Prediction method for wheat standard ileum amino acid digestibility of laying hens in brooding period

Abstract

The invention discloses a method for predicting wheat standard ileum amino acid digestibility of laying hens in a brooding period. The method comprises the following steps: determining physical characteristics, chemical components and amino acid contents of wheat samples from ten different sources; preparing a test feed, and carrying out a feeding test on Jingjing No.8 laying hens in a brooding period (28-31 days old); determining the standard ileum amino acid digestibility of the 31-day-old laying hens to the wheat of each source; and based on the data correlation, establishing a prediction equation of the wheat standard ileum amino acid digestibility of the laying hens in the brooding period by adopting a stepwise regression method. The constructed prediction equation can accurately predict the standard ileum amino acid digestibility of the laying hens in the brooding period to the wheat, an effective tool is provided for achieving efficient utilization of wheat resources and promoting practice of precise nutrition, and a theoretical basis and data support are provided for feed and breeding enterprises to scientifically design a daily ration formula of laying chicks.

Description

Technical Field

[0001] This invention relates to the field of animal feed technology, specifically providing a method for predicting the digestibility of standard ileal amino acids from wheat in laying hens during the brooding period. Background Technology

[0002] In recent years, driven by multiple factors such as fluctuations in the international supply chain, frequent extreme weather events, and surging demand for biofuels, domestic corn prices have remained high, significantly increasing feed production costs. Wheat, as an important energy feed ingredient, has higher levels of crude protein and some digestible amino acids than corn. Its scientific application in feed formulation can not only help alleviate the protein feed resource shortage caused by the reduction of corn and soybean meal substitution, but also further reduce formulation costs. However, existing wheat amino acid digestibility data mainly come from experimental results of 7–21-day-old broilers or growing pigs weighing around 30 kg, lacking measured digestibility data for the critical physiological stage of laying hens around 31 days old. Currently, formulation software typically uses broiler parameters or employs fixed coefficients to calculate the standard ileal amino acid digestibility (SID) of laying hens, which can easily lead to an underestimation of amino acid supply, causing problems such as decreased early weight uniformity and increased nitrogen emissions in chicks. Therefore, it is urgent to establish a wheat amino acid SID database for 28-31 day old laying hens and to construct a predictive model based on conventional chemical components to support the precise formulation of laying hen feed during this stage and promote the efficient and scientific utilization of wheat resources. Summary of the Invention

[0003] This study used 28-31 day old laying chicks as the research subjects and constructed a precision feed formulation based on the prediction method of the digestible amino acid nutritional value of wheat. The obtained data will be integrated to form an independent database of wheat amino acid nutritional value for laying hens during the brooding period, providing core data support for dynamic nutrition prediction models and the national livestock big data platform. The ultimate goal is to guide feed companies to scientifically use wheat resources to formulate daily rations for laying chicks, achieving multiple objectives such as reducing feed costs, reducing nitrogen emissions, and enhancing the autonomy and controllability of the feed supply chain.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for establishing a standard ileal amino acid digestibility prediction equation for wheat in laying hens during the brooding period includes the following steps:

[0006] 1) Determine the content of chemical nutrients and physicochemical properties of wheat from different sources;

[0007] 2) Experimental feed formulation and feeding of laying hens during the brooding period (28-31 days old);

[0008] 3) Collect post-ileal digesta from 31-day-old brooding hens to determine (1) the apparent ileal amino acid digestibility (AID) of the test diet, (2) the endogenous amino acid (EAA) flow measured using a nitrogen-free diet (NFD), and (3) the standard ileal amino acid digestibility (SID) of the test diet.

[0009] 4) Construct a predictive equation for amino acid SID by utilizing the relationship between the chemical composition of wheat and the standard ileal amino acid digestibility (SID) of wheat by laying hens during the brooding period, and the relationship between the amino acid content of wheat and SID.

[0010] In step 4), the prediction equation for the standard ileal amino acid digestibility of wheat in laying hens during the brooding period is: SIDLys = 126.339 - 7.765ADF - 7.502EE, with a coefficient of determination R. 2 The p-value was 0.893, and the p-value was <0.001.

