Establishment method and evaluation method of model for monitoring and calculating maintenance demand amount of essential amino acid

Abstract

The invention provides an establishment method and an evaluation method of a model for monitoring and calculating the maintenance demand amount of essential amino acids, and the establishment method of the model for monitoring and calculating the maintenance demand amount of the essential amino acids comprises the following steps: the method is applied to monitoring and calculating the dynamic maintenance demand amount of broiler chicken essential amino acids; an automatic weighing system is used for recording the growth performance of the weight, weight gain and food consumption of the broiler chickens every day; collecting excrement of the broiler chickens by adopting a full excrement collecting method for continuous 3 days per week in the growth period of the broiler chickens, recording feed intake and excrement discharge amount, and calculating the remaining amount of each necessary amino acid per week; and performing multiple linear regression equation fitting according to the obtained growth performance and the amino acid remaining amount, and setting the weight gain to be 0 on the basis of the equation to obtain a new regression equation, namely the dynamic essential amino acid maintenance demand model. The structure and components of daily ration for feeding animals do not need to be changed, so that the stress generated when the animals are in contact with different daily ration can be eliminated, the real necessary amino acid maintenance required amount of the animals can be reflected, and the purpose of precise nutrition is achieved.

Description

Technical Field

[0001] The invention belongs to the field of livestock and poultry breeding, and specifically relates to a method for establishing and evaluating a model for monitoring and calculating the maintenance requirement of essential amino acids. Background Art

[0002] The modern broiler industry is developing rapidly, and the implementation of precise nutrition supply can achieve the goal of reducing costs and increasing efficiency to the greatest extent. At present, broiler breeding widely adopts a 2-3 stage feeding method to meet the protein nutrition needs of broilers at different stages; however, the nutritional needs of animals are not static, and only by providing appropriate dietary protein and amino acid concentrations according to the different conditions of animals can the purpose of dynamic precise nutrition be truly achieved; therefore, it is necessary to monitor the growth and protein and amino acid utilization of broilers at different stages.

[0003] At present, maintenance needs are determined by direct measurement and linear regression. The direct measurement method refers to the requirement of animals at the zero point of nitrogen balance after eliminating the influence of endogenous nitrogen when they are fed with low-nitrogen diets and nitrogen-free diets. However, when animals are fed with nitrogen-free diets, they are in an abnormal life state, and the zero point of nitrogen balance obtained at this time may not be true. In addition, under the influence of nitrogen-free diets, the viscosity of the chyme in the intestines of animals is extremely large, and the amount of feces collected within a given time is not the total amount of animal excretion. Therefore, there is a discrepancy between the actual value and the excretion of nitrogen. The linear regression method is based on the dose-response method. According to the intake and weight gain of animals under different concentration gradients of a certain amino acid, the intake of the amino acid at the zero point of weight gain is obtained through a linear fitting equation, which is the maintenance requirement. This method blindly believes that the maintenance requirement of animals for a certain amino acid is a fixed value, ignoring three important factors: 1) During the feeding process, the body shape and weight of animals are constantly changing. The larger the weight, the higher the basal metabolism, and the more nutrients are consumed to maintain vital signs. Therefore, the maintenance needs of animals at different weights must be different. 2) There are synergistic or antagonistic effects between different amino acids. When a certain amino acid acts in the body, it must be affected by other amino acids. The maintenance requirement obtained by simply controlling the change in the concentration of a certain amino acid is not necessarily the true value. 3) The protein and fat concentrations in the carcasses of animals with the same weight are not necessarily the same, which will make the maintenance requirements of different nutrients different; for example, animals with more muscle and less fat have different maintenance requirements from animals with less muscle and more fat.

