Evaluation model and calculation method for dynamically suitable standard ileum digestible Lys demand amount of weaned piglets

Abstract

The invention relates to a model for evaluating the demand amount of dynamically suitable standard ileum digestible Lys of weaned piglets, which comprises a fold-linear model and a fold-linear quadratic model, wherein the fold-linear model is Y = L + U * (R-X), and X is less than R; y = L, X > = R, Y = L + U * (R-X) 2, and X < R; y is equal to L, X is larger than or equal to R, a weaned piglet lysine demand amount dynamic model of weaned piglets with 7-25 kg of weaned piglets or weaned piglets with 20-25 kg of weaned piglets is established, and a weaned piglet dynamic suitable standard ileum digestible Lys demand amount calculated according to the dynamic model is provided. According to the method, the dynamic evaluation model for the lysine demand amount of the weaned piglets is established, the SID lysine demand amount of the weaned piglets is optimized based on ADG, G: F and body protein deposition indexes, the nutritional requirements of the piglets are accurately evaluated, the balance of feeding cost, piglet growth performance and environmental pollution is achieved, and the problems of high feeding cost, environmental pollution and the like are effectively relieved.

Description

Technical Field

[0001] The present invention relates to the technical field of animal nutrition and feed science, and specifically relates to an evaluation model and calculation method for the dynamic appropriate standard ileal digestible Lys requirement of weaned piglets. Background Art

[0002] In a corn-soybean meal-based diet for weaned piglets, lysine, as the first limiting amino acid, is mainly used for the deposition of carcass muscle protein. Therefore, the SID lysine requirement corresponds to the amount required for protein deposition (PD). The lysine requirement is usually regarded as a reference for the requirements of other amino acids. In the prior art, there are the following problems with the evaluation methods for lysine requirements: Lee et al. (2021) determined the SID lysine requirement for weaned piglets by extrapolation, that is, using the previously estimated average value to obtain the SID lysine requirement per kilogram of body weight gain. And NRC (2012) was based on the regression analysis of the SID lysine requirement and body weight of pigs weighing 5 - 20 kg observed in previous experiments. The recommended SID lysine requirement for pigs weighing 7 kg - 11 kg by NRC is 1.35% (NRC, 2012). Kahindi et al. (Kahindi et al., 2016) obtained the optimal SID Lys content of 1.32% for 7 - 16 kg based on the best daily weight gain. However, the research reports of Nemechek et al. (2012) and Park and Kim (2015) gave different results for the SID lysine requirement of weaned piglets. The reason is that the effects of nutritional components and body composition (Lange, 2001), gender (Cromwell et al.), and genotype (Dean et al., 2007; Schneider et al., 2010; Kahindi et al., 2016) on the SID lysine requirement were not fully considered. In addition to these reasons, there are also differences in the statistical methods used for data analysis (Nemechek et al., 2012a; Park and Kim, 2015). Using the straight broken-line model and the quadratic broken-line model, the SID Lys requirements based on feed efficiency are 1.37% and 1.54% respectively (Nemechek et al., 2012a). It can be seen that these methods in the prior art do not fully consider the influencing factors and the statistical methods are inconsistent, resulting in inaccurate evaluation results, so that the most desired breeding purpose cannot be achieved according to the dynamic changes in actual production requirements. Summary of the Invention

[0003] To solve the above problems, the present invention provides a method for improving the accuracy of the formula for the amino acid supply in pig diets, realizing the dynamic change of the lysine content in the diet according to the actual production requirements, achieving the most desired breeding purpose, providing a method for determining the SID lysine requirement of weaned piglets weighing 7 - 25 kg fed a corn - soybean meal diet based on G:F, average daily gain or daily protein deposition, and establishing a dynamic model for the lysine requirement of piglets and applying this dynamic model to calculate the dynamic appropriate standard ileal digestible Lys requirement of weaned piglets.