[0011] SIDThr = 59.620 + 22.986Ash - 7.644ADF, Coefficient of Determination R 2 The value was 0.695, and the p-value was 0.012.

[0012] SIDIle = 118.291 - 8.780EE - 0.319NDF, Coefficient of determination R 2 The value was 0.698, and the p-value was 0.013.

[0013] SIDLeu = 117.802 - 4.982EE - 3.911ADF, coefficient of determination R 2 The value was 0.774, and the p-value was 0.005.

[0014] SIDPhe = 84.196 - 3.682EE + 0.255TS, coefficient of determination R 2 The value was 0.764, and the p-value was 0.006.

[0015] SIDVal = 156.522 - 10.535EE - 2.992CP, coefficient of determination R 2 The value was 0.833, and the p-value was 0.002.

[0016] SIDHis = 116.647 - 6.193EE - 4.014ADF, Coefficient of determination R 2 The value was 0.846, and the p-value was 0.002.

[0017] SIDArg = 123.952 - 6.887EE - 5.712ADF, coefficient of determination R 2 The value was 0.655, and the p-value was 0.017.

[0018] SIDAsp = 63.460 - 5.799EE + 0.580TS - 9.975PA, Coefficient of Determination R 2 The value was 0.849, and the p-value was 0.005.

[0019] SIDSer = 72.839 + 14.953Ash - 4.543ADF, Coefficient of Determination R 2 The p-value was 0.625, and the p-value was 0.018.

[0020] SIDGlu = 92.589 - 2.107EE + 0.122TS, coefficient of determination R 2 The value was 0.809, and the p-value was 0.003.

[0021] SIDGly = 112.927 - 11.829EE, coefficient of determination R 2 The value was 0.674, and the p-value was 0.004.

[0022] SIDAla=95.951-58.815His-9.214EE+0.447TS, coefficient of determination R 2 The p-value was 0.965, and the p-value was 0.001.

[0023] SIDPro = -234.529 + 16.051GE + 0.544TS, Coefficient of Determination R 2 The value was 0.772, and the p-value was 0.005.

[0024] SIDTyr = 118.311 - 5.696EE - 3.885ADF, coefficient of determination R 2 The p-value was 0.802, and the p-value was 0.003.

[0025] The left side of the equation represents the predicted standard ileal digestibility of each amino acid; the chemical composition (including amino acids and conventional chemical components) on the right side refers to the content of each chemical component in wheat, where ADF is acid detergent fiber; Ash is crude ash; CP is crude protein; EE is fat; GE is total energy; His is histidine; NDF is neutral detergent fiber; and TS is total starch.

[0026] Furthermore, the accuracy of the predictive equation for the standard ileal amino acid digestibility of brooding hens obtained in step 4) was verified using the standard ileal amino acid digestibility of wheat from different sources in brooding hens obtained in step 3).

[0027] The physical properties measured in step 1) of the technical solution implementation include bulk density, thousand-grain weight, and thousand-grain volume; the chemical composition measurements include: dry matter, crude protein, crude fat, total energy, starch, crude ash, crude fiber, neutral detergent fiber, acid detergent fiber, calcium, total phosphorus, and phytic acid; the 18 amino acids measured include essential amino acids: lysine, methionine, threonine, tryptophan, arginine, leucine, isoleucine, phenylalanine, valine, and histidine; and non-essential amino acids: aspartic acid, serine, glutamic acid, glycine, alanine, proline, cysteine, and tyrosine.

[0028] In step 2) of the implementation of the technical solution, an experimental diet for brooding laying hens with wheat as the sole protein source was conducted. The formula of the experimental diet was as follows: wheat 92.53%, soybean oil 3.00%, limestone powder 1.30%, anhydrous dicalcium phosphate 1.90%, salt 0.30%, 50% choline chloride 0.25%, vitamin premix 0.02%, trace element premix 0.20%, and titanium dioxide 0.5%. The experiment was conducted on laying hens aged 28 days for 72 hours to 31 days.