[0004] A large number of studies have shown that the growth performance of broilers is significantly different when fed diets with different protein levels; some scholars have found that the growth performance of broilers was restored after using different essential amino acid ratios in low-protein diets, which means that the essential amino acid balance pattern in diets with different protein levels should not be the same; understanding and clarifying the adjustment and optimization direction of the essential amino acid balance pattern in low-protein diets is of great significance for improving the growth performance of broilers and promoting the vigorous development of animal husbandry. Summary of the invention

[0005] The embodiment of the present invention provides a method and system for testing and evaluating scientific and technological achievements based on knowledge management, aiming to solve the problems of the prior art testing and evaluation system for scientific and technological achievements and rationality.

[0006] A first aspect of an embodiment of the present invention provides a method for establishing a model for monitoring and calculating the maintenance requirement of essential amino acids, characterized in that the method comprises:

[0007] The method is applied to monitor and calculate the dynamic maintenance requirement of essential amino acids in broilers, using an automatic weighing system to record the growth performance of broilers in terms of weight, weight gain and feed intake daily; and using a full feces collection method to collect broiler feces for 3 consecutive days per week of age during the broiler growth period, and record the feed intake and feces discharge, and calculate the retention of each essential amino acid per week of age;

[0008] A multivariate linear regression equation was fitted based on the obtained growth performance and amino acid retention, and a new regression equation was obtained by setting the weight gain to 0 on the basis of the equation, namely, the dynamic essential amino acid maintenance requirement model.

[0009] In the above embodiment of the present invention, optionally, the entire life stage of the broiler is divided into 6 growth cycles, each 7 days being one growth cycle.

[0010] In the above embodiment of the present invention, optionally, starting from the second growth cycle, an automatic weighing system is used to record the body weight of broilers in each growth cycle, and feces are collected for three consecutive days before the end of each growth cycle, and the feces excretion and feed consumption of the broilers during the collection period are recorded.

[0011] In the above embodiment of the present invention, optionally, after the collection is completed, the test fecal samples are mixed and then sampled in proportion; the sample is placed in a 65°C oven to dry for 72 hours, and after drying is completed, it is also placed in a grinder and ground into powder.

[0012] In the above embodiment of the present invention, optionally, all feces and feed samples are tested for amino acid content using an automatic amino acid analyzer, and the data obtained are used to calculate the following parameters: daily intake of essential amino acids (g / d) = daily feed intake (Kg / d) × essential amino acid concentration in the diet (%) × 1000; daily excretion of essential amino acids (g / d) = daily excretion (Kg / d) × essential amino acid concentration in feces (%) × 1000; daily retention of essential amino acids (g / d) = daily intake of essential amino acids (g / d) - daily excretion of essential amino acids (g / d).

[0013] A second aspect of an embodiment of the present invention provides a method for evaluating the essential amino acid balance pattern of a low-protein diet for broiler chickens. According to the above-mentioned method for establishing a model for monitoring and calculating the essential amino acid maintenance requirement, the essential amino acid maintenance requirement model is obtained by fitting and improving the multivariate linear regression analysis method. The specific calculation method is shown in formulas (1) and (2):

[0014] Y1=aX+bZ+C Formula (1)

[0015] Wherein, Y1 is the daily retention requirement of digestible essential amino acids (g); a is the body weight coefficient; X is the body weight of broilers at different ages (kg); b is the weight gain coefficient; Z is the weight gain of broilers at different ages (kg); and C is the equation constant.

[0016] When the weight gain in formula (1) is 0, the broiler is in a maintenance state, and the dynamic maintenance requirement model of essential amino acids for broilers is obtained:

[0017] Y2=aX+C Formula (2)

[0018] Y2 is the dynamic daily maintenance requirement of digestible essential amino acids (g); a is the body weight coefficient; X is the body weight of broilers at different ages (kg); C is the equation constant.

[0019] The body weights of broilers of different ages under different diets were brought into Y2 to obtain the corresponding essential amino acid maintenance requirements. Based on the conventional protein diet, the increasing or decreasing trends of the maintenance requirements of each essential amino acid in the low-protein diet were evaluated, thereby providing a reference for adjustment directions for optimizing the essential amino acid balance pattern.