[0004] The technical solution adopted by the present invention to solve the above - mentioned technical problems is as follows: An evaluation model for the dynamic appropriate standard ileal digestible Lys requirement of weaned piglets, including a broken - line model and a broken - line quadratic model:

[0005] Broken - line linear model: Y = L + U×(R - X), X < R; Y = L, X ≥ R,

[0006] Broken - line quadratic model: Y = L + U×(R - X) 2 , X < R; Y = L, X ≥ R;

[0007] Where: Y is the G:F, average daily gain (g / d) or daily protein deposition (g / d) of weaned piglets; X is the dietary SID Lys level (%) or the daily SID Lys intake (g / d) of weaned piglets; R is the appropriate SID Lys (%) or the daily SID Lys requirement (g / d) of weaned piglets; L is the intercept; U is the slope; the % is the mass percentage content;

[0008] The weaned piglets are 7 - 25 kg weaned piglets,

[0009] When Y is the G:F of 7 - 25 kg weaned piglets, the evaluation model is as follows:

[0010] Broken - line linear model: Y = 0.585+( - 0.374)×(1.267 - X),

[0011] Broken - line quadratic model: Y = 0.583+( - 0.571)×(1.399 - X) 2 ;

[0012] When Y is the average daily gain of 7 - 25 kg weaned piglets, the evaluation model is as follows:

[0013] Broken - line linear model: Y = 0.489+( - 0.199)×(1.299 - X),

[0014] Broken - line quadratic model: Y = 0.489+( - 0.271)×(1.456 - X) 2 ;

[0015] When Y is the daily protein deposition of weaned piglets weighing 7 - 25 kg, the evaluation model is as follows:

[0016] Piecewise linear model: Y = 87.373 + (-39.107)×(1.190 - X),

[0017] Piecewise quadratic model: Y = 86.614 + (-67.733)×(1.323 - X) 2 。

[0018] Preferably, the weaned piglets are 20 - 25 kg weaned piglets;

[0019] When Y is the G:F of 20 - 25 kg weaned piglets, the evaluation model is as follows:

[0020] Piecewise linear model: Y = 0.563 + (-0.300)×(1.200 - X),

[0021] Piecewise quadratic model: Y = 0.564 + (-0.430)×(1.437 - X) 2 ;

[0022] When Y is the average daily gain of 20 - 25 kg weaned piglets, the evaluation model is as follows:

[0023] Piecewise linear model: Y = 0.713 + (-2.377)×(1.041 - X),

[0024] Piecewise quadratic model: Y = 0.713 + (-9.783)×(1.092 - X) 2 。

[0025] A method for calculating the dynamic appropriate standard ileal digestible Lys requirement of weaned piglets, applying the above - mentioned evaluation model, the specific steps are as follows:

[0026] S1. Determine which weight stage the weight of the weaned piglets belongs to, 7 - 25 kg or 20 - 25 kg, and select the corresponding evaluation model;

[0027] S2. When the weight of the weaned piglets is 7 - 25 kg, calculate the dynamic appropriate standard ileal digestible Lys requirement of the weaned piglets based on three indicators: G:F, average daily gain, and daily protein deposition;

[0028] S201. Measure Y of the weaned piglets based on three indicators: G:F, average daily gain, and daily protein deposition, and obtain X by fluctuating the SID Lys at 7 different levels up and down based on the Lys feeding amount recommended by NRC;

[0029] S202. Substitute Y and X in S201 into the corresponding evaluation model for fitting to obtain the standardized ileal digestible Lys requirement calculated by the broken-line linear model and the broken-line quadratic model respectively based on the three indicators of G:F, average daily gain, and daily protein deposition.

[0030] S203. Sum up the standardized ileal digestible Lys requirements calculated by all models under the three indicators of G:F, average daily gain, and daily protein deposition in S202, and then divide by the total number of model types to obtain the average value, so as to determine the standardized ileal digestible Lys requirement in the diet.

