp met the requirements, respectively. Their body weight and total oxygen consumption data were substituted into the above linear equation for regression analysis to obtain the slope b value for that temperature range. The above measurements were repeated at three temperature ranges: 24.5~25.5℃, 26.5~27.5℃, and 28.5~29.5℃, to obtain the corresponding metabolic body mass indices b1, b2, and b3. Figures 2-4 ).

[0043] (7) Establish the correspondence between metabolic body mass index and temperature: b = f(T) = b(T); For any given actual aquaculture temperature T0, first determine which temperature range it falls within, and then calculate the value of b according to the corresponding formula: S1: When 25 ≤ T0 < 27 (low temperature range): b(T0) = 0.608 + (0.631- 0.608) / (27-25)×(T0- 25); S2: When 27 ≤ T0 ≤ 29 (high temperature range): b(T0) = 0.631 + (0.694- 0.631) / (29-27)×(T0- 27); 2. Acquisition of individual food intake data Eighty hundred independent culture units were set up in the recirculating aquaculture system. Each unit had a mesh bottom to separate uneaten feed from feces. Eighty hundred Litopenaeus vannamei shrimp (3-5 g each) were selected and placed individually in each unit. They were fed adequately multiple times daily, and uneaten feed was collected daily, dried, and weighed. The culture test lasted for six weeks, with the temperature controlled within the target range of 28 ± 0.5℃.

[0044] During the test period, the total feeding amount W for each shrimp was recorded. total_fed The total residual amount W is obtained by summing the residual dry weight of the feed measured each time. total_res Calculate the total amount of food consumed by each shrimp: W intake = W total_fed - W total_res Then calculate the average daily food intake: DFI = W intake / D, where D is the number of days for the breeding test.

[0045] At the beginning and end of the test period, the weight of each shrimp was measured as BW1 and BW2 (accurate to 0.01 g), and the weight gain was calculated as: ΔBW = BW2 - BW1; Calculate the average daily weight gain: ADG = ΔBW / D; Calculate median body weight: MW = (BW1 + BW2) / 2.

[0046] After a 6-week test, and after removing dead individuals, 787 shrimp were harvested. The ADG and DFI distributions of these individuals are as follows: Figure 5 As shown.

[0047] 3. Precise calculation of remaining feed intake based on metabolic weight gain Substitute the metabolic body mass index b (i.e., b=0.663) obtained from the correspondence of b = f(T) based on the actual breeding temperature of 28℃ in step one into the following regression model for predicting feed intake: DFI = a1×MW 0.663 +a2×ADG0.663 +ε; Multiple linear regression analysis was performed using the DFI, ADG, and MW data of 787 shrimp tails. The fitted values ​​were a1 (0.0455) and a2 (0.2946). The coefficient of determination R of the regression model was [value missing]. 2 It is 0.9761.

[0048] The predicted average daily feed intake (pDFI) per shrimp was calculated based on the regression equation above. pDFI = 0.0455×MW 0.663 + 0.2946×ADG 0.663 ; The final residual feed intake (RFI) of the shrimp is the difference between the actual average daily feed intake (DFI) and the predicted average daily feed intake (pDFI). RFI = DFI - pDFI; The pDFI and DFI distributions of 787 shrimp are as follows: Figure 6 As shown, the RFI distribution is as follows Figure 7 As shown.

[0049] Among them, the minimum value of pDFI is 0.123 g / d, the maximum value is 0.337 g / d, and the average value is 0.217 g / d, which generally conforms to a normal distribution. In contrast, the minimum value of DFI is 0.101 g / d, the maximum value is 0.315 g / d, and the average value is 0.221 g / d, which generally deviates from a normal distribution. The minimum value of RFI is -0.141 g / d, the maximum value is 0.074 g / d, and the average value is 0.0035 g / d, which generally deviates from a normal distribution.

[0050] This invention constructs an RFI prediction model by replacing body weight gain with metabolic weight gain, so that RFI can truly reflect the energy utilization efficiency of shrimp.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions claimed by the present invention.

Claims

1. A method for determining the metabolic body mass index of shrimp, characterized in that, The determination method specifically includes the following steps: (1) Prepare m well-sealed plastic boxes with lids, make holes in the lids, and equip them with rubber plugs to completely seal the holes; (2) Prepare fully aerated natural seawater, add more than two-thirds of the volume of seawater with the same salinity to the plastic box, and keep the water volume V in each plastic box the same. (3) Measure the total oxygen consumption rate R of each shrimp at three temperatures: T1, T2 and T3, where T1 < T2 < T3; (4) Based on the power law relationship between the total oxygen consumption rate R per shrimp and the body weight W per shrimp, R = a × W b Taking the natural logarithm of both sides of the equation, we get the linear equation: ln(R) = ln(a) + b × ln(W); Substitute the body weight W and total oxygen consumption rate R of shrimp individuals in good condition and with normal oxygen consumption at each temperature into the linear equation for regression analysis to obtain the slope b value at the corresponding temperature. (5) Based on the three different temperatures T1, T2, T3, b1, b2, b3 obtained above, establish the correspondence between metabolic body mass index and temperature b=f(T), and obtain the shrimp metabolic body mass index b(T0) corresponding to the actual farming temperature T0.