[0020] In the above embodiment of the present invention, optionally, the conventional protein diet chicken feed used includes the following raw materials by weight:

[0021] 50.16 parts of corn, 35.02 parts of soybean meal, 4.3 parts of corn gluten meal, 1.59 parts of calcium hydrogen phosphate, 5.66 parts of soybean oil, 1.39 parts of stone powder, 0.35 parts of salt, 0.2 parts of choline chloride 50%, 0.2 parts of broiler trace element premix, 0.16 parts of DL-methionine, 0.13 parts of L-lysine hydrochloride, 0.02 parts of broiler multivitamin premix, 0.03 parts of cystine, 0.02 parts of L-threonine, 0.21 parts of L-arginine, 0.05 parts of L-isoleucine, 0.05 parts of L-tryptophan, 0.05 parts of L-valine, 0.35 parts of alanine, 0.02 parts of phytase, 0.03 parts of potassium carbonate and 0.01 parts of sodium bicarbonate.

[0022] In the above embodiment of the present invention, optionally, in the broiler feed, the types and mass ratios of trace elements included in the broiler trace element premix are: Cu: Zn: Fe: Mn: Se: I = 8: 75: 80: 100: 0.15: 0.35.

[0023] In the above embodiments of the present invention, optionally,

[0024] In broiler feed, the types and mass ratios of vitamins included in broiler multivitamin premix are: Vitamin A: Vitamin D3: Vitamin E: Vitamin K3: Vitamin B1: Vitamin B2: Vitamin B6: Vitamin B12: Pantothenic acid: Niacin: Folic acid: Biotin = 15000IU: 3000IU: 22.5IU: 3mg: 3mg: 8mg: 6mg: 0.03mg: 17.64mg: 44mg: 17.64mg: 0.15mg.

[0025] After the present invention adopts the above technical solution, it mainly has the following effects:

[0026] 1. Compared with the previous maintenance needs detection methods, the model provided by the present invention does not need to change the diet structure and composition of the animals, thereby eliminating the stress caused by the animals when exposed to different diets, and can reflect the animals' real essential amino acid maintenance requirements, thereby achieving the purpose of precise nutrition.

[0027] 2. The model provided by the present invention is easy to operate, monitors the normal growth of animals, does not harm animals during operation, and meets the requirements of animal welfare.

[0028] 3. The model provided by the present invention obtains the maintenance requirement of essential amino acids under different conditions according to the growth performance of broilers, which enables breeders to adjust the daily diet according to the growth changes of broilers, directly improving the economic benefits of the broiler farming industry, and responding to the development concept of dynamic nutrition while reducing costs and increasing efficiency.

[0029] 4. The method for evaluating the essential amino acid balance pattern of a low-protein diet provided by the present invention can quickly and accurately screen out the types of essential amino acids that need to be adjusted and the specific directions of the adjustments, without the need for large-scale repeated experiments, and can reduce the experimental costs to a minimum.

[0030] Through analysis and reconstruction based on knowledge management indicators, data processing and information transmission processes have been automated. The normative reference documents cited in the outline preparation, the International System of Units and its derived units, and the compiled and verified test outline data are more rigorous and have a wide range of applications. This has effectively improved the efficiency of the preparation and reconstruction of the scientific and technological achievement indicator test outline, provided a scientific and effective testing basis for the test and evaluation of scientific and technological achievements, and helped high-end scientific and technological achievements demonstrate their scientific and technological level and value. DETAILED DESCRIPTION

[0031] In order to better understand the technical solution of the present invention, the embodiments of the present invention are described in detail below.

[0032] It should be clear that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the embodiments of the present invention are further described in detail below, but the described embodiments are only some embodiments of the present invention, not all. Based on the embodiments of the present invention, other embodiments of the present invention that are not creative work by technicians in this field belong to the scope of protection of the present invention.

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the following specific embodiments are provided, but are not intended to limit the scope of the present invention.