[0029] In step 3) of the technical solution implementation, the calculation method is as follows:

[0030] Apparent ileal amino acid digestibility AID = [1 - (AAil / AAd1) × (Md1 / Mi1)] × 100%;

[0031] In the formula: AAi1 represents the content of amino acids based on dry matter in the ileal digest; AAdl represents the content of amino acids based on dry matter in the diet; Md1 and Mi1 represent the concentrations of TiO2 indicators based on dry matter in the diet and digest, respectively.

[0032] Basal loss of endogenous amino acids in the terminal ileum: IAAend = AAi2 × (Md2 / Mi2), in mg / kg;

[0033] In the formula: AAi2 represents the amino acid content based on dry matter in the ileal digest of the nitrogen-free diet group, and Md2 and Mi2 represent the TiO2 content in the nitrogen-free diet and the TiO2 content based on dry matter in the ileal digest of the nitrogen-free diet group, respectively.

[0034] Standard ileal amino acid digestibility (SID), % = AID + (IAAend / AAd1) × 100%;

[0035] In the formula: IAAend represents the loss of endogenous amino acids in the terminal ileum, and AAd1 represents the amino acid content in the diet based on dry matter.

[0036] In this invention, we first quantified the correlation between the conventional chemical components of wheat and amino acids (based on DM) and their correlation with standardized ileal amino acid digestibility (SID). Then, we used stepwise regression to identify key predictors among these variables, thereby obtaining an optimal predictive model for wheat amino acid SID, which can be used to predict the nutritional value of wheat amino acids during the brooding stage.

[0037] A method for predicting the amino acid digestibility of wheat in laying hens during the brooding period involves detecting the content of chemical components in wheat, including amino acids and conventional chemical components, and substituting these contents into a standard ileal amino acid digestibility prediction equation for wheat in laying hens during the brooding period, established according to any one of claims 1-6, to calculate the predicted standard ileal digestibility of each amino acid.

[0038] The beneficial effects of this invention are as follows:

[0039] The prediction model constructed in this invention exhibits significantly lower prediction errors for the SID (Superoxide Dismutase) of various amino acids in wheat compared to the traditional fixed-coefficient method, resulting in a significant improvement in prediction accuracy. This provides crucial data support for dynamic prediction models and big data platforms, offering a reliable theoretical basis for the efficient utilization of wheat resources, precision animal nutrition, and the rational formulation of poultry diets by feed and livestock enterprises. This method only requires the measurement of major conventional nutrients such as CP, NDF, ADF, and EE, as well as the content of a few amino acids, enabling rapid prediction of SID values ​​within 5 minutes. This drastically shortens the formulation design cycle from the traditional 14–21 days to 2–3 days. This improvement significantly reduces overall costs and enhances economic efficiency. Furthermore, this invention can also provide a dedicated prediction module for wheat SID in laying hens during the brooding period, offering reliable data support for the efficient utilization of wheat in feed and related policy formulation.

[0040] This invention selects 28-31 day old laying hens as experimental subjects and chooses 10 representative wheat samples. The basal endogenous amino acid flux is determined using a nitrogen-free diet method, and the apparent ileal digestibility of the wheat diet is combined to accurately calculate the SID values ​​of 18 amino acids, including lysine (Lys), threonine (Thr), and methionine (Met). Simultaneously, the contents of crude protein, phytic acid, and mineral elements in wheat are measured, and a stepwise regression prediction equation is established with these chemical components as independent variables and SID values ​​as dependent variables. This invention fills the gap in my country's database of wheat amino acid SIDs for laying hens during the brooding period, providing core parameters for a big data platform on the nutritional value of laying hen feed ingredients, and contributing to the implementation of precise formulations that save feed, reduce emissions, improve quality, and increase efficiency.

[0041] This invention selects 28-31 day old laying hens as a standardized research and evaluation animal model. This stage is a critical physiological stage of rapid development of intestinal villi and a surge in pancreatic enzyme activity, which is conducive to the accurate determination of the SID value of wheat amino acids. It has good application value and promotion prospects. Detailed Implementation

[0042] The present invention will be described in detail below with reference to specific embodiments.