[0031] S3. When the weight of the weaned piglets is 20 - 25 kg, determine the dynamic appropriate standardized ileal digestible Lys requirement of the weaned piglets based on the two indicators of G:F and average daily gain.

[0032] S301. Measure Y of the weaned piglets based on the two indicators of G:F and average daily gain, and obtain X according to the SID Lys at 7 different levels fluctuating up and down from the Lys feeding amount recommended by NRC.

[0033] S302. Substitute Y and X in S301 into the corresponding evaluation model for fitting to obtain the standardized ileal digestible Lys requirement calculated by the broken-line linear model and the broken-line quadratic model respectively based on the two indicators of G:F and average daily gain.

[0034] S303. Sum up the standardized ileal digestible Lys requirements calculated by all models under the two indicators of G:F and average daily gain in S302, and then divide by the total number of model types to obtain the average value, so as to determine the standardized ileal digestible Lys requirement in the diet.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention optimizes the Lys requirement of weaned piglets, accurately evaluates the nutritional requirements of pigs, establishes a dynamic model for the Lys requirement of weaned piglets, realizes the balance in aspects such as feeding cost, growth performance of piglets, and environmental pollution, thus alleviating problems such as high feeding cost and environmental pollution.

[0037] 2. The present invention optimizes the evaluation model for the standardized ileal digestible Lys requirement of weaned piglets with a body weight of 20 - 25 kg compared with the prior art. Through the evaluation model of the present invention, the optimal Lys requirement for weaned piglets with a body weight of 20 - 25 kg is 1.19%. At the same time, through the evaluation model of the present invention based on three indicators of ADG, G:F, and body protein deposition, the Lys requirement for weaned piglets with a body weight of 7 - 25 kg is 1.31%. Compared with 1.36% (7 - 25 kg) of NRC and 1.32% (7 - 25 kg) of Nutrient Requirements of Swine in China, this patent adds the calculation of the body protein deposition index and optimizes the Lys requirement of weaned piglets when calculating based on the three indicators of ADG, G:F, and body protein deposition simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Optimal SID Lys requirement for 20 - 25 kg weaned piglets based on ADG (average daily gain);

[0039] Figure 2 Optimal SID Lys requirement for 20 - 25 kg weaned piglets based on G:F;

[0040] Figure 3 Optimal SID Lys requirement for 7 - 25 kg weaned piglets based on ADG (average daily gain);

[0041] Figure 4 Optimal SID Lys requirement for 7 - 25 kg weaned piglets based on G:F;

[0042] Figure 5 Optimal SID Lys requirement for 7 - 25 kg weaned piglets based on PD (daily protein deposition). DETAILED DESCRIPTION OF THE INVENTION

[0043] The present invention will be described in detail below. Here, the illustrative embodiments of the present invention and the description are used to explain the present invention, but not to limit the present invention. Figures 1-5 An evaluation model for the dynamic appropriate standardized ileal digestible Lys requirement of weaned piglets, the evaluation model includes a broken - line model and a broken - line quadratic model:

[0044] Broken - line linear model: Y = L + U×(R - X), X < R; Y = L, X ≥ R,

[0045] Broken - line quadratic model: Y = L + U×(R - X)

[0046] , X < R; Y = L, X ≥ R; 2 , X < R; Y = L, X ≥ R;

[0047] Wherein: Y is the G:F, average daily gain (g / d), or daily protein deposition (g / d) of weaned piglets; X is the dietary SID Lys level (%) or the daily SID Lys intake (g / d) of weaned piglets; R is the appropriate SID Lys (%) or the daily SID Lys requirement (g / d) of weaned piglets; L is the intercept; U is the slope; the % is the mass percentage content;

[0048] The weaned piglets are 7 - 25 kg weaned piglets,

[0049] When Y is the G:F of 7 - 25 kg weaned piglets, the evaluation model is specifically as follows:

[0050] Piecewise linear model: Y = 0.585 + (-0.374)×(1.267 - X),

[0051] Piecewise quadratic model: Y = 0.583 + (-0.571)×(1.399 - X) 2 ;