[0036] Example 1. Statistics of growth performance of broiler chickens at different ages

[0037] The experiment selected 60 healthy Cobb broiler chicks of 0 days old, half male and half female (identified by feather speed), with an initial body weight of 46g±0.5g, and randomly assigned to 6 groups according to gender, with 10 chickens in each group. The experimental period was 42 days, divided into three stages: brooding period (0-14 days old), rearing period (15-28 days old) and fattening period (29-42 days old). The chickens were raised in cages and fed, and the weight of broilers of different ages was recorded using an automatic weighing system. They were allowed to eat and drink freely, and the light cycle of the poultry house was gradually reduced from 24 hours a day to 20 hours a day; the temperature was gradually reduced from 35°C to 22°C, and the vaccination procedure was carried out according to the management manual. The poultry house environment and the health status of the broilers were tested daily. The conventional protein diet chicken feed used included the following raw materials by weight:

[0038] 50.16 parts of corn, 35.02 parts of soybean meal, 4.3 parts of corn gluten meal, 1.59 parts of calcium hydrogen phosphate, 5.66 parts of soybean oil, 1.39 parts of stone powder, 0.35 parts of salt, 0.2 parts of choline chloride 50%, 0.2 parts of broiler trace element premix, 0.16 parts of DL-methionine, 0.13 parts of L-lysine hydrochloride, 0.02 parts of broiler multivitamin premix, 0.03 parts of cystine, 0.02 parts of L-threonine, 0.21 parts of L-arginine, 0.05 parts of L-isoleucine, 0.05 parts of L-tryptophan, 0.05 parts of L-valine, 0.35 parts of alanine, 0.02 parts of phytase, 0.03 parts of potassium carbonate and 0.01 parts of sodium bicarbonate.

[0039] In the above-mentioned broiler feed, the types and mass ratios of the trace elements included in the broiler trace element premix are: Cu:Zn:Fe:Mn:Se:I=8:75:80:100:0.15:0.35.

[0040] In the above-mentioned broiler feed, the vitamin types and mass ratios included in the broiler multivitamin premix are: Vitamin A: Vitamin D3: Vitamin E: Vitamin K3: Vitamin B1: Vitamin B2: Vitamin B6: Vitamin B12: Pantothenic acid: Niacin: Folic acid: Biotin = 15000 IU: 3000 IU: 22.5 IU: 3 mg: 3 mg: 8 mg: 6 mg: 0.03 mg: 17.64 mg: 44 mg: 17.64 mg: 0.15 mg.

[0041] The low protein diet chicken feed includes the following ingredients by weight:

[0042] 56.95 parts of corn, 29.44 parts of soybean meal, 3.71 parts of corn gluten meal, 1.63 parts of calcium hydrogen phosphate, 4.55 parts of soybean oil, 1.36 parts of stone powder, 0.31 parts of salt, 0.23 parts of choline chloride (50%), 0.2 parts of trace element premix for broilers, 0.21 parts of DL-methionine, 0.25 parts of L-lysine hydrochloride, 0.02 parts of multivitamin premix for broilers, 0.03 parts of cystine, 0.08 parts of L-threonine, 0.25 parts of L-arginine, 0.03 parts of L-histidine, 0.09 parts of L-isoleucine, 0.12 parts of L-leucine, 0.04 parts of L-tryptophan, 0.12 parts of L-valine, 0.14 parts of alanine, 0.02 parts of phytase, 0.016 parts of potassium carbonate and 0.06 parts of sodium bicarbonate.

[0043] In the above broiler feed, the types and mass ratios of the trace elements included in the broiler trace element premix and the types and mass ratios of the vitamins included in the multidimensional premix are the same as those in the conventional protein diet.