[0043] This invention provides a method for predicting the standard ileal amino acid digestibility of wheat in laying hens during the brooding period. After the pre-feeding period, the experimental group and the nitrogen-free diet group were fed the experimental diet and the nitrogen-free diet for three consecutive days (28–31 days of age), respectively. At 31 days of age, the laying hens were slaughtered, and the ileal digesta was collected to determine the standard ileal amino acid digestibility of the wheat diet to be tested.

[0044] The experimental diet described in this invention is a semi-homozygous diet with wheat as the sole protein source, specifically designed to evaluate the SID (Single Intake Index) value of wheat amino acids. Based on the SID data obtained by the described method, a predictive equation for SID is further constructed. Unless otherwise specified, the technical means used in the embodiments of this invention are all conventional methods in the art, and the raw materials used are all commercially available products.

[0045] Example 1: Evaluation of Chemical Components in Wheat from Different Sources

[0046] This experiment used wheat from 10 different sources: Tianjin wheat (W1), Yangzhou wheat (W2), Chengde wheat (W3), Chengdu wheat (W4), Panjin wheat (W5), Zhumadian wheat (W6), Huainan wheat (W7), Xianyang wheat (W8), Wuhan wheat (W9), and Nanjing wheat (W10). The physical properties of the selected 10 wheat varieties were measured, including thousand-grain weight (TKW), thousand-grain volume (TKV), and test weight (BD). Chemical components included dry matter (DM), crude protein (CP), crude fat (EE), crude fiber (CF), total energy (GE), neutral detergent fiber (NDF), acid detergent fiber (ADF), total starch (TS), calcium (Ca), total phosphorus (TP), and phytic acid (PA). The analysis of BD was conducted according to GB / T5498-2013 standard; thousand-grain weight and thousand-grain volume were determined according to GB / T5519-2018 standard; DM according to GB / T6435-2014; CP according to GB / T6432-2018; EE according to GB / T6433-2006; Ash according to GB / T6438-2007; Ca according to GB / T6436-2022; TP according to GB / T6437-2002; NDF according to GB / T20806-2022; and ADF according to NY / T1459-2007 standard. All content determinations were performed according to national standards. GE was determined using an oxygen and nitrogen calorimeter (TYHW-V); TS was determined using a Solarbio starch content assay kit; and phytic acid was determined using a Solarbio phytic acid content assay kit. Determination of amino acid content in raw materials: (1) Essential amino acids (EAAs): Lysine (Lys), Methionine (Met), Tryptophan (Trp), Threonine (Thr), Arginine (Arg), Leucine (Leu), Isoleucine (Ile), Phenylalanine (Phe), Valine (Val), Histidine (His); (2) Non-essential amino acids (NEAAs): Aspartic acid (Asp), Serine (Ser), Glutamic acid (Glu), Glycine (Gly), Alanine (Ala), Cysteine ​​(Cys), Proline (Pro), Tyrosine (Tyr); The content of sulfur-containing amino acids (cysteine ​​and methionine) was determined according to GB / T 15399-2018; For tryptophan, alkaline hydrolysis method was used.The content of amino acids was determined using a liquid chromatograph (U3000, Thermo Fisher Scientific) according to GB / T 15400-2018. The content of the other 15 amino acids was determined using a conventional acid hydrolysis method and an automated amino acid analyzer (LA8080, Hitachi) according to GB / T18246-2019. Tryptophan was determined using liquid chromatography, referring to GB / T 15399-2018. The results of the conventional chemical nutrient content (%, dry matter basis) of wheat raw materials from different sources are shown in Table 1. The results of the amino acid content (%, dry matter basis) of wheat from different sources are shown in Table 2.

[0047]

[0048]

[0049]

[0050] Example 2: Evaluation of wheat standard ileal amino acid digestibility in laying hens during the brooding period

[0051] 1. Test materials

[0052] Same as Example 1.