[0052] When Y is the average daily gain of 7 - 25 kg weaned piglets, the evaluation model is specifically as follows:

[0053] Piecewise linear model: Y = 0.489 + (-0.199)×(1.299 - X),

[0054] Piecewise quadratic model: Y = 0.489 + (-0.271)×(1.456 - X) 2 ;

[0055] When Y is the daily protein deposition of 7 - 25 kg weaned piglets, the evaluation model is specifically as follows:

[0056] Piecewise linear model: Y = 87.373 + (-39.107)×(1.190 - X),

[0057] Piecewise quadratic model: Y = 86.614 + (-67.733)×(1.323 - X) 2 。

[0058] The weaned piglets are 20 - 25 kg weaned piglets;

[0059] When Y is the G:F of 20 - 25 kg weaned piglets, the evaluation model is specifically as follows:

[0060] Piecewise linear model: Y = 0.563 + (-0.300)×(1.200 - X),

[0061] Piecewise quadratic model: Y = 0.564 + (-0.430)×(1.437 - X) 2 ;

[0062] When Y is the average daily gain of weaned piglets weighing 20 - 25 kg, the evaluation model is as follows:

[0063] Piecewise linear model: Y = 0.713 + (-2.377)×(1.041 - X),

[0064] Piecewise quadratic model: Y = 0.713 + (-9.783)×(1.092 - X) 2 。

[0065] A calculation method for the dynamic appropriate standard ileal digestible Lys requirement of weaned piglets, applying the above-mentioned evaluation model, the specific steps are as follows:

[0066] S1. Determine which weight stage the weight of the weaned piglets belongs to, 7 - 25 kg or 20 - 25 kg, and select the corresponding evaluation model;

[0067] S2. When the weight of the weaned piglets is 7 - 25 kg, calculate the dynamic appropriate standard ileal digestible Lys requirement of the weaned piglets based on three indicators: G:F, average daily gain, and daily protein deposition;

[0068] S201. Measure Y of the weaned piglets based on three indicators: G:F, average daily gain, and daily protein deposition. According to the Lys feeding amount recommended by NRC, fluctuate up and down to 7 different levels of SID Lys to obtain X;

[0069] S202. Substitute Y and X in S201 into the corresponding evaluation model for fitting to obtain the standard ileal digestible Lys requirements calculated by the piecewise linear model and the piecewise quadratic model respectively based on the three indicators of G:F, average daily gain, and daily protein deposition;

[0070] S203. Sum up the standard ileal digestible Lys requirements calculated by all models under the three indicators of G:F, average daily gain, and daily protein deposition in S202 and divide by the total number of model types to obtain the average value, and determine the standard ileal digestible Lys requirement in the diet;

[0071] S3. When the weight of the weaned piglets is 20 - 25 kg, calculate the dynamic appropriate standard ileal digestible Lys requirement of the weaned piglets based on two indicators: G:F and average daily gain;

[0072] S301. Measure Y of the weaned piglets based on two indicators: G:F and average daily gain. According to the Lys feeding amount recommended by NRC, fluctuate up and down to 7 different levels of SID Lys to obtain X;

[0073] S302. Substitute Y and X in S301 into the corresponding evaluation model for fitting to obtain the standardized ileal digestible Lys requirements calculated by the broken-line linear model and the broken-line quadratic model respectively based on the two indexes of G:F and average daily gain.

[0074] S303. Sum up the standardized ileal digestible Lys requirements calculated by all models under the two indexes of G:F and average daily gain in S302, and then divide by the total number of model types to obtain the average value, so as to determine the standardized ileal digestible Lys requirement in the diet.