[0044] Table 1 Broiler production performance under different diets and ages in the present invention

[0045]

[0046]

[0047] Note:

[0048] NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0049] The growth performance of broilers fed with conventional protein diet (NP) and low protein diet (LP) was significantly changed (P<0.05); at 14 days of age, different dietary treatments had no significant effect on the body weight of broilers; starting from 21 days of age, the body weight of roosters increased significantly with the increase of dietary protein level, and the corresponding daily weight gain and daily feed intake also increased significantly. It is worth noting that the FCR of roosters fed with low protein diet showed a trend of first decreasing and then increasing with age. The growth performance of hens was not significantly changed until 35 days later, and its significance was significantly lower than that of roosters. In general, with the continuous increase of age, the gap between the growth performance of broilers in different dietary treatments gradually increased, indicating that long-term feeding of low protein diets will have a negative impact on the growth performance of animals; in addition, roosters are significantly more sensitive to changes in dietary protein nutrition than hens.

[0050] Example 2: Different essential amino acid retention levels in broiler chickens

[0051] Fecal samples were collected continuously during the last three days of each week of broiler age, and the feed intake and feces output were recorded. The samples were processed and measured to obtain the essential amino acid retention in broilers at different ages.

[0052] Table 2 Nitrogen retention of broilers at different diets and ages in the present invention

[0053]

[0054]

[0055] Note:

[0056] NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0057] Table 3 Lysine retention in broiler chickens at different diets and ages in the present invention

[0058]

[0059]

[0060] Note:

[0061] NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0062] Table 4 Meat methionine retention in different diets and ages in the present invention

[0063]

[0064]

[0065] Note:

[0066] NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0067] Table 5 Threonine retention in broiler chickens at different diets and ages in the present invention

[0068]

[0069]

[0070] Note:

[0071] NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0072] Table 6 Tryptophan retention in broiler chickens at different diets and ages in the present invention

[0073]

[0074]

[0075] Note: NP-M: conventional protein diet for roosters; NP-F: conventional protein diet for hens; LP-M: low protein diet for roosters; LP-F: low protein diet for hens.

[0076] Table 7 Valine retention in broiler chickens at different diets and ages in the present invention

[0077]

[0078]

[0079] Note: NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0080] Table 8 Isoleucine retention in broiler chickens at different diets and ages in the present invention

[0081]

[0082]

[0083] Note: NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0084] Table 9 Leucine retention in broiler chickens at different diets and ages in the present invention

[0085]

[0086]

[0087] Note: NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0088] Table 10 Arginine retention in broiler chickens at different diets and ages in the present invention

[0089]

[0090] Note: NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0091] Table 11 Histidine retention in broiler chickens at different diets and ages in the present invention

[0092]

[0093]

[0094] Note:

[0095] NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0096] Table 12 Phenylalanine retention in broilers at different diets and ages in the present invention

[0097]

[0098]

[0099] Note: NP-M: conventional protein diet - roosters; NP-F: conventional protein diet - hens; LP-M: low protein diet - roosters; LP-F: low protein diet - hens.

[0100] Example 3. Dynamic essential amino acid maintenance requirement model for broiler chickens and maintenance requirements at different ages

[0101] The broiler body weight, daily weight gain and essential amino acid retention obtained in Examples 1 and 2 were fitted with a multiple linear regression equation. On this basis, the weight gain was set to 0 to obtain a dynamic essential amino acid maintenance requirement model. The broiler maintenance requirement at different ages and weights was obtained by bringing the broiler body weights into the model.

[0102]

[0103]

[0104] Table 14 Essential amino acid maintenance requirements for broiler chickens at different diets and ages in the present invention

[0105]

[0106]

[0107] Note: NP-M: conventional protein diet - rooster; LP-M: low protein diet - rooster.

[0108] Table 15 Essential amino acid maintenance requirements for broiler hens at different diets and ages in the present invention

[0109]

[0110]

[0111] Note: NP-F: conventional protein diet - hens; LP-F: low protein diet - hens.