[0053] 2. Experimental diet and experimental design

[0054] 594 healthy, uniformly weighted 28-day-old laying hens (Jingfen No. 8) were randomly divided into 11 treatments, with 6 replicates per treatment and 9 hens per replicate. Treatment 1 was fed a nitrogen-free diet, while treatments 2-11 were fed an experimental diet. Following the "NY / T33-2004 Chicken Feeding Standards," the diets were formulated with glucose and corn starch as the base ingredients, supplemented with minerals, vitamins, and exogenous indicator TiO2, ensuring that all nutrients except protein met the needs of the laying hens. A semi-homogeneous diet was formulated using wheat from 10 different sources as the sole protein source, supplemented with soybean oil, TiO2, minerals, and vitamins. The composition and nutrient levels of the nitrogen-free and experimental diets are shown in Table 3.

[0055] Table 3. Amino acid content (dry matter basis) of wheat from 10 different sources (%)

[0056] nitrogen-free diets wheat experimental diet wheat - 92.53 glucose 64.00 - corn starch 22.16 - Soybean oil 4.00 3.00 Sodium carboxymethyl cellulose 4.00 - Sodium bicarbonate 1.20 - stone powder 1.30 1.30 Anhydrous dicalcium phosphate 1.90 1.90 salt - 0.30 Potassium chloride 0.40 - magnesium oxide 0.07 - Choline chloride (50%) 0.25 0.25 Vitamin premix 0.02 0.02 Trace element premix 0.20 0.20 Titanium dioxide 0.50 0.5 Metabolizable energy (MJ / kg) 12.58 12.82 crude protein 0.26 12.06(10.89-12.80) calcium 1.04 1.10(1.05-1.30) Non-phytic acid phosphorus 0.44 0.64(0.60-0.72)

[0057] 3. Sample collection and processing

[0058] At 31 days of age, experimental chickens were euthanized by stunning them with CO2 gas and bleeding them out of their carotid artery while on free access to feed. The abdominal cavity was opened, the ileum was quickly separated, folded in half, and the posterior half of the ileum was removed (discarding the last 2cm). Ileal chyme was flushed into an aluminum box using a 25mL syringe filled with distilled water. All the chyme from each replicate was placed in one aluminum box or corresponding container, then stored at -20℃, freeze-dried, and then refluxed at room temperature for 24 hours. The chyme was then pulverized for later determination of amino acid and TiO2 indicator content.

[0059] 4. Formula for calculating the digestibility of amino acids in the standard ileum

[0060] Apparent ileal amino acid digestibility (AID, %) = [1 - (AAil / AAd1) × (Md1 / Mi1)] × 100;

[0061] In the formula: AAi1 represents the amino acid content in the ileal digesta (dry matter basis); AAdl represents the amino acid content in the diet (dry matter basis); Md1 and Mi1 represent the concentrations of indicators in the diet and digesta, respectively (dry matter basis).

[0062] Basal loss of endogenous amino acids in the terminal ileum (IAAend, mg / kg) = AAi2 × (Md2 / Mi2);

[0063] In the formula: AAi2 represents the amino acid content (dry matter basis) in the ileal digesta of the nitrogen-free diet group, and Md2 and Mi2 represent the TiO2 content in the nitrogen-free diet and the TiO2 content (dry matter basis) in the ileal digesta of the nitrogen-free diet group, respectively.

[0064] Standard ileal amino acid digestibility (SID, %) = AID + (IAAend / AAd1) × 100%;

[0065] In the formula: IAAend represents the loss of endogenous amino acids at the end of the ileum, and AAD1 represents the amino acid content in the diet (dry matter basis).

[0066] 5. Data Analysis

[0067] In this experiment, Microsoft Excel 2019 was used for preliminary data processing, and SPSS Statistics 27.0 software was used for one-way ANOVA. Duncan's method was used for significance testing. Results are expressed as the mean of repeated trials for each treatment group. P < 0.05 indicates a significant difference, and P < 0.01 indicates an extremely significant difference.