[0075] In the evaluation model of the present invention, X is the Lys concentration adjusted up and down based on the NRC feeding standard, aiming to explore the optimal dynamic change of Lys in weaned piglets under the background of genetics and breeding in recent years. Under normal circumstances, the feed intake is basically consistent at the same body weight, and the dietary Lys level (%) causes fluctuations in intake. Based on different levels of Lys intake, x (g / d), the optimal value R is obtained, which is the daily requirement (g / d) of weaned piglets.

[0076] When applying the evaluation model of the present invention, Y of weaned piglets is measured, and X is obtained according to the Lys feeding amount recommended by NRC, including seven different levels of SID Lys with up and down fluctuations (step size 0.1); substitute Y and X into the evaluation model of the present invention for fitting to determine the appropriate level R of standardized ileal digestible lysine in the diet.

[0077] The present invention refines the optimal Lys requirement for 20 - 25 kg body weight weaned piglets to 1.19%. Specifically, first, when Y is the G:F of 20 - 25 kg weaned piglets, the average value of the Lys requirements calculated by the broken-line linear model and the broken-line quadratic model is 1.319%. Then, when Y is the average daily gain of 20 - 25 kg weaned piglets, the average value of the Lys requirements calculated by the broken-line linear model and the broken-line quadratic model is 1.067%. Finally, the sum of 1.319% and 1.067% is averaged to 1.19%. At the same time, through the evaluation model of the present invention, the Lys requirement for 7 - 25 kg weaned piglets is calculated to be 1.31%. Compared with 1.36% (7 - 25 kg) of NRC and 1.32% (7 - 25 kg) of Chinese Swine Nutrient Requirements, this patent optimizes the Lys requirement of weaned piglets based on the indexes of ADG, G:F and body protein deposition.

[0078] In the specific implementation process, the process is as follows.

[0079] 1. Feeding management

[0080] A single-factor completely randomized design was adopted. Eighty-four weaned piglets weighing about 7 kg were randomly divided into 7 treatment groups, with 4 replicates in each treatment group and 3 pigs in each replicate. Each group was fed different levels of lysine diets daily. The feeds for each stage were formulated with reference to the nutrient recommendations of NRC (2012). The diets of other groups were formulated by mixing feed A and feed B in different proportions. The whole experiment was divided into 4 stages: 7-11, 11-15, 15-20, and 20-25 kg. The corresponding diets for each stage were fed respectively, and the experiment lasted for 50 days. The pigs were weighed every 10 days. At the beginning of the experiment, 6 piglets with good body condition and similar body weights were selected for slaughter comparison test to detect body composition as the baseline value.

[0081] The piglets were group-fed, and the body weight and feed intake of each individual were recorded every 10 days with replicates as units. Most pigs in each group had to reach the stage body weight point to progress to the next stage and be fed the feed for the next stage. During the mid-term of each stage of the experiment, a digestion test was conducted on all piglets using the (titanium dioxide) indicator method. Feces were collected regularly every day for three days. Fecal samples and feed samples were collected in 4 stages: 7-11, 11-15, 15-20, and 20-25 kg. The feed samples were collected by the quartering method. About 500 g of each treatment was taken, put into a sample bag, marked, and stored in a -20°C refrigerator for the analysis of conventional nutrients.

[0082] Dilute sulfuric acid accounting for one-tenth of the feces weight and two to three drops of toluene were added for anti-corrosion and nitrogen fixation, and then stored in a -20°C refrigerator. After the collection period ended, the fecal samples collected in each stage were weighed and mixed evenly. An appropriate amount of fecal samples was placed in a container, put into a 65°C oven for 48 h, then allowed to air-dry for 24 h and weighed. Then, the oven temperature remained unchanged and it was dried for another 24 h, allowed to air-dry for 24 h and weighed again. The above steps were repeated until a constant weight was achieved. The fecal samples after constant weight were crushed, filtered through a 40-mesh sieve, collected and stored at -20°C for the analysis of conventional nutrients. 10% sulfuric acid was evenly sprayed into the self-sealing bag containing fecal samples to fix the nitrogen in the feces. The ratio of sulfuric acid sprayed to fecal samples was 20 mL sulfuric acid / 100 g fecal samples. The collected fecal samples were stored in a self-sealing bag in the refrigerator for detecting the digestibility of a certain nutrient in the feed.