[0112] Example 4, evaluation of the essential amino acid balance pattern of low-protein diets based on the essential amino acid maintenance requirements of broilers. According to the essential amino acid maintenance requirements obtained in Example 3, it can be seen that the nitrogen maintenance requirements have the same changing pattern in male and female chickens, and the maintenance requirements are significantly increased under low-protein diet feeding. Lysine shows opposite phenomena between different genders. The maintenance requirements of roosters increase significantly under low-protein diet feeding, while hens decrease instead, which indicates that there are differences in the amino acid requirements of male and female chickens during growth and development. Methionine, as the first limiting amino acid for poultry, actually decreases in the maintenance requirements of broilers after feeding with a low-protein diet, which indicates that the current supply of methionine in the low-protein diet is sufficient. There is no difference in threonine between broilers of different genders, and the maintenance requirement increases significantly after feeding with a low-protein diet; while tryptophan is the opposite. Compared with conventional protein diets, the maintenance requirements of male and female chickens are significantly reduced. The maintenance requirements of valine and isoleucine were different only in roosters fed with low-protein diets, and the difference in isoleucine was not significant, while leucine showed significant changes in both male and female roosters, and the change pattern was similar to that of valine, which may imply the trend of changes in the ratio of the three branched-chain amino acids. Similarly, arginine and lysine showed the same performance in roosters, and the changes in hens were not as obvious as lysine; arginine and lysine are both basic amino acids and share the same transporter, so it is expected that they have the same change trend. From the retention and utilization efficiency of histidine and the maintenance requirement in the current results, the relevant indicators of histidine in broilers were significantly increased after feeding with a low-protein diet, which indicates that the role of histidine in low-protein diets may have been seriously underestimated in previous studies, and it is necessary to focus on the function of histidine in amino acid balance and metabolism in animals in the future. As expected, the maintenance requirement and proportion of phenylalanine did not change significantly among the different treatment groups, indicating that its metabolic function in the amino acid nutrition of broiler egg white is relatively stable, and it may be used as a calibration amino acid to judge the utilization effect of protein nutrition.

[0113] In general, except for methionine, tryptophan, isoleucine and phenylalanine, the maintenance requirements and proportions of nitrogen and other essential amino acids of broilers under low-protein feeding were significantly increased, indicating that different essential amino acids have their own unique roles and utilization priorities in protein amino acid nutrition, which also means that it is necessary to increase the proportion of lysine, threonine, valine, leucine, arginine and histidine in the essential amino acid balance pattern of low-protein diets; the proportion of methionine, isoleucine and phenylalanine should remain unchanged, while the proportion of tryptophan should be reduced.

[0114] The above is only an embodiment of the present invention. The common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. Ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the relevant field can improve and implement the present scheme under the inspiration given by this application and in combination with their own abilities. Some typical known structures or known methods should not become an obstacle for ordinary technicians in the relevant field to implement the present application.

[0115] It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for establishing a model for monitoring and calculating the maintenance requirement of essential amino acids, characterized in that: The method comprises: The method is applied to monitor and calculate the dynamic maintenance requirement of essential amino acids in broilers, using an automatic weighing system to record the growth performance of broilers in terms of weight, weight gain and feed intake daily; and using a full feces collection method to collect broiler feces for 3 consecutive days per week of age during the broiler growth period, and record the feed intake and feces discharge, and calculate the retention of each essential amino acid per week of age; A multivariate linear regression equation was fitted based on the obtained growth performance and amino acid retention, and a new regression equation was obtained by setting the weight gain to 0 on the basis of the equation, namely, the dynamic essential amino acid maintenance requirement model.

2. The method for establishing a model for monitoring and calculating the maintenance requirement of essential amino acids according to claim 1, characterized in that: The entire life stage of broiler chickens is divided into 6 growth cycles, each growth cycle is 7 days.

3. The method for establishing a model for monitoring and calculating the maintenance requirement of essential amino acids according to claim 2, characterized in that: Starting from the second growth cycle, an automatic weighing system was used to record the body weight of broilers in each growth cycle, and feces were collected for three consecutive days before the end of each growth cycle. The amount of feces excreted and feed consumption of broilers during the collection period were also recorded.

4. The method for establishing a model for monitoring and calculating the maintenance requirement of essential amino acids according to claim 3, characterized in that: After the collection is completed, mix the test fecal samples and take samples in proportion; place the taken samples in a 65°C oven to dry for 72 hours, and after drying, place them in a grinder and grind them into powder.