[0068] 6. Results

[0069] The results of the standard ileal amino acid digestibility of wheat for laying hens during the brooding period, calculated according to the standard ileal amino acid digestibility calculation formula, are shown in Table 4.

[0070]

[0071]

[0072] Example 3: Establishment of a predictive equation for the standard ileal amino acid digestibility of wheat in laying hens during the brooding period

[0073] This study analyzed the correlation between wheat's conventional chemical indicators, amino acid content, and the standard ileal amino acid digestibility (SID) of laying hens during the brooding period. Subsequently, using SID as the dependent variable and wheat's conventional chemical indicators and amino acid content as independent variables, stepwise regression was used to screen key predictive factors (inclusion P < 0.05, exclusion P > 0.1), constructing the optimal regression equation, and using Ri... 2 To evaluate the fit, the original data were first processed into 9 groups using Excel 2019 (excluding the 10th group), and then correlation analysis and stepwise regression modeling were completed in SPSS 27.

[0074] 1. Correlation analysis was performed on the standard ileal amino acid digestibility of wheat for laying hens during the brooding period, excluding group 10, with conventional chemical composition and amino acid content (dry matter basis). The results are shown in Tables 5 and 6.

[0075]

[0076]

[0077]

[0078]

[0079] 2. Prediction equation for standard ileal amino acid digestibility of wheat in laying hens during the brooding period

[0080] The data from the nine groups other than group 10 were initially processed using Excel 2019. Then, using these nine groups of data, a stepwise regression method was employed to construct a predictive equation for the standard ileal amino acid digestibility of wheat in laying hens during the brooding period (using conventional chemical components and amino acid content of raw materials as predictive factors in regression analysis). The equation was calculated using R0. 2 As a standard for evaluating the goodness of fit of the equation, the prediction accuracy was then used for evaluation and selection. Finally, the corresponding optimal prediction equation was established, and the results are shown in Table 7. The established prediction equation was verified using the 10th set of data, and the results are shown in Table 8.

[0081] Table 7. Predictive equations for the standard ileal amino acid digestibility of wheat in laying hens during the brooding period (dry matter basis).

[0082] Prediction equation Coefficient of determination p-value SIDLys=126.339-7.765ADF-7.502EE 0.893 <0.001 SIDThr=59.620+22.986Ash-7.644ADF 0.695 0.012 SIDIle=118.291-8.780EE-0.319NDF 0.689 0.013 SIDLeu=117.802-4.982EE-3.911ADF 0.774 0.005 SIDPhe=84.196-3.682EE+0.255TS 0.764 0.006 SIDVal=156.522-10.535EE-2.992CP 0.833 0.002 SIDHis=116.647-6.193EE-4.014ADF 0.846 0.002 SIDArg=123.952-6.887EE-5.712ADF 0.655 0.017 SIDAsp=63.460-5.799EE+0.580TS-9.975PA 0.849 0.005 SIDSer=72.839+14.953Ash-4.543ADF 0.625 0.018 SIDglu=92.589-2.107EE+0.122TS 0.809 0.003 SIDGly = 112.927 - 11.829EE 0.674 0.004 SIDAla=95.951-58.815His-9.214EE+0.447TS 0.965 0.001 SIDPro=-234.529+16.051GE+0.544TS 0.772 0.005 SIDTyr=118.311-5.696EE-3.885ADF 0.802 0.003

[0083] Table 8. Validation of the prediction equation (Data set 10)

[0084]

[0085]

[0086] The experimental results above show that the predicted values ​​of the established prediction equation all fall within the range of the measured mean ± standard deviation, and can accurately predict the standard ileal amino acid digestibility of wheat for laying hens during the brooding period. Therefore, this method can provide a direct and practical technical approach for the efficient utilization of wheat resources and the precise formulation of laying hen diets.