2. The determination method according to claim 1, characterized in that, In step (1), m ≥ 60.

3. The determination method according to claim 1, characterized in that, In step (3), T1, T2 and T3 are taken from temperatures in the range of 22~32℃.

4. The determination method according to claim 1, characterized in that, The method for determining the total oxygen consumption rate R per shrimp in step (3) includes the following steps: S1: Prepare 3×m healthy shrimp and temporarily raise them for 3-5 days to ensure that they have molted once and their physiological state is stable. Weigh and record the weight W of each shrimp. Under each temperature condition, put one shrimp into each plastic box, cover the box and seal it. Remove the rubber stopper and insert the dissolved oxygen meter probe into the seawater through the hole in the cover to read the initial dissolved oxygen concentration C1. At the same time, measure the initial water temperature T. Then immediately replace the rubber stopper with the hole in the box to keep it sealed. S2: After standing for 3-4 hours, remove the rubber stopper again, insert the dissolved oxygen meter probe into the seawater, read the final dissolved oxygen concentration C2, and measure the final water temperature at the same time. During the measurement, the ambient temperature should be kept constant within the actual aquaculture temperature T0±0.5℃ range, and direct sunlight should be avoided. S3: When the temperature difference does not exceed 1℃ within 3-4 hours, calculate the total oxygen consumption rate R of each shrimp. The formula for the total oxygen consumption rate R is as follows: R=(C1-C2)×V / ΔT; Where R is in mgO2 / h; V is the water volume in L; and ΔT is the measurement time interval in h.

5. The determination method according to claim 4, characterized in that, In step S1, the weight of the shrimp is 2-20 g.

6. The determination method according to claim 1, characterized in that, The method for determining the shrimp metabolic body mass index b(T0) corresponding to the actual culture temperature T0 in step (5) specifically includes: Divide the temperature axis into two continuous intervals: Interval 1: T1 ≤ T0 < T2, which is the low temperature to medium temperature range; Interval 2: T2 ≤ T0 ≤ T3, which is the medium to high temperature range; For a given actual aquaculture temperature T0, first determine the temperature range in which T0 falls, and then calculate the value of b(T0) according to the aforementioned correspondence b=f(T), as follows: (1) When T1 ≤ T0 ≤ T2, then b(T0) = b1 + (b2-b1) / (T2-T1)×(T0-T1); (2) When T2 ≤ T0 ≤ T3, then b(T0) = b2 + (b3-b2) / (T3-T2)×(T0-T2); (3) Boundary extrapolation processing: When T0 < T1, take b(T0) = b1; When T0 > T3, take b(T0) = b3.

7. The method for determining the metabolic body mass index of shrimp according to claim 1, characterized in that, The shrimp mentioned include Litopenaeus vannamei.

8. A method for determining the remaining feed intake of shrimp based on the method for determining the metabolic body mass index of shrimp according to claim 1, characterized in that, Specifically, it includes the following steps: (1) Acquisition of individual food intake data In a recirculating aquaculture system, n independent culture units are set up. Each culture unit is covered with a mesh screen at the bottom to separate uneaten feed from feces. n shrimp weighing 2-5 g are selected and each shrimp is placed in a separate culture unit. They are fed in sufficient quantities multiple times a day. The uneaten feed of each shrimp is collected daily, dried, and weighed. The culture test period is 6-10 weeks, and the temperature is controlled within the actual culture temperature T0 ± 0.5℃. During the test period, the total feeding amount W for each shrimp was recorded. total_fed The total residual amount W is obtained by summing the residual dry weight of the feed measured each time. total_res Calculate the total amount of food consumed by each shrimp: W intake = W total_fed -W total_res ; Based on the total feed intake per shrimp, calculate the average daily feed intake (DFI): DFI = W intake / D, where D is the number of days for the aquaculture test; At the beginning and end of the test period, the weight of each shrimp was measured as BW1 and BW2, respectively, with the weight of each shrimp accurate to 0.01g. The weight gain was calculated as: ΔBW = BW2-BW1. Calculate the average daily weight gain: ADG = ΔBW / D; Calculate median body weight: MW = (BW1 + BW2) / 2; (2) Accurate calculation of remaining feed intake Based on the shrimp metabolic body mass index b(T0) corresponding to the actual culture temperature T0, b(T0) is substituted into the following regression model for predicting feed intake: DFI =a1×MW b(T0) + a2×ADG b(T0) + ε; Among them, ADG b(T0) This refers to the metabolic weight gain of shrimp, which represents the daily weight gain rate per unit metabolic body weight. Multiple linear regression analysis was performed using DFI, ADG, and MW data of n shrimp to obtain the values ​​of a1 and a2. Based on the predicted feed intake regression model, the predicted average daily feed intake (pDFI) per shrimp was calculated: pDFI =a1×MW b(T0) + a2×ADG b(T0) ; The difference between the actual average daily feed intake (DFI) and the predicted average daily feed intake (pDFI) is ultimately used as the remaining feed intake (RFI) of the shrimp: RFI = DFI - pDFI.

9. The method for determining the remaining feed intake of shrimp according to claim 8, characterized in that, In step (1), n ​​is not less than 300.

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