[0083] At the end of each stage of the experiment, 6 pigs with comparable body weights and health conditions were selected from each group for slaughter comparison test. All blood was collected after exsanguination. The contents of the stomach, intestines, gallbladder, and bladder were emptied. Excessive moisture was removed from the organs and the weighed organs. The whole body, plus the head, feet, blood, and organs were frozen, crushed, homogenized, and sub-sampled.

[0084] 2. Slaughter process:

[0085] 2-1. After anesthesia with sodium pentobarbital, the pigs were slaughtered by exsanguination, and all the blood was collected and weighed again (to calculate the difference in total blood volume);

[0086] 2 - 2. Rinse the contents of the stomach and intestine with clear water and dry them. Meanwhile, clean the contents of the bladder and gallbladder to obtain the empty body of each piglet after removing the contents and weigh it.

[0087] 2 - 3. Record the weights of the heart, liver, spleen, lungs, kidneys, stomach, and intestine of each piglet.

[0088] 2 - 4. After weighing, store the carcass at -20 °C for further processing.

[0089] 3. Obtaining body composition samples:

[0090] Weigh the live pig, collect blood from the anterior vena cava, bleed the pig during slaughter (collect all the blood, put it into a self-sealing bag and then transfer it to the cold storage for further analysis), rinse, remove the hooves, dry with a towel or absorbent paper, and then weigh again (calculate the difference in total blood volume and total hoof weight).

[0091] Dissection: Remove the head (at the atlanto-occipital joint), open the abdominal cavity and take out the heart, kidneys, liver, lungs, spleen, mesentery, abdominal fat, pancreas, whole gallbladder, stomach, large intestine, and small intestine. Weigh the heart, kidneys, liver, lungs, spleen, mesentery, abdominal fat, and pancreas separately and put them into self-sealing bags, then transfer them to the cold storage for further analysis. Then remove the contents of the intestine, bladder, and gallbladder, rinse them thoroughly with tap water, and dry with a towel or absorbent paper. Subsequently, weigh the intestine (distinguish between large and small intestine), bladder, and gallbladder, and measure the length of the intestine (distinguish between large and small intestine). Then put the intestine (distinguish between large and small intestine), bladder, and gallbladder into self-sealing bags and transfer them to the cold storage for further analysis.

[0092] Carcass processing: Split the pig along the spine into two sides of the carcass, and select the left side of the carcass for carcass segmentation. Divide the left side of the carcass into neck, forelimb, shoulder, chest, abdomen, and hindlimb and weigh them separately. Further divide the muscles, fats, bones, and skins of the neck, shoulder, chest, abdomen, and hindlimb. Weigh all the muscles, fats, bones, and skins of the left side of the carcass separately. Subsequently, put the muscles, fats, bones, and skins into self-sealing bags or plastic bags and transfer them to the cold storage for further analysis. At the same time, put the remaining right side of the carcass, pig head, tail, blood, and hooves into plastic bags and transfer them to the cold storage for further analysis.

[0093] Note: Empty body: The sum of the carcass, blood, bile, organs, intestine, hair, and hooves.

[0094] Crushing: Primary crushing in the crushing step, into small pieces of 20 - 30 mm (double-shaft shredder, L-SP380, Zhengzhou Liwei Environmental Protection Equipment Co., Ltd., China); secondary crushing, into small pieces of 8 mm (ordinary shredder, Shandong Guoya Machinery, China); tertiary crushing, into a paste (bone paste mill GN-130, Xingtai Yusheng Machinery Manufacturing Factory, China). Mix evenly (stuffer, Xingtai Yusheng Machinery Manufacturing Factory, China) Figure 2Diagram of the grinder and grinding effect.