[0087] This invention relates to a rapid method for accurately predicting the standard ileal amino acid digestibility of wheat feed in laying hens during the brooding period, and provides a set of corresponding prediction equations. The specific steps include: selecting representative wheat samples from 10 different sources and using them as the sole dietary protein source to formulate a semi-homozygous experimental diet; conducting a 72-hour feeding trial using 28-day-old Jingfen No. 8 laying hens as experimental subjects; collecting ileal digesta after the feeding period, measuring the standard ileal amino acid digestibility, and analyzing its correlation with wheat chemical composition and amino acid content; finally, using wheat chemical composition and amino acid content as predictive factors, constructing a prediction equation for the standard ileal amino acid digestibility of wheat feed in laying hens during the brooding period using a stepwise regression method.

[0088] This invention can also be flexibly applied according to the resource conditions of different regions, providing core technical support for wheat-based basic feed formulations for livestock enterprises in various regions. This method, by accurately predicting the nutritional value of digestible amino acids in wheat, can generate feed formulations that better meet the precise nutritional needs of laying hens during the brooding period, thereby significantly improving feed conversion efficiency, reducing formulation costs, and ultimately enhancing the economic benefits of livestock farming.

Claims

1. A method for predicting the standard ileal amino acid digestibility of wheat in laying hens during the brooding period, characterized in that, Includes the following steps: 1) The physical properties, chemical composition, and amino acid content of wheat from ten different sources were determined; 2) A wheat experimental diet was formulated with the wheat described above as the sole source of protein, and 28-day-old Jingfen No. 8 laying hens were fed it until they were 31 days old, for a feeding period of 3 days. 3) Collect ileal digesta from 31-day-old laying hens and determine the amino acid content of the digesta, experimental diet, and nitrogen-free diet. Calculate the apparent ileal amino acid digestibility, endogenous amino acid loss, and standard ileal amino acid digestibility of the experimental diet. 4) Based on the correlation between wheat chemical composition, amino acid content and standard ileal amino acid digestibility of laying hens during the brooding period, a predictive equation for the standard ileal amino acid digestibility of wheat for laying hens during the brooding period was established based on the relevant data of 9 of the 10 different wheat sources in step 1), and then the relevant data of the remaining one were used for verification.

2. The method according to claim 1, characterized in that: In step 1), ten different types of wheat were used, produced in Tianjin, Yangzhou (Jiangsu), Chengde (Hebei), Chengdu (Sichuan), Panjin (Liaoning), Zhumadian (Henan), Huainan (Anhui), Xianyang (Shaanxi), Wuhan (Hubei), and Nanjing (Jiangsu).

3. The method according to claim 1, characterized in that: In step 1), the physical properties measured include bulk density, thousand-grain weight, and thousand-grain volume; the chemical composition measured includes: dry matter, crude protein, crude fat, total energy, starch, crude ash, crude fiber, neutral detergent fiber, acid detergent fiber, calcium, total phosphorus, and phytic acid; the 18 amino acids measured include essential amino acids: lysine, methionine, threonine, tryptophan, arginine, leucine, isoleucine, phenylalanine, valine, and histidine; and non-essential amino acids: aspartic acid, serine, glutamic acid, glycine, alanine, proline, cysteine, and tyrosine.

4. The method according to claim 1, characterized in that: In step 2), the experimental diet for brooding laying hens with wheat as the sole protein source was as follows: wheat 92.53%, soybean oil 3.00%, limestone powder 1.30%, anhydrous dicalcium phosphate 1.90%, salt 0.30%, 50% choline chloride 0.25%, vitamin premix 0.02%, trace element premix 0.20%, and titanium dioxide 0.5%. The experiment was conducted on 28-day-old laying hens for 72 hours to 31 days of age.