5. The method for establishing a model for monitoring and calculating the maintenance requirement of essential amino acids according to claim 4, characterized in that: The amino acid content of all feces and feed samples was determined using an automatic amino acid analyzer, and the data obtained were used to calculate the following parameters: daily intake of essential amino acids (g / d) = daily feed intake (Kg / d) × essential amino acid concentration in the diet (%) × 1000; daily excretion of essential amino acids (g / d) = daily excretion (Kg / d) × essential amino acid concentration in feces (%) × 1000; daily retention of essential amino acids (g / d) = daily intake of essential amino acids (g / d) - daily excretion of essential amino acids (g / d).

6. A method for evaluating the essential amino acid balance pattern of a low-protein diet for broiler chickens, characterized in that: According to the method for establishing a model according to claim 5, the essential amino acid maintenance requirement model is obtained by fitting and improving the multivariate linear regression analysis method, and the specific calculation method is shown in formulas (1) and (2): Y1=aX+bZ+C Formula (1) In the formula, Y1 is the daily retention requirement of digestible essential amino acids (g); a is the body weight coefficient; X is the body weight of broilers at different ages (kg); b is the weight gain coefficient; Z is the weight gain of broilers at different ages (kg); C is the equation constant; When the weight gain in formula (1) is 0, the broiler is in a maintenance state, and the dynamic maintenance requirement model of essential amino acids for broilers is obtained: Y2=aX+C Formula (2) Y2 is the dynamic daily maintenance requirement of digestible essential amino acids (g); a is the body weight coefficient; X is the body weight of broilers at different ages (kg); C is the equation constant; The body weights of broilers of different ages under different diets were brought into Y2 to obtain the corresponding essential amino acid maintenance requirements. Based on the conventional protein diet, the increasing or decreasing trends of the maintenance requirements of each essential amino acid in the low-protein diet were evaluated, thereby providing a reference for adjustment directions for optimizing the essential amino acid balance pattern.

7. The method for evaluating the essential amino acid balance pattern of a low-protein diet for broiler chickens according to claim 6, characterized in that: The conventional protein diet chicken feed used includes the following raw materials by weight: 50.16 parts of corn, 35.02 parts of soybean meal, 4.3 parts of corn gluten meal, 1.59 parts of calcium hydrogen phosphate, 5.66 parts of soybean oil, 1.39 parts of stone powder, 0.35 parts of salt, 0.2 parts of choline chloride 50%, 0.2 parts of broiler trace element premix, 0.16 parts of DL-methionine, 0.13 parts of L-lysine hydrochloride, 0.02 parts of broiler multivitamin premix, 0.03 parts of cystine, 0.02 parts of L-threonine, 0.21 parts of L-arginine, 0.05 parts of L-isoleucine, 0.05 parts of L-tryptophan, 0.05 parts of L-valine, 0.35 parts of alanine, 0.02 parts of phytase, 0.03 parts of potassium carbonate and 0.01 parts of sodium bicarbonate.

8. The method for evaluating the essential amino acid balance pattern of a low-protein diet for broiler chickens according to claim 6, characterized in that: In broiler feed, the types and mass ratios of trace elements included in broiler trace element premix are: Cu: Zn: Fe: Mn: Se: I = 8: 75: 80: 100: 0.15: 0.

35.

9. The method for evaluating the essential amino acid balance pattern of a low-protein diet for broiler chickens according to claim 6, characterized in that: In broiler feed, the vitamin types and mass ratios included in the broiler multivitamin premix are: Vitamin A: Vitamin D3: Vitamin E: Vitamin K3: Vitamin B1: Vitamin B2: Vitamin B6: Vitamin B12: Pantothenic acid: Niacin: Folic acid: Biotin = 15000 IU: 3000 IU: 22.5 IU: 3 mg: 3 mg: 8 mg: 6 mg: 0.03mg: 17.64mg: 44 mg: 17.64 mg: 0.15mg.

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