[0095] Internal organ grinding: Take out all the frozen internal organs, weigh them. Subsequently, grind each internal organ (heart, kidney, liver, lung, spleen, brain, stomach, large intestine, small intestine) separately. Take samples (2 portions) of the ground internal organs and put them into self-sealing bags, and store them at -20°C (the sampling ratio is shown in Table 1).

[0096] Grinding of muscle, fat, bone, and fur of carcass and empty body: Take out all the muscle, fat, bone, and fur of the left carcass after freezing, and weigh them. Subsequently, grind muscle, fat, bone, and fur separately. Take samples (2 portions) of the ground muscle, fat, bone, and fur and put them into self-sealing bags, and store them at -20°C. For all carcass samples (left and right), take out the frozen right carcass, weigh it, and grind it. After grinding, add the ground muscle, fat, bone, and fur, mix well, and then take samples (2 portions) and put them into self-sealing bags, and store them at -20°C.

[0097] Empty body weight: Take out the frozen pig head, pig blood, hooves, and tail. After weighing and grinding, add the ground carcass and internal organs. Stir well, take samples (2 portions) and put them into self-sealing bags, and store them at -20°C (the sampling ratio is shown in Table 1).

[0098] Sampling:

[0099] Use the quartering method to take about 2.5 kg (2 portions) of wet samples and spread them flat on a tray. One portion is placed in an oven at 65°C and dried for 72 h, then naturally moisturized at room temperature for 24 h. The other portion is freeze-dried, then ground with a high-speed grinder and sampled by the quartering method for measuring the body composition. All body composition samples are measured in duplicate.

[0100] The samples are further transferred to a meat mixer to be fully mixed. Use the quartering method to take about 2.5 kg of wet samples and spread them flat on a tray. Place them in an oven at 65°C and dry for 72 h, then naturally moisturize at room temperature for 24 h. Then grind with a high-speed grinder and sample by the quartering method for measuring the body composition. Weigh the homogenized carcass sample and freeze-dry it to measure the dry matter content; after freeze-drying, grind and mix again for secondary sampling to measure the contents of moisture, energy, crude protein, crude fat, ash, calcium, and phosphorus.

[0101] The calculation method for nutrient deposition is as follows:

[0102] Nutrient deposition (g / d) = (empty body weight of piglets at the end age × average percentage content of nutrients in the empty body of piglets at the end age - empty body weight of piglets at the initial age × average percentage content of nutrients in the empty body of piglets at the initial age) / total number of days.

[0103] 4. Model establishment

[0104] First, Excel 2019 was used to organize the data, and IBM SPSS Statistics 26 was used to perform linear and quadratic significance analyses on the data. For the data with linear and quadratic significance, the BLL and BLQ models were subsequently established using SAS 9.4 software.

[0105] 5. Model Application

[0106] When applying the above evaluation model, Y of weaned piglets was measured, and X was obtained by including the upper and lower fluctuations (step size 0.1) to 7 different levels of SID Lys in the Lys feeding amount recommended by NRC; Y and X were substituted into the evaluation model described in the present invention for fitting to determine the appropriate level R of standard ileal digestible lysine in the diet.