5. The method according to claim 1, characterized in that: In step 3), the calculation methods for apparent ileal amino acid digestibility, endogenous amino acid loss, and standard ileal amino acid digestibility are as follows: Apparent ileal amino acid digestibility AID = [1 - (AAi1 / AAd1) × (Md1 / Mi1)] × 100%; where: AAi1 represents the content of amino acids on a dry matter basis in the ileal digest; AAd1 represents the content of amino acids on a dry matter basis in the diet; Md1 and Mi1 represent the concentrations of TiO2 indicators on a dry matter basis in the diet and digest, respectively. The basal loss of endogenous amino acids in the terminal ileum is calculated as IAAend = AAi2 × (Md2 / Mi2), in mg / kg. Where AAi2 represents the dry matter-based amino acid content in the ileal digest of the nitrogen-free diet group, and Md2 and Mi2 represent the TiO2 content in the nitrogen-free diet and the dry matter-based TiO2 content in the ileal digest of the nitrogen-free diet group, respectively. Standard ileal amino acid digestibility (SID), % = AID + (IAAend / AAd1) × 100%; In the formula: IAAend represents the loss of endogenous amino acids in the terminal ileum, and AAd1 represents the amino acid content in the diet based on dry matter.

6. The method according to claim 1, characterized in that: In step 4), the predictive equation for the standard ileal amino acid digestibility of wheat in laying hens during the brooding period is: SIDLys = 126.339 - 7.765ADF - 7.502EE, Coefficient of determination R 2 The p-value was 0.893, and the p-value was <0.

001. SIDThr = 59.620 + 22.986Ash - 7.644ADF, Coefficient of Determination R 2 The value was 0.695, and the p-value was 0.

012. SIDIle = 118.291 - 8.780EE - 0.319NDF, Coefficient of determination R 2 The value was 0.698, and the p-value was 0.

013. SIDLeu = 117.802 - 4.982EE - 3.911ADF, coefficient of determination R 2 The value was 0.774, and the p-value was 0.

005. SIDPhe = 84.196 - 3.682EE + 0.255TS, coefficient of determination R 2 The value was 0.764, and the p-value was 0.

006. SIDVal = 156.522 - 10.535EE - 2.992CP, coefficient of determination R 2 The value was 0.833, and the p-value was 0.

002. SIDHis = 116.647 - 6.193EE - 4.014ADF, Coefficient of determination R 2 The value was 0.846, and the p-value was 0.

002. SIDArg = 123.952 - 6.887EE - 5.712ADF, coefficient of determination R 2 The value was 0.655, and the p-value was 0.

017. SIDAsp = 63.460 - 5.799EE + 0.580TS - 9.975PA, Coefficient of Determination R 2 The coefficient of determination (R²) was 0.849, with a p-value of 0.005; SIDSer = 72.839 + 14.953Ash - 4.543ADF, and the coefficient of determination (R²) was 0.

849. 2 The p-value was 0.625, and the p-value was 0.

018. SIDGlu = 92.589 - 2.107EE + 0.122TS, coefficient of determination R 2 The value was 0.809, and the p-value was 0.

003. SIDGly = 112.927 - 11.829EE, coefficient of determination R 2 The value was 0.674, and the p-value was 0.

004. SIDAla=95.951-58.815His-9.214EE+0.447TS, coefficient of determination R 2 The coefficient of determination (R²) is 0.965, with a p-value of 0.001; SIDPro = -234.529 + 16.051GE + 0.544TS, and the coefficient of determination (R²) is 0.

965. 2 The value was 0.772, and the p-value was 0.

005. SIDTyr = 118.311 - 5.696EE - 3.885ADF, coefficient of determination R 2 The p-value was 0.802, and the p-value was 0.

003. SID represents the standard ileal amino acid digestibility; The left side of the equation represents the predicted standard ileal digestibility of each amino acid; the right side represents the chemical composition, including amino acids and conventional chemical components, indicating the content of each chemical component in wheat. Among them, ADF is acid detergent fiber; Ash is crude ash; CP is crude protein; EE is fat; GE is total energy; His is histidine; NDF is neutral detergent fiber; and TS is total starch.

7. A method for predicting the digestibility of wheat amino acids in laying hens during the brooding period, characterized in that: The content of chemical components in wheat, including amino acids and conventional chemical components, is detected and substituted into the standard ileal amino acid digestibility prediction equation for wheat in brooding hens established according to any one of claims 1-6, and the predicted standard ileal digestibility of each amino acid is calculated.

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