[0107] The technical solutions provided by the embodiments of the present invention have been introduced in detail above. Specific examples have been used in this article to elaborate on the principles and implementation manners of the embodiments of the present invention. The descriptions of the above embodiments are only applicable to help understand the principles of the embodiments of the present invention; at the same time, for those of ordinary skill in the art, according to the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A model for evaluating the dynamic suitable standard ileal digestible Lys requirement of weaned piglets, characterized in that: The evaluation model includes a broken linear model and a broken linear quadratic model: Broken Linear Model: Y = L + U × (RX), X < R; Y = L, X ≥ R, Broken line quadratic model: Y = L + U × (RX) 2 , X<R; Y=L, X≥R; Wherein: Y is the G:F, average daily weight gain (g / d) or daily protein deposition (g / d) of weaned piglets; X is the SID Lys level in the diet (%) or the daily SID Lys intake (g / d) of weaned piglets; R is the appropriate SID Lys (%) or the daily SIDLys requirement (g / d) of weaned piglets; L is the intercept; U is the slope; the % is the mass percentage content; The weaned piglets are 7-25 kg weaned piglets, When Y is the G:F of 7-25kg weaned piglets, the evaluation model is as follows: Broken line linear model: Y = 0.585 + (-0.374) × (1.267-X), Broken line quadratic model: Y = 0.583 + (-0.571) × (1.399-X) 2 ; When Y is the average daily weight gain of weaned piglets of 7-25 kg, the evaluation model is as follows: Broken line linear model: Y = 0.489 + (-0.199) × (1.299-X), Broken line quadratic model: Y = 0.489 + (-0.271) × (1.456-X) 2 ; When Y is the daily protein deposition of 7-25 kg weaned piglets, the evaluation model is as follows: Broken line linear model: Y = 87.373 + (-39.107) × (1.190-X), Broken line quadratic model: Y = 86.614 + (-67.733) × (1.323-X) 2 .

2. The evaluation model for the dynamic suitable standard ileal digestible Lys requirement of weaned piglets according to claim 1, characterized in that: The weaned piglets are 20-25 kg weaned piglets; When Y is the G:F of 20-25kg weaned piglets, the evaluation model is as follows: Broken line linear model: Y = 0.563 + (-0.300) × (1.200-X), Broken line quadratic model: Y = 0.564 + (-0.430) × (1.437-X) 2 ; When Y is the average daily weight gain of weaned piglets of 20-25 kg, the evaluation model is as follows: Broken line linear model: Y = 0.713 + (-2.377) × (1.041-X), Broken line quadratic model: Y = 0.713 + (-9.783) × (1.092-X) 2 .

3. A method for calculating the dynamic suitable standard ileal digestible Lys requirement of weaned piglets, characterized by: Apply the evaluation model described in any one of claims 1-2, and the specific steps are as follows: S1, determine whether the weight of the weaned piglets belongs to the weight stage of 7-25kg or 20-25kg, and select the corresponding evaluation model; S2, when the weight of weaned piglets is 7-25kg, the dynamic suitable standard ileal digestible Lys requirement of weaned piglets is calculated based on three indicators: G:F, average daily weight gain and daily protein deposition; S201, measured Y based on G:F, average daily weight gain and daily protein deposition in weaned piglets, and obtained X by fluctuating the Lys feeding amount up and down to 7 different levels of SID Lys according to the NRC recommendation; S202, substituting Y and X in S201 into the corresponding evaluation model for fitting, and obtaining the standard ileal digestible Lys requirement calculated by the broken line linear model and the broken line quadratic model respectively based on the three indicators of G:F, average daily weight gain and daily protein deposition; S203, summing up the standard ileal digestible Lys requirement calculated by all models under the three indicators of G:F, average daily weight gain and daily protein deposition in S202 and dividing it by the total number of model types to obtain an average, thereby determining the standard ileal digestible Lys requirement in the diet; S3, when the weight of weaned piglets is 20-25kg, the dynamic suitable standard ileal digestible Lys requirement of weaned piglets is calculated based on the two indicators of G:F and average daily weight gain; S301, measure Y based on G:F and average daily weight gain of weaned piglets, and adjust the Lys feeding amount up and down to 7 different levels of SID Lys according to the NRC recommended Lys feeding amount to obtain X; S302, substituting Y and X in S301 into the corresponding evaluation model for fitting, and obtaining the standard ileal digestible Lys requirement calculated by the broken line linear model and the broken line quadratic model respectively based on the two indicators of G:F and average daily weight gain; S303, summing up the standard ileal digestible Lys requirement calculated by all models under the two indicators of G:F and average daily gain in S302 and dividing it by the total number of model types to obtain an average, thereby determining the standard ileal digestible Lys requirement in the diet